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1. PHANGS–JWST First Results: A Statistical View on Bubble Evolution in NGC 628

Author

Elizabeth J. Watkins, Ashley T. Barnes, Kiana Henny, Hwihyun Kim, Kathryn Kreckel, Sharon E. Meidt, Ralf S. Klessen, Simon C. O. Glover, Thomas G. Williams, Benjamin W. Keller, Adam K. Leroy, Erik Rosolowsky, Janice C. Lee, Gagandeep S. Anand, Francesco Belfiore, Frank Bigiel, Guillermo A. Blanc, Médéric Boquien, Yixian Cao, Rupali Chandar, Ness Mayker Chen, Mélanie Chevance, Enrico Congiu, Daniel A. Dale, Sinan Deger, Oleg V. Egorov, Eric Emsellem, Christopher M. Faesi, Kathryn Grasha, Brent Groves, Hamid Hassani, Jonathan D. Henshaw, Cinthya Herrera, Annie Hughes, Sarah Jeffreson, María J. Jiménez-Donaire, Eric W. Koch, J. M. Diederik Kruijssen, Kirsten L. Larson, Daizhong Liu, Laura A. Lopez, Ismael Pessa, Jérôme Pety, Miguel Querejeta, Toshiki Saito, Karin Sandstrom, Fabian Scheuermann, Eva Schinnerer, Mattia C. Sormani, Sophia K. Stuber, David A. Thilker, Antonio Usero, and Bradley C. Whitmore

Subjects
Superbubbles, Stellar wind bubbles, Infrared astronomy, H II regions, Stellar feedback, Astrophysics, QB460-466
Abstract

The first JWST observations of nearby galaxies have unveiled a rich population of bubbles that trace the stellar-feedback mechanisms responsible for their creation. Studying these bubbles therefore allows us to chart the interaction between stellar feedback and the interstellar medium, and the larger galactic flows needed to regulate star formation processes globally. We present the first catalog of bubbles in NGC 628, visually identified using Mid-Infrared Instrument F770W Physics at High Angular resolution in Nearby GalaxieS (PHANGS)–JWST observations, and use them to statistically evaluate bubble characteristics. We classify 1694 structures as bubbles with radii between 6 and 552 pc. Of these, 31% contain at least one smaller bubble at their edge, indicating that previous generations of star formation have a local impact on where new stars form. On large scales, most bubbles lie near a spiral arm, and their radii increase downstream compared to upstream. Furthermore, bubbles are elongated in a similar direction to the spiral-arm ridgeline. These azimuthal trends demonstrate that star formation is intimately connected to the spiral-arm passage. Finally, the bubble size distribution follows a power law of index p = −2.2 ± 0.1, which is slightly shallower than the theoretical value by 1–3.5 σ that did not include bubble mergers. The fraction of bubbles identified within the shells of larger bubbles suggests that bubble merging is a common process. Our analysis therefore allows us to quantify the number of star-forming regions that are influenced by an earlier generation, and the role feedback processes have in setting the global star formation rate. With the full PHANGS–JWST sample, we can do this for more galaxies.

Published
2023
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2. PHANGS–JWST First Results: Duration of the Early Phase of Massive Star Formation in NGC 628

Author

Jaeyeon Kim, Mélanie Chevance, J. M. Diederik Kruijssen, Ashley. T. Barnes, Frank Bigiel, Guillermo A. Blanc, Médéric Boquien, Yixian Cao, Enrico Congiu, Daniel A. Dale, Oleg V. Egorov, Christopher M. Faesi, Simon C. O. Glover, Kathryn Grasha, Brent Groves, Hamid Hassani, Annie Hughes, Ralf S. Klessen, Kathryn Kreckel, Kirsten L. Larson, Janice C. Lee, Adam K. Leroy, Daizhong Liu, Steven N. Longmore, Sharon E. Meidt, Hsi-An Pan, Jérôme Pety, Miguel Querejeta, Erik Rosolowsky, Toshiki Saito, Karin Sandstrom, Eva Schinnerer, Rowan J. Smith, Antonio Usero, Elizabeth J. Watkins, and Thomas G. Williams

Subjects
Star formation, Galaxies, Giant molecular clouds, Interstellar medium, Astrophysics, QB460-466
Abstract

The earliest stages of star formation, when young stars are still deeply embedded in their natal clouds, represent a critical phase in the matter cycle between gas clouds and young stellar regions. Until now, the high-resolution infrared observations required for characterizing this heavily obscured phase (during which massive stars have formed, but optical emission is not detected) could only be obtained for a handful of the most nearby galaxies. One of the main hurdles has been the limited angular resolution of the Spitzer Space Telescope. With the revolutionary capabilities of the James Webb Space Telescope (JWST), it is now possible to investigate the matter cycle during the earliest phases of star formation as a function of the galactic environment. In this Letter, we demonstrate this by measuring the duration of the embedded phase of star formation and the implied time over which molecular clouds remain inert in the galaxy NGC 628 at a distance of 9.8 Mpc, demonstrating that the cosmic volume where this measurement can be made has increased by a factor of >100 compared to Spitzer. We show that young massive stars remain embedded for ${5.1}_{-1.4}^{+2.7}$ Myr ( ${2.3}_{-1.4}^{+2.7}$ Myr of which being heavily obscured), representing ∼20% of the total cloud lifetime. These values are in broad agreement with previous measurements in five nearby ( D < 3.5 Mpc) galaxies and constitute a proof of concept for the systematic characterization of the early phase of star formation across the nearby galaxy population with the PHANGS–JWST survey.

Published
2023
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3. PHANGS–JWST First Results: Dust-embedded Star Clusters in NGC 7496 Selected via 3.3 μm PAH Emission

Author

M. Jimena Rodríguez, Janice C. Lee, B. C. Whitmore, David A. Thilker, Daniel Maschmann, Rupali Chandar, Sinan Deger, Médéric Boquien, Daniel A. Dale, Kirsten L. Larson, Thomas G. Williams, Hwihyun Kim, Eva Schinnerer, Erik Rosolowsky, Adam K. Leroy, Eric Emsellem, Karin M. Sandstrom, J. M. Diederik Kruijssen, Kathryn Grasha, Elizabeth J. Watkins, Ashley. T. Barnes, Mattia C. Sormani, Jaeyeon Kim, Gagandeep S. Anand, Mélanie Chevance, F. Bigiel, Ralf S. Klessen, Hamid Hassani, Daizhong Liu, Christopher M. Faesi, Yixian Cao, Francesco Belfiore, Ismael Pessa, Kathryn Kreckel, Brent Groves, Jérôme Pety, Rémy Indebetouw, Oleg V. Egorov, Guillermo A. Blanc, Toshiki Saito, and Annie Hughes

Subjects
Star formation, Star clusters, Young star clusters, Spiral galaxies, Surveys, Interstellar dust, Astrophysics, QB460-466
Abstract

The earliest stages of star formation occur enshrouded in dust and are not observable in the optical. Here we leverage the extraordinary new high-resolution infrared imaging from JWST to begin the study of dust-embedded star clusters in nearby galaxies throughout the Local Volume. We present a technique for identifying dust-embedded clusters in NGC 7496 (18.7 Mpc), the first galaxy to be observed by the PHANGS–JWST Cycle 1 Treasury Survey. We select sources that have strong 3.3 μ m PAH emission based on a F300M − F335M color excess and identify 67 candidate embedded clusters. Only eight of these are found in the PHANGS-HST optically selected cluster catalog, and all are young (six have SED fit ages of ∼1 Myr). We find that this sample of embedded cluster candidates may significantly increase the census of young clusters in NGC 7496 from the PHANGS-HST catalog; the number of clusters younger than ∼2 Myr could be increased by a factor of 2. Candidates are preferentially located in dust lanes and are coincident with the peaks in the PHANGS-ALMA CO (2–1) maps. We take a first look at concentration indices, luminosity functions, SEDs spanning from 2700 Å to 21 μ m, and stellar masses (estimated to be between ∼10 ^4 and 10 ^5 M _⊙ ). The methods tested here provide a basis for future work to derive accurate constraints on the physical properties of embedded clusters, characterize the completeness of cluster samples, and expand analysis to all 19 galaxies in the PHANGS–JWST sample, which will enable basic unsolved problems in star formation and cluster evolution to be addressed.

Published
2023
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4. The PHANGS–JWST Treasury Survey: Star Formation, Feedback, and Dust Physics at High Angular Resolution in Nearby GalaxieS

Author

Janice C. Lee, Karin M. Sandstrom, Adam K. Leroy, David A. Thilker, Eva Schinnerer, Erik Rosolowsky, Kirsten L. Larson, Oleg V. Egorov, Thomas G. Williams, Judy Schmidt, Eric Emsellem, Gagandeep S. Anand, Ashley T. Barnes, Francesco Belfiore, Ivana Bešlić, Frank Bigiel, Guillermo A. Blanc, Alberto D. Bolatto, Médéric Boquien, Jakob den Brok, Yixian Cao, Rupali Chandar, Jérémy Chastenet, Mélanie Chevance, I-Da Chiang, Enrico Congiu, Daniel A. Dale, Sinan Deger, Cosima Eibensteiner, Christopher M. Faesi, Simon C. O. Glover, Kathryn Grasha, Brent Groves, Hamid Hassani, Kiana F. Henny, Jonathan D. Henshaw, Nils Hoyer, Annie Hughes, Sarah Jeffreson, María J. Jiménez-Donaire, Jaeyeon Kim, Hwihyun Kim, Ralf S. Klessen, Eric W. Koch, Kathryn Kreckel, J. M. Diederik Kruijssen, Jing Li, Daizhong Liu, Laura A. Lopez, Daniel Maschmann, Ness Mayker Chen, Sharon E. Meidt, Eric J. Murphy, Justus Neumann, Nadine Neumayer, Hsi-An Pan, Ismael Pessa, Jérôme Pety, Miguel Querejeta, Francesca Pinna, M. Jimena Rodríguez, Toshiki Saito, Patricia Sánchez-Blázquez, Francesco Santoro, Amy Sardone, Rowan J. Smith, Mattia C. Sormani, Fabian Scheuermann, Sophia K. Stuber, Jessica Sutter, Jiayi Sun, Yu-Hsuan Teng, Robin G. Treß, Antonio Usero, Elizabeth J. Watkins, Bradley C. Whitmore, and Alessandro Razza

Subjects
Star formation, Spiral galaxies, Surveys, Young star clusters, Interstellar medium, Polycyclic aromatic hydrocarbons, Astrophysics, QB460-466
Abstract

The PHANGS collaboration has been building a reference data set for the multiscale, multiphase study of star formation and the interstellar medium (ISM) in nearby galaxies. With the successful launch and commissioning of JWST, we can now obtain high-resolution infrared imaging to probe the youngest stellar populations and dust emission on the scales of star clusters and molecular clouds (∼5–50 pc). In Cycle 1, PHANGS is conducting an eight-band imaging survey from 2 to 21 μ m of 19 nearby spiral galaxies. Optical integral field spectroscopy, CO(2–1) mapping, and UV-optical imaging for all 19 galaxies have been obtained through large programs with ALMA, VLT-MUSE, and Hubble. PHANGS–JWST enables a full inventory of star formation, accurate measurement of the mass and age of star clusters, identification of the youngest embedded stellar populations, and characterization of the physical state of small dust grains. When combined with Hubble catalogs of ∼10,000 star clusters, MUSE spectroscopic mapping of ∼20,000 H ii regions, and ∼12,000 ALMA-identified molecular clouds, it becomes possible to measure the timescales and efficiencies of the earliest phases of star formation and feedback, build an empirical model of the dependence of small dust grain properties on local ISM conditions, and test our understanding of how dust-reprocessed starlight traces star formation activity, all across a diversity of galactic environments. Here we describe the PHANGS–JWST Treasury survey, present the remarkable imaging obtained in the first few months of science operations, and provide context for the initial results presented in the first series of PHANGS–JWST publications.

Published
2023
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5. PHANGS–JWST First Results: Mapping the 3.3 μm Polycyclic Aromatic Hydrocarbon Vibrational Band in Nearby Galaxies with NIRCam Medium Bands

Author

Karin M. Sandstrom, Jérémy Chastenet, Jessica Sutter, Adam K. Leroy, Oleg V. Egorov, Thomas G. Williams, Alberto D. Bolatto, Médéric Boquien, Yixian Cao, Daniel A. Dale, Janice C. Lee, Erik Rosolowsky, Eva Schinnerer, Ashley. T. Barnes, Francesco Belfiore, F. Bigiel, Mélanie Chevance, Kathryn Grasha, Brent Groves, Hamid Hassani, Annie Hughes, Ralf S. Klessen, J. M. Diederik Kruijssen, Kirsten L. Larson, Daizhong Liu, Laura A. Lopez, Sharon E. Meidt, Eric J. Murphy, Mattia C. Sormani, David A. Thilker, and Elizabeth J. Watkins

Subjects
Polycyclic aromatic hydrocarbons, Interstellar dust, Medium band photometry, James Webb Space Telescope, Astrophysics, QB460-466
Abstract

We present maps of the 3.3 μ m polycyclic aromatic hydrocarbon (PAH) emission feature in NGC 628, NGC 1365, and NGC 7496 as observed with the Near-Infrared Camera imager on JWST from the PHANGS–JWST Cycle 1 Treasury project. We create maps that isolate the 3.3 μ m PAH feature in the F335M filter (F335M _PAH ) using combinations of the F300M and F360M filters for removal of starlight continuum. This continuum removal is complicated by contamination of the F360M by PAH emission and variations in the stellar spectral energy distribution slopes between 3.0 and 3.6 μ m. We modify the empirical prescription from Lai et al. to remove the starlight continuum in our highly resolved galaxies, which have a range of starlight- and PAH-dominated lines of sight. Analyzing radially binned profiles of the F335M _PAH emission, we find that between 5% and 65% of the F335M intensity comes from the 3.3 μ m feature within the inner 0.5 r _25 of our targets. This percentage systematically varies from galaxy to galaxy and shows radial trends within the galaxies related to each galaxy’s distribution of stellar mass, interstellar medium, and star formation. The 3.3 μ m emission is well correlated with the 11.3 μ m PAH feature traced with the MIRI F1130W filter, as is expected, since both features arise from C–H vibrational modes. The average F335M _PAH /F1130W ratio agrees with the predictions of recent models by Draine et al. for PAHs with size and charge distributions shifted toward larger grains with normal or higher ionization.

