25 results on '"Phadke, Kedar"'
Search Results
2. TEMPLATES: Characterization of a Merger in the Dusty Lensing SPT0418–47 System.
- Author
-
Cathey, Jared, Gonzalez, Anthony H., Lower, Sidney, Phadke, Kedar A., Spilker, Justin, Aravena, Manuel, Bayliss, Matthew, Birkin, Jack E., Birrer, Simon, Chapman, Scott, Dahle, Håkon, Hayward, Christopher C., Hezaveh, Yashar, Hill, Ryley, Hutchison, Taylor A., Kim, Keunho J., Mahler, Guillaume, Marrone, Daniel P., Narayanan, Desika, and Navarre, Alexander
- Subjects
STELLAR mass ,MERGERS & acquisitions ,STAR formation ,GALACTIC redshift ,GALAXIES ,SUBMILLIMETER astronomy - Abstract
We present JWST and Atacama Large Millimeter/submillimeter Array (ALMA) imaging for the lensing system SPT0418−47, which includes a strongly lensed, dusty, star-forming galaxy at redshift z = 4.225 and an associated multiply imaged companion. The JWST NIRCam and MIRI imaging observations presented in this paper were acquired as part of the Early Release Science program Targeting Extremely Magnified Panchromatic Lensed Arcs and Their Extended Star formation (TEMPLATES). This data set provides robust mutiwavelength detections of stellar light in both the main (SPT0418A) and companion (SPT0418B) galaxies, while the ALMA detection of [C ii ] emission confirms that SPT0418B lies at the same redshift as SPT0418A. We infer that the projected physical separation of the two galaxies is 4.42 ± 0.05 kpc. We derive total magnifications of μ = 29 ± 1 and μ = 4.1 ± 0.7 for SPT0418A and SPT0418B, respectively. We use both prospector and cigale to derive stellar masses. We find that SPT0418A has a stellar mass of M * = 3.4 − 0.6 + 1.1 × 10 10 M ⊙ from prospector or M
* = 1.5 ± 0.3 × 1010 M⊙ from cigale. The stellar mass ratio of SPT0418A and SPT0418B is roughly between 4 and 7 ( 4.2 − 1.6 + 1.9 for prospector and 7.5 ± 3.7 for cigale). We see evidence of extended structure associated with SPT0418A that is suggestive of a tidal feature. These features, along with the close projected proximity, imply that the system is interacting. Interestingly, the star formation rates and stellar masses of both galaxies are consistent with the main sequence of star-forming galaxies at this epoch, indicating that this ongoing interaction has not noticeably elevated the star formation levels. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
3. Stem cell/cellular interventions in human spinal cord injury: Is it time to move from guidelines to regulations and legislations? Literature review and Spinal Cord Society position statement
- Author
-
Chhabra, Harvinder S., Sarda, Kanchan, Jotwani, Geeta, Gourie-Devi, M., Kaptanoglu, Erkan, Charlifue, Susan, Yadav, S. L., Mohapatra, B., Srivastava, Abhishek, and Phadke, Kedar
- Published
- 2019
- Full Text
- View/download PDF
4. TEMPLATES: Characterization of a Merger in the Dusty Lensing SPT0418-47 System
- Author
-
Cathey, Jared, Gonzalez, Anthony H., Lower, Sidney, Phadke, Kedar A., Spilker, Justin, Aravena, Manuel, Birkin, Jack E., Birrer, Simon, Chapman, Scott, Dahle, Håkon, Hayward, Cristopher C., Hezaveh, Yashar, Hill, Ryley, Hutchison, Taylor A., Mahler, Guillaume, Marrone, Daniel P., Narayanan, Desika, Navarre, Alexander, Reuter, Cassie, Rigby, Jane R., Sharon, Keren, Solimano, Manuel, Sulzenauer, Nikolaus, Vieira, Joaquin, and Vizgan, David
- Subjects
Astrophysics of Galaxies (astro-ph.GA) ,FOS: Physical sciences ,Astrophysics - Astrophysics of Galaxies - Abstract
We present JWST and ALMA results for the lensing system SPT0418-47, which includes a strongly-lensed, dusty star-forming galaxy at redshift z=4.225 and an associated multiply-imaged companion. JWST NIRCam and MIRI imaging observations presented in this paper were acquired as part of the Early Release Science program Targeting Extremely Magnified Panchromatic Lensed Arcs and Their Extended Star Formation (TEMPLATES). This data set provides robust, mutiwavelength detection of stellar light in both the main (SPT0418A) and companion (SPT0418B) galaxies, while the ALMA detection of [C II] emission confirms that SPT0418B lies at the same redshift as SPT0418A. From a source plane reconstruction, we infer that the projected physical separation of the two galaxies is $4.42\pm 0.05$ kpc. We derive total magnifications of $\mu=29.5\pm1.2$ and $\mu=4.2\pm 0.9$ for SPT0418A and SPT0418B, respectively. We use both CIGALE and PROSPECTOR to derive stellar masses. The stellar mass ratio of SPT0418A and SPT0418B is approximately 4 to 1 ($4.5\pm 1.0$ for CIGALE and $4.2^{+1.9}_{-1.6}$ for PROSPECTOR). We also see evidence of extended structure associated with SPT0418A in the lensing reconstruction that is suggestive of a tidal feature. Interestingly, the star formation rates and stellar masses of both galaxies are consistent with the main sequence of star-forming galaxies at this epoch, indicating that this ongoing interaction has not noticeably elevated the star formation levels., Comment: Submitted to AAS Journals,14 pages, 7 figures
- Published
- 2023
5. JWST's TEMPLATES for Star Formation: The First Resolved Gas-Phase Metallicity Maps of Dust-Obscured Star-Forming Galaxies at $z$ $\sim$ 4
- Author
-
