131 results on '"D. Christopher Martin"'
Search Results
2. Resolving the H i in damped Lyman α systems that power star formation
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Rongmon Bordoloi, John M. O’Meara, Keren Sharon, Jane R. Rigby, Jeff Cooke, Ahmed Shaban, Mateusz Matuszewski, Luca Rizzi, Greg Doppmann, D. Christopher Martin, Anna M. Moore, Patrick Morrissey, and James D. Neill
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Multidisciplinary ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Astrophysics::Galaxy Astrophysics - Abstract
Reservoirs of dense atomic gas (primarily hydrogen), contain approximately 90 percent of the neutral gas at a redshift of 3, and contribute to 2-3 percent of the total baryons in the Universe. These damped Lyman-${\alpha}$ systems (so called because they absorb Lyman-${\alpha}$ photons from within and from background sources) have been studied for decades, but only through absorption lines present in the spectra of background quasars and gamma-ray bursts. Such pencil beams do not constrain the physical extent of the systems. Here, we report integral-field spectroscopy of a bright, gravitationally lensed galaxy at a redshift of 2.7 with two foreground damped Lyman-${\alpha}$ systems. These systems are $>$ 238 $kpc^2$ in extent, with column densities of neutral hydrogen varying by more than an order of magnitude on $ 5.5 \times 10^{8}$ - $1.4 \times 10^{9} M_{\odot}$, showing that they contain the necessary fuel for the next generation of star formation, consistent with relatively massive, low-luminosity primeval galaxies at redshifts $>$ 2., Comment: 31 pages, 4 Figures, 4 Extended Data figures, 2 Extended Data tables, Author's version, Accepted: 4 March 2022, Published online by Nature on May 18, 2022
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- 2022
3. Balloon-borne FIREBall-2 ultraviolet spectrograph stray light control based on nonsequential reverse modeling of on-sky data
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Trenton Brendel, Aafaque Khan, Simran Agarwal, Heejoo Choi, Daewook Kim, Erika Hamden, Vincent Picouet, D. Christopher Martin, Bruno Milliard, David Schiminovich, Shouleh Nikzad, Jean Evrard, Nicolas Bray, Johan Montel, Keri Hoadley, Drew M. Miles, Gillian Kyne, Jessica Li, Zeren Lin, Haeun Chung, Philippe Balard, Patrick Blanchard, Marty Crabill, Charles-Antoine Chevrier, Alain Peus, Ignacio Cevallos-Aleman, Olivia Jones, Harrison Bradley, Naz Ipek Kerkeser, Matthew Werneken, Didier Vibert, Nicole Melso, and David Valls-Gabaud
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Space and Planetary Science ,Control and Systems Engineering ,Mechanical Engineering ,Astronomy and Astrophysics ,Instrumentation ,Electronic, Optical and Magnetic Materials - Published
- 2022
4. FIREBall-2: The Faint Intergalactic Medium Redshifted Emission Balloon Telescope
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Erika Hamden, D. Christopher Martin, Bruno Milliard, David Schiminovich, Shouleh Nikzad, Jean Evrard, Gillian Kyne, Robert Grange, Johan Montel, Etienne Pirot, Keri Hoadley, Donal O’Sullivan, Nicole Melso, Vincent Picouet, Didier Vibert, Philippe Balard, Patrick Blanchard, Marty Crabill, Sandrine Pascal, Frederi Mirc, Nicolas Bray, April Jewell, Julia Blue Bird, Jose Zorilla, Hwei Ru Ong, Mateusz Matuszewski, Nicole Lingner, Ramona Augustin, Michele Limon, Albert Gomes, Pierre Tapie, Xavier Soors, Isabelle Zenone, and Muriel Saccoccio
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- 2020
- Full Text
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5. A blue ring nebula from a stellar merger several thousand years ago
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Brian D. Metzger, Andrew J. Monson, D. Christopher Martin, Keri Hoadley, Mark Seibert, Ken J. Shen, James D. Neill, Gudmundur Stefansson, Andrew McWilliam, and Bradley E. Schaefer
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Physics ,Nebula ,Multidisciplinary ,010308 nuclear & particles physics ,Astronomy ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Galactic plane ,Surface gravity ,01 natural sciences ,Luminosity ,Stars ,13. Climate action ,Bipolar outflow ,0103 physical sciences ,Binary star ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,010303 astronomy & astrophysics ,Stellar evolution ,Astrophysics::Galaxy Astrophysics - Abstract
Stellar mergers are a brief but common phase in the evolution of binary star systems1,2. These events have many astrophysical implications; for example, they may lead to the creation of atypical stars (such as magnetic stars3, blue stragglers4 and rapid rotators5), they play an important part in our interpretation of stellar populations6 and they represent formation channels of compact-object mergers7. Although a handful of stellar mergers have been observed directly8,9, the central remnants of these events were shrouded by an opaque shell of dust and molecules10, making it impossible to observe their final state (for example, as a single merged star or a tighter, surviving binary11). Here we report observations of an unusual, ring-shaped ultraviolet (‘blue’) nebula and the star at its centre, TYC 2597-735-1. The nebula has two opposing fronts, suggesting a bipolar outflow of material from TYC 2597-735-1. The spectrum of TYC 2597-735-1 and its proximity to the Galactic plane suggest that it is an old star, yet it has abnormally low surface gravity and a detectable long-term luminosity decay, which is uncharacteristic for its evolutionary stage. TYC 2597-735-1 also exhibits Hα emission, radial-velocity variations, enhanced ultraviolet radiation and excess infrared emission—signatures of dusty circumstellar disks12, stellar activity13 and accretion14. Combined with stellar evolution models, the observations suggest that TYC 2597-735-1 merged with a lower-mass companion several thousand years ago. TYC 2597-735-1 provides a look at an unobstructed stellar merger at an evolutionary stage between its dynamic onset and the theorized final equilibrium state, enabling the direct study of the merging process. Observations and stellar evolution models of a blue ring nebula and its central star (TYC 2597-735-1) suggest that the remnant star merged with a lower-mass companion several thousand years ago.