Published
2023
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6. PHANGS–JWST First Results: Tracing the Diffuse Interstellar Medium with JWST Imaging of Polycyclic Aromatic Hydrocarbon Emission in Nearby Galaxies

Author

Karin M. Sandstrom, Eric W. Koch, Adam K. Leroy, Erik Rosolowsky, Eric Emsellem, Rowan J. Smith, Oleg V. Egorov, Thomas G. Williams, Kirsten L. Larson, Janice C. Lee, Eva Schinnerer, David A. Thilker, Ashley T. Barnes, Francesco Belfiore, F. Bigiel, Guillermo A. Blanc, Alberto D. Bolatto, Médéric Boquien, Yixian Cao, Jérémy Chastenet, Mélanie Chevance, I-Da Chiang, Daniel A. Dale, Christopher M. Faesi, Simon C. O. Glover, Kathryn Grasha, Brent Groves, Hamid Hassani, Jonathan D. Henshaw, Annie Hughes, Jaeyeon Kim, Ralf S. Klessen, Kathryn Kreckel, J. M. Diederik Kruijssen, Laura A. Lopez, Daizhong Liu, Sharon E. Meidt, Eric J. Murphy, Hsi-An Pan, Miguel Querejeta, Toshiki Saito, Amy Sardone, Mattia C. Sormani, Jessica Sutter, Antonio Usero, and Elizabeth J. Watkins

Subjects
Polycyclic aromatic hydrocarbons, Interstellar atomic gas, Interstellar medium, Astronomical simulations, Astrophysics, QB460-466
Abstract

JWST observations of polycyclic aromatic hydrocarbon (PAH) emission provide some of the deepest and highest resolution views of the cold interstellar medium (ISM) in nearby galaxies. If PAHs are well mixed with the atomic and molecular gas and illuminated by the average diffuse interstellar radiation field, PAH emission may provide an approximately linear, high-resolution, high-sensitivity tracer of diffuse gas surface density. We present a pilot study that explores using PAH emission in this way based on Mid-Infrared Instrument observations of IC 5332, NGC 628, NGC 1365, and NGC 7496 from the Physics at High Angular resolution in Nearby GalaxieS-JWST Treasury. Using scaling relationships calibrated in Leroy et al., scaled F1130W provides 10–40 pc resolution and 3 σ sensitivity of Σ _gas ∼ 2 M _⊙ pc ^−2 . We characterize the surface densities of structures seen at

Published
2023
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7. PHANGS–JWST First Results: Mid-infrared Emission Traces Both Gas Column Density and Heating at 100 pc Scales

Author

Adam K. Leroy, Karin Sandstrom, Erik Rosolowsky, Francesco Belfiore, Alberto D. Bolatto, Yixian Cao, Eric W. Koch, Eva Schinnerer, Ashley. T. Barnes, Ivana Bešlić, F. Bigiel, Guillermo A. Blanc, Jérémy Chastenet, Ness Mayker Chen, Mélanie Chevance, Ryan Chown, Enrico Congiu, Daniel A. Dale, Oleg V. Egorov, Eric Emsellem, Cosima Eibensteiner, Christopher M. Faesi, Simon C. O. Glover, Kathryn Grasha, Brent Groves, Hamid Hassani, Jonathan D. Henshaw, Annie Hughes, María J. Jiménez-Donaire, Jaeyeon Kim, Ralf S. Klessen, Kathryn Kreckel, J. M. Diederik Kruijssen, Kirsten L. Larson, Janice C. Lee, Rebecca C. Levy, Daizhong Liu, Laura A. Lopez, Sharon E. Meidt, Eric J. Murphy, Justus Neumann, Ismael Pessa, Jérôme Pety, Toshiki Saito, Amy Sardone, Jiayi Sun, David A. Thilker, Antonio Usero, Elizabeth J. Watkins, Cory M. Whitcomb, and Thomas G. Williams

Subjects
Disk galaxies, Galaxy physics, Dust continuum emission, Molecular gas, Infrared astronomy, Millimeter astronomy, Astrophysics, QB460-466
Abstract

We compare mid-infrared (mid-IR), extinction-corrected H α , and CO (2–1) emission at 70–160 pc resolution in the first four PHANGS–JWST targets. We report correlation strengths, intensity ratios, and power-law fits relating emission in JWST’s F770W, F1000W, F1130W, and F2100W bands to CO and H α . At these scales, CO and H α each correlate strongly with mid-IR emission, and these correlations are each stronger than the one relating CO to H α emission. This reflects that mid-IR emission simultaneously acts as a dust column density tracer, leading to a good match with the molecular-gas-tracing CO, and as a heating tracer, leading to a good match with the H α . By combining mid-IR, CO, and H α at scales where the overall correlation between cold gas and star formation begins to break down, we are able to separate these two effects. We model the mid-IR above I _ν = 0.5 MJy sr ^−1 at F770W, a cut designed to select regions where the molecular gas dominates the interstellar medium (ISM) mass. This bright emission can be described to first order by a model that combines a CO-tracing component and an H α -tracing component. The best-fitting models imply that ∼50% of the mid-IR flux arises from molecular gas heated by the diffuse interstellar radiation field, with the remaining ∼50% associated with bright, dusty star-forming regions. We discuss differences between the F770W, F1000W, and F1130W bands and the continuum-dominated F2100W band and suggest next steps for using the mid-IR as an ISM tracer.

Published
2023
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8. PHANGS–JWST First Results: A Global and Moderately Resolved View of Mid-infrared and CO Line Emission from Galaxies at the Start of the JWST Era

Author

Adam K. Leroy, Alberto D. Bolatto, Karin Sandstrom, Erik Rosolowsky, Ashley. T. Barnes, F. Bigiel, Médéric Boquien, Jakob S. den Brok, Yixian Cao, Jérémy Chastenet, Mélanie Chevance, I-Da Chiang, Ryan Chown, Dario Colombo, Sara L. Ellison, Eric Emsellem, Kathryn Grasha, Jonathan D. Henshaw, Annie Hughes, Ralf S. Klessen, Eric W. Koch, Jaeyeon Kim, Kathryn Kreckel, J. M. Diederik Kruijssen, Kirsten L. Larson, Janice C. Lee, Rebecca C. Levy, Lihwai Lin, Daizhong Liu, Sharon E. Meidt, Jérôme Pety, Miguel Querejeta, Mónica Rubio, Toshiki Saito, Samir Salim, Eva Schinnerer, Mattia C. Sormani, Jiayi Sun, David A. Thilker, Antonio Usero, Stuart N. Vogel, Elizabeth J. Watkins, Cory M. Whitcomb, Thomas G. Williams, and Christine D. Wilson

Subjects
Disk galaxies, Galaxy physics, Molecular gas, Dust continuum emission, Infrared astronomy, Millimeter astronomy, Astrophysics, QB460-466
Abstract

We explore the relationship between mid-infrared (mid-IR) and CO rotational line emission from massive star-forming galaxies, which is one of the tightest scalings in the local universe. We assemble a large set of unresolved and moderately (∼1 kpc) spatially resolved measurements of CO (1–0) and CO (2–1) intensity, I _CO , and mid-IR intensity, I _MIR , at 8, 12, 22, and 24 μ m. The I _CO versus I _MIR relationship is reasonably described by a power law with slopes 0.7–1.2 and normalization I _CO ∼ 1 K km s ^−1 at I _MIR ∼ 1 MJy sr ^−1 . Both the slopes and intercepts vary systematically with choice of line and band. The comparison between the relations measured for CO (1–0) and CO (2–1) allow us to infer that ${R}_{21}\propto {I}_{\mathrm{MIR}}^{0.2}$ , in good agreement with other work. The 8 μ m and 12 μ m bands, with strong polycyclic aromatic hydrocarbon (PAH) features, show steeper CO versus mid-IR slopes than the 22 and 24 μ m, consistent with PAH emission arising not just from CO-bright gas but also from atomic or CO-dark gas. The CO-to-mid-IR ratio correlates with global galaxy stellar mass ( M _⋆ ) and anticorrelates with star formation rate/ M _⋆ . At ∼1 kpc resolution, the first four PHANGS–JWST targets show CO-to-mid-IR relationships that are quantitatively similar to our larger literature sample, including showing the steep CO-to-mid-IR slopes for the JWST PAH-tracing bands, although we caution that these initial data have a small sample size and span a limited range of intensities.

Published
2023
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9. PHANGS–JWST First Results: Variations in PAH Fraction as a Function of ISM Phase and Metallicity

Author

Jérémy Chastenet, Jessica Sutter, Karin Sandstrom, Francesco Belfiore, Oleg V. Egorov, Kirsten L. Larson, Adam K. Leroy, Daizhong Liu, Erik Rosolowsky, David A. Thilker, Elizabeth J. Watkins, Thomas G. Williams, Ashley. T. Barnes, Frank Bigiel, Médéric Boquien, Mélanie Chevance, I-Da Chiang, Daniel A. Dale, J. M. Diederik Kruijssen, Eric Emsellem, Kathryn Grasha, Brent Groves, Hamid Hassani, Annie Hughes, Kathryn Kreckel, Sharon E. Meidt, Ryan J. Rickards Vaught, Amy Sardone, and Eva Schinnerer

Subjects
Dust physics, Interstellar dust, Polycyclic aromatic hydrocarbons, Astrophysics, QB460-466
Abstract

We present maps tracing the fraction of dust in the form of polycyclic aromatic hydrocarbons (PAHs) in IC 5332, NGC 628, NGC 1365, and NGC 7496 from JWST/MIRI observations. We trace the PAH fraction by combining the F770W (7.7 μ m) and F1130W (11.3 μ m) filters to track ionized and neutral PAH emission, respectively, and comparing the PAH emission to F2100W, which traces small, hot dust grains. We find the average R _PAH = (F770W + F1130W)/F2100W values of 3.3, 4.7, 5.1, and 3.6 in IC 5332, NGC 628, NGC 1365, and NGC 7496, respectively. We find that H ii regions traced by MUSE H α show a systematically low PAH fraction. The PAH fraction remains relatively constant across other galactic environments, with slight variations. We use CO+H i +H α to trace the interstellar gas phase and find that the PAH fraction decreases above a value of ${{\rm{I}}}_{{\rm{H}}\alpha }/{{\rm{\Sigma }}}_{{\rm{H}}{\rm\small{I}}+{{\rm{H}}}_{2}}\sim {10}^{37.5}\,\mathrm{erg}\,{{\rm{s}}}^{-1}\,{\mathrm{kpc}}^{-2}\,{({M}_{\odot }\,{\mathrm{pc}}^{-2})}^{-1}$ in all four galaxies. Radial profiles also show a decreasing PAH fraction with increasing radius, correlated with lower metallicity, in line with previous results showing a strong metallicity dependence to the PAH fraction. Our results suggest that the process of PAH destruction in ionized gas operates similarly across the four targets.

Published
2023
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10. PHANGS–JWST First Results: Measuring Polycyclic Aromatic Hydrocarbon Properties across the Multiphase Interstellar Medium

Author

Jérémy Chastenet, Jessica Sutter, Karin Sandstrom, Francesco Belfiore, Oleg V. Egorov, Kirsten L. Larson, Adam K. Leroy, Daizhong Liu, Erik Rosolowsky, David A. Thilker, Elizabeth J. Watkins, Thomas G. Williams, Ashley. T. Barnes, F. Bigiel, Médéric Boquien, Mélanie Chevance, Daniel A. Dale, J. M. Diederik Kruijssen, Eric Emsellem, Kathryn Grasha, Brent Groves, Hamid Hassani, Annie Hughes, Kathryn Kreckel, Sharon E. Meidt, Hsi-An Pan, Miguel Querejeta, Eva Schinnerer, and Cory M. Whitcomb

Subjects
Dust physics, Interstellar dust, Polycyclic aromatic hydrocarbons, Astrophysics, QB460-466
Abstract

Ratios of polycyclic aromatic hydrocarbon (PAH) vibrational bands are a promising tool for measuring the properties of the PAH population and their effect on star formation. The photometric bands of the MIRI and NIRCam instruments on JWST provide the opportunity to measure PAH emission features across entire galaxy disks at unprecedented resolution and sensitivity. Here we present the first results of this analysis in a sample of three nearby galaxies: NGC 628, NGC 1365, and NGC 7496. Based on the variations observed in the 3.3, 7.7, and 11.3 μ m features, we infer changes to the average PAH size and ionization state across the different galaxy environments. High values of F335M _PAH /F1130W and low values of F1130W/F770W are measured in H ii regions in all three galaxies. This suggests that these regions are populated by hotter PAHs, and/or that the PAH ionization fraction is larger. We see additional evidence of heating and/or changes in PAH size in regions with higher molecular gas content as well as increased ionization in regions with higher H α intensity.

Published
2023
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11. Star Formation Laws and Efficiencies across 80 Nearby Galaxies

Author

Jiayi Sun, Adam K. Leroy, Eve C. Ostriker, Sharon Meidt, Erik Rosolowsky, Eva Schinnerer, Christine D. Wilson, Dyas Utomo, Francesco Belfiore, Guillermo A. Blanc, Eric Emsellem, Christopher Faesi, Brent Groves, Annie Hughes, Eric W. Koch, Kathryn Kreckel, Daizhong Liu, Hsi-An Pan, Jérôme Pety, Miguel Querejeta, Alessandro Razza, Toshiki Saito, Amy Sardone, Antonio Usero, Thomas G. Williams, Frank Bigiel, Alberto D. Bolatto, Mélanie Chevance, Daniel A. Dale, Jindra Gensior, Simon C. O. Glover, Kathryn Grasha, Jonathan D. Henshaw, María J. Jiménez-Donaire, Ralf S. Klessen, J. M. Diederik Kruijssen, Eric J. Murphy, Lukas Neumann, Yu-Hsuan Teng, and David A. Thilker

Subjects
Interstellar medium, Star formation, Galaxy evolution, Scaling relations, Astrophysics, QB460-466
Abstract

We measure empirical relationships between the local star formation rate (SFR) and properties of the star-forming molecular gas on 1.5 kpc scales across 80 nearby galaxies. These relationships, commonly referred to as “star formation laws,” aim at predicting the local SFR surface density from various combinations of molecular gas surface density, galactic orbital time, molecular cloud free fall time, and the interstellar medium dynamical equilibrium pressure. Leveraging a multiwavelength database built for the Physics at High Angular Resolution in Nearby Galaxies (PHANGS) survey, we measure these quantities consistently across all galaxies and quantify systematic uncertainties stemming from choices of SFR calibrations and the CO-to-H _2 conversion factors. The star formation laws we examine show 0.3–0.4 dex of intrinsic scatter, among which the molecular Kennicutt–Schmidt relation shows a ∼10% larger scatter than the other three. The slope of this relation ranges β ≈ 0.9–1.2, implying that the molecular gas depletion time remains roughly constant across the environments probed in our sample. The other relations have shallower slopes ( β ≈ 0.6–1.0), suggesting that the star formation efficiency per orbital time, the star formation efficiency per free fall time, and the pressure-to-SFR surface density ratio (i.e., the feedback yield) vary systematically with local molecular gas and SFR surface densities. Last but not least, the shapes of the star formation laws depend sensitively on methodological choices. Different choices of SFR calibrations can introduce systematic uncertainties of at least 10%–15% in the star formation law slopes and 0.15–0.25 dex in their normalization, while the CO-to-H _2 conversion factors can additionally produce uncertainties of 20%–25% for the slope and 0.10–0.20 dex for the normalization.