Birkin, Jack E., Hutchison, Taylor A., Welch, Brian, Spilker, Justin S., Aravena, Manuel, Bayliss, Matthew B., Cathey, Jared, Chapman, Scott C., Gonzalez, Anthony H., Gururajan, Gayathri, Hayward, Christopher C., Khullar, Gourav, Kim, Keunho J., Mahler, Guillaume, Malkan, Matthew A., Narayanan, Desika, Olivier, Grace M., Phadke, Kedar A., Reuter, Cassie, Rigby, Jane R., Solimano, Manuel, Sulzenauer, Nikolaus, Vieira, Joaquin D., Vizgan, David, and Weiss, Axel
- Subjects
Astrophysics of Galaxies (astro-ph.GA) ,FOS: Physical sciences ,Astrophysics - Astrophysics of Galaxies - Abstract
We present the first spatially resolved maps of gas-phase metallicity for dust-obscured star-forming galaxies (DSFGs) at $z$ $\sim$ 4, from the JWST TEMPLATES Early Release Science program, derived from NIRSpec integral field unit spectroscopy of the H$\alpha$ and [NII] emission lines. Empirically derived literature optical line calibrations are used to determine that the sources are highly metal rich, with both appearing to display regions of supersolar metallicity, particularly in SPT2147-50. While we cannot rule out shocks or AGN in these regions, we suggest that the two systems have already undergone significant enrichment as a result of their extremely high star-formation rates. Utilising ALMA rest-frame 380$\mu$m continuum and [CI]($^3$P$_2$-$^3$P$_1$) line maps we compare metallicity and gas-to-dust ratio variations in the two galaxies, finding the two to be anticorrelated on highly resolved spatial scales, consistent with various literature studies of $z$ $\sim$ 0 galaxies. The data are indicative of the enormous potential of JWST to probe the enrichment of the interstellar medium on $\sim$kpc scales in extremely dust-obscured systems at $z$ $\sim$ 4 and beyond., Comment: 12 pages, 5 figures, submitted to ApJ
- Published
- 2023
6. The ISM in the z = 6.9 Interacting Galaxies of SPT0311-58
- Author
-
Litke, Katrina C., Marrone, Daniel P., Aravena, Manuel, Archipley, Melanie, Béthermin, Matthieu, Burgoyne, James, Cathey, Jared, Chapman, Scott C., Gonzalez, Anthony H., Greve, Thomas R., Gururajan, Gayathri, Hayward, Christopher C., Malkan, Matthew A., Phadke, Kedar A., Reuter, Cassie A., Rotermund, Kaja M., Spilker, Justin S., Stark, Antony A., Sulzenauer, Nikolaus, Vieira, Joaquin D., Vizgan, David, and Weiß, Axel
- Subjects
Interstellar medium ,High-redshift galaxies - Abstract
SPT0311-58, a system of two interacting galaxies in the Epoch of Reionization, exists in one of the rarest, most massive dark matter halos theoretically possible in that era. Studying the interstellar medium (ISM) in these galaxies can illuminate the process of galaxy formation in the early Universe. In this work, we explore the multiphase ISM in this system, using ALMA observations of the [C ii] 158, [O i] 146, [N ii] 122, and [O iii] 88 fine-structure lines and dust continuum. We find wide variations in line ratios between the eastern and western galaxies, as well as across the western galaxy.
- Published
- 2023
7. A census of the stellar content in the protocluster core SPT2349$-$56 at $z\,{=}\,4.3$
- Author
-
Hill, Ryley, Chapman, Scott, Phadke, Kedar A., Aravena, Manuel, Archipley, Melanie, Bethermin, Matthieu, Canning, Rebecca E.A., Gonzalez, Anthony, Greve, Thomas R., Gururajan, Gayathri, Hayward, Christopher C., Hezaveh, Yashar, Jarugula, Sreevani, Marrone, Daniel P., Miller, Tim, Reuter, Cassie, Rotermund, Kaja, Scott, Douglas, Spilker, Justin, Vieira, Joaquin D., Wang, George, Weiss, Axel, Laboratoire d'Astrophysique de Marseille (LAM), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)
- Subjects
Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,Astrophysics::Galaxy Astrophysics - Abstract
The protocluster core SPT2349$-$56 at $z\,{=}\,4.3$ is one of the most actively star-forming regions known, yet constraints on the total stellar mass of this system are highly uncertain. We have therefore carried out deep optical and infrared observations of this system, probing rest-frame ultraviolet to infrared wavelengths. Using the positions of the spectroscopically-confirmed protocluster members, we identify counterparts and perform detailed source deblending, allowing us to fit spectral energy distributions in order to estimate stellar masses. We show that the galaxies in SPT2349$-$56 have stellar masses proportional to their high star-formation rates, consistent with other protocluster galaxies and field submillimetre galaxies (SMGs) around redshift 4. The galaxies in SPT2349$-$56 have on average lower molecular gas-to-stellar mass fractions and depletion timescales than field SMGs, although with considerable scatter. We construct the stellar-mass function for SPT2349$-$56 and compare it to the stellar-mass function of $z\,{=}\,1$ galaxy clusters, finding both to be best described by a Schechter function. We measure rest-frame ultraviolet half-light radii from our {\it HST\/}-F160W imaging, finding that on average the galaxies in our sample are similar in size to typical star-forming galaxies around the same redshift. However, the brightest {\it HST\/}-detected galaxy in our sample, found near the luminosity-weighted centre of the protocluster core, remains unresolved at this wavelength. Hydrodynamical simulations predict that the core galaxies will quickly merge into a brightest cluster galaxy, thus our observations provide a direct view of the early formation mechanisms of this class of object.