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- 2020
6. Resolving the H I in damped Lyman α systems that power star formation
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Rongmon, Bordoloi, John M, O'Meara, Keren, Sharon, Jane R, Rigby, Jeff, Cooke, Ahmed, Shaban, Mateusz, Matuszewski, Luca, Rizzi, Greg, Doppmann, D Christopher, Martin, Anna M, Moore, Patrick, Morrissey, and James D, Neill
- Abstract
Reservoirs of dense atomic gas (primarily hydrogen) contain approximately 90 per cent of the neutral gas at a redshift of 3, and contribute to between 2 and 3 per cent of the total baryons in the Universe
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- 2021
7. Discovery of a Damped Lyα Galaxy at z ∼ 3 toward the Quasar SDSS J011852+040644
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Patrick Petitjean, Raghunathan Srianand, Marc Rafelski, D. Christopher Martin, Pasquier Noterdaeme, Ruari Mackenzie, Qiong Li, Luis C. Ho, Xue-Bing Wu, Linhua Jiang, Zheng Cai, Siwei Zou, Ravi Joshi, Michele Fumagalli, Joshi, R, Fumagalli, M, Srianand, R, Noterdaeme, P, Petitjean, P, Rafelski, M, Mackenzie, R, Li, Q, Cai, Z, Martin, D, Zou, S, Wu, X, Jiang, L, and Ho, L
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Physics ,010504 meteorology & atmospheric sciences ,Space and Planetary Science ,Star formation ,0103 physical sciences ,absorption line systems ,Astronomy and Astrophysics ,Quasar ,Astrophysics ,010303 astronomy & astrophysics ,01 natural sciences ,Galaxy ,0105 earth and related environmental sciences - Abstract
We report the detection of the host galaxy of a damped Lyα system (DLA) with log N(H i) [cm−2] = 21.0 ± 0.10 at z ≈ 3.0091 toward the background quasar SDSS J011852+040644 using the Palomar Cosmic Web Imager at the Hale (P200) telescope. We detect Lyα emission in the dark core of the DLA trough at a 3.3σ confidence level, with Lyα luminosity of L Lyα = (3.8 ± 0.8) × 1042 erg s−1, corresponding to a star formation rate of ≳2 M ⊙ yr−1 (considering a lower limit on Lyα escape fraction f esc Ly α ∼ 2 % ) as typical for Lyman break galaxies at these redshifts. The Lyα emission is blueshifted with respect to the systemic redshift derived from metal absorption lines by 281 ± 43 km s−1. The associated galaxy is at very small impact parameter of ≲12 kpc from the background quasar, which is in line with the observed anticorrelation between column density and impact parameter in spectroscopic searches tracing the large-scale environments of DLA host galaxies.
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- 2021
8. FIREBAll-2 thermal control system: Performance of the 2018 flight and improvements for 2021
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Bruno Milliard, Hung Pham, Keri Hoadley, Zeren Lin, Vincent Picouet, Gillian Kyne, D. Christopher Martin, David Schiminovich, Erika T. Hamden, and Shouleh Nikzad
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business.industry ,Detector ,Thermal ,Water cooling ,Environmental science ,Aerospace engineering ,Cryocooler ,business ,Spectrograph ,Redshift ,Noise (radio) ,Dark current - Abstract
The Faint Intergalactic Medium Redshifted Emission Balloon (FIREBall-2) is a UV multi-object spectrograph exploring the CGM of galaxies at low redshifts (0.3 < z < 1.0). The science detector is a EMCCD cooled by a Sunpower cryocooler to minimize the noise contributions from dark current. To efficiently remove the heat generated by the cryocooler and other critical hardware, we built a custom water cooling circuit which uses a water/alcohol/ice mixture to regulate temperatures during flight. We report the ground and flight performances of the thermal system during the 2018 campaign and the lessons learned since then. We will discuss the model predictions of the potential impacts of several major upgrades as well as modifications to adapt to those impacts, and the ground performance of the thermal system during the rebuild of FIREBall-2, compared with the model predictions, for the next launch of FIREBall-2 in Fort Sumner in 2020.
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- 2020
9. FIREBall-2: The Faint Intergalactic Medium Redshifted Emission Balloon Telescope
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Pierre Tapie, April D. Jewell, D. Christopher Martin, Jean Evrard, Gillian Kyne, Vincent Picouet, Xavier Soors, Frederi Mirc, Jose Zorilla, Mateusz Matuszewski, Keri Hoadley, Nicole Lingner, Philippe Balard, P. Blanchard, Muriel Saccoccio, Nicolas Bray, Marty Crabill, Nicole Melso, Etienne Pirot, Donal O'Sullivan, Julia Blue Bird, Hwei Ru Ong, Shouleh Nikzad, Isabelle Zenone, David Schiminovich, Johan Montel, Robert Grange, Albert Gomes, Bruno Milliard, Michele Limon, Ramona Augustin, D. Vibert, Sandrine Pascal, and Erika T. Hamden
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Physics ,010504 meteorology & atmospheric sciences ,Stray light ,Payload ,Astronomy ,FOS: Physical sciences ,Astronomy and Astrophysics ,01 natural sciences ,Galaxy ,Redshift ,law.invention ,Telescope ,Space and Planetary Science ,law ,Ultraviolet astronomy ,0103 physical sciences ,Astrophysics - Instrumentation and Methods for Astrophysics ,010303 astronomy & astrophysics ,Spectrograph ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,Noise (radio) ,0105 earth and related environmental sciences - Abstract
The Faint Intergalactic Medium Redshifted Emission Balloon (FIREBall) is a mission designed to observe faint emission from the circumgalactic medium of moderate redshift (z~0.7) galaxies for the first time. FIREBall observes a component of galaxies that plays a key role in how galaxies form and evolve, likely contains a significant amount of baryons, and has only recently been observed at higher redshifts in the visible. Here we report on the 2018 flight of the FIREBall-2 Balloon telescope, which occurred on September 22nd, 2018 from Fort Sumner, New Mexico. The flight was the culmination of a complete redesign of the spectrograph from the original FIREBall fiber-fed IFU to a wide-field multi-object spectrograph. The flight was terminated early due to a hole in the balloon, and our original science objectives were not achieved. The overall sensitivity of the instrument and telescope was 90,000 LU, due primarily to increased noise from stray light. We discuss the design of the FIREBall-2 spectrograph, modifications from the original FIREBall payload, and provide an overview of the performance of all systems. We were able to successfully flight test a new pointing control system, a UV-optimized, delta-doped and coated EMCCD, and an aspheric grating. The FIREBall-2 team is rebuilding the payload for another flight attempt in the Fall of 2021, delayed from 2020 due to COVID-19., 23 Pages, 14 Figures, Accepted for Publication in ApJ