Published
2023
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12. Erratum: 'Molecular Gas Properties on Cloud Scales across the Local Star-forming Galaxy Population' (2020, ApJL, 901, L8)

Author

Jiayi Sun, Adam K. Leroy, Eva Schinnerer, Annie Hughes, Erik Rosolowsky, Miguel Querejeta, Andreas Schruba, Daizhong Liu, Toshiki Saito, Cinthya N. Herrera, Christopher Faesi, Antonio Usero, Jérôme Pety, J. M. Diederik Kruijssen, Eve C. Ostriker, Frank Bigiel, Guillermo A. Blanc, Alberto D. Bolatto, Médéric Boquien, Mélanie Chevance, Daniel A. Dale, Sinan Deger, Eric Emsellem, Simon C. O. Glover, Kathryn Grasha, Brent Groves, Jonathan Henshaw, Maria J. Jimenez-Donaire, Jenny J. Kim, Ralf S. Klessen, Kathryn Kreckel, Janice C. Lee, Sharon Meidt, Karin Sandstrom, Amy E. Sardone, Dyas Utomo, and Thomas G. Williams

Subjects
Astrophysics, QB460-466
Published
2023
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13. Comparing the Locations of Supernovae to CO (2–1) Emission in Their Host Galaxies

Author

Ness Mayker Chen, Adam K. Leroy, Laura A. Lopez, Samantha Benincasa, Mélanie Chevance, Simon C. O. Glover, Annie Hughes, Kathryn Kreckel, Sumit Sarbadhicary, Jiayi Sun, Todd A. Thompson, Dyas Utomo, Frank Bigiel, Guillermo A. Blanc, Daniel A. Dale, Kathryn Grasha, J. M. Diederik Kruijssen, Hsi-An Pan, Miguel Querejeta, Eva Schinnerer, Elizabeth J. Watkins, and Thomas G. Williams

Subjects
Supernovae, Type II supernovae, Type Ia supernovae, Type Ib supernovae, Type Ic supernovae, Molecular gas, Astrophysics, QB460-466
Abstract

We measure the molecular gas environment near recent (

Published
2023
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15. Transparency Isn't Spoon-Feeding: How a Transformative Approach to the Use of Explicit Assessment Criteria Can Support Student Self-Regulation

Author

Kieran Balloo, Carol Evans, Annie Hughes, Xiaotong Zhu, and Naomi Winstone

Subjects
assessment, feedback, criteria, higher education, inclusive curriculum, self-regulation, Education (General), L7-991
Abstract

If little care is taken when establishing clear assessment requirements, there is the potential for spoon-feeding. However, in this conceptual article we argue that transparency in assessment is essential to providing equality of opportunity and promoting students’ self-regulatory capacity. We begin by showing how a research-informed inclusive pedagogy, the EAT Framework, can be used to improve assessment practices to ensure that the purposes, processes, and requirements of assessment are clear and explicit to students. The EAT Framework foregrounds how students' and teachers' conceptions of learning (i.e., whether one has a transactional or transformative conception of learning within a specific context) impact assessment practices. In this article, we highlight the importance of being explicit in promoting access to learning, and in referencing the EAT Framework, the importance of developing transformative rather than transactional approaches to being explicit. Firstly, we discuss how transparency in the assessment process could lead to “criteria compliance” (Torrance, 2007, p. 282) and learner instrumentalism if a transactional approach to transparency, involving high external regulation, is used. Importantly, we highlight how explicit assessment criteria can hinder learner autonomy if paired with an overreliance on criteria-focused ‘coaching’ from teachers. We then address how ‘being explicit with assessment’ does not constitute spoon-feeding when used to promote understanding of assessment practices, and the application of deeper approaches to learning as an integral component of an inclusive learning environment. We then provide evidence on how explicit assessment criteria allow students to self-assess as part of self-regulation, noting that explicit criteria may be more effective when drawing on a transformative approach to transparency, which acknowledges the importance of transparent and mutual student-teacher communications about assessment requirements. We conclude by providing recommendations to teachers and students about how explicit assessment criteria can be used to improve students' learning. Through an emphasis on transparency of process, clarity of roles, and explication of what constitutes quality within a specific discipline, underpinned by a transformative approach, students and teachers should be better equipped to self-manage their own learning and teaching.

Published
2018
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16. New, Old, Indifferent: The United Kingdom’s Preferences Regarding the Architecture and Design of Public Libraries. A Review of: Black, A. (2011). ‘We don’t do public libraries like we used to’: Attitudes to public library buildings in the UK at the start of the 21st century. Journal of Librarianship and Information Science, 43(1), 30-45.

Author

Annie Hughes

Subjects
public libraries, attitudes and perceptions, architecture and design, Bibliography. Library science. Information resources
Abstract

Objective – Analysis and discussion of attitudes of U.K. citizens toward the architecture and design of the country’s public libraries.Design – Content analysis of essays submitted to the U.K. Mass Observation Archive (MOA).Setting – Citizens of the United Kingdom.Subjects – 180 respondents from a panel of 500 Mass Observation Archive (MOA) volunteers.Methods – The MOA originated in the 1930s as a way to gather qualitative evidence regarding everyday life of the British public. Most of the data gathered takes the form of variable length essays written by a panel of 500 anonymous volunteers. The volunteers respond to specific directives, and in this article, Black summarized responses to a directive he originally posed to the 500 volunteers in 2005: ‘Public Library Buildings’. Black issued this particular directive to the panel of volunteers in the autumn of 2005 and results were made available to the public by mid-2006.The MOA received a total of 180 responses, of which 121 were from women and 59 were from men. Both users of libraries and non-users were included in the sample. The respondents were not a representative sample of the British public because men, ethnic minorities, lower socio-economic groups, and those living outside of the South of England were underrepresented.The author analyzed the content of the 180 submitted essays to gain insight on attitudes regarding public library design and architecture. Respondents were asked about public library location, environmental fit, architectural style, sensory aspects of the building, and whether or not the building resembled other types of public buildings. Although he posed several questions, Black focused on answers to three questions: what do you think about the design of modern library buildings? Do you prefer them to older style buildings? Have you seen older libraries renovated into more modern libraries, and what do you think of them? Black then analyzed the responses and grouped them into four major attitudes toward the architecture and design of public libraries. The author chose not to code any of the responses and instead chose to analyze the ‘discourse’ in and not necessarily the ‘content’ of the essays. After analyzing the discourse, Black contextualized the evidence he discovered. He then discussed political and cultural issues with relation to the four major attitudes and how these issues affected the current landscape of libraries.Main Results – The four major categories derived from the essays that Black analyzed included: preference for the new; preference for the old; preference for a mixing of the old and the new; architectural indifference, the library as ‘place’ and the concept of ‘libraryness.’ Those with a preference for the new preferred the newer, more modern building because it fit better within the world of information technology. These respondents also felt that the older buildings were too intimidating and cold. Those who preferred the older architecture and design felt that the buildings allowed them to access a piece of the past, and they thought an older library to be more impressive, historic, and generally have more elaborate and interesting architecture. These respondents pointed out the fewer places to hide in new libraries, and indicated that new architecture is boring and stolid. The third group of respondents preferred an older exterior, but an up-to-date interior with a more modern infrastructure. They enjoyed the large impressive buildings but liked the interior to contain comfortable, modern furniture, good lighting, as well as updated technological tools. Finally, the remaining group of respondents did not place importance on the physical space of a library, but more so the services and collections within the physical space.Conclusion – The discourse derived from the MOA and analyzed in Black’s article summarizes the attitudes and preferences that citizens of the UK have regarding public library architecture. Among the 180 responses to the ‘Public Library Buildings’ directive, there is a clear tension in these attitudes and preferences. The information gathered in the MOA directive on public libraries could also provide political and cultural leaders with evidence of a need for renewal or rethinking of the country’s public libraries.

Published
2011

17. Pre-supernova feedback mechanisms drive the destruction of molecular clouds in nearby star-forming disc galaxies

Author

Mélanie Chevance, J M Diederik Kruijssen, Mark R Krumholz, Brent Groves, Benjamin W Keller, Annie Hughes, Simon C O Glover, Jonathan D Henshaw, Cinthya N Herrera, Jaeyeon Kim, Adam K Leroy, Jérôme Pety, Alessandro Razza, Erik Rosolowsky, Eva Schinnerer, Andreas Schruba, Ashley T Barnes, Frank Bigiel, Guillermo A Blanc, Daniel A Dale, Eric Emsellem, Christopher M Faesi, Kathryn Grasha, Ralf S Klessen, Kathryn Kreckel, Daizhong Liu, Steven N Longmore, Sharon E Meidt, Miguel Querejeta, Toshiki Saito, Jiayi Sun, and Antonio Usero

Published
2021
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18. A Fully Bayesian Approach For Inferring Physical Properties With Credibility Intervals From Noisy Astronomical Data.

Author

Maxime Vono, Javier R. Goicoechea, Pierre Gratier, Viviana V. Guzmán, Annie Hughes, Jouni Kainulainen, David Languignon, Jacques Le Bourlot, François Levrier, Harvey S. Listz, Karin I. Oberg, Emeric Bron, Jan H. Orkisz, Nicolas Peretto, Jérome Pety, Antoine Roueff, èvelyne Roueff, Albrecht Sievers, Victor de Souza Magalhaes, Pascal Tremblin, Pierre Chainais, Franck Le Petit, Sébastien Bardeau, Sébastien Bourguignon, Jocelyn Chanussot, Mathilde Gaudel, and Maryvonne Gerin

Published
2019
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19. The lifecycle of molecular clouds in nearby star-forming disc galaxies

Author

Mélanie Chevance, J M Diederik Kruijssen, Alexander P S Hygate, Andreas Schruba, Steven N Longmore, Brent Groves, Jonathan D Henshaw, Cinthya N Herrera, Annie Hughes, Sarah M R Jeffreson, Philipp Lang, Adam K Leroy, Sharon E Meidt, Jérôme Pety, Alessandro Razza, Erik Rosolowsky, Eva Schinnerer, Frank Bigiel, Guillermo A Blanc, Eric Emsellem, Christopher M Faesi, Simon C O Glover, Daniel T Haydon, I-Ting Ho, Kathryn Kreckel, Janice C Lee, Daizhong Liu, Miguel Querejeta, Toshiki Saito, Jiayi Sun, Antonio Usero, and Dyas Utomo

Published
2019
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20. Molecular Cloud Populations in the Context of Their Host Galaxy Environments: A Multiwavelength Perspective

Author

Jiayi 嘉懿 Sun 孙, Adam K. Leroy, Erik Rosolowsky, Annie Hughes, Eva Schinnerer, Andreas Schruba, Eric W. Koch, Guillermo A. Blanc, I-Da 宜達 Chiang 江, Brent Groves, Daizhong Liu, Sharon Meidt, Hsi-An Pan, Jérôme Pety, Miguel Querejeta, Toshiki Saito, Karin Sandstrom, Amy Sardone, Antonio Usero, Dyas Utomo, Thomas G. Williams, Ashley T. Barnes, Samantha M. Benincasa, Frank Bigiel, Alberto D. Bolatto, Médéric Boquien, Mélanie Chevance, Daniel A. Dale, Sinan Deger, Eric Emsellem, Simon C. O. Glover, Kathryn Grasha, Jonathan D. Henshaw, Ralf S. Klessen, Kathryn Kreckel, J. M. Diederik Kruijssen, Eve C. Ostriker, and David A. Thilker

Published
2022
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23. Estimate of the carbon footprint of astronomical research infrastructures

Author

Jürgen Knödlseder, Sylvie Brau-Nogué, Mickael Coriat, Philippe Garnier, Annie Hughes, Pierrick Martin, Luigi Tibaldo, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU]Sciences of the Universe [physics], FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM)
Abstract

The carbon footprint of astronomical research is an increasingly topical issue with first estimates of research institute and national community footprints having recently been published. As these assessments have typically excluded the contribution of astronomical research infrastructures, we complement these studies by providing an estimate of the contribution of astronomical space missions and ground-based observatories using greenhouse gas emission factors that relates cost and payload mass to carbon footprint. We find that worldwide active astronomical research infrastructures currently have a carbon footprint of 20.3$\pm$3.3 MtCO$_2$ equivalent (CO$_2$e) and an annual emission of 1,169$\pm$249 ktCO$_2$e yr$^{-1}$ corresponding to a footprint of 36.6$\pm$14.0 tCO$_2$e per year per astronomer. Compared with contributions from other aspects of astronomy research activity, our results suggest that research infrastructures make the single largest contribution to the carbon footprint of an astronomer. We discuss the limitations and uncertainties of our method and explore measures that can bring greenhouse gas emissions from astronomical research infrastructures towards a sustainable level., Comment: 48 pages, 6 tables, 2 figures

Published
2022

24. PHANGS-JWST First Results: Mapping the 3.3 micron Polycyclic Aromatic Hydrocarbon Vibrational Band in Nearby Galaxies with NIRCam Medium Bands

Author

Karin M. Sandstrom, Jérémy Chastenet, Jessica Sutter, Adam K. Leroy, Oleg V. Egorov, Thomas G. Williams, Alberto D. Bolatto, Médéric Boquien, Yixian Cao, Daniel A. Dale, Janice C. Lee, Erik Rosolowsky, Eva Schinnerer, Ashley. T. Barnes, Francesco Belfiore, F. Bigiel, Mélanie Chevance, Kathryn Grasha, Brent Groves, Hamid Hassani, Annie Hughes, Ralf S. Klessen, J. M. Diederik Kruijssen, Kirsten L. Larson, Daizhong Liu, Laura A. Lopez, Sharon E. Meidt, Eric J. Murphy, Mattia C. Sormani, David A. Thilker, and Elizabeth J. Watkins

Subjects
Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract

We present maps of the 3.3 micron polycyclic aromatic hydrocarbon (PAH) emission feature in NGC 628, NGC 1365, and NGC 7496 as observed with the Near-Infrared Camera (NIRCam) imager on JWST from the PHANGS-JWST Cycle 1 Treasury project. We create maps that isolate the 3.3 micron PAH feature in the F335M filter (F335M$_{\rm PAH}$) using combinations of the F300M and F360M filters for removal of starlight continuum. This continuum removal is complicated by contamination of the F360M by PAH emission and variations in the stellar spectral energy distribution slopes between 3.0 and 3.6 micron. We modify the empirical prescription from Lai et al. (2020) to remove the starlight continuum in our highly resolved galaxies, which have a range of starlight- and PAH-dominated lines-of-sight. Analyzing radially binned profiles of the F335M$_{\rm PAH}$ emission, we find that between 5-65% of the F335M intensity comes from the 3.3 micron feature within the inner 0.5 $r_{25}$ of our targets. This percentage systematically varies from galaxy to galaxy, and shows radial trends within the galaxies related to each galaxy's distribution of stellar mass, interstellar medium, and star formation. The 3.3 micron emission is well correlated with the 11.3 micron PAH feature traced with the MIRI F1130W filter, as is expected, since both features arise from C-H vibrational modes. The average F335M$_{\rm PAH}$/F1130W ratio agrees with the predictions of recent models by Draine et al. (2021) for PAHs with size and charge distributions shifted towards larger grains with normal or higher ionization., Comment: submitted to AAS journals and revised according to referee comments, part of a PHANGS-JWST Focus Issue to appear in ApJ

Published
2023
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26. PHANGS-JWST First Results: Mid-infrared emission traces both gas column density and heating at 100 pc scales

Author

Adam K. Leroy, Karin Sandstrom, Erik Rosolowsky, Francesco Belfiore, Alberto D. Bolatto, Yixian Cao, Eric W. Koch, Eva Schinnerer, Ashley. T. Barnes, Ivana Bešlić, F. Bigiel, Guillermo A. Blanc, Jérémy Chastenet, Ness Mayker Chen, Mélanie Chevance, Ryan Chown, Enrico Congiu, Daniel A. Dale, Oleg V. Egorov, Eric Emsellem, Cosima Eibensteiner, Christopher M. Faesi, Simon C. O. Glover, Kathryn Grasha, Brent Groves, Hamid Hassani, Jonathan D. Henshaw, Annie Hughes, María J. Jiménez-Donaire, Jaeyeon Kim, Ralf S. Klessen, Kathryn Kreckel, J. M. Diederik Kruijssen, Kirsten L. Larson, Janice C. Lee, Rebecca C. Levy, Daizhong Liu, Laura A. Lopez, Sharon E. Meidt, Eric J. Murphy, Justus Neumann, Ismael Pessa, Jérôme Pety, Toshiki Saito, Amy Sardone, Jiayi Sun, David A. Thilker, Antonio Usero, Elizabeth J. Watkins, Cory M. Whitcomb, and Thomas G. Williams

Subjects
Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract

We compare mid-infrared (mid-IR), extinction-corrected H$\alpha$, and CO (2-1) emission at 70--160 pc resolution in the first four PHANGS-JWST targets. We report correlation strengths, intensity ratios, and power law fits relating emission in JWST's F770W, F1000W, F1130W, and F2100W bands to CO and H$\alpha$. At these scales, CO and H$\alpha$ each correlate strongly with mid-IR emission, and these correlations are each stronger than the one relating CO to H$\alpha$ emission. This reflects that mid-IR emission simultaneously acts as a dust column density tracer, leading to the good match with the molecular gas-tracing CO, and as a heating tracer, leading to the good match with the H$\alpha$. By combining mid-IR, CO, and H$\alpha$ at scales where the overall correlation between cold gas and star formation begins to break down, we are able to separate these two effects. We model the mid-IR above $I_\nu = 0.5$~MJy sr$^{-1}$ at F770W, a cut designed to select regions where the molecular gas dominates the interstellar medium (ISM) mass. This bright emission can be described to first order by a model that combines a CO-tracing component and an H$\alpha$-tracing component. The best-fitting models imply that $\sim 50\%$ of the mid-IR flux arises from molecular gas heated by the diffuse interstellar radiation field, with the remaining $\sim 50\%$ associated with bright, dusty star forming regions. We discuss differences between the F770W, F1000W, F1130W bands and the continuum dominated F2100W band and suggest next steps for using the mid-IR as an ISM tracer., Comment: 49 pages, 17 figures, Section 8 provides a detailed summary, accepted for publication in ApJ Letters, part of a PHANGS-JWST Focus Issue to appear in ApJ