- Published
- 2021
8. Dwarf AGNs from Optical Variability for the Origins of Seeds (DAVOS): insights from the dark energy survey deep fields.
- Author
-
Burke, Colin J, Liu, Xin, Shen, Yue, Phadke, Kedar A, Yang, Qian, Hartley, Will G, Harrison, Ian, Palmese, Antonella, Guo, Hengxiao, Zhang, Kaiwen, Kron, Richard, Turner, David J, Giles, Paul A, Lidman, Christopher, Chen, Yu-Ching, Gruendl, Robert A, Choi, Ami, Amon, Alexandra, Sheldon, Erin, and Aguena, M
- Subjects
DARK energy ,LIGHT curves ,SPECTRAL energy distribution ,OPTICAL spectra ,STELLAR mass ,GALACTIC nuclei ,ACTIVE galactic nuclei - Abstract
We present a sample of 706, z < 1.5 active galactic nuclei (AGNs) selected from optical photometric variability in three of the Dark Energy Survey (DES) deep fields (E2, C3, and X3) over an area of 4.64 deg
2 . We construct light curves using difference imaging aperture photometry for resolved sources and non-difference imaging PSF photometry for unresolved sources, respectively, and characterize the variability significance. Our DES light curves have a mean cadence of 7 d, a 6-yr baseline, and a single-epoch imaging depth of up to g ∼ 24.5. Using spectral energy distribution (SED) fitting, we find 26 out of total 706 variable galaxies are consistent with dwarf galaxies with a reliable stellar mass estimate (|$M_{\ast }\lt 10^{9.5}\, {\rm M}_\odot$| ; median photometric redshift of 0.9). We were able to constrain rapid characteristic variability time-scales (∼ weeks) using the DES light curves in 15 dwarf AGN candidates (a subset of our variable AGN candidates) at a median photometric redshift of 0.4. This rapid variability is consistent with their low black hole (BH) masses. We confirm the low-mass AGN nature of one source with a high S/N optical spectrum. We publish our catalogue, optical light curves, and supplementary data, such as X-ray properties and optical spectra, when available. We measure a variable AGN fraction versus stellar mass and compare to results from a forward model. This work demonstrates the feasibility of optical variability to identify AGNs with lower BH masses in deep fields, which may be more 'pristine' analogues of supermassive BH seeds. [ABSTRACT FROM AUTHOR]- Published
- 2022
- Full Text
- View/download PDF
9. Rapid build-up of the stellar content in the protocluster core SPT2349−56 at z = 4.3.
- Author
-
Hill, Ryley, Chapman, Scott, Phadke, Kedar A, Aravena, Manuel, Archipley, Melanie, Ashby, Matthew L N, Béthermin, Matthieu, Canning, Rebecca E A, Gonzalez, Anthony, Greve, Thomas R, Gururajan, Gayathri, Hayward, Christopher C, Hezaveh, Yashar, Jarugula, Sreevani, MacIntyre, Duncan, Marrone, Daniel P, Miller, Tim, Rennehan, Douglas, Reuter, Cassie, and Rotermund, Kaja M
- Subjects
GALAXY clusters ,HIGH mass stars ,SPECTRAL energy distribution ,STELLAR mass ,PROTOSTARS ,STAR formation ,GALACTIC evolution - Abstract
The protocluster SPT2349−56 at |$z = 4.3$| contains one of the most actively star-forming cores known, yet constraints on the total stellar mass of this system are highly uncertain. We have therefore carried out deep optical and infrared observations of this system, probing rest-frame ultraviolet to infrared wavelengths. Using the positions of the spectroscopically confirmed protocluster members, we identify counterparts and perform detailed source deblending, allowing us to fit spectral energy distributions in order to estimate stellar masses. We show that the galaxies in SPT2349−56 have stellar masses proportional to their high star formation rates, consistent with other protocluster galaxies and field submillimetre galaxies (SMGs) around redshift 4. The galaxies in SPT2349−56 have on average lower molecular gas-to-stellar mass fractions and depletion time-scales than field SMGs, although with considerable scatter. We construct the stellar-mass function for SPT2349−56 and compare it to the stellar-mass function of |$z = 1$| galaxy clusters, finding consistent shapes between the two. We measure rest-frame galaxy ultraviolet half-light radii from our HST -F160W imaging, finding that on average the galaxies in our sample are similar in size to typical star-forming galaxies at these redshifts. However, the brightest HST -detected galaxy in our sample, found near the luminosity-weighted centre of the protocluster core, remains unresolved at this wavelength. Hydrodynamical simulations predict that the core galaxies will quickly merge into a brightest cluster galaxy, thus our observations provide a direct view of the early formation mechanisms of this class of object. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
10. An extended proto-cluster of galaxies surrounding SPT2349$-$56 at $z\,{=}\,4.3$
- Author
-
Hill, Ryley, Chapman, Scott, Scott, Douglas, Apostolovski, Yordanka, Aravena, Manuel, Béthermin, Matthieu, Bradford, C.M., De Breuck, Carlos, Canning, Rebecca E.A., Dong, Chenxing, Gonzalez, Anthony, Greve, Thomas R., Hayward, Christopher C., Hezaveh, Yashar, Litke, Katrina, Malkan, Matt, Marrone, Daniel P., Phadke, Kedar, Reuter, Cassie, Spilker, Justin, Vieira, Joaquin D., Weiß, Axel, Laboratoire d'Astrophysique de Marseille (LAM), and Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Aix Marseille Université (AMU)-Centre National d'Études Spatiales [Toulouse] (CNES)
- Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] - Abstract
The $z\,{=}\,4.3$ overdensity SPT2349$-$56 has been proposed as one of the most actively star-forming proto-clusters known, and we have undertaken an extensive ALMA spectroscopic follow-up programme of this system to search for far infrared-luminous proto-cluster members via their [CII] 158$\,\mu$m and CO(4-3) line emission. In addition to robustly detecting the 14 previously published galaxies in this structure, we identify a further 15 associated galaxies at $z\,{=}\,4.3$. These proto-cluster members are distributed into a central core containing 23 galaxies extending out to 300$\,$kpc in diameter, and a northern extension, offset from the core by 400$\,$kpc and containing three galaxies. We discovered three additional galaxies in a red Herschel-SPIRE source 2$\,$Mpc from the main structure, suggesting the existence of many other sources at the same redshift as SPT2349$-$56 that are not yet detected in the limited coverage of our data. An analysis of the velocity distribution within the core indicates that this region may be a nearly virialized structure with a mass of (9$\pm$5)$\,{\times}\,$10$^{12}\,$M$_{\odot}$, while the two offset substructures show significant velocity offsets from the central structure. We calculate the [CII] and far-infrared number counts, and find evidence for a break in the [CII] luminosity function around 4$\,{\times}\,10^9\,$L$_{\odot}$. We estimate the average SFR density within the region of SPT2349$-$56 containing single-dish emission (a proper diametre of 720$\,$kpc), assuming spherical symmetry, to be roughly 40,000$\,$M$_{\odot}\,$yr$^{-1}\,$Mpc$^{-3}$; this is an order of magnitude greater than the most extreme examples seen in simulations.