- Published
- 2020
10. A blue ring nebula from a stellar merger several thousand years ago
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Keri, Hoadley, D Christopher, Martin, Brian D, Metzger, Mark, Seibert, Andrew, McWilliam, Ken J, Shen, James D, Neill, Gudmundur, Stefansson, Andrew, Monson, and Bradley E, Schaefer
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Stellar mergers are a brief but common phase in the evolution of binary star systems
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- 2020
11. Delta-doped Electron Multiplying CCDs for FIREBall-2
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Nicole Lingner, Shouleh Nikzad, Bruno Milliard, David Schiminovich, D. Christopher Martin, Erika T. Hamden, Michael E. Hoenk, Olivier Daigle, Samuel Cheng, Robert Grange, Keri Hoadley, Todd J. Jones, April D. Jewell, Gillian Kyne, 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)
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Chromium ,Physics - Instrumentation and Detectors ,01 natural sciences ,7. Clean energy ,delta-doped ,Spectrographs ,ultraviolet ,010303 astronomy & astrophysics ,Instrumentation ,Clocks ,Physics ,Noise measurement ,Detector ,dark current ,Astrophysics::Instrumentation and Methods for Astrophysics ,Instrumentation and Detectors (physics.ins-det) ,Temperature metrology ,Electron multiplying charge coupled devices ,Electronic, Optical and Magnetic Materials ,Calibration ,Astrophysics - Instrumentation and Methods for Astrophysics ,Noise (radio) ,Dark current ,Ultraviolet radiation ,Charge-coupled devices ,FOS: Physical sciences ,Cosmic ray ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Quantum efficiency ,010309 optics ,Optics ,clock-induced-charge ,0103 physical sciences ,Noise control ,electron-multiplying CCD ,[PHYS.PHYS.PHYS-INS-DET]Physics [physics]/Physics [physics]/Instrumentation and Detectors [physics.ins-det] ,Spectrograph ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,photon counting ,detector ,business.industry ,Sensors ,Mechanical Engineering ,clocking ,Astronomy and Astrophysics ,Photon counting ,13. Climate action ,Space and Planetary Science ,Control and Systems Engineering ,business - Abstract
We present the status of on-going detector development efforts for our joint NASA/CNES balloon-borne UV multi-object spectrograph, the Faint Intergalactic Redshifted Emission Balloon (FIREBall-2; FB-2). FB-2 demonstrates a new UV detector technology, the delta-doped Electron Multiplying CCD (EMCCD), in a low risk suborbital environment, to prove the performance of EMCCDs for future space missions and Technology Readiness Level (TRL) advancement. EMCCDs can be used in photon counting (PC) mode to achieve extremely low readout noise ($, Comment: 36 pages, 9 figures
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- 2020
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12. Direct evidence of AGN feedback: a post-starburst galaxy stripped of its gas by AGN-driven winds
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Zheng Cai, Patrick Morrissey, Sebastiano Cantalupo, Mateusz Matuszewski, Hagai Netzer, J. Xavier Prochaska, D. Christopher Martin, James D. Neill, Dalya Baron, Anna M. Moore, Baron, D, Netzer, H, Xavier Prochaska, J, Cai, Z, Cantalupo, S, Christopher Martin, D, Matuszewski, M, Moore, A, Morrissey, P, and Neill, J
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Galaxies: general ,Active galactic nucleus ,Direct evidence ,Astrophysics::High Energy Astrophysical Phenomena ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Photoionization ,Astrophysics ,01 natural sciences ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Spectroscopy ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Physics ,Galaxies: star formation ,010308 nuclear & particles physics ,Star formation ,Spatially resolved ,Galaxies: evolution ,Astronomy and Astrophysics ,Galaxies: active ,Astrophysics - Astrophysics of Galaxies ,active ,galaxies: evolution ,galaxies: general ,galaxies: interactions ,galaxies: star formation [galaxies] ,Galaxy ,Stars ,Galaxies: interaction ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) - Abstract
Post starburst E+A galaxies show indications of a powerful starburst that was quenched abruptly. Their disturbed, bulge-dominated morphologies suggest that they are merger remnants. The more massive E+A galaxies are suggested to be quenched by AGN feedback, yet little is known about AGN-driven winds in this short-lived phase. We present spatially-resolved IFU spectroscopy by the Keck Cosmic Web Imager of SDSS J003443.68+251020.9, at z=0.118. The system consists of two galaxies, the larger of which is a post starburst E+A galaxy hosting an AGN. Our modelling suggests a 400 Myrs starburst, with a peak star formation rate of 120 Msun/yr. The observations reveal stationary and outflowing gas, photoionized by the central AGN. We detect gas outflows to a distance of 17 kpc from the central galaxy, far beyond the region of the stars (about 3 kpc), inside a conic structure with an opening angle of 70 degrees. We construct self-consistent photoionization and dynamical models for the different gas components and show that the gas outside the galaxy forms a continuous flow, with a mass outflow rate of about 24 Msun/yr. The gas mass in the flow, roughly $10^9$ Msun, is larger than the total gas mass within the galaxy, some of which is outflowing too. The continuity of the flow puts a lower limit of 60 Myrs on the duration of the AGN feedback. Such AGN are capable of removing, in a single episode, most of the gas from their host galaxies and expelling enriched material into the surrounding CGM., Comment: submitted to MNRAS; comments are welcome!