Published
2022

27. The PHANGS-JWST Treasury Survey: Star Formation, Feedback, and Dust Physics at High Angular resolution in Nearby GalaxieS

Author

Janice C. Lee, Karin M. Sandstrom, Adam K. Leroy, David A. Thilker, Eva Schinnerer, Erik Rosolowsky, Kirsten L. Larson, Oleg V. Egorov, Thomas G. Williams, Judy Schmidt, Eric Emsellem, Gagandeep S. Anand, Ashley T. Barnes, Francesco Belfiore, Ivana Bešlić, Frank Bigiel, Guillermo A. Blanc, Alberto D. Bolatto, Médéric Boquien, Jakob den Brok, Yixian Cao, Rupali Chandar, Jérémy Chastenet, Mélanie Chevance, I-Da Chiang, Enrico Congiu, Daniel A. Dale, Sinan Deger, Cosima Eibensteiner, Christopher M. Faesi, Simon C. O. Glover, Kathryn Grasha, Brent Groves, Hamid Hassani, Kiana F. Henny, Jonathan D. Henshaw, Nils Hoyer, Annie Hughes, Sarah Jeffreson, María J. Jiménez-Donaire, Jaeyeon Kim, Hwihyun Kim, Ralf S. Klessen, Eric W. Koch, Kathryn Kreckel, J. M. Diederik Kruijssen, Jing Li, Daizhong Liu, Laura A. Lopez, Daniel Maschmann, Ness Mayker Chen, Sharon E. Meidt, Eric J. Murphy, Justus Neumann, Nadine Neumayer, Hsi-An Pan, Ismael Pessa, Jérôme Pety, Miguel Querejeta, Francesca Pinna, M. Jimena Rodríguez, Toshiki Saito, Patricia Sánchez-Blázquez, Francesco Santoro, Amy Sardone, Rowan J. Smith, Mattia C. Sormani, Fabian Scheuermann, Sophia K. Stuber, Jessica Sutter, Jiayi Sun, Yu-Hsuan Teng, Robin G. Treß, Antonio Usero, Elizabeth J. Watkins, Bradley C. Whitmore, and Alessandro Razza

Subjects
Ciencias Astronómicas, Spiral galaxies, Star formation, FOS: Physical sciences, forming galaxies, galactic environment, Astronomy and Astrophysics, Surveys, Astrophysics - Astrophysics of Galaxies, Polycyclic aromatic hydrocarbons, Young star clusters, h alpha morphologies, formation efficiency, uncertainty principle, Interstellar medium, formation cycle, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), molecular gas properties, formation rates, stellar feedback, polycyclic aromatic-hydrocarbon, Interstellar dust
Abstract

The PHANGS collaboration has been building a reference data set for the multiscale, multiphase study of star formation and the interstellar medium (ISM) in nearby galaxies. With the successful launch and commissioning of JWST, we can now obtain high-resolution infrared imaging to probe the youngest stellar populations and dust emission on the scales of star clusters and molecular clouds (∼5–50 pc). In Cycle 1, PHANGS is conducting an eight-band imaging survey from 2 to 21 μm of 19 nearby spiral galaxies. Optical integral field spectroscopy, CO(2–1) mapping, and UV-optical imaging for all 19 galaxies have been obtained through large programs with ALMA, VLT-MUSE, and Hubble. PHANGS–JWST enables a full inventory of star formation, accurate measurement of the mass and age of star clusters, identification of the youngest embedded stellar populations, and characterization of the physical state of small dust grains. When combined with Hubble catalogs of ∼10,000 star clusters, MUSE spectroscopic mapping of ∼20,000 H II regions, and ∼12,000 ALMA-identified molecular clouds, it becomes possible to measure the timescales and efficiencies of the earliest phases of star formation and feedback, build an empirical model of the dependence of small dust grain properties on local ISM conditions, and test our understanding of how dust-reprocessed starlight traces star formation activity, all across a diversity of galactic environments. Here we describe the PHANGS–JWST Treasury survey, present the remarkable imaging obtained in the first few months of science operations, and provide context for the initial results presented in the first series of PHANGS–JWST publications., La lista completa de autores que integran el documento puede consultarse en el archivo., Instituto de Astrofísica de La Plata

Published
2022

29. Performance of the polarization leakage correction in the PILOT data

Author

Jean-Philippe Bernard, Adam Bernard, Helene Roussel, Choubani Ilyes, Dana Alina, Aumont Jonathan, Annie Hughes, Isabelle Ristorcelli, Stever Samantha, Tomotake Matsumura, Shinji Sugiyama, Kunimoto Komatsu, Giancarlo de Gasperis, Katia Ferrière, Vincent Guillet, Nathalie Ysard, Paolo de Bernardis, Sylvia Masi, Bruno Maffei, Baptiste Mot, Francois Pajot, Nicolas Ponthieu, Giorgio Savini, Francois Vacher, Peter Ade, Carole Tucker, Bruno Crane, Jean-Pierre Dubois, Yuying Longval, and Valentin Sauvage

Abstract

The Polarized Instrument for Long-wavelength Observation of the Tenuous interstellar medium (PILOT) is a balloon-borne experiment that aims to measure the polarized emission of thermal dust at a wavelength of 240 μm (1.2THz). The PILOT experiment flew from Timmins, Ontario, Canada in 2015 and 2019 and from Alice Springs, Australia in April 2017. The in-flight performance of the instrument during the second flight was described in [1]. In this paper,we present data processing steps that were not presented in [1] and that we have recently implemented to correct for several remaining instrumental effects. The additional data processing concerns corrections related to detector cross-talk and readout circuit memory effects, and leakage from total intensity to polarization. We illustrate the above effects and the performance of our corrections using data obtained during the third flight of PILOT, but the methods used to assess the impact of these effects on the final science-ready data, and our strategies for correcting them will be applied to all PILOT data. We show that the above corrections, and in particular that for the intensity to polarization leakage, which is most critical for accurate polarization measurements with PILOT, are accurate to better than 0.4% as measured on Jupiter during flight#3.

Published
2022

30. The Gas-Star Formation Cycle in Nearby Star-forming Galaxies. II. Resolved Distributions of CO and Hα Emission for 49 PHANGS Galaxies

Author

Hsi-An Pan, Eva Schinnerer, Annie Hughes, Adam Leroy, Brent Groves, Ashley Thomas Barnes, Francesco Belfiore, Frank Bigiel, Guillermo A. Blanc, Yixian Cao, Mélanie Chevance, Enrico Congiu, Daniel A. Dale, Cosima Eibensteiner, Eric Emsellem, Christopher M. Faesi, Simon C. O. Glover, Kathryn Grasha, Cinthya N. Herrera, I-Ting Ho, Ralf S. Klessen, J. M. Diederik Kruijssen, Philipp Lang, Daizhong Liu, Rebecca McElroy, Sharon E. Meidt, Eric J. Murphy, Jérôme Pety, Miguel Querejeta, Alessandro Razza, Erik Rosolowsky, Toshiki Saito, Francesco Santoro, Andreas Schruba, Jiayi Sun, Neven Tomičić, Antonio Usero, Dyas Utomo, Thomas G. Williams, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], FORMATION EFFICIENCY, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics - Astrophysics of Galaxies, ATOMIC GAS, DIFFUSE IONIZED-GAS, Physics and Astronomy, CO-TO-H-2 CONVERSION FACTOR, Space and Planetary Science, LUMINOSITY FUNCTION, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), MILKY-WAY, Astrophysics::Earth and Planetary Astrophysics, MAGELLANIC-CLOUD, GIANT MOLECULAR CLOUDS, UNCERTAINTY PRINCIPLE, Astrophysics::Galaxy Astrophysics, SDSS-IV MANGA
Abstract

The relative distribution of molecular gas and star formation in galaxies gives insight into the physical processes and timescales of the cycle between gas and stars. In this work, we track the relative spatial configuration of CO and H$\alpha$ emission at high resolution in each of our galaxy targets, and use these measurements to quantify the distributions of regions in different evolutionary stages of star formation: from molecular gas without star formation traced by H$\alpha$ to star-forming gas, and to HII regions. The large sample, drawn from the Physics at High Angular resolution in Nearby GalaxieS ALMA and narrowband H$\alpha$ (PHANGS-ALMA and PHANGS-H$\alpha$) surveys, spans a wide range of stellar mass and morphological types, allowing us to investigate the dependencies of the gas-star formation cycle on global galaxy properties. At a resolution of 150 pc, the incidence of regions in different stages shows a dependence on stellar mass and Hubble type of galaxies over the radial range probed. Massive and/or earlier-type galaxies exhibit a significant reservoir of molecular gas without star formation traced by H$\alpha$, while lower-mass galaxies harbor substantial HII regions that may have dispersed their birth clouds or formed from low-mass, more isolated clouds. Galactic structures add a further layer of complexity to relative distribution of CO and H$\alpha$ emission. Trends between galaxy properties and distributions of gas traced by CO and H$\alpha$ are visible only when the observed spatial scale is $\ll$ 500 pc, reflecting the critical resolution requirement to distinguish stages of star formation process., Comment: 60 pages, 22 figures, 9 tables, accepted for publication in The Astrophysical Journal

Published
2022

31. The PHANGS-MUSE survey. Probing the chemo-dynamical evolution of disc galaxies

Author

Eric Emsellem, Eva Schinnerer, Francesco Santoro, Francesco Belfiore, Ismael Pessa, Rebecca McElroy, Guillermo A. Blanc, Enrico Congiu, Brent Groves, I-Ting Ho, Kathryn Kreckel, Alessandro Razza, Patricia Sanchez-Blazquez, Oleg Egorov, Chris Faesi, Ralf S. Klessen, Adam K. Leroy, Sharon Meidt, Miguel Querejeta, Erik Rosolowsky, Fabian Scheuermann, Gagandeep S. Anand, Ashley T. Barnes, Ivana Bešlić, Frank Bigiel, Médéric Boquien, Yixian Cao, Mélanie Chevance, Daniel A. Dale, Cosima Eibensteiner, Simon C. O. Glover, Kathryn Grasha, Jonathan D. Henshaw, Annie Hughes, Eric W. Koch, J. M. Diederik Kruijssen, Janice Lee, Daizhong Liu, Hsi-An Pan, Jérôme Pety, Toshiki Saito, Karin M. Sandstrom, Andreas Schruba, Jiayi Sun, David A. Thilker, Antonio Usero, Elizabeth J. Watkins, Thomas G. Williams, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
Astrofísica, galaxies: spiral, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], stars: kinematics and dynamics, FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, surveys, Space and Planetary Science, techniques: imaging spectroscopy, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), galaxies: star formation, Astrophysics - Instrumentation and Methods for Astrophysics, Instrumentation and Methods for Astrophysics (astro-ph.IM), ISM: general
Abstract

We present the PHANGS-MUSE survey, a programme using the MUSE IFS at the ESO VLT to map 19 massive $(9.4 < \log(M_{*}/M_\odot) < 11.0)$ nearby (D < 20 Mpc) star-forming disc galaxies. The survey consists of 168 MUSE pointings (1'x1' each), a total of nearly 15 Million spectra, covering ~1.5 Million independent spectra. PHANGS-MUSE provides the first IFS view of star formation across different local environments (including galaxy centres, bars, spiral arms) in external galaxies at a median resolution of 50~pc, better than the mean inter-cloud distance in the ionised interstellar medium. This `cloud-scale' resolution allows detailed demographics and characterisations of HII regions and other ionised nebulae. PHANGS-MUSE further delivers a unique view on the associated gas and stellar kinematics, and provides constraints on the star formation history. The PHANGS-MUSE survey is complemented by dedicated ALMA CO(2-1) and multi-band HST observations, therefore allowing us to probe the key stages of the star formation process from molecular clouds to HII regions and star clusters. This paper describes the scientific motivation, sample selection, observational strategy, data reduction and analysis process of the PHANGS-MUSE survey. We present our bespoke automated data-reduction framework, which is built on the reduction recipes provided by ESO, but additionally allows for mosaicking and homogenisation of the point spread function. We further present a detailed quality assessment and a brief illustration of the potential scientific applications of the large set of PHANGS-MUSE data products generated by our data analysis framework. The data cubes and analysis data products described in this paper represent the basis for the first PHANGS-MUSE public data release and are available in the ESO archive and via the Canadian Astronomy Data Centre., 48 pages, 28 figures, 4 tables, accepted for pub in A&A, Dec 8, 2021. Data products released publicly at this address https://archive.eso.org/scienceportal/home?data_collection=PHANGS

Published
2022

32. CI and CO in Nearby Spiral Galaxies -- I. Line Ratio and Abundance Variations at ~ 200 pc Scales

Author

Daizhong Liu, Eva Schinnerer, Toshiki Saito, Erik Rosolowsky, Adam Leroy, Antonio Usero, Karin Sandstrom, Ralf S. Klessen, Simon C. O. Glover, Yiping Ao, Ivana Bešlić, Frank Bigiel, Yixian Cao, Jérémy Chastenet, Mélanie Chevance, Daniel A. Dale, Yu Gao, Annie Hughes, Kathryn Kreckel, J. M. Diederik Kruijssen, Hsi-An Pan, Jérôme Pety, Dragan Salak, Francesco Santoro, Andreas Schruba, Jiayi Sun, Yu-Hsuan Teng, and Thomas Williams

Subjects
Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies
Abstract

We present new neutral atomic carbon [CI](3P1-3P0) mapping observations within the inner ~7 kpc and ~4 kpc of the disks of NGC3627 and NGC4321 at a spatial resolution of 190 pc and 270 pc, respectively, using the ALMA Atacama Compact Array (ACA). We combine these with the CO(2-1) data from PHANGS-ALMA, and literature [CI] and CO data for two other starburst and/or active galactic nucleus (AGN) galaxies (NGC1808, NGC7469), to study: a) the spatial distributions of CI and CO emission; b) the observed line ratio RCICO = I_[CI](1-0)/I_CO(2-1) as a function of various galactic properties; and c) the abundance ratio of [CI/CO]. We find excellent spatial correspondence between CI and CO emission and nearly uniform RCICO ~0.1 across the majority of the star-forming disks of NGC3627 and NGC4321. However, RCICO strongly varies from ~0.05 at the centre of NGC4321 to >0.2-0.5 in NGC1808's starburst centre and NGC7469's centre with an X-ray AGN. Meanwhile, RCICO does not obviously vary with $U$, similar to the prediction of PDR models. We also find a mildly decreasing RCICO with an increasing metallicity over 0.7-0.85 solar metallicity, consistent with the literature. Assuming various typical ISM conditions representing GMCs, active star-forming regions and strong starbursting environments, we calculate the LTE radiative transfer and estimate the [CI/CO] abundance ratio to be ~0.1 across the disks of NGC3627 and NGC4321, similar to previous large-scale findings in Galactic studies. However, this abundance ratio likely has a substantial increase to ~1 and >1-5 in NGC1808's starburst and NGC7469's strong AGN environments, respectively, in line with the expectations for cosmic-ray dominated region (CRDR) and X-ray dominated region (XDR) chemistry. Finally, we do not find a robust evidence for a generally CO-dark, CI-bright gas in the disk areas we probed. (abbreviated), 23 pages, 13 figures and one table in total (17 pages and 9 figures in main text). Accepted for publication in A&A. For associated data cubes and moment maps, see https://www.canfar.net/storage/vault/list/phangs/RELEASES/DZLIU_etal_2022

Published
2022
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33. Around the hybrid conference world in the COVID-19 era

Author

Vanessa A. Moss, Lola Balaguer-Nuñez, Krzysztof Bolejko, Leonard Burtscher, Anthony Carr, Enrico M. Di Teodoro, Brenne Gregory, Esther Hanko, Alex S. Hill, Annie Hughes, Lex Kaper, Emily F. Kerrison, Felix J. Lockman, Nataliea Lowson, Adam R. H. Stevens, and High Energy Astrophys. & Astropart. Phys (API, FNWI)

Subjects
Astronomy and Astrophysics
Abstract

In-person and online conferences each have their benefits, with hybrid conferences intended to blend the best of both worlds. But do hybrid conferences fulfil the promise? Fifteen attendees across three global conferences share their collective experiences.