- Published
- 2020
11. Chaotic and Clumpy Galaxy Formation in an Extremely Massive Reionization-era Halo.
- Author
-
Spilker, Justin S., Hayward, Christopher C., Marrone, Daniel P., Aravena, Manuel, BĂ©thermin, Matthieu, Burgoyne, James, Chapman, Scott C., Greve, Thomas R., Gururajan, Gayathri, Hezaveh, Yashar D., Hill, Ryley, Litke, Katrina C., Lovell, Christopher C., Malkan, Matthew A., Murphy, Eric J., Narayanan, Desika, Phadke, Kedar A., Reuter, Cassie, Stark, Antony A., and Sulzenauer, Nikolaus
- Published
- 2022
- Full Text
- View/download PDF
12. Molecular gas along the old radio jets of the cluster-central type 2 quasar IRAS 09104+4109.
- Author
-
O'Sullivan, Ewan, Combes, Françoise, Babul, Arif, Chapman, Scott, Phadke, Kedar A, Schellenberger, Gerrit, and Salomé, Philippe
- Subjects
QUASARS ,ACTIVE galactic nuclei ,IONIZED gases ,THERMAL instability ,GAS reservoirs ,GALAXY clusters - Abstract
We present Northern Extended Millimeter Array (NOEMA) CO(2–1) maps of the z = 0.4418 cluster-central quasi-stellar object (QSO) IRAS 09104+4109, which trace ∼4.5 × 10
10 M⊙ of molecular gas in and around the galaxy. As in many low-redshift cool-core clusters, the molecular gas is located in a series of clumps extending along the old radio jets and lobes. It has a relatively low velocity dispersion [336 |$^{+39}_{-35}$| km s−1 full width at half-maximum (FWHM)] and shows no velocity gradients indicative of outflow or infall. Roughly half the gas is located in a central clump on the north-east side of the galaxy, overlapping a bright ionized gas filament and a spur of excess X-ray emission, suggesting that this is a location of rapid cooling. The molecular gas is unusually extended, out to ∼55 kpc radius, comparable to the scale of the filamentary nebula in the Perseus cluster, despite the much higher redshift of this system. The extent falls within the thermal instability radius of the intracluster medium (ICM), with tcool / |$t_{\rm ff} \lt 25$| and tcool / |$t_{\rm eddy} \sim 1$| within ∼70 kpc. Continuum measurements at 159.9 GHz from NOEMA and 850 |$\mu$| m from the James Clerk Maxwell Telescope (JCMT) Submillimeter Common-User Bolometer Array 2 (SCUBA-2) show excess far-infrared emission, which we interpret as free–free emission arising from the ongoing starburst. These observations suggest that ICM cooling is not strongly affected by the buried QSO, and that cooling from the ICM can build gas reservoirs sufficient to fuel quasar-mode activity and drive the reorientation of the central active galactic nuclei (AGN). [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
13. Overdensities of submillimetre-bright sources around candidate protocluster cores selected from the South Pole Telescope survey.