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- 2018
13. The Initial Mass Function in the Extended Ultraviolet Disk of M83
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D. Christopher Martin, Adam B. Watts, David A. Thilker, Luciana Bianchi, Gerhardt R. Meurer, Barry F. Madore, R. Michael Rich, S. M. Bruzzese, A. Gil de Paz, and Annette M. N. Ferguson
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Astrofísica ,Initial mass function ,astro-ph.GA ,Population ,FOS: Physical sciences ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Photometry (optics) ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,education ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Physics ,education.field_of_study ,010308 nuclear & particles physics ,Star formation ,Astronomy and Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Red-giant branch ,Stars ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Extreme ultraviolet ,Astrophysics::Earth and Planetary Astrophysics - Abstract
Using Hubble Space Telescope ACS/WFC data we present the photometry and spatial distribution of resolved stellar populations of four fields within the extended ultraviolet disk (XUV disk) of M83. These observations show a clumpy distribution of main-sequence stars and a mostly smooth distribution of red giant branch stars. We constrain the upper-end of the initial mass function (IMF) in the outer disk using the detected population of main-sequence stars and an assumed constant star formation rate (SFR) over the last 300 Myr. By comparing the observed main-sequence luminosity function to simulations, we determine the best-fitting IMF to have a power law slope $\alpha=-2.35 \pm 0.3$ and an upper-mass limit $\rm M_{u}=25_{-3}^{+17} \, M_\odot$. This IMF is consistent with the observed H$\alpha$ emission, which we use to provide additional constraints on the IMF. We explore the influence of deviations from the constant SFR assumption, finding that our IMF conclusions are robust against all but strong recent variations in SFR, but these are excluded by causality arguments. These results, along with our similar studies of other nearby galaxies, indicate that some XUV disks are deficient in high-mass stars compared to a Kroupa IMF. There are over one hundred galaxies within 5 Mpc, many already observed with HST, thus allowing a more comprehensive investigation of the IMF, and how it varies, using the techniques developed here., Comment: MNRAS accepted. 28 pages, 7 Tables, 19 Figures. See published article or contact third author for paper with figures at full resolution. (V2: small error in metadata corrected)
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- 2019
14. WiggleZ Dark Energy Survey: Cosmological neutrino mass constraint from blue high-redshift galaxies
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Signe Riemer–Sørensen, Chris Blake, David Parkinson, Tamara M. Davis, Sarah Brough, Matthew Colless, Carlos Contreras, Warrick Couch, Scott Croom, Darren Croton, Michael J. Drinkwater, Karl Forster, David Gilbank, Mike Gladders, Karl Glazebrook, Ben Jelliffe, Russell J. Jurek, I-hui Li, Barry Madore, D. Christopher Martin, Kevin Pimbblet, Gregory B. Poole, Michael Pracy, Rob Sharp, Emily Wisnioski, David Woods, Ted K. Wyder, and H. K. C. Yee
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- 2012
- Full Text
- View/download PDF
15. The FIREBall-2 UV balloon telescope: 2018 flight and improvements for 2020
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Bruno Milliard, Keri Hoadley, Aafaque R. Khan, Erika T. Hamden, David Schiminovich, Gillian Kyne, Simran Agarwal, D. Christopher Martin, Jean Evrard, Zeren Lin, and Siegmund, Oswald H.
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Physics ,Telescope ,law ,Detector ,Galaxy formation and evolution ,Astronomy ,Scattered light ,Balloon ,Spectrograph ,Galaxy ,Redshift ,law.invention - Abstract
The Faint Intergalactic-medium Redshifted Emission Balloon (FIREBall-2, FB-2) is designed to discover and map faint UV emission from the circumgalactic medium around low redshift galaxies (z ~ 0.3 (C IV); z ~ 0.7 (Lyα); z ~ 1.0 (O VI)). FIREBall-2's first launch, on September 22nd 2018 out of Ft. Sumner, NM, was abruptly cut short due to a hole that developed in the balloon. FIREBall-2 was unable to observe above its minimum require altitude (25 km; nominal: 32 km) for its shortest required time (2 hours; nominal: 8+ hours). The shape of the deflated balloon, as well as a concurrent full moon close to our observed target field, revealed a severe, off-axis scattered light path directly to the UV science detector. Additional damage to FB-2 added complications to the ongoing effort to prepare FB-2 for a quick re-flight. Upon landing, several mirrors in the optical chain, including the two large telescope mirrors, were damaged, resulting in chunks of material broken off the sides and reflecting surfaces. The magnifying optical element, called the focal corrector, was discovered to be misaligned beyond tolerance after the 2018 flight, with one of its two mirrors damaged from the landing impact. We describe the steps taken thus far to mitigate the damage to the optics, as well as procedures and results from the ongoing efforts to re-align the focal corrector and spectrograph optics. We report the throughput of the spectrograph before and after the 2018 flight and plans for improving it. Finally, we describe several methods by which we address the scattered light issues seen from FIREBall-2's 2018 campaign and present the current status of FB-2 to fly during the summer campaign in Palestine, TX in 2020.
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- 2019
16. FIREBall-2: advancing TRL while doing proof-of-concept astrophysics on a suborbital platform
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Keri Hoadley, Donal O'Sullivan, Shouleh Nikzad, Erika T. Hamden, D. Vibert, B. Smiley, Bruno Milliard, Hwei Ru Ong, Nicole Lingner, April D. Jewell, Michele Limon, Nicole Melso, Vincent Picouet, David Schiminovich, Robert Grange, Frederi Mirc, P. Balard, Johan Montel, D. Christopher Martin, Jose Zorrilla, Jean Evrard, Xavier Soors, Etienne Perot, Mateusz Matuszewski, Isabelle Zenone, Nicolas Bray, Muriel Saccoccio, Pierre Tapie, Albert Gomes, Marty Crabill, Sandrine Pascal, Gillian Kyne, Ramona Augustin, P. Blanchard, Julia Gross, George, Thomas, and Islam, M. Saif
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Engineering ,business.industry ,Astrophysics::High Energy Astrophysical Phenomena ,Astrophysics::Instrumentation and Methods for Astrophysics ,Foundation (engineering) ,FOS: Physical sciences ,Library science ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Proof of concept ,Physics::Space Physics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics - Instrumentation and Methods for Astrophysics ,business ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,GeneralLiterature_REFERENCE(e.g.,dictionaries,encyclopedias,glossaries) ,Astrophysics::Galaxy Astrophysics ,ComputingMilieux_MISCELLANEOUS - Abstract