Published
2022

34. Low-J CO Line Ratios from Single-dish CO Mapping Surveys and PHANGS-ALMA

Author

Adam K. Leroy, Erik Rosolowsky, Antonio Usero, Karin Sandstrom, Eva Schinnerer, Andreas Schruba, Alberto D. Bolatto, Jiayi Sun, Ashley. T. Barnes, Francesco Belfiore, Frank Bigiel, Jakob S. den Brok, Yixian Cao, I-Da Chiang, Mélanie Chevance, Daniel A. Dale, Cosima Eibensteiner, Christopher M. Faesi, Simon C. O. Glover, Annie Hughes, María J. Jiménez Donaire, Ralf S. Klessen, Eric W. Koch, J. M. Diederik Kruijssen, Daizhong Liu, Sharon E. Meidt, Hsi-An Pan, Jérôme Pety, Johannes Puschnig, Miguel Querejeta, Toshiki Saito, Amy Sardone, Elizabeth J. Watkins, Axel Weiss, Thomas G. Williams, Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
MASS-METALLICITY RELATION, PHYSICAL-PROPERTIES, FOS: Physical sciences, STAR-FORMATION, Interstellar medium, DENSE GAS, FORMING MOLECULAR GAS, CO(2-1) SURVEY, Molecular gas, INTERSTELLAR-MEDIUM, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], OPTICAL DEPTH, Astronomy and Astrophysics, Interstellar molecules, Galaxies, Astrophysics - Astrophysics of Galaxies, Physics and Astronomy, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), NEARBY SPIRAL GALAXIES, SUBMILLIMETER-C
Abstract

We measure the low-J CO line ratio R21=CO(2-1)/CO(1-0), R32=CO(3-2)/CO(2-1), and R31 = CO(3-2)/CO(1-0) using whole-disk CO maps of nearby galaxies. We draw CO(2-1) from PHANGS--ALMA, HERACLES, and follow-up IRAM surveys; CO(1-0) from COMING and the Nobeyama CO Atlas of Nearby Spiral Galaxies; and CO(3-2) from the JCMT NGLS and APEX LASMA mapping. Altogether this yields 76, 47, and 29 maps of R21, R32, and R31 at 20" \sim 1.3 kpc resolution, covering 43, 34, and 20 galaxies. Disk galaxies with high stellar mass, log10 M_* [Msun]=10.25-11 and star formation rate, SFR=1-5 Msun/yr, dominate the sample. We find galaxy-integrated mean values and 16%-84% range of R21 = 0.65 (0.50-0.83), R32=0.50 (0.23-0.59), and R31=0.31 (0.20-0.42). We identify weak trends relating galaxy-integrated line ratios to properties expected to correlate with excitation, including SFR/M_* and SFR/L_CO. Within galaxies, we measure central enhancements with respect to the galaxy-averaged value of \sim 0.18^{+0.09}_{-0.14} dex for R21, 0.27^{+0.13}_{-0.15} dex for R31, and 0.08^{+0.11}_{-0.09} dex for R32. All three line ratios anti-correlate with galactocentric radius and positively correlate with the local star formation rate surface density and specific star formation rate, and we provide approximate fits to these relations. The observed ratios can be reasonably reproduced by models with low temperature, moderate opacity, and moderate densities, in good agreement with expectations for the cold ISM. Because the line ratios are expected to anti-correlate with the CO(1-0)-to-H_2 conversion factor, alphaCO^(1-0), these results have general implications for the interpretation of CO emission from galaxies., Comment: 34 pages; 12 figures; accepted for publication in the Astrophysical Journal; data tables available http://www.astronomy.ohio-state.edu/~leroy.42/int_corat_tab.ecsv and http://www.astronomy.ohio-state.edu/~leroy.42/co_model.ecsv before publication

Published
2022
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35. Gas kinematics around filamentary structures in the Orion B cloud

Author

Mathilde Gaudel, Jan H. Orkisz, Maryvonne Gerin, Jérôme Pety, Antoine Roueff, Antoine Marchal, François Levrier, Marc-Antoine Miville-Deschênes, Javier R. Goicoechea, Evelyne Roueff, Franck Le Petit, Victor de Souza Magalhaes, Pierre Palud, Miriam G. Santa-Maria, Maxime Vono, Sébastien Bardeau, Emeric Bron, Pierre Chainais, Jocelyn Chanussot, Pierre Gratier, Viviana Guzman, Annie Hughes, Jouni Kainulainen, David Languignon, Jacques Le Bourlot, Harvey Liszt, Karin Öberg, Nicolas Peretto, Albrecht Sievers, Pascal Tremblin, Agence Nationale de la Recherche (France), Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), l'Observatoire de Paris, Ministerio de Ciencia, Innovación y Universidades (España), Swedish Research Council, Orkisz, Jan H., Pety, Jérôme, Roueff, Antoine, Marchal, Antoine, Levrier, François, Miville-Deschênes, Marc-Antoine, Goicoechea, Javier R., Roueff, Evelyne, Santa-Maria, Miriam G., Bron, Emeric, Chainais, Pierre, Chanussot, Jocelyn, Gratier, Pierre, Guzman, Viviana, Le Bourlot,Jacques, and Liszt, Harvey

Subjects
ISM: kinematics and dynamics, HII regions, ISM: individual objects: Orion B, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), Stars: formation, FOS: Physical sciences, Astronomy and Astrophysics, ISM: clouds, Astrophysics - Astrophysics of Galaxies, Radio lines: ISM
Abstract

39 pags., 78 figs., 2 tabs. 6 apps., Understanding the initial properties of star-forming material and how they affect the star formation process is key. From an observational point of view, the feedback from young high-mass stars on future star formation properties is still poorly constrained. In the framework of the IRAM 30m ORION-B large program, we obtained observations of the translucent and moderately dense gas, which we used to analyze the kinematics over a field of 5 deg^2 around the filamentary structures. We used the ROHSA algorithm to decompose and de-noise the C18O(1-0) and 13CO(1-0) signals by taking the spatial coherence of the emission into account. We produced gas column density and mean velocity maps to estimate the relative orientation of their spatial gradients. We identified three cloud velocity layers at different systemic velocities and extracted the filaments in each velocity layer. The filaments are preferentially located in regions of low centroid velocity gradients. By comparing the relative orientation between the column density and velocity gradients of each layer from the ORION-B observations and synthetic observations from 3D kinematic toy models, we distinguish two types of behavior in the dynamics around filaments: (i) radial flows perpendicular to the filament axis that can be either inflows (increasing the filament mass) or outflows and (ii) longitudinal flows along the filament axis. The former case is seen in the Orion B data, while the latter is not identified. We have also identified asymmetrical flow patterns, usually associated with filaments located at the edge of an HII region. This is the first observational study to highlight feedback from HII regions on filament formation and, thus, on star formation in the Orion B cloud. This simple statistical method can be used for any molecular cloud to obtain coherent information on the kinematics., This work was supported in part by the French Agence Nationale de la Recherche through the DAOISM grant ANR21-CE31-0010 and by the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP, co-funded by CEA and CNES. We thank “le centre Jules Jensen” from Observatoire de Paris for its hospitality during the workshops devoted to this project. This research has made use of data from the Herschel Gould Belt Survey (HGBS) project (http: //gouldbelt-herschel.cea.fr). The HGBS is a Herschel Key Programme jointly carried out by SPIRE Specialist Astronomy Group 3 (SAG 3), scientists of several institutes in the PACS Consortium (CEA Saclay, INAF-IFSI Rome and INAF-Arcetri, KU Leuven, MPIA Heidelberg), and scientists of the Herschel Science Center (HSC). J.R.G. and M.G.S.M. thank the Spanish MCIYU for funding support under grant PID2019-106110GB-I00. J.O. acknowledges funding from the Swedish Research Council, grant No. 2017-03864.

Published
2023

37. PHANGS-ALMA: Arcsecond CO(2-1) Imaging of Nearby Star-forming Galaxies

Author

Eric W. Koch, Axel García-Rodríguez, Miguel Querejeta, Ashley T. Barnes, Enrico Congiu, Guillermo A. Blanc, Rebecca McElroy, Yixian Cao, Ralf S. Klessen, Rupali Chandar, Amanda A. Kepley, Cinthya N. Herrera, Alberto D. Bolatto, Simon C. O. Glover, Fabian Scheuermann, Antonio Usero, Jordan A. Turner, Eve C. Ostriker, Karin Sandstrom, Jiayi Sun, Ivana Bešlić, Ismael Pessa, Sinan Deger, Elizabeth J. Watkins, Johannes Puschnig, Kirsten L. Larson, Ness Mayker, Erik Rosolowsky, Daniel A. Dale, Frank Bigiel, Annie Hughes, Amy Sardone, Gagandeep S. Anand, I-Ting Ho, Andreas Schruba, Hsi-An Pan, Adam K. Leroy, Kathryn Grasha, Jaeyeon Kim, Bradley C. Whitmore, Eric J. Murphy, Jérôme Pety, Samantha M. Benincasa, Erica A. Behrens, I-Da Chiang, Kathryn Kreckel, Cosima Eibensteiner, Mattia C. Sormani, Alessandro Razza, J. M. Diederik Kruijssen, David A. Thilker, Daizhong Liu, Sharon E. Meidt, Patricia Sanchez-Blazquez, Jonathan D. Henshaw, Dyas Utomo, Eric Emsellem, Eva Schinnerer, Laura A. Lopez, Sophia K. Stuber, Janice C. Lee, Toshiki Saito, Oleg V. Egorov, Josh Machado, Francesco Belfiore, Jérémy Chastenet, Jakob S. den Brok, Francesco Santoro, Kazimierz Sliwa, Christopher Faesi, Mélanie Chevance, Thomas G. Williams, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Centre National de la Recherche Scientifique (CNRS), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), and Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Population, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Luminosity, 0103 physical sciences, KINEMATICS, education, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Line (formation), Physics, education.field_of_study, 010308 nuclear & particles physics, Star formation, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, Galaxy, Interstellar medium, Stars, Physics and Astronomy, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), MOLECULAR GAS PROPERTIES, Astrophysics::Earth and Planetary Astrophysics
Abstract

We present PHANGS-ALMA, the first survey to map CO J=2-1 line emission at ~1" ~ 100pc spatial resolution from a representative sample of 90 nearby (d, Comment: 76 pages, 33 figures. Accepted for publication in the Astrophysical Journal Supplement series. Full resolution version and the image atlas to appear as a figure set in the published version can be found https://sites.google.com/view/phangs/publications . Data release coming soon to the ALMA archive and CADC temporarily available at http://phangs.org/data

Published
2021

38. The Organization of Cloud-scale Gas Density Structure: High-resolution CO versus 3.6 μm Brightness Contrasts in Nearby Galaxies

Author

Frank Bigiel, Brent Groves, Toshiki Saito, M. Querejeta, Annie Hughes, Christopher M Faesi, S. C. O. Glover, Ashley T. Barnes, Yixian Cao, M. Chevance, Daizhong Liu, Jonathan D. Henshaw, Eva Schinnerer, C. N. Herrera, Eric Emsellem, Guillermo A. Blanc, Andreas Schruba, J. M. Diederik Kruijssen, Thomas G. Williams, Elizabeth Watkins, K. Grasha, Jiayi Sun, R. S. Klessen, Erik Rosolowsky, Arjen Van der Wel, Hsi-An Pan, J. Pety, K. Kreckel, A. Usero, Daniel A. Dale, Adam K. Leroy, Sharon Meidt, Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Astrophysique de Marseille (LAM), Aix Marseille Université (AMU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS), Institut de RadioAstronomie Millimétrique (IRAM), and Centre National de la Recherche Scientifique (CNRS)

Subjects
PROBABILITY-DISTRIBUTION FUNCTIONS, Brightness, Galaxy structure, Scale (ratio), High resolution, Cloud computing, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, STAR-FORMATION EFFICIENCY, 01 natural sciences, Interstellar medium, TO-LIGHT-RATIO, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, Disk galaxies, Astrophysics::Galaxy Astrophysics, Physics, Molecular gas, Spiral galaxy, Spiral galaxies, 010308 nuclear & particles physics, business.industry, SPITZER SURVEY, S(4)G IRAC 3.6, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, SELF-GRAVITATION, Galaxy, Physics and Astronomy, Space and Planetary Science, [SDU]Sciences of the Universe [physics], MOLECULAR CLOUDS, STELLAR MASS DISTRIBUTIONS, VELOCITY DISPERSION, business, SPIRAL GALAXIES
Abstract

In this paper we examine the factors that shape the distribution of molecular gas surface densities on the 150 pc scale across 67 morphologically diverse star-forming galaxies in the PHANGS-ALMA CO (2-1) survey. Dividing each galaxy into radial bins, we measure molecular gas surface density contrasts, defined here as the ratio between a fixed high percentile of the CO distribution and a fixed reference level in each bin. This reference level captures the level of the faint CO floor that extends between bright filamentary features, while the intensity level of the higher percentile probes the structures visually associated with bright, dense ISM features like spiral arms, bars, and filaments. We compare these contrasts to matched percentile-based measurements of the 3.6 $\mu$m emission measured using Spitzer/IRAC imaging, which trace the underlying stellar mass density. We find that the logarithms of CO contrasts on 150 pc scales are 3-4 times larger than, and positively correlated with, the logarithms of 3.6 $\mu$m contrasts probing smooth non-axisymmetric stellar bar and spiral structures. The correlation appears steeper than linear, consistent with the compression of gas as it flows supersonically in response to large-scale stellar structures, even in the presence of weak or flocculent spiral arms. Stellar dynamical features appear to play an important role in setting the cloud-scale gas density in our galaxies, with gas self-gravity perhaps playing a weaker role in setting the 150 pc-scale distribution of gas densities., Comment: Accepted for publication in ApJ, 16 pages, 7 figures

Published
2021
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39. Dense molecular gas properties on 100 pc scales across the disc of NGC 3627

Author

Mattia C. Sormani, Daizhong Liu, Annie Hughes, Andreas Schruba, Christopher M Faesi, M. J. Jimenez-Donaire, Takashi Saito, J. M. D. Kruijssen, Francesco Belfiore, Frank Bigiel, Eric Emsellem, Ismael Pessa, Ralf S. Klessen, Simon C. O. Glover, Jérôme Pety, Ashley T. Barnes, Mélanie Chevance, Sharon Meidt, Eva Schinnerer, Ivana Bešlić, Thomas G. Williams, Kathryn Kreckel, F. Santoro, C. Herrera Contreras, A. Usero, Cosima Eibensteiner, Kathryn Grasha, J. Puschnig, Adam K. Leroy, M. Querejeta, J. S. den Brok, Erik Rosolowsky, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)