- Author
-
Wang, George C P, Hill, Ryley, Chapman, S C, Weiß, A, Scott, Douglas, Apostolovski, Yordanka, Aravena, Manuel, Archipley, Melanie Ann, Béthermin, Matthieu, Canning, R E A, De Breuck, Carlos, Dong, Chenxing, Everett, W B, Gonzalez, Anthony, Greve, Thomas R, Hayward, Christopher C, Hezaveh, Yashar, Jarugula, Sreevani, Marrone, D P, and Phadke, Kedar A
- Subjects
TELESCOPES ,STAR formation ,SUBMILLIMETER astronomy ,SUPERGIANT stars ,GALACTIC redshift ,GALAXY clusters - Abstract
We present APEX-LABOCA 870-μm observations of the fields surrounding the nine brightest high-redshift unlensed objects discovered in the South Pole Telescope's (SPT) 2500 deg
2 survey. Initially seen as point sources by SPT's 1-arcmin beam, the 19-arcsec resolution of our new data enables us to deblend these objects and search for submillimetre (submm) sources in the surrounding fields. We find a total of 98 sources above a threshold of 3.7σ in the observed area of 1300 arcmin2 , where the bright central cores resolve into multiple components. After applying a radial cut to our LABOCA sources to achieve uniform sensitivity and angular size across each of the nine fields, we compute the cumulative and differential number counts and compare them to estimates of the background, finding a significant overdensity of |$\delta \, {\approx }\,$| 10 at |$S_{870}= 14$| mJy. The large overdensities of bright submm sources surrounding these fields suggest that they could be candidate protoclusters undergoing massive star formation events. Photometric and spectroscopic redshifts of the unlensed central objects range from |$z= $| 3 to 7, implying a volume density of star-forming protoclusters of approximately 0.1 Gpc−3 . If the surrounding submm sources in these fields are at the same redshifts as the central objects, then the total star formation rates of these candidate protoclusters reach 10 000 M⊙ yr−1 , making them much more active at these redshifts than seen so far in either simulations or observations. [ABSTRACT FROM AUTHOR]- Published
- 2021
- Full Text
- View/download PDF
14. Spatially Resolved [C ii] Emission in SPT0346-52: A Hyper-starburst Galaxy Merger at z ~ 5.7
- Author
-
Litke, Katrina C., Marrone, Daniel P., Spilker, Justin S., Aravena, Manuel, Bethermin, Matthieu, Chapman, Scott, Chen, Chian-Chou, De Breuck, Carlos, Dong, Chenxing, Gonzalez, Anthony, Greve, Thomas R., Hayward, Christopher C., Hezaveh, Yashar, Jarugula, Sreevani, Ma, Jingzhe, Morningstar, Warren, Narayanan, Desika, Phadke, Kedar, Reuter, Cassie, Vieira, Joaquin, Weiss, Axel, Litke, Katrina, Marrone, Daniel, Spilker, Justin, Breuck, Carlos de, Chen, Chenxing, Greve, Thomas, Hayward, Christopher, AUTRES, Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut d'Astrophysique de Paris (IAP), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Department of Physics [Montréal], McGill University = Université McGill [Montréal, Canada], and Max-Planck-Institut für Radioastronomie (MPIFR)
- Subjects
Physics ,010308 nuclear & particles physics ,[SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] ,Spatially resolved ,Foundation (engineering) ,Astronomy ,FOS: Physical sciences ,Astronomy and Astrophysics ,galaxies: starburst ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Galaxy merger ,Astrophysics - Astrophysics of Galaxies ,01 natural sciences ,Radio astronomy observatory ,high-redshift [Galaxies] ,starburst [Galaxies] ,Space and Planetary Science ,galaxies: high-redshift ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,[SDU.ASTR.GA]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Galactic Astrophysics [astro-ph.GA] ,10. No inequality ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
SPT0346-52 is one of the most most luminous and intensely star-forming galaxies in the universe, with L_FIR > 10^13 L_sol and Sigma_SFR ~ 4200 M_sol yr^-1 kpc^-2. In this paper, we present ~0.15'' ALMA observations of the [CII]158micron emission line in this z=5.7 dusty star-forming galaxy. We use a pixellated lensing reconstruction code to spatially and kinematically resolve the source-plane [CII] and rest-frame 158 micron dust continuum structure at ~700 pc (~0.12'') resolution. We discuss the [CII] deficit with a pixellated study of the L_[CII]/L_FIR ratio in the source plane. We find that individual pixels within the galaxy follow the same trend found using unresolved observations of other galaxies, indicating that the deficit arises on scales, Accepted for publication in ApJ
- Published
- 2019
15. Ubiquitous Molecular Outflows in z > 4 Massive, Dusty Galaxies. I. Sample Overview and Clumpy Structure in Molecular Outflows on 500 pc Scales.
- Author
-
Spilker, Justin S., Phadke, Kedar A., Aravena, Manuel, Béthermin, Matthieu, Chapman, Scott C., Dong, Chenxing, Gonzalez, Anthony H., Hayward, Christopher C., Hezaveh, Yashar D., Jarugula, Sreevani, Litke, Katrina C., Malkan, Matthew A., Marrone, Daniel P., Narayanan, Desika, Reuter, Cassie, Vieira, Joaquin D., and Weiss, Axel
- Subjects
- *
MOLECULAR structure , *GALAXIES , *GALAXY formation , *GALACTIC evolution , *STAR formation - Abstract
Massive galaxy-scale outflows of gas are one of the most commonly invoked mechanisms to regulate the growth and evolution of galaxies throughout the universe. While the gas in outflows spans a large range of temperatures and densities, the cold molecular phase is of particular interest because molecular outflows may be capable of suppressing star formation in galaxies by removing the star-forming gas. We have conducted the first survey of molecular outflows at z > 4, targeting 11 strongly lensed dusty, star-forming galaxies (DSFGs) with high-resolution Atacama Large Millimeter/submillimeter Array observations of OH 119 μm absorption as an outflow tracer. In this first paper, we give an overview of the survey, focusing on the detection rate and structure of molecular outflows. We find unambiguous evidence for outflows in 8/11 galaxies (73%), more than tripling the number known at z > 4. This implies that molecular winds in z > 4 DSFGs must have both a near-unity occurrence rate and large opening angles to be detectable in absorption. Lensing reconstructions reveal that 500 pc scale clumpy structures in the outflows are common. The individual clumps are not directly resolved, but from optical depth arguments we expect that future observations will require 50–200 pc spatial resolution to resolve them. We do not detect high-velocity [C ii ] wings in any of the sources with clear OH outflows, indicating that [C ii ] is not a reliable tracer of molecular outflows. Our results represent a first step toward characterizing molecular outflows at z > 4 at the population level, demonstrating that large-scale outflows are ubiquitous among early massive, dusty galaxies. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
16. Ubiquitous Molecular Outflows in z > 4 Massive, Dusty Galaxies. II. Momentum-driven Winds Powered by Star Formation in the Early Universe.