Here we discuss advances in UV technology over the last decade, with an emphasis on photon counting, low noise, high efficiency detectors in sub-orbital programs. We focus on the use of innovative UV detectors in a NASA astrophysics balloon telescope, FIREBall-2, which successfully flew in the Fall of 2018. The FIREBall-2 telescope is designed to make observations of distant galaxies to understand more about how they evolve by looking for diffuse hydrogen in the galactic halo. The payload utilizes a 1.0-meter class telescope with an ultraviolet multi-object spectrograph and is a joint collaboration between Caltech, JPL, LAM, CNES, Columbia, the University of Arizona, and NASA. The improved detector technology that was tested on FIREBall-2 can be applied to any UV mission. We discuss the results of the flight and detector performance. We will also discuss the utility of sub-orbital platforms (both balloon payloads and rockets) for testing new technologies and proof-of-concept scientific ideas, Submitted to the Proceedings of SPIE, Defense + Commercial Sensing (SI19)
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- 2019
17. Multi-filament gas inflows fuelling young star-forming galaxies
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Anna M. Moore, Donal O'Sullivan, Mateusz Matuszewski, Joel R. Primack, Patrick Morrissey, D. Christopher Martin, Sebastiano Cantalupo, Jason X. Prochaska, Luca Rizzi, Erika T. Hamden, Avishai Dekel, Charles C. Steidel, Daniel Ceverino, Ryan F. Trainor, James D. Neill, Sharon Lapiner, Martin, D, O'Sullivan, D, Matuszewski, M, Hamden, E, Dekel, A, Lapiner, S, Morrissey, P, Neill, J, Cantalupo, S, Prochaska, J, Steidel, C, Trainor, R, Moore, A, Ceverino, D, Primack, J, and Rizzi, L
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Physics ,Angular momentum ,010504 meteorology & atmospheric sciences ,Star formation ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy and Astrophysics ,Quasar ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Inflow ,01 natural sciences ,Accretion (astrophysics) ,Galaxy ,0103 physical sciences ,galaxies ,Astrophysics::Earth and Planetary Astrophysics ,Halo ,intergalactic medium ,Spectral resolution ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,0105 earth and related environmental sciences - Abstract
Theory suggests that there are two primary modes of accretion through which dark-matter halos acquire the gas to form and fuel galaxies: hot- and cold-flow accretion. In cold-flow accretion, gas streams along cosmic web filaments to the centre of the halo, allowing for the efficient delivery of star-forming fuel. Recently, two quasar-illuminated H i Lyman ɑ (Lyα)-emitting objects were reported to have properties of cold, rotating structures1,2. However, the spatial and spectral resolution available was insufficient to constrain the radial flows associated with connecting filaments. With the Keck Cosmic Web Imager (KCWI)3, we now have eight times the spatial resolution, permitting the detection of these inspiralling flows. To detect these inflows, we introduce a suite of models that incorporate zonal radial flows, demonstrate their performance on a numerical simulation that exhibits cold-flow accretion, and show that they are an excellent match to KCWI velocity maps of two Lyα emitters observed around high-redshift quasars. These multi-filament inflow models kinematically isolate zones of radial inflow that correspond to extended filamentary emission. The derived gas flux and inflow path is sufficient to fuel the inferred central galaxy star-formation rate and angular momentum. Thus, our kinematic emission maps provide strong evidence that the inflow of gas from the cosmic web is building galaxies at the peak of star formation.
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- 2019
18. Emission-line Data Cubes of the HH 32 Stellar Jet
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Patrick Morrissey, James D. Neill, Lynne A. Hillenbrand, Patrick Hartigan, D. Christopher Martin, Anna M. Moore, M. Matuszewski, and Arlindo Chan Borges
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Physics ,Jet (fluid) ,010504 meteorology & atmospheric sciences ,Astrophysics::High Energy Astrophysical Phenomena ,Doubly ionized oxygen ,Balmer series ,Astronomy and Astrophysics ,Astrophysics ,01 natural sciences ,symbols.namesake ,Mach number ,Space and Planetary Science ,Ionization ,0103 physical sciences ,Shock diamond ,symbols ,Herbig–Haro object ,Emission spectrum ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,0105 earth and related environmental sciences - Abstract
We analyze datacubes of over 60 emission lines in the HH 32 stellar jet acquired with the Keck Cosmic Web Imager (KCWI). The data cover the less-explored blue portion of the spectrum between 3586A and 6351A , and have both high spectral (R $\sim$ 10000) and spatial ($\lesssim$ 1" ) resolution. The study includes all three major ionization states of oxygen, three Balmer lines, multiple lines of Fe II and Fe III, as well as the first datacubes ever acquired for important unblended diagnostic lines such as He II $\lambda$4686, Ca I $\lambda$3933, and Mg I] $\lambda$4571. The data cubes generally sort according to excitation, and have a relatively continuous progression from the highest-excitation ions (He II, O III) through the intermediate-excitation ions (O I and H I) to the lowest-excitation ions (Ca II and Mg I). Merging the KCWI cubes with HST images leads to several new insights about the flow, including evidence for bow shocks, partial bow shocks, spur shocks, Mach disks, jet deflection shocks, a wiggling jet, and potential shock precursors. The most surprising result is that one of the velocity components of Fe II in the Mach disk suddenly increases in flux relative to other lines by a factor of two, implying that the Mach disk vaporizes dust in the jet. Hence, jets must accelerate or entrain dust to speeds of over 300 km/s without destroying the grains.
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- 2020
19. The Keck Cosmic Web Imager Integral Field Spectrograph
- Author
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Sam Park, Jerry Cabak, Jason Weiss, Marty Crabill, Constance M. Rockosi, Bob Weber, Greg Doppman, Kirk Seaman, Luca Rizzi, Anna M. Moore, Ray Zarzaca, Shui Kwok, Donal O'Sullivan, Steve Allen, James D. Neill, Harland W. Epps, W. Deich, Justin Belicki, Kyle Lanclos, Shawn Callahan, M. Matuszewski, Michael Kokorowski, Jason Fucik, Patrick Morrissey, Steve Kaye, Sean M. Adkins, Dave Cowley, Prachi Parihar, Andrew N. Phillips, Randy Bartos, David Sheikh, Hector P. Rodriguez, Yves Salaun, Alex Delecroix, Steve Milner, Ean James, D. Christopher Martin, Behnam Darvish, and David F. Hilyard
- Subjects
Physics ,business.industry ,media_common.quotation_subject ,Holography ,FOS: Physical sciences ,Astronomy and Astrophysics ,Field of view ,01 natural sciences ,law.invention ,010309 optics ,Telescope ,Wavelength ,Optics ,Integral field spectrograph ,Space and Planetary Science ,Observatory ,Sky ,law ,0103 physical sciences ,Spectral resolution ,business ,Astrophysics - Instrumentation and Methods for Astrophysics ,010303 astronomy & astrophysics ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,media_common - Abstract
We report on the design and performance of the Keck Cosmic Web Imager (KCWI), a general purpose optical integral field spectrograph that has been installed at the Nasmyth port of the 10 m Keck II telescope on Mauna Kea, HI. The novel design provides blue-optimized seeing-limited imaging from 350-560 nm with configurable spectral resolution from 1000 - 20000 in a field of view up to 20"x33". Selectable volume phase holographic (VPH) gratings and high performance dielectric, multilayer silver and enhanced aluminum coatings provide end-to-end peak efficiency in excess of 45% while accommodating the future addition of a red channel that will extend wavelength coverage to 1 micron. KCWI takes full advantage of the excellent seeing and dark sky above Mauna Kea with an available nod-and-shuffle observing mode. The instrument is optimized for observations of faint, diffuse objects such as the intergalactic medium or cosmic web. In this paper, a detailed description of the instrument design is provided with measured performance results from the laboratory test program and ten nights of on-sky commissioning during the spring of 2017. The KCWI team is lead by Caltech and JPL (project management, design and implementation) in partnership with the University of California at Santa Cruz (camera optical and mechanical design) and the W. M. Keck Observatory (observatory interfaces)., 33 pages, 31 figures. Accepted to the Astrophysical Journal