Subjects
H-ALPHA, FOS: Physical sciences, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, STAR-FORMATION RATES, BIMA SURVEY, ISM STRUCTURE, 01 natural sciences, ISM: clouds, 0103 physical sciences, LINE SPECTRA, NEARBY GALAXIES, Emission spectrum, 010303 astronomy & astrophysics, molecules [ISM], evolution [galaxies], Astrophysics::Galaxy Astrophysics, Physics, [PHYS]Physics [physics], Spiral galaxy, formation [stars], stars: formation, ISM [galaxies], 010308 nuclear & particles physics, Star formation, Astronomy and Astrophysics, Radius, Astrophysics - Astrophysics of Galaxies, Galaxy, ISM: molecules, Interstellar medium, Barred spiral galaxy, Stars, Physics and Astronomy, 13. Climate action, Space and Planetary Science, galaxies: star formation, Astrophysics of Galaxies (astro-ph.GA), COMPUTER-PROGRAM, MILKY-WAY, Astrophysics::Earth and Planetary Astrophysics, star formation [galaxies], galaxies: evolution, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], clouds [ISM], UNCERTAINTY PRINCIPLE, galaxies: ISM, GALACTIC-CENTER
Abstract

It is still poorly constrained how the densest phase of the interstellar medium varies across galactic environment. A large observing time is required to recover significant emission from dense molecular gas at high spatial resolution, and to cover a large dynamic range of extragalactic disc environments. We present new NOrthern Extended Millimeter Array (NOEMA) observations of a range of high critical density molecular tracers (HCN, HNC, HCO+) and CO isotopologues (13CO, C18O) towards the nearby (11.3 Mpc), strongly barred galaxy NGC 3627. These observations represent the current highest angular resolution (1.85"; 100 pc) map of dense gas tracers across a disc of a nearby spiral galaxy, which we use here to assess the properties of the dense molecular gas, and their variation as a function of galactocentric radius, molecular gas, and star formation. We find that the HCN(1-0)/CO(2-1) integrated intensity ratio does not correlate with the amount of recent star formation. Instead, the HCN(1-0)/CO(2-1) ratio depends on the galactic environment, with differences between the galaxy centre, bar, and bar end regions. The dense gas in the central 600 pc appears to produce stars less efficiently despite containing a higher fraction of dense molecular gas than the bar ends where the star formation is enhanced. In assessing the dynamics of the dense gas, we find the HCN(1-0) and HCO+(1-0) emission lines showing multiple components towards regions in the bar ends that correspond to previously identified features in CO emission. These features are co-spatial with peaks of Halpha emission, which highlights that the complex dynamics of this bar end region could be linked to local enhancements in the star formation., Comment: 25 pages, 12 figures; accepted for publication in MNRAS

Published
2021
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40. PHANGS-ALMA Data Processing and Pipeline

Author

I. Da Chiang, K. Larson, Miguel Querejeta, S. Deger, Patricia Sanchez-Blazquez, Cinthya N. Herrera, Axel García-Rodríguez, Enrico Congiu, Alexander P.S. Hygate, Cosima Eibensteiner, Frank Bigiel, Guillermo A. Blanc, Annie Hughes, Christopher M Faesi, J. Puschnig, Eric W. Koch, Adam K. Leroy, David Will, J. M. Diederik Kruijssen, Ness Mayker, Jordan A. Turner, Daniel A. Dale, David A. Thilker, Leonardo Ubeda, Eva Schinnerer, Amanda A. Kepley, Gagandeep S. Anand, Antonio Usero, Simon C. O. Glover, Brent Groves, Ashley T. Barnes, Hsi-An Pan, Jakob S. den Brok, A. Razza, Daizhong Liu, Sharon Meidt, Kathryn Grasha, Christine D. Wilson, Jérémy Chastenet, Kathryn Kreckel, Jiayi Sun, Ivana Bešlić, Ralf S. Klessen, Jonathan D. Henshaw, Karin Sandstrom, Dyas Utomo, Janice C. Lee, Fabian Scheuermann, Alberto D. Bolatto, Erik Rosolowsky, Rupali Chandar, Angus Mok, Médéric Boquien, Rebecca McElroy, Yixian Cao, Toshiki Saito, K. Sliwa, Eric Emsellem, Maria J. Jimenez Donaire, Francesco Belfiore, F. Santoro, Elizabeth J. Watkins, Thomas G. Williams, Mélanie Chevance, Jaeyeon Kim, Andreas Schruba, Amy Sardone, Jérôme Pety, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)

Subjects
Astrophysics - instrumentation and methods for astrophysics, 1346, 847, 262, 1061, 1861, 573, 1569, Astrophysics - astrophysics of galaxies, Pipeline (computing), FOS: Physical sciences, Millimeter astronomy, 01 natural sciences, Interstellar medium, 0103 physical sciences, KINEMATICS, Instrumentation and Methods for Astrophysics (astro-ph.IM), 010303 astronomy & astrophysics, [PHYS]Physics [physics], Physics, Data processing, 010308 nuclear & particles physics, Star formation, Astronomy, Astronomy and Astrophysics, Galaxies, Astrophysics - Astrophysics of Galaxies, Galaxy, Physics and Astronomy, Astronomy data reduction, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), MOLECULAR GAS PROPERTIES, Radio interferometry, Astrophysics - Instrumentation and Methods for Astrophysics, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], CO line emission
Abstract

We describe the processing of the PHANGS-ALMA survey and present the PHANGS-ALMA pipeline, a public software package that processes calibrated interferometric and total power data into science-ready data products. PHANGS-ALMA is a large, high-resolution survey of CO J=2-1 emission from nearby galaxies. The observations combine ALMA's main 12-m array, the 7-m array, and total power observations and use mosaics of dozens to hundreds of individual pointings. We describe the processing of the u-v data, imaging and deconvolution, linear mosaicking, combining interferometer and total power data, noise estimation, masking, data product creation, and quality assurance. Our pipeline has a general design and can also be applied to VLA and ALMA observations of other spectral lines and continuum emission. We highlight our recipe for deconvolution of complex spectral line observations, which combines multiscale clean, single scale clean, and automatic mask generation in a way that appears robust and effective. We also emphasize our two-track approach to masking and data product creation. We construct one set of "broadly masked" data products, which have high completeness but significant contamination by noise, and another set of "strictly masked" data products, which have high confidence but exclude faint, low signal-to-noise emission. Our quality assurance tests, supported by simulations, demonstrate that 12-m+7-m deconvolved data recover a total flux that is significantly closer to the total power flux than the 7-m deconvolved data alone. In the appendices, we measure the stability of the ALMA total power calibration in PHANGS--ALMA and test the performance of popular short-spacing correction algorithms., Accepted for publication in the Astrophysical Journal Supplement series. 65 pages, 33 figures. Software available at https://github.com/akleroy/phangs_imaging_scripts . For a full resolution version see https://sites.google.com/view/phangs/publications

Published
2021

41. Giant molecular cloud catalogues for PHANGS-ALMA : methods and initial results

Author

Adam K. Leroy, Ralf S. Klessen, Cinthya N. Herrera, Ivana Bešlić, Daizhong Liu, Jiayi Sun, Annie Hughes, Simon C. O. Glover, Jonathan D. Henshaw, Frank Bigiel, Sharon Meidt, M. Querejeta, S. Deger, Jérôme Pety, David A. Thilker, Janice C. Lee, K. Larson, Guillermo A. Blanc, Angus Mok, Eva Schinnerer, Erik Rosolowsky, Andreas Schruba, Toshiki Saito, Daniel A. Dale, A. Usero, J. M. Diederik Kruijssen, Mélanie Chevance, Thomas G. Williams, Christopher M Faesi, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
NGC 6300), GAS PROPERTIES, FOS: Physical sciences, NGC 5643, PHYSICAL-PROPERTIES, Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, NGC 5068, CONVERSION FACTOR, SCALING RELATIONS, ISM: clouds, 01 natural sciences, Virial theorem, STAR-FORMATION, NGC 4826, galaxies: individual (NGC 0628, 0103 physical sciences, individual (NGC 0628 [galaxies], 010303 astronomy & astrophysics, Scaling, NGC 1637, Astrophysics::Galaxy Astrophysics, Line (formation), NGC 2903, Physics, stars: formation, Spiral galaxy, formation [stars], Mass distribution, INTERSTELLAR-MEDIUM, 010308 nuclear & particles physics, Molecular cloud, SPITZER SURVEY, MASS FUNCTIONS, Astronomy and Astrophysics, Radius, Astrophysics - Astrophysics of Galaxies, Galaxy, NGC 3627, CO SURVEY, Physics and Astronomy, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), NGC 3521, NGC 3621, clouds [ISM], STELLAR STRUCTURE
Abstract

We present improved methods for segmenting CO emission from galaxies into individual molecular clouds, providing an update to the CPROPS algorithms presented by Rosolowsky & Leroy (2006; arXiv:astro-ph/0601706 ). The new code enables both homogenization of the noise and spatial resolution among data, which allows for rigorous comparative analysis. The code also models the completeness of the data via false source injection and includes an updated segmentation approach to better deal with blended emission. These improved algorithms are implemented in a publicly available python package, PYCPROPS. We apply these methods to ten of the nearest galaxies in the PHANGS-ALMA survey, cataloguing CO emission at a common 90 pc resolution and a matched noise level. We measure the properties of 4986 individual clouds identified in these targets. We investigate the scaling relations among cloud properties and the cloud mass distributions in each galaxy. The physical properties of clouds vary among galaxies, both as a function of galactocentric radius and as a function of dynamical environment. Overall, the clouds in our target galaxies are well-described by approximate energy equipartition, although clouds in stellar bars and galaxy centres show elevated line widths and virial parameters. The mass distribution of clouds in spiral arms has a typical mass scale that is 2.5x larger than interarm clouds and spiral arms clouds show slightly lower median virial parameters compared to interarm clouds (1.2 versus 1.4)., Accepted to MNRAS. Catalogues, code, and atlas available at http://phangs.org/data

Published
2021

42. New Constraints on the $^{12}$CO(2-1)/(1-0) Line Ratio Across Nearby Disc Galaxies

Author

Christopher M Faesi, Sophia Stuber, M. J. Jimenez-Donaire, D. Chatzigiannakis, Erik Rosolowsky, Takashi Saito, Frank Bigiel, J. S. den Brok, Adam K. Leroy, L. Neumann, Daizhong Liu, Annie Hughes, Kathryn Grasha, Eva Schinnerer, J. Puschnig, Ashley T. Barnes, J. M. D. Kruijssen, A. Usero, M. Querejeta, Jérôme Pety, Andreas Schruba, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)

Subjects
Physics, radio lines: galaxies, [PHYS]Physics [physics], Spiral galaxy, 010308 nuclear & particles physics, Star formation, Order (ring theory), FOS: Physical sciences, Astronomy and Astrophysics, Astrophysics, Radius, Disc galaxy, Astrophysics - Astrophysics of Galaxies, 01 natural sciences, Galaxy, Space and Planetary Science, Brightness temperature, SM: molecules, Astrophysics of Galaxies (astro-ph.GA), 0103 physical sciences, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], 010303 astronomy & astrophysics, Intensity (heat transfer), galaxies: ISM
Abstract

Both the CO(2-1) and CO(1-0) lines are used to trace the mass of molecular gas in galaxies. Translating the molecular gas mass estimates between studies using different lines requires a good understanding of the behaviour of the CO(2-1)-to-CO(1-0) ratio, $R_{21}$. We compare new, high quality CO(1-0) data from the IRAM 30-m EMPIRE survey to the latest available CO(2-1) maps from HERACLES, PHANGS-ALMA, and a new IRAM 30-m M51 Large Program. This allows us to measure $R_{21}$ across the full star-forming disc of nine nearby, massive, star-forming spiral galaxies at 27" (${\sim} 1{-}2$ kpc) resolution. We find an average $R_{21} = 0.64\pm0.09$ when we take the luminosity-weighted mean of all individual galaxies. This result is consistent with the mean ratio for disc galaxies that we derive from single-pointing measurements in the literature, $R_{\rm 21, lit}~=~0.59^{+0.18}_{-0.09}$. The ratio shows weak radial variations compared to the point-to-point scatter in the data. In six out of nine targets the central enhancement in $R_{21}$ with respect to the galaxy-wide mean is of order $\sim 10{-}20\%$. We estimate an azimuthal scatter of $\sim$20% in $R_{21}$ at fixed galactocentric radius but this measurement is limited by our comparatively coarse resolution of 1.5 kpc. We find mild correlations between $R_{21}$ and CO brightness temperature, IR intensity, 70-to-160$ \mu$m ratio, and IR-to-CO ratio. All correlations indicate that $R_{21}$ increases with gas surface density, star formation rate surface density, and the interstellar radiation field., Comment: 27 pages, 18 figures, 5 tables; accepted for publication in MNRAS

Published
2021
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43. ALMA resolves giant molecular clouds in a tidal dwarf galaxy

Author

Cinthya N. Herrera, Dario Colombo, Frank Bigiel, Annie Hughes, M. Querejeta, Andrew Rigby, Santiago García-Burillo, Eva Schinnerer, Sharon Meidt, Toby J. T. Moore, C. G. Mundell, Ute Lisenfeld, Federico Lelli, J. M. D. Kruijssen, Jérôme Pety, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY)

Subjects
II, PROPAGATING STAR-FORMATION, Milky Way, FOS: Physical sciences, PHYSICAL-PROPERTIES, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, interactions [Galaxies], 01 natural sciences, star formation [Galaxies], Virial theorem, 0103 physical sciences, ISM [Galaxies], galaxies: interactions, SCHMIDT, 010303 astronomy & astrophysics, galaxies: kinematics and dynamics, Astrophysics::Galaxy Astrophysics, Dwarf galaxy, [PHYS]Physics [physics], Physics, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], INTERSTELLAR-MEDIUM, 010308 nuclear & particles physics, Star formation, kinematics and dynamics [Galaxies], Molecular cloud, Velocity dispersion, Astronomy and Astrophysics, galaxies: dwarf, Astrophysics - Astrophysics of Galaxies, Galaxy, dwarf [Galaxies], Stars, Physics and Astronomy, GAS, 13. Climate action, Space and Planetary Science, galaxies: star formation, Astrophysics of Galaxies (astro-ph.GA), LUMINOSITY, LARGE-MAGELLANIC-CLOUD, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], CLUSTERS, galaxies: ISM, UNCERTAINTY PRINCIPLE
Abstract

Tidal dwarf galaxies (TDGs) are gravitationally bound condensations of gas and stars that formed during galaxy interactions. Here we present multi-configuration ALMA observations of J1023+1952, a TDG in the interacting system Arp 94, where we resolved CO(2–1) emission down to giant molecular clouds (GMCs) at 0.6400 ∼ 45 pc resolution. We find a remarkably high fraction of extended molecular emission (∼80−90%), which is filtered out by the interferometer and likely traces diffuse gas. We detect 111 GMCs that give a similar mass spectrum as those in the Milky Way and other nearby galaxies (a truncated power law with a slope of −1.76±0.13). We also study Larson’s laws over the available dynamic range of GMC properties (∼2 dex in mass and ∼1 dex in size): GMCs follow the sizemass relation of the Milky Way, but their velocity dispersion is higher such that the size-linewidth and virial relations appear superlinear, deviating from the canonical values. The global molecular-to-atomic gas ratio is very high (∼1) while the CO(2–1)/CO(1–0) ratio is quite low (∼0.5), and both quantities vary from north to south. Star formation predominantly takes place in the south of the TDG, where we observe projected offsets between GMCs and young stellar clusters ranging from ∼50 pc to ∼200 pc; the largest offsets correspond to the oldest knots, as seen in other galaxies. In the quiescent north, we find more molecular clouds and a higher molecular-to-atomic gas ratio (∼1.5); atomic and diffuse molecular gas also have a higher velocity dispersion there. Overall, the organisation of the molecular interstellar medium in this TDG is quite different from other types of galaxies on large scales, but the properties of GMCs seem fairly similar, pointing to near universality of the star-formation process on small scales., Instituto de Salud Carlos III Spanish Government PID2019-106027GA-C44, Spanish Ministerio de Economia y Competitividad AYA2017-84897-P, European Commission, Junta de Andalucia European Commission FQM108, European Research Council (ERC) 726384/EMPIRE 714907, MCIU/AEI/FEDER,UE PGC2018-094671-B-I00 AYA2016-76682-C3-2-P, German Research Foundation (DFG) KR4801/1-1, German Research Foundation (DFG) KR4801/2-1