- Author
-
Spilker, Justin S., Aravena, Manuel, Phadke, Kedar A., Béthermin, Matthieu, Chapman, Scott C., Dong, Chenxing, Gonzalez, Anthony H., Hayward, Christopher C., Hezaveh, Yashar D., Litke, Katrina C., Malkan, Matthew A., Marrone, Daniel P., Narayanan, Desika, Reuter, Cassie, Vieira, Joaquin D., and Weiß, Axel
- Subjects
STAR formation ,STELLAR winds ,EARLY stars ,WIND power ,GALAXIES ,GALACTIC nuclei - Abstract
Galactic outflows of molecular gas are a common occurrence in galaxies and may represent a mechanism by which galaxies self-regulate their growth, redistributing gas that could otherwise have formed stars. We previously presented the first survey of molecular outflows at z > 4 toward a sample of massive, dusty galaxies. Here we characterize the physical properties of the molecular outflows discovered in our survey. Using low-redshift outflows as a training set, we find agreement at the factor of 2 level between several outflow rate estimates. We find molecular outflow rates of 150–800 yr
−1 and infer mass loading factors just below unity. Among the high-redshift sources, the molecular mass loading factor shows no strong correlations with any other measured quantity. The outflow energetics are consistent with expectations for momentum-driven winds with star formation as the driving source, with no need for energy-conserving phases. There is no evidence for active galactic nucleus activity in our sample, and while we cannot rule out deeply buried active galactic nuclei, their presence is not required to explain the outflow energetics, in contrast to nearby obscured galaxies with fast outflows. The fraction of the outflowing gas that will escape into the circumgalactic medium (CGM), though highly uncertain, may be as high as 50%. This nevertheless constitutes only a small fraction of the total cool CGM mass based on a comparison to z ∼ 2–3 quasar absorption line studies, but could represent ≳10% of the CGM metal mass. Our survey offers the first statistical characterization of molecular outflow properties in the very early universe. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
17. Dark Energy Survey identification of a low-mass active galactic nucleus at redshift 0.823 from optical variability.
- Author
-
Guo, Hengxiao, Burke, Colin J, Liu, Xin, Phadke, Kedar A, Zhang, Kaiwen, Chen, Yu-Ching, Gruendl, Robert A, Lidman, Christopher, Shen, Yue, Morganson, Eric, Aguena, Michel, Allam, Sahar, Avila, Santiago, Bertin, Emmanuel, Brooks, David, Rosell, Aurelio Carnero, Carollo, Daniela, Kind, Matias Carrasco, Costanzi, Matteo, and da Costa, Luiz N
- Subjects
GALACTIC redshift ,ACTIVE galactic nuclei ,DARK energy ,SPECTRAL energy distribution ,STELLAR mass ,SEYFERT galaxies - Abstract
We report the identification of a low-mass active galactic nucleus (AGN), DES J0218−0430, in a redshift z = 0.823 galaxy in the Dark Energy Survey (DES) Supernova field. We select DES J0218−0430 as an AGN candidate by characterizing its long-term optical variability alone based on DES optical broad-band light curves spanning over 6 yr. An archival optical spectrum from the fourth phase of the Sloan Digital Sky Survey shows both broad Mg ii and broad H β lines, confirming its nature as a broad-line AGN. Archival XMM–Newton X-ray observations suggest an intrinsic hard X-ray luminosity of |$L_{{\rm 2-12\, keV}}\approx 7.6\pm 0.4\times 10^{43}$| erg s
−1 , which exceeds those of the most X-ray luminous starburst galaxies, in support of an AGN driving the optical variability. Based on the broad H β from SDSS spectrum, we estimate a virial black hole (BH) mass of M• ≈ 106.43 –106.72 M⊙ (with the error denoting the systematic uncertainty from different calibrations), consistent with the estimation from OzDES, making it the lowest mass AGN with redshift > 0.4 detected in optical. We estimate the host galaxy stellar mass to be M* ≈ 1010.5 ± 0.3 M⊙ based on modelling the multiwavelength spectral energy distribution. DES J0218−0430 extends the M• – M* relation observed in luminous AGNs at z ∼ 1 to masses lower than being probed by previous work. Our work demonstrates the feasibility of using optical variability to identify low-mass AGNs at higher redshift in deeper synoptic surveys with direct implications for the upcoming Legacy Survey of Space and Time at Vera C. Rubin Observatory. [ABSTRACT FROM AUTHOR]- Published
- 2020
- Full Text
- View/download PDF
18. DOES IPO GRADING IMPACT PRICE EFFICIENCY IN INDIA?
- Author
-
PHADKE, KEDAR MUKUND and KAMAT, MANOJ S.