- Published
- 2018
20. The WiggleZ Dark Energy Survey: final data release and the metallicity of UV-luminous galaxies
- Author
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Samuel Hinton, Michael J. Drinkwater, Ted K. Wyder, Russell J. Jurek, Scott M. Croom, Chris Blake, Michael Pracy, David Gilbank, Warrick J. Couch, Emily Wisnioski, Karl Glazebrook, Max Spolaor, Jon Smillie, Darren J. Croton, I-hui Li, D. Christopher Martin, Karl Forster, Tamara M. Davis, Rob Sharp, Matthew Colless, Zachary J. Byrne, Gregory B. Poole, Kevin A. Pimbblet, Sarah Brough, David Woods, Ben Jelliffe, and Howard K. C. Yee
- Subjects
Physics ,Stellar mass ,010308 nuclear & particles physics ,Metallicity ,Astrophysics::Instrumentation and Methods for Astrophysics ,Doubly ionized oxygen ,FOS: Physical sciences ,Astronomy ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Redshift ,Luminosity ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,Dark energy ,Astrophysics::Solar and Stellar Astrophysics ,10. No inequality ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Line (formation) - Abstract
The WiggleZ Dark Energy Survey measured the redshifts of over 200,000 UV-selected (NUV, Comment: Catalogue available at MNRAS (DOI link below) and also at: https://espace.library.uq.edu.au/view/UQ:3e43575
- Published
- 2018
21. Andromeda's Parachute: A Bright Quadruply Lensed Quasar at z=2.377
- Author
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Kate H. R. Rubin, Mateusz Matuszewski, Shui Kwok, James D. Neill, Patrick Morrissey, D. Christopher Martin, Anna M. Moore, John M. O'Meara, Luca Rizzi, Kathy L. Cooksey, and Greg W. Doppmann
- Subjects
Physics ,010308 nuclear & particles physics ,FOS: Physical sciences ,Astronomy and Astrophysics ,Quasar ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Astrophysics - Astrophysics of Galaxies ,Redshift ,Galaxy ,Andromeda ,Cosmic web ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,Absorption (electromagnetic radiation) ,Spectroscopy ,010303 astronomy & astrophysics ,Equivalent width ,Astrophysics::Galaxy Astrophysics - Abstract
We present Keck Cosmic Web Imager spectroscopy of the four putative images of the lensed quasar candidate J014709+463037 recently discovered by Berghea et al. (2017). The data verify the source as a quadruply lensed, broad absorption-line quasar having z_S = 2.377 +/- 0.007. We detect intervening absorption in the FeII 2586, 2600, MgII 2796, 2803, and/or CIV 1548, 1550 transitions in eight foreground systems, three of which have redshifts consistent with the photometric-redshift estimate reported for the lensing galaxy (z_L ~ 0.57). By virtue of their positions on the sky, the source images probe these absorbers over transverse physical scales of ~0.3-21 kpc, permitting assessment of the variation in metal-line equivalent width W_r as a function of sight-line separation. We measure differences in W_r,2796 of 50% over the same scales across the majority of sight-line pairs, while CIV absorption exhibits a wide range in W_r,1548 differences of ~5-80% within transverse distances less than ~3 kpc. J014709+463037 is one of only a handful of z > 2 quadruply lensed systems for which all four source images are very bright (r = 15.4-17.7 mag) and are easily separated in ground-based seeing conditions. As such, it is an ideal candidate for higher-resolution spectroscopy probing the spatial variation in the kinematic structure and physical state of intervening absorbers., Submitted to ApJL. 9 pages, 3 figures. Uses aastex61 format
- Published
- 2017
22. Cosmic web of galaxies in the COSMOS field:public catalog and different quenching for centrals and satellites
- Author
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Shoubaneh Hemmati, Behnam Darvish, David Sobral, Bahram Mobasher, Jeyhan S. Kartaltepe, Andra Stroe, Nick Scoville, and D. Christopher Martin
- Subjects
Physics ,Quenching ,education.field_of_study ,Field (physics) ,010308 nuclear & particles physics ,Astrophysics::High Energy Astrophysical Phenomena ,Population ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Astrophysics - Astrophysics of Galaxies ,Redshift ,Galaxy ,Cosmic web ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,0103 physical sciences ,Web extraction ,Galaxy formation and evolution ,education ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
We use a mass complete (log($M/M_{\odot}$) $\geqslant$ 9.6) sample of galaxies with accurate photometric redshifts in the COSMOS field to construct the density field and the cosmic web to $z$=1.2. The comic web extraction relies on the density field Hessian matrix and breaks the density field into clusters, filaments and the field. We provide the density field and cosmic web measures to the community. We show that at $z$ $\lesssim$ 0.8, the median star-formation rate (SFR) in the cosmic web gradually declines from the field to clusters and this decline is especially sharp for satellites ($\sim$ 1 dex vs. $\sim$ 0.5 dex for centrals). However, at $z$ $\gtrsim$ 0.8, the trend flattens out for the overall galaxy population and satellites. For star-forming galaxies only, the median SFR is constant at $z$ $\gtrsim$ 0.5 but declines by $\sim$ 0.3-0.4 dex from the field to clusters for satellites and centrals at $z$ $\lesssim$ 0.5. We argue that for satellites, the main role of the cosmic web environment is to control their star-forming fraction, whereas for centrals, it is mainly to control their overall SFR at $z$ $\lesssim$ 0.5 and to set their fraction at $z$ $\gtrsim$ 0.5. We suggest that most satellites experience a rapid quenching mechanism as they fall from the field into clusters through filaments, whereas centrals mostly undergo a slow environmental quenching at $z$ $\lesssim$ 0.5 and a fast mechanism at higher redshifts. Our preliminary results highlight the importance of the large-scale cosmic web on galaxy evolution., Comment: submitted to ApJ. comments welcome
- Published
- 2017
23. Charge Coupled Device detectors with high quantum efficiency at UV wavelengths
- Author
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D. Christopher Martin, Michael E. Hoenk, David Schiminovich, Todd J. Jones, Charles Shapiro, Erika T. Hamden, Shouleh Nikzad, John Hennessy, Sam Gordon, April D. Jewell, Hwei Ru Ong, Tim M. Goodsall, and Samuel R. Cheng
- Subjects
Materials science ,Silicon ,FOS: Physical sciences ,chemistry.chemical_element ,engineering.material ,01 natural sciences ,010309 optics ,Coating ,0103 physical sciences ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,010303 astronomy & astrophysics ,Instrumentation ,business.industry ,Mechanical Engineering ,Detector ,Astronomy and Astrophysics ,3. Good health ,Electronic, Optical and Magnetic Materials ,Wavelength ,chemistry ,Space and Planetary Science ,Control and Systems Engineering ,engineering ,Optoelectronics ,Antireflection coating ,Quantum efficiency ,Charge-coupled device ,business ,Astrophysics - Instrumentation and Methods for Astrophysics ,Layer (electronics) - Abstract