Published
2021

44. Tracers of the ionization fraction in dense and translucent gas: I. Automated exploitation of massive astrochemical model grids

Author

Emeric Bron, Antoine Roueff, Nicolas Peretto, Franck Le Petit, Albrecht Sievers, Viviana V. Guzmán, François Levrier, David Languignon, Victor de Souza Magalhaes, Javier R. Goicoechea, E. Roueff, Annie Hughes, Pierre Chainais, Mathilde Gaudel, Karin I. Öberg, Sébastien Bardeau, Maryvonne Gerin, Jacques Le Bourlot, Jouni Kainulainen, Harvey S. Liszt, Pierre Gratier, Jan H. Orkisz, Maxime Vono, Jérôme Pety, Centre National de la Recherche Scientifique (France), Centre National D'Etudes Spatiales (France), Ministerio de Ciencia, Innovación y Universidades (España), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), FORMATION STELLAIRE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Pontificia Universidad Católica de Chile (UC), Onsala Space Observatory (OSO), Chalmers University of Technology [Göteborg], Signal et Communications (IRIT-SC), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées, Centre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 (CRIStAL), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Instituto de Física Fundamental [Madrid] (IFF), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Astrophysique, Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), National Radio Astronomy Observatory [Charlottesville] (NRAO), National Radio Astronomy Observatory (NRAO), Harvard-Smithsonian Center for Astrophysics (CfA), Smithsonian Institution-Harvard University [Cambridge], School of Physics and Astronomy [Cardiff], Cardiff University, Institut FRESNEL (FRESNEL), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), PhyTI (PhyTI), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Programme National 'Physique et Chimie du Milieu Interstel-laire' (PCMI) of CNRS/INSU with INC/INP, co-funded by CEA and CNES, MIT Iinterdisciplinary programs, Paris Observatory through the AFAstrochimie program, Spanish MICI - grant AYA2017-85111-P, Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Toulouse Mind & Brain Institut (TMBI), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire de physique de l'ENS - ENS Paris (LPENS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Harvard University-Smithsonian Institution, Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), and Harvard University [Cambridge]-Smithsonian Institution

Subjects
Astrochemistry, 010504 meteorology & atmospheric sciences, FOS: Physical sciences, Flux, Fraction (chemistry), Context (language use), Astrophysics, ISM: clouds, 7. Clean energy, 01 natural sciences, Ionization, TRACER, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Methods: statistical, 0105 earth and related environmental sciences, Physics, Methods: numerical, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, ISM: lines and bands, Interstellar medium, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA)
Abstract

28 pags., 15 figs., 12 tabs., Context. The ionization fraction in the neutral interstellar medium (ISM) plays a key role in the physics and chemistry of the ISM, from controlling the coupling of the gas to the magnetic field to allowing fast ion-neutral reactions that drive interstellar chemistry. Most estimations of the ionization fraction have relied on deuterated species such as DCO+, whose detection is limited to dense cores representing an extremely small fraction of the volume of the giant molecular clouds that they are part of. As large field-of-view hyperspectral maps become available, new tracers may be found. The growth of observational datasets is paralleled by the growth of massive modeling datasets and new methods need to be devised to exploit the wealth of information they contain. Aims. We search for the best observable tracers of the ionization fraction based on a grid of astrochemical models, with the broader aim of finding a general automated method applicable to searching for tracers of any unobservable quantity based on grids of models. Methods. We built grids of models that randomly sample a large range of physical conditions (unobservable quantities such as gas density, temperature, elemental abundances, etc.) and computed the corresponding observables (line intensities, column densities) and the ionization fraction. We estimated the predictive power of each potential tracer by training a random forest model to predict the ionization fraction from that tracer, based on these model grids. Results. In both translucent medium and cold dense medium conditions, we found several observable tracers with very good predictive power for the ionization fraction. Many tracers in cold dense medium conditions are found to be better and more widely applicable than the traditional DCO+/HCO+ ratio. We also provide simpler analytical fits for estimating the ionization fraction from the best tracers, and for estimating the associated uncertainties. We discuss the limitations of the present study and select a few recommended tracers in both types of conditions. Conclusions. The method presented here is very general and can be applied to the measurement of any other quantity of interest (cosmic ray flux, elemental abundances, etc.) from any type of model (PDR models, time-dependent chemical models, etc.)., This work was supported in part by the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP, co-funded by CEA and CNES. This project has received financial support from the CNRS through the MITI interdisciplinary programs. The authors also acknowledge funding by Paris Observatory through the AF Astrochimie program. J.R.G. thanks Spanish MICI for funding support under grant AYA2017-85111-P.

Published
2020

45. C18O, 13CO, and 12CO abundances and excitation temperatures in the Orion B molecular cloud

Author

Emeric Bron, Marc-Antoine Miville-Deschenes, Pierre Gratier, Jérôme Pety, Jan H. Orkisz, Nicolas Peretto, Maxime Vono, Evelyne Roueff, Antoine Roueff, Albrecht Sievers, Javier R. Goicoechea, Jacques Le Bourlot, Victor de Souza Magalhaes, Jouni Kainulainen, Annie Hughes, Franck Petit, Viviana V. Guzmán, Maryvonne Gerin, Harvey S. Liszt, François Levrier, Antoine Marchal, Jocelyn Chanussot, David Languignon, Sébastien Bardeau, M. Gaudel, Pierre Chainais, Centre National de la Recherche Scientifique (France), Max Planck Society, Instituto Geográfico Nacional (España), European Space Agency, Centre National D'Etudes Spatiales (France), Agencia Estatal de Investigación (España), PhyTI (PhyTI), Institut FRESNEL (FRESNEL), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), FORMATION STELLAIRE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Astrophysique, Laboratoire de physique de l'ENS - ENS Paris (LPENS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Instituto de Física Fundamental [Madrid] (IFF), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Onsala Space Observatory (OSO), Chalmers University of Technology [Göteborg], Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Signal et Communications (IRIT-SC), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Toulouse Mind & Brain Institut (TMBI), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), GIPSA - Signal Images Physique (GIPSA-SIGMAPHY), GIPSA Pôle Sciences des Données (GIPSA-PSD), Grenoble Images Parole Signal Automatique (GIPSA-lab), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Grenoble Alpes (UGA), Centre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 (CRIStAL), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Pontificia Universidad Católica de Chile (UC), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Laboratoire Univers et Théories (LUTH (UMR_8102)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), National Radio Astronomy Observatory [Charlottesville] (NRAO), National Radio Astronomy Observatory (NRAO), Canadian Institute for Theoretical Astrophysics (CITA), Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Cardiff University, ANR-19-P3IA-0003,MIAI,MIAI @ Grenoble Alpes(2019), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Onsala Space Observatory, Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Ecole Centrale de Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université de Lille-Ecole Centrale de Lille-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Observatoire de Paris, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)

Subjects
statistical [Methods], Astrophysics, 7. Clean energy, 01 natural sciences, Molecular physics, ISM: clouds, Spectral line, Methods: data analysis, 0103 physical sciences, Radiative transfer, Astrophysics::Solar and Stellar Astrophysics, Isotopologue, [INFO]Computer Science [cs], data analysis [Methods], 010303 astronomy & astrophysics, molecules [ISM], Astrophysics::Galaxy Astrophysics, Methods: statistical, Line (formation), Physics, 010308 nuclear & particles physics, Molecular cloud, Estimator, Velocity dispersion, Astronomy and Astrophysics, ISM: molecules, 3. Good health, 13. Climate action, Space and Planetary Science, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], clouds [ISM], Excitation
Abstract

27 pags., 23 figs., 3 tabs., Context. CO isotopologue transitions are routinely observed in molecular clouds for the purpose of probing the column density of the gas and the elemental ratios of carbon and oxygen, in addition to tracing the kinematics of the environment. Aims. Our study is aimed at estimating the abundances, excitation temperatures, velocity field, and velocity dispersions of the three main CO isotopologues towards a subset of the Orion B molecular cloud, which includes IC 434, NGC 2023, and the Horsehead pillar. Methods. We used the Cramer Rao bound (CRB) technique to analyze and estimate the precision of the physical parameters in the framework of local-thermodynamic-equilibrium (LTE) excitation and radiative transfer with added white Gaussian noise. We propose a maximum likelihood estimator to infer the physical conditions from the 1-0 and 2-1 transitions of CO isotopologues. Simulations show that this estimator is unbiased and proves efficient for a common range of excitation temperatures and column densities (Tex > 6 K, N > 1014-1015 cm-2). Results. Contrary to general assumptions, the various CO isotopologues have distinct excitation temperatures and the line intensity ratios between different isotopologues do not accurately reflect the column density ratios. We find mean fractional abundances that are consistent with previous determinations towards other molecular clouds. However, significant local deviations are inferred, not only in regions exposed to the UV radiation field, but also in shielded regions. These deviations result from the competition between selective photodissociation, chemical fractionation, and depletion on grain surfaces. We observe that the velocity dispersion of the C18O emission is 10% smaller than that of 13CO. The substantial gain resulting from the simultaneous analysis of two different rotational transitions of the same species is rigorously quantified. Conclusions. The CRB technique is a promising avenue for analyzing the estimation of physical parameters from the fit of spectral lines. Future works will generalize its application to non-LTE excitation and radiative transfer methods., This work is based on observations carried out under project numbers 019-13, 022-14, 145-14, 122-15, 018-16, and finally the large program number 124-16 with the IRAM 30m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). This research also used data from the Herschel Gould Belt survey (HGBS) project (http:// gouldbelt-herschel.cea.fr). The HGBS is a Herschel Key Programme jointly carried out by SPIRE Specialist Astronomy Group 3 (SAG 3), scientists of several institutes in the PACS Consortium (CEA Saclay, INAF-IFSI Rome and INAF-Arcetri, KU Leuven, MPIA Heidelberg), and scientists of the Herschel Science Center (HSC). We thank CIAS for their hospitality during the many workshops devoted to the ORION-B project. This project has received financial support from the CNRS through the MITI interdisciplinary programs. This work was supported in part by the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP, co-funded by CEA and CNES. JRG thanks Spanish MICI for funding support under grant AYA2017- 85111-P. Finally, we thank the anonymous referee for helpful comments on the manuscript.

Published
2020

46. Quantitative inference of the H2 column densities from 3 mm molecular emission: A case study towards Orion B

Author

Javier R. Goicoechea, M. Gaudel, Victor de Souza Magalhaes, François Levrier, David Languignon, Maryvonne Gerin, Franck Petit, Viviana V. Guzmán, Pierre Chainais, Annie Hughes, Albrecht Sievers, Harvey S. Liszt, Pierre Gratier, Jan H. Orkisz, Maxime Vono, Sébastien Bardeau, Nicolas Peretto, Jocelyn Chanussot, Jérôme Pety, Jacques Le Bourlot, Evelyne Roueff, Antoine Roueff, Jouni Kainulainen, Emeric Bron, FORMATION STELLAIRE 2020, Laboratoire d'Astrophysique de Bordeaux [Pessac] (LAB), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Institut FRESNEL (FRESNEL), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), PhyTI (PhyTI), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Onsala Space Observatory, Chalmers University of Technology [Göteborg], Signal et Communications (IRIT-SC), Institut de recherche en informatique de Toulouse (IRIT), Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1)-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, GIPSA - Signal Images Physique (GIPSA-SIGMAPHY), GIPSA Pôle Sciences des Données (GIPSA-PSD), Grenoble Images Parole Signal Automatique (GIPSA-lab), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Grenoble Images Parole Signal Automatique (GIPSA-lab), Université Grenoble Alpes (UGA), Centre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 (CRIStAL), Université de Lille-Ecole Centrale de Lille-Centre National de la Recherche Scientifique (CNRS), Instituto de Física Fundamental [Madrid] (IFF), Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), Pontificia Universidad Católica de Chile (UC), Institut de recherche en astrophysique et planétologie (IRAP), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS), Laboratoire de physique de l'ENS - ENS Paris (LPENS (UMR_8023)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), National Radio Astronomy Observatory [Charlottesville] (NRAO), National Radio Astronomy Observatory (NRAO), School of Physics and Astronomy [Cardiff], Cardiff University, CNRS through the MITI interdisciplinary programs, Spanish MICI under grant AYA2017-85111-P, ORION-B project, Programme National 'Physique et Chimie du Milieu Interstellaire' (PCMI) - CNRS/INSU - INC/INP, co-funded by CEA and CNES, IRAM supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain), Data from the CEA Herschel Gould Belt survey (HGBS) project (http://gouldbelt-herschel.cea.fr), HGBS : Herschel Key Programme, SPIRE Specialist Astronomy Group 3 (SAG 3), PACS Consortium (CEA Saclay, INAF-IFSI Rome INAF-Arcetri,KU Leuven, MPIA Heidelberg), Herschel Science Center (HSC), Université de Bordeaux (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres (LERMA), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-CY Cergy Paris Université (CY), Chalmers University of Technology [Gothenburg, Sweden], Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Toulouse Mind & Brain Institut (TMBI), Université Toulouse - Jean Jaurès (UT2J), Université de Toulouse (UT)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université Toulouse Capitole (UT Capitole), Université de Toulouse (UT), Apprentissage de modèles à partir de données massives (Thoth), Inria Grenoble - Rhône-Alpes, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Laboratoire Jean Kuntzmann (LJK), Institut National de Recherche en Informatique et en Automatique (Inria)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Centrale Lille-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Astrophysique, Laboratoire de physique de l'ENS - ENS Paris (LPENS), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité)-Département de Physique de l'ENS-PSL, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), ANR-19-P3IA-0003,MIAI,MIAI @ Grenoble Alpes(2019), Laboratoire Univers et Théories (LUTH (UMR_8102)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Centre National de la Recherche Scientifique (CNRS)-École Centrale de Marseille (ECM)-Aix Marseille Université (AMU), Université Toulouse 1 Capitole (UT1), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse - Jean Jaurès (UT2J)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse 1 Capitole (UT1), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Diderot - Paris 7 (UPD7), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Centre National de la Recherche Scientifique (France), Max Planck Society, Instituto Geográfico Nacional (España), Université Paris-Saclay, Istituto Nazionale di Astrofisica, and Ministerio de Ciencia, Innovación y Universidades (España)

Subjects
statistical [Methods], Field (physics), Astro-ph.IM, FOS: Physical sciences, Context (language use), Astrophysics, 7. Clean energy, 01 natural sciences, Column (database), ISM: clouds, 0103 physical sciences, Angular resolution, [INFO]Computer Science [cs], 010303 astronomy & astrophysics, Stellar density, Instrumentation and Methods for Astrophysics (astro-ph.IM), molecules [ISM], Astrophysics::Galaxy Astrophysics, Line (formation), Physics, methods: statistical, 010308 nuclear & particles physics, Molecular cloud, Astronomy and Astrophysics, Astrophysics - Astrophysics of Galaxies, ISM: molecules, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Astrophysics of Galaxies (astro-ph.GA), Millimeter, Astrophysics - Instrumentation and Methods for Astrophysics, Astro-ph.GA, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], clouds [ISM]
Abstract