- Subjects
STOCK exchanges ,FISCAL year - Abstract
Securities and Exchange Board of India (SEBI) launched compulsory grading of IPOs in May-2007. The listing day and long-run performance of IPOs are analyzed to examine the effects of IPO certification among underpriced graded IPOs listed in India listed between fiscal years 2006 and 2013. Using a sample of 114 underpriced graded IPOs, this study reveals that (1) the effects of certification are demonstrated with higher-grade IPOs underpriced the least, (2) certification effects do not continue to persist over the long run, and (3) Price corrections are extreme over the long run with lower grade IPOs. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
19. A dense, solar metallicity ISM in the z = 4.2 dusty star-forming galaxy SPT 0418−47.
- Author
-
De Breuck, Carlos, Weiß, Axel, Béthermin, Matthieu, Cunningham, Daniel, Apostolovski, Yordanka, Aravena, Manuel, Archipley, Melanie, Chapman, Scott, Chen, Chian-Chou, Fu, Jianyang, Jarugula, Sreevani, Malkan, Matt, Mangian, Amelia C., Phadke, Kedar A., Reuter, Cassie A., Stacey, Gordon, Strandet, Maria, Vieira, Joaquin, and Vishwas, Amit
- Subjects
GALAXIES - Abstract
We present a study of six far-infrared fine structure lines in the z = 4.225 lensed dusty star-forming galaxy SPT 0418−47 to probe the physical conditions of its interstellar medium (ISM). In particular, we report Atacama Pathfinder EXperiment (APEX) detections of the [OI] 145 μm and [OIII] 88 μm lines and Atacama Compact Array (ACA) detections of the [NII] 122 and 205 μm lines. The [OI] 145 μm/[CII] 158 μm line ratio is ∼5× higher compared to the average of local galaxies. We interpret this as evidence that the ISM is dominated by photo-dissociation regions with high gas densities. The line ratios, and in particular those of [OIII] 88 μm and [NII] 122 μm imply that the ISM in SPT 0418−47 is already chemically enriched to nearly solar metallicity. While the strong gravitational amplification was required to detect these lines with APEX, larger samples can be observed with the Atacama Large Millimeter/submillimeter Array (ALMA), and should allow observers to determine if the dense, solar metallicity ISM is common among these highly star-forming galaxies. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
20. On Deriving Gravity Wave Characteristics in the Daytime Upper Atmosphere Using Radio Technique.
- Author
-
Mandal, Subir, Pallamraju, Duggirala, Karan, Deepak K., Phadke, Kedar A., Singh, Ravindra P., and Suryawanshi, Pradip
- Subjects
GRAVITY waves ,UPPER atmosphere ,OPTICAL measurements ,PHASE shift (Nuclear physics) ,RADIO measurements - Abstract
The importance of neutral wave dynamics in the understanding of the upper atmospheric processes is well known. Conventionally, optical methods are used to derive information on the neutral wave dynamics by obtaining gravity wave (GW) characteristics. Optical measurement techniques use airglow emissions as tracers to obtain such information that correspond to altitudes from where the emissions emanate. However, in this paper, we describe a method using radio wave measurement technique (digisonde) to obtain information on the neutral GW behavior. It involves monitoring of variations in the heights of isoelectron densities as a function of time, and their phase shifts, if any, to derive vertical propagation speeds and scale sizes of GWs. The daytime values of GW time periods, vertical phase speeds, and vertical scale sizes obtained for the duration of 16–21 May 2015 are in the range of 1.47 ± 0.05 to 2.64 ± 0.07 hr, 30.06 ± 4.35 to 45.69 ± 11.84 m/s, and 183.21 ± 39.23 to 393.07 ± 66.38 km, respectively. Further, we have used the GW dispersion relation to make a first‐order estimation of the horizontal scale sizes. This method of deriving neutral GW characteristics through radio measurement technique is effective for the daytime conditions and opens up new possibilities of investigations of the wave dynamical behavior in the upper atmosphere during all weather conditions. Key Points: New approach using digisonde for determining gravity wave time periods, vertical propagation speeds, and scale sizes is presentedGravity wave time periods from digisonde match with those obtained using optical measurements, indicating the presence of a common driverThis approach opens up new possibilities for obtaining gravity wave characteristics in all weather conditions [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
21. Do IPOs in Cold Markets Provide Better Returns?
- Author
-
Phadke, Kedar Mukund and Kamat, Manoj Subhash
- Subjects
GOING public (Securities) ,RATE of return ,ECONOMIC development ,REAL property ,ECONOMICS - Abstract
Significant listing day returns for IPOs is a phenomenon that is observed when companies go public. Using a larger timeframe (1999-2014), we attempt to determine the long-run performance of underpriced IPOs issued in an emerging economy such as India during the hot and cold IPO markets for 36-months. The results indicate that IPOs perform significantly better when issued during cold markets. We find that the distribution of returns is the same across cold and hot markets at specific periods during the 36-month period of study. [ABSTRACT FROM AUTHOR]
- Published
- 2017
22. First three dimensional wave characteristics in the daytime upper atmosphere derived from ground-based multiwavelength oxygen dayglow emission measurements.
- Author
-
Pallamraju, Duggirala, Karan, Deepak K., and Phadke, Kedar A.
- Published
- 2016
- Full Text
- View/download PDF
23. Utilizing design of experiments to reduce IT system testing cost.
- Author
-
Phadke, Madhav S. and Phadke, Kedar M.
- Published
- 2014
- Full Text
- View/download PDF
24. Utilizing Design of Experiments to Reduce IT System Testing Cost.
- Author
-
Phadke, Kedar M. and Phadke, Madhav S.