We report on multilayer high efficiency antireflection coating (ARC) design and development for use at UV wavelengths on CCDs and other Si-based detectors. We have previously demonstrated a set of single-layer coatings, which achieve >50% quantum efficiency (QE) in four bands from 130 to 300 nm. We now present multilayer coating designs that significantly outperform our previous work between 195 and 215 nm. Using up to 11 layers, we present several model designs to reach QE above 80%. We also demonstrate the successful performance of 5 and 11 layer ARCs on silicon and fused silica substrates. Finally, we present a five-layer coat- ing deposited onto a thinned, delta-doped CCD and demonstrate external QE greater than 60% between 202 and 208 nm, with a peak of 67.6% at 206 nm., 11 pages, 8 figures. Published by JATIS
- Published
- 2017
24. The WiggleZ Dark Energy Survey: constraining galaxy bias and cosmic growth with three-point correlation functions
- Author
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Cameron K. McBride, Rob Sharp, Felipe A. Marín, Ben Jelliffe, Michael D. Gladders, Karl Forster, H. K. C. Yee, Michael Pracy, Michael J. Drinkwater, David Woods, Sarah Brough, David Gilbank, D. Christopher Martin, Russell J. Jurek, Karl Glazebrook, Tamara M. Davis, I-hui Li, Ted K. Wyder, Scott M. Croom, Emily Wisnioski, Matthew Colless, Kevin A. Pimbblet, Chris Blake, Barry F. Madore, Carlos Contreras, Darren J. Croton, Gregory B. Poole, and Warrick J. Couch
- Subjects
Physics ,Cold dark matter ,Dark matter ,Astronomy ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Redshift survey ,Cosmology ,Galaxy ,Redshift ,Space and Planetary Science ,Dark energy ,Baryon acoustic oscillations ,Astrophysics::Galaxy Astrophysics - Abstract
Higher order statistics are a useful and complementary tool for measuring the clustering of galaxies, containing information on the non-Gaussian evolution and morphology of large-scale structure in the Universe. In this work we present measurements of the three-point correlation function (3PCF) for 187 000 galaxies in the WiggleZ spectroscopic galaxy survey. We explore the WiggleZ 3PCF scale and shape dependence at three different epochs z = 0.35, 0.55 and 0.68, the highest redshifts where these measurements have been made to date. Using N-body simulations to predict the clustering of dark matter, we constrain the linear and non-linear bias parameters of WiggleZ galaxies with respect to dark matter, and marginalize over them to obtain constraints on σ8(z), the variance of perturbations on a scale of 8 h^−1 Mpc and its evolution with redshift. These measurements of σ_8(z), which have 10–20 per cent accuracies, are consistent with the predictions of the Λ cold dark matter concordance cosmology and test this model in a new way.
- Published
- 2013
25. The WiggleZ Dark Energy Survey: probing the epoch of radiation domination using large-scale structure
- Author
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Michael J. Drinkwater, David Gilbank, Darren J. Croton, Karl Forster, Sarah Brough, Karl Glazebrook, Gregory B. Poole, David Woods, David Parkinson, Ted K. Wyder, Michael Pracy, Michael D. Gladders, Matthew Colless, Scott M. Croom, H. K. C. Yee, Ben Jelliffe, Chris Blake, Kevin A. Pimbblet, Warrick J. Couch, Rob Sharp, Carlos Contreras, Barry F. Madore, Russell J. Jurek, I-hui Li, Emily Wisnioski, D. Christopher Martin, and Tamara M. Davis
- Subjects
Physics ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Primordial fluctuations ,Matter power spectrum ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,CMB cold spot ,Cosmology ,Redshift ,Baryon ,Space and Planetary Science ,Dark energy ,Baryon acoustic oscillations ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We place the most robust constraint to date on the scale of the turnover in the cosmological matter power spectrum using data from the WiggleZ Dark Energy Survey. We find this feature to lie at a scale of $k_0=0.0160^{+0.0041}_{-0.0035}$ [h/Mpc] (68% confidence) for an effective redshift of 0.62 and obtain from this the first-ever turnover-derived distance and cosmology constraints: a measure of the cosmic distance-redshift relation in units of the horizon scale at the redshift of radiation-matter equality (r_H) of D_V(z=0.62)/r_H=18.3 (+6.3/-3.3) and, assuming a prior on the number of extra relativistic degrees of freedom $N_{eff}=3$, constraints on the matter density parameter $\Omega_Mh^2=0.136^{+0.026}_{-0.052}$ and on the redshift of matter-radiation equality $z_{eq}=3274^{+631}_{-1260}$. All results are in excellent agreement with the predictions of standard LCDM models. Our constraints on the logarithmic slope of the power spectrum on scales larger than the turnover is bounded in the lower limit with values only as low as -1 allowed, with the prediction of standard LCDM models easily accommodated by our results. Lastly, we generate forecasts for the achievable precision of future surveys at constraining $k_0$, $\Omega_Mh^2$, $z_{eq}$ and $N_{eff}$. We find that BOSS should substantially improve upon the WiggleZ turnover constraint, reaching a precision on $k_0$ of $\pm$9% (68% confidence), translating to precisions on $\Omega_Mh^2$ and $z_{eq}$ of $\pm$10% (assuming a prior $N_{eff}=3$) and on $N_{eff}$ of (+78/-56)% (assuming a prior $\Omega_Mh^2=0.135$). This is sufficient precision to sharpen the constraints on $N_{eff}$ from WMAP, particularly in its upper limit. For Euclid, we find corresponding attainable precisions on $(k_0, \Omega_Mh^2, N_eff)$ of (3,4,+17/-21)%. This represents a precision approaching our forecasts for the Planck Surveyor., Comment: 12 pages, 7 figures, accepted for publication in MNRAS
- Published
- 2013
26. The faint intergalactic-medium red-shifted emission balloon: future UV observations with EMCCDs
- Author
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Nicole Lingner, Patrick Morrissey, Shouleh Nikzad, Erika T. Hamden, Gillian Kyne, D. Christopher Martin, Holland, Andrew D., and Beletic, James
- Subjects
Physics ,Galactic astronomy ,business.industry ,Astrophysics::Instrumentation and Methods for Astrophysics ,Astronomy ,Astrophysics::Cosmology and Extragalactic Astrophysics ,01 natural sciences ,Redshift ,Galaxy ,Photon counting ,law.invention ,010309 optics ,Telescope ,Optics ,law ,0103 physical sciences ,business ,010303 astronomy & astrophysics ,Spectrograph ,Astrophysics::Galaxy Astrophysics ,Noise (radio) ,Dark current - Abstract
We present the latest developments in our joint NASA/CNES suborbital project. This project is a balloon-borne UV multi-object spectrograph, which has been designed to detect faint emission from the circumgalactic medium (CGM) around low redshift galaxies. One major change from FIREBall-1 has been the use of a delta-doped Electron Multiplying CCD (EMCCD). EMCCDs can be used in photon-counting (PC) mode to achieve extremely low readout noise (¡ 1e-). Our testing initially focused on reducing clock-induced-charge (CIC) through wave shaping and well depth optimisation with the CCD Controller for Counting Photons (CCCP) from Nüvü. This optimisation also includes methods for reducing dark current, via cooling and substrate voltage adjustment. We present result of laboratory noise measurements including dark current. Furthermore, we will briefly present some initial results from our first set of on-sky observations using a delta-doped EMCCD on the 200 inch telescope at Palomar using the Palomar Cosmic Web Imager (PCWI).