27 pags., 19 figs., 4 tabs., Molecular hydrogen being unobservable in cold molecular clouds, the column density measurements of molecular gas currently rely either on dust emission observation in the far-IR or on star counting. (Sub-)millimeter observations of numerous trace molecules are effective from ground based telescopes, but the relationships between the emission of one molecular line and the H2 column density (NH2) is non-linear and sensitive to excitation conditions, optical depths, abundance variations due to the underlying physico-chemistry. We aim to use multi-molecule line emission to infer NH2 from radio observations. We propose a data-driven approach to determine NH2 from radio molecular line observations. We use supervised machine learning methods (Random Forests) on wide-field hyperspectral IRAM-30m observations of the Orion B molecular cloud to train a predictor of NH2, using a limited set of molecular lines as input, and the Herschel-based dust-derived NH2 as ground truth output. For conditions similar to the Orion B molecular cloud, we obtain predictions of NH2 within a typical factor of 1.2 from the Herschel-based estimates. An analysis of the contributions of the different lines to the predictions show that the most important lines are $^{13}$CO(1-0), $^{12}$CO(1-0), C$^{18}$O(1-0), and HCO$^+$(1-0). A detailed analysis distinguishing between diffuse, translucent, filamentary, and dense core conditions show that the importance of these four lines depends on the regime, and that it is recommended to add the N$_2$H$^+$(1-0) and CH$_3$OH(20-10) lines for the prediction of NH2 in dense core conditions. This article opens a promising avenue to directly infer important physical parameters from the molecular line emission in the millimeter domain. The next step will be to try to infer several parameters simultaneously (e.g., NH2 and far-UV illumination field) to further test the method. [Abridged], This work is based on observations carried out under project numbers 019-13, 022-14, 145-14, 122-15, 018-16, and finally the large program number 124-16 with the IRAM 30 m telescope. IRAM is supported by INSU/CNRS (France), MPG (Germany) and IGN (Spain). This research also used data from the Herschel Gould Belt survey (HGBS) project (http:// gouldbelt-herschel.cea.fr). The HGBS is a Herschel Key Programme jointly carried out by SPIRE Specialist Astronomy Group 3 (SAG 3), scientists of several institutes in the PACS Consortium (CEA Saclay, INAF-IFSI Rome and INAF-Arcetri, KU Leuven, MPIA Heidelberg), and scientists of the Herschel Science Center (HSC). We thank CIAS for their hospitality during the many workshops devoted to the ORION-B project. This work was supported in part by the Programme National “Physique et Chimie du Milieu Interstellaire” (PCMI) of CNRS/INSU with INC/INP, co-funded by CEA and CNES. This project has received financial support from the CNRS through the MITI interdisciplinary programs. J.R.G. thanks Spanish MICI for funding support under grant AYA2017-85111-P.

Published
2020

47. Improving equality of opportunity in Higher Education through the adoption of an inclusive curriculum framework

Author

Fiona Ross, Annie Hughes, Elizabeth Morrow, John Tatam, and Nona McDuff

Subjects
education, Higher education, Curriculum framework, business.industry, Pedagogy, Sociology, business
Abstract

Within higher education, inclusion of students from diverse nations, socioeconomic, ethnic and cultural backgrounds is vital for social mobility and economic development. Despite some international successes in widening participation, inequalities in student experiences and differentials in degree attainment for traditionally underrepresented groups, remain a major challenge. Institutional approaches to inclusion that value diversity as an inherent source of learning are underdeveloped. This paper adds theoretical insights and evidence to the debate on inclusive curricula by showing the benefits of institutional change through a strategic approach and innovation in practice (case studies). We argue that the Inclusive Curriculum Framework (ICF), underpinned by core principles of inclusion, can enhance equality of opportunity all the way through the student journey. The paper innovatively and rigorously bridges theory and practice in relation to inclusivity in learning and teaching and student success. It describes early and positive impact at Kingston University, adoption and spread in other institutions in England and potential international relevance.

Published
2020

48. PHANGS CO kinematics: disk orientations and rotation curves at 150 pc resolution

Author

Dario Colombo, Joseph Nofech, Sharon Meidt, Daizhong Liu, J. M. Diederik Kruijssen, Frank Bigiel, Erik Rosolowsky, Annie Hughes, Adam K. Leroy, Christopher Faesi, Brent Groves, Eva Schinnerer, Simon C. O. Glover, Jiayi Sun, Philipp Lang, Toshiki Saito, Mélanie Chevance, Jonathan D. Henshaw, Antonio Usero, Cinthya N. Herrera, Ismael Pessa, Eric Emsellem, Johannes Puschnig, Jérôme Pety, Andreas Schruba, Miguel Querejeta, and Guillermo A. Blanc

Subjects
010504 meteorology & atmospheric sciences, Library science, FOS: Physical sciences, Astrophysics::Cosmology and Extragalactic Astrophysics, 01 natural sciences, Atomic energy commission, MASS MODELS, German, Interstellar medium, Molecular clouds, 0103 physical sciences, DARK-MATTER, media_common.cataloged_instance, European union, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, media_common, Physics, NUCLEI, GALAXIES NUGA, European research, CLOUDS, Astronomy and Astrophysics, NONCIRCULAR MOTIONS, Astrophysics - Astrophysics of Galaxies, MOLECULAR GAS, EVOLUTION, language.human_language, Galaxy dynamics, Physics and Astronomy, 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), BLACK-HOLE, language, SPIRALS
Abstract

We present kinematic orientations and high resolution (150 pc) rotation curves for 67 main sequence star-forming galaxies surveyed in CO (2-1) emission by PHANGS-ALMA. Our measurements are based on the application of a new fitting method tailored to CO velocity fields. Our approach identifies an optimal global orientation as a way to reduce the impact of non-axisymmetric (bar and spiral) features and the uneven spatial sampling characteristic of CO emission in the inner regions of nearby galaxies. The method performs especially well when applied to the large number of independent lines-of-sight contained in the PHANGS CO velocity fields mapped at 1'' resolution. The high resolution rotation curves fitted to these data are sensitive probes of mass distribution in the inner regions of these galaxies. We use the inner slope as well as the amplitude of our fitted rotation curves to demonstrate that CO is a reliable global dynamical mass tracer. From the consistency between photometric orientations from the literature and kinematic orientations determined with our method, we infer that the shapes of stellar disks in the mass range of log($\rm M_{\star}(M_{\odot})$)=9.0-10.9 probed by our sample are very close to circular and have uniform thickness., 19 figures, 36 pages, accepted for publication in ApJ. Table of PHANGS rotation curves available from http://phangs.org/data

Published
2020

49. Dynamical Equilibrium in the Molecular ISM in 28 Nearby Star-Forming Galaxies

Author

Daniel A. Dale, Kathryn Grasha, Sharon Meidt, Jiayi Sun, Eve C. Ostriker, Alberto D. Bolatto, I-Da Chiang, Karin Sandstrom, Janice C. Lee, Eric Emsellem, Toshiki Saito, Jonathan D. Henshaw, Dyas Utomo, Cinthya N. Herrera, Antonio Usero, Erik Rosolowsky, Simon C. O. Glover, Frank Bigiel, Jérôme Pety, Annie Hughes, Andreas Schruba, María J. Jiménez-Donaire, Christopher Faesi, Miguel Querejeta, Guillermo A. Blanc, Mélanie Chevance, J. M. Diederik Kruijssen, Adam K. Leroy, Eva Schinnerer, Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Centre de Recherche Astrophysique de Lyon (CRAL), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010504 meteorology & atmospheric sciences, Interstellar dynamics, Funding grant, FOS: Physical sciences, Library science, Astrophysics::Cosmology and Extragalactic Astrophysics, PRESSURE, MASS, 01 natural sciences, MAGNETIC-FIELDS, Atomic energy commission, German, 3-DIMENSIONAL DISTRIBUTION, 0103 physical sciences, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, 0105 earth and related environmental sciences, Physics, INTERSTELLAR-MEDIUM, European research, Star formation, CLOUDS, GAS CONTENT, Astronomy and Astrophysics, Interstellar molecules, Astrophysics - Astrophysics of Galaxies, language.human_language, Physics and Astronomy, [SDU]Sciences of the Universe [physics], 13. Climate action, Space and Planetary Science, Astrophysics of Galaxies (astro-ph.GA), SUPERNOVA FEEDBACK, language, MILKY-WAY, TURBULENCE
Abstract

We compare the observed turbulent pressure in molecular gas, $P_\mathrm{turb}$, to the required pressure for the interstellar gas to stay in equilibrium in the gravitational potential of a galaxy, $P_\mathrm{DE}$. To do this, we combine arcsecond resolution CO data from PHANGS-ALMA with multi-wavelength data that traces the atomic gas, stellar structure, and star formation rate (SFR) for 28 nearby star-forming galaxies. We find that $P_\mathrm{turb}$ correlates with, but almost always exceeds the estimated $P_\mathrm{DE}$ on kiloparsec scales. This indicates that the molecular gas is over-pressurized relative to the large-scale environment. We show that this over-pressurization can be explained by the clumpy nature of molecular gas; a revised estimate of $P_\mathrm{DE}$ on cloud scales, which accounts for molecular gas self-gravity, external gravity, and ambient pressure, agrees well with the observed $P_\mathrm{turb}$ in galaxy disks. We also find that molecular gas with cloud-scale ${P_\mathrm{turb}}\approx{P_\mathrm{DE}}\gtrsim{10^5\,k_\mathrm{B}\,\mathrm{K\,cm^{-3}}}$ in our sample is more likely to be self-gravitating, whereas gas at lower pressure appears more influenced by ambient pressure and/or external gravity. Furthermore, we show that the ratio between $P_\mathrm{turb}$ and the observed SFR surface density, $\Sigma_\mathrm{SFR}$, is compatible with stellar feedback-driven momentum injection in most cases, while a subset of the regions may show evidence of turbulence driven by additional sources. The correlation between $\Sigma_\mathrm{SFR}$ and kpc-scale $P_\mathrm{DE}$ in galaxy disks is consistent with the expectation from self-regulated star formation models. Finally, we confirm the empirical correlation between molecular-to-atomic gas ratio and kpc-scale $P_\mathrm{DE}$ reported in previous works., Comment: 28 pages + 3 appendices, ApJ in press. See https://www.youtube.com/watch?v=qxkd-RXB0Ek for a short video describing the main results. Data tables available at https://www.canfar.net/storage/list/phangs/RELEASES/Sun_etal_2020 prior to publication

Published
2020

50. The headlight cloud in NGC 628 : an extreme giant molecular cloud in a typical galaxy disk

Author

Alexander P. S. Hygate, Cinthya N. Herrera, Dyas Utomo, Mélanie Chevance, Kathryn Kreckel, Antonio Usero, Jiayi Sun, Ismael Pessa, Daniel A. Dale, Simon C. O. Glover, Andreas Schruba, Sharon E. Meidt, Jérôme Pety, Kathryn Grasha, Diane Cormier, Adam K. Leroy, Toshiki Saito, Frank Bigiel, Annie Hughes, Miguel Querejeta, Eva Schinnerer, Philipp Lang, Guillermo A. Blanc, Erik Rosolowsky, J. M. Diederik Kruijssen, Christopher Faesi, María J. Jiménez-Donaire, Kazimierz Sliwa, Institut de RadioAstronomie Millimétrique (IRAM), Centre National de la Recherche Scientifique (CNRS), Laboratoire d'Etude du Rayonnement et de la Matière en Astrophysique (LERMA (UMR_8112)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Max-Planck-Institut für Astronomie (MPIA), Max-Planck-Gesellschaft, Sterrenkundig Observatorium, Universiteit Gent = Ghent University (UGENT), European Southern Observatory (ESO), Observatorio Astronomico Nacional, Madrid, Harvard-Smithsonian Center for Astrophysics (CfA), Harvard University-Smithsonian Institution, Carnegie Observatories, Carnegie Institution for Science, Astrophysique Interprétation Modélisation (AIM (UMR7158 / UMR_E_9005 / UM_112)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Universidad de Chile = University of Chile [Santiago] (UCHILE), Argelander-Institut für Astronomie (AlfA), Rheinische Friedrich-Wilhelms-Universität Bonn, Zentrum für Astronomie der Universität Heidelberg (ZAH), Universität Heidelberg [Heidelberg] = Heidelberg University, University of Wyoming (UW), Australian National University (ANU), Ohio State University [Columbus] (OSU), University of Alberta, Max-Planck-Institut für Extraterrestrische Physik (MPE), Programme National 'Physique et Chimie du Milieu Interstellaire' (PCMI) of CNRS/INSU with INC/INP co-funded by CEA and CNES., Programme National Cosmology and Galaxies (PNCG) of CNRS/INSU with INP and IN2P3, co-funded by CEA and CNES., European Union’s Horizon 2020 research and innovation programme (grant agreement No726384)., European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme via the ERC Starting Grant MUSTANG (grant agreement number 714907)., Sorbonne Université (SU)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Cergy Pontoise (UCP), Université Paris-Seine-Université Paris-Seine-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Universiteit Gent, Harvard University [Cambridge]-Smithsonian Institution, Carnegie Institution for Science [Washington], Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), Universidad de Chile, Universität Heidelberg [Heidelberg], PSL Research University (PSL)-PSL Research University (PSL)-Université de Cergy Pontoise (UCP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), and The Observatories of the Carnegie Institution for Science

Subjects
HII regions, Stellar population, FOS: Physical sciences, Context (language use), Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics, I, ISM: clouds, 01 natural sciences, Galaxy: disk, STAR-FORMATION, 0103 physical sciences, NEARBY GALAXIES, Disc, 010303 astronomy & astrophysics, Astrophysics::Galaxy Astrophysics, Physics, SPIRAL STRUCTURE, stars: formation, Spiral galaxy, formation [stars], 010308 nuclear & particles physics, Star formation, Molecular cloud, Astronomy and Astrophysics, kinematics and dynamics [Galaxy], Astrophysics - Astrophysics of Galaxies, Galaxy, CO, Stars, STELLAR CLUSTERS, Physics and Astronomy, 13. Climate action, Space and Planetary Science, GAS, Astrophysics of Galaxies (astro-ph.GA), MILKY-WAY, PATTERN SPEEDS, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Galaxy: kinematics and dynamics, clouds [ISM], disk [Galaxy], UNCERTAINTY PRINCIPLE
Abstract

Cloud-scale surveys of molecular gas reveal the link between molecular clouds properties and star formation (SF) across a range of galactic environments. Cloud populations in galaxy disks are considered to be representative of the `normal' SF. At high resolution, however, clouds with exceptional gas properties and SF activity may also be observed in normal disk environments. In this paper, we study the brightest cloud traced in CO emission in the disk of NGC628. The cloud is spatially coincident with an extremely bright HII region. We characterize its molecular gas properties and investigate how feedback and large-scale processes influence the properties of the molecular gas. High resolution CO ALMA observations are used to characterize its mass and dynamical state, which are compared to other clouds in NGC628. A LVG analysis is used to constrain the beam-diluted density and temperature of the molecular gas. We analyze the MUSE spectrum using Starburst99 to characterize the young stellar population associated with the HII region. The cloud is massive ($1-2\times10^7$M$_{\odot}$), with a beam-diluted density of $n_{\rm H_2}=5\times10^4$ cm$^{-3}$. It has a low virial parameter, suggesting that its CO emission may be overluminous due to heating by the HII region. A young ($2-4$ Myr), massive $3\times10^{5}$ M$_{\odot}$ stellar population is associated. We argue that the cloud is currently being destroyed by feedback from young massive stars. Due to the cloud's large mass, this phase of the cloud's evolution is long enough for the impact of feedback on the excitation of the gas to be observed. Its high mass may be related to its location at a spiral co-rotation radius, where gas experiences reduced galactic shear compared to other regions of the disk, and receives a sustained inflow of gas that can promote the cloud's mass growth., Comment: A&A accepted

Published
2020

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