- Subjects
- *
TIME to market (New products) , *PRODUCTION scheduling , *CONCURRENT engineering , *ECONOMIC conversion of defense industries , *MILITARY budgets , *SOFTWARE engineering , *DEFENSE industries - Abstract
Software and system testing cost the commercial and defense industry hundreds of millions of dollars annually. In addition, conducting each set of tests takes multiple man-months, delaying time to market of key technologies. In this current economic environment, organizations are looking for ways to reduce the cost of testing and time to market while ensuring that defects are not passed on to the customer. At the same time, organizations are very reluctant to change their standard testing processes due to the heavy cost of field failures, regulatory concerns, and risk-averse culture. [ABSTRACT FROM AUTHOR]
- Published
- 2011
25. Dark Energy Survey Identification of A Low-Mass Active Galactic Nucleus at Redshift 0.823 from Optical Variability
- Author
-
Daniel Gruen, S. Everett, Marcos Lima, Colin J. Burke, K. Honscheid, Kyler Kuehn, A. Roodman, Luiz N. da Costa, D. W. Gerdes, David J. Brooks, M. Costanzi, Brad E. Tucker, Ricardo L. C. Ogando, A. K. Romer, Devon L. Hollowood, C. Lidman, E. J. Sanchez, Daniela Carollo, Peter Doel, Yu-Ching Chen, Michel Aguena, Aurelio Carnero Rosell, Emmanuel Bertin, E. Suchyta, Enrique Gaztanaga, N. E. Sommer, Juan Garcia-Bellido, Michael Schubnell, Samuel Hinton, G. Gutierrez, V. Scarpine, Eric Morganson, Juan de Vicente, Molly E. C. Swanson, Marcelle Soares-Santos, T. N. Varga, S. Allam, Robert A. Gruendl, Santiago Serrano, F. Paz-Chinchón, Anais Möller, Xin Liu, Kedar A. Phadke, Tim Eifler, Santiago Avila, A. A. Plazas, Ramon Miquel, Marcio A. G. Maia, J. Gschwend, Felipe Menanteau, Kaiwen Zhang, Matias Carrasco Kind, David J. James, Gregory Tarle, Hengxiao Guo, Shantanu Desai, Yue Shen, Mathew Smith, Antonella Palmese, Institut d'Astrophysique de Paris (IAP), Institut national des sciences de l'Univers (INSU - CNRS)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique de Clermont (LPC), Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), DES, Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Guo, Hengxiao, Burke, Colin J., Liu, Xin, Phadke, Kedar A., Zhang, Kaiwen, Chen, Yu-Ching, Gruendl, Robert A., Lidman, Christopher, Shen, Yue, Morganson, Eric, Aguena, Michel, Allam, Sahar, Avila, Santiago, Bertin, Emmanuel, Brooks, David, Rosell, Aurelio Carnero, Carollo, Daniela, Kind, Matias Carrasco, Costanzi, Matteo, da Costa, Luiz N., De Vicente, Juan, Desai, Shantanu, Doel, Peter, Eifler, Tim F., Everett, Spencer, García-Bellido, Juan, Gaztanaga, Enrique, Gerdes, David W., Gruen, Daniel, Gschwend, Julia, Gutierrez, Gaston, Hinton, Samuel R., Hollowood, Devon L., Honscheid, Klau, James, David J., Kuehn, Kyler, Lima, Marco, Maia, Marcio A. G., Menanteau, Felipe, Miquel, Ramon, Möller, Anai, Ogando, Ricardo L. C., Palmese, Antonella, Paz-Chinchón, Francisco, Plazas, Andrés A., Romer, Anita K., Roodman, Aaron, Sanchez, Eusebio, Scarpine, Vic, Schubnell, Michael, Serrano, Santiago, Smith, Mathew, Soares-Santos, Marcelle, Sommer, Natalia E., Suchyta, Eric, Swanson, Molly E. C., Tarle, Gregory, Tucker, Brad E., and Varga, Tamas N. (DES Collaboration)
- Subjects
Active galactic nucleus ,Stellar mass ,Astrophysics::High Energy Astrophysical Phenomena ,black hole physics ,galaxies: active ,nuclei [galaxies] ,FOS: Physical sciences ,active, [galaxies] ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,surveys ,galaxies: high-redshift ,galaxies: nuclei ,quasars: general ,01 natural sciences ,Luminosity ,0103 physical sciences ,survey ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Dwarf galaxy ,Physics ,Supermassive black hole ,general [quasars] ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,Quasar ,black hole physic ,Astrophysics - Astrophysics of Galaxies ,Redshift ,Galaxy ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph] ,high-redshift [galaxies] - Abstract
We report the identification of a low-mass AGN, DES J0218$-$0430, in a redshift $z = 0.823$ galaxy in the Dark Energy Survey (DES) Supernova field. We select DES J0218$-$0430 as an AGN candidate by characterizing its long-term optical variability alone based on DES optical broad-band light curves spanning over 6 years. An archival optical spectrum from the fourth phase of the Sloan Digital Sky Survey shows both broad Mg II and broad H$\beta$ lines, confirming its nature as a broad-line AGN. Archival XMM-Newton X-ray observations suggest an intrinsic hard X-ray luminosity of $L_{{\rm 2-12\,keV}}\sim7.6\pm0.4\times10^{43}$ erg s$^{-1}$, which exceeds those of the most X-ray luminous starburst galaxies, in support of an AGN driving the optical variability. Based on the broad H$\beta$ from SDSS spectrum, we estimate a virial BH mass of $M_{\bullet}\approx10^{6.43}$-$10^{6.72}M_{\odot}$ (with the error denoting 1$\sigma$ statistical uncertainties only), consistent with the estimation from OzDES, making it the lowest mass AGN with redshift $>$ 0.4 detected in optical. We estimate the host galaxy stellar mass to be $M_{\ast}\sim10^{10.5\pm0.3}M_{\odot}$ based on modeling the multi-wavelength spectral energy distribution. DES J0218$-$0430 extends the $M_{\bullet}$-$M_{\ast}$ relation observed in luminous AGNs at $z\sim1$ to masses lower than being probed by previous work. Our work demonstrates the feasibility of using optical variability to identify low-mass AGNs at higher redshift in deeper synoptic surveys with direct implications for the upcoming Legacy Survey of Space and Time at Vera C. Rubin Observatory., Comment: 13 pages, 8 figures, 1 table, accepted to MNRAS
- Published
- 2020
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.