- Published
- 2016
27. THE LOCAL HOSTS OF TYPE Ia SUPERNOVAE
- Author
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Tom A. Barlow, David Schiminovich, Luciana Bianchi, D. Andrew Howell, Mark Seibert, James D. Neill, R. Michael Rich, D. Christopher Martin, Karl Foster, Ted K. Wyder, Young-Wook Lee, Susan G. Neff, Bruno Milliard, Barry F. Madore, Alexander S. Szalay, Timothy M. Heckman, Mark Sullivan, Patrick Morrissey, A. Conley, Jose Donas, and Peter G. Friedman
- Subjects
Physics ,education.field_of_study ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Stellar mass ,Metallicity ,Astrophysics::High Energy Astrophysical Phenomena ,Population ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Light curve ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Redshift ,Photometry (optics) ,Supernova ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,education ,Astrophysics::Galaxy Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
We use multi-wavelength, matched aperture, integrated photometry from GALEX, SDSS and the RC3 to estimate the physical properties of 166 nearby galaxies hosting 168 well-observed Type Ia supernovae (SNe Ia). Our data corroborate well-known features that have been seen in other SN Ia samples. Specifically, hosts with active star formation produce brighter and slower SNe Ia on average, and hosts with luminosity-weighted ages older than 1 Gyr produce on average more faint, fast and fewer bright, slow SNe Ia than younger hosts. New results include that in our sample, the faintest and fastest SNe Ia occur only in galaxies exceeding a stellar mass threshhold of ~10^10 M_sun, indicating that their progenitors must arise in populations that are older and/or more metal rich than the general SN Ia population. A low host extinction sub-sample hints at a residual trend in peak luminosity with host age, after correcting for light-curve shape, giving the appearance that older hosts produce less-extincted SNe Ia on average. This has implications for cosmological fitting of SNe Ia and suggests that host age could be useful as a parameter in the fitting. Converting host mass to metallicity and computing 56Ni mass from the supernova light curves, we find that our local sample is consistent with a model that predicts a shallow trend between stellar metallicity and the 56Ni mass that powers the explosion, but we cannot rule out the absence of a trend. We measure a correlation between 56Ni mass and host age in the local universe that is shallower and not as significant as that seen at higher redshifts. The details of the age -- 56Ni mass correlations at low and higher redshift imply a luminosity-weighted age threshhold of ~3 Gyr for SN Ia hosts, above which they are less likely to produce SNe Ia with 56Ni masses above ~0.5 M_sun. (Abridged), 21 pages, 15 figures, accepted for ApJ
- Published
- 2016
28. THE DETECTION RATE of EARLY UV EMISSION from SUPERNOVAE: A DEDICATED GALEX/PTF SURVEY and CALIBRATED THEORETICAL ESTIMATES
- Author
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S. Ben-Ami, Joshua S. Bloom, Udi Nakar, D. Christopher Martin, Noam Ganot, Peter Nugent, Dovi Poznanski, Iair Arcavi, Tom A. Barlow, Doron Chelouche, Suvi Gezari, Shrinivas R. Kulkarni, Avishay Gal-Yam, Stephen E. Rafter, Mansi M. Kasliwal, Ari Laor, Ehud Behar, James D. Neill, Benny Trakhtenbrot, Ilan Sagiv, Eran O. Ofek, Mark Sullivan, Dan Maoz, Ofer Lapid, and Eli Waxman
- Subjects
Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Extinction (astronomy) ,FOS: Physical sciences ,Astrophysics ,Astronomy & Astrophysics ,01 natural sciences ,Atomic ,Physical Chemistry ,Particle and Plasma Physics ,Clinical Research ,0103 physical sciences ,Blue supergiant ,Red supergiant ,Nuclear ,010303 astronomy & astrophysics ,Physics ,astro-ph.HE ,High Energy Astrophysical Phenomena (astro-ph.HE) ,010308 nuclear & particles physics ,Molecular ,Astronomy and Astrophysics ,Radius ,Light curve ,Galaxy ,Stars ,Supernova ,Space and Planetary Science ,astro-ph.CO ,Astrophysics - High Energy Astrophysical Phenomena ,general [supernovae] ,Astronomical and Space Sciences ,Astrophysics - Cosmology and Nongalactic Astrophysics ,Physical Chemistry (incl. Structural) - Abstract
The radius and surface composition of an exploding massive star,as well as the explosion energy per unit mass, can be measured using early UV observations of core collapse supernovae (SNe). We present the first results from a simultaneous GALEX/PTF search for early UV emission from SNe. Six Type II SNe and one Type II superluminous SN (SLSN-II) are clearly detected in the GALEX NUV data. We compare our detection rate with theoretical estimates based on early, shock-cooling UV light curves calculated from models that fit existing Swift and GALEX observations well, combined with volumetric SN rates. We find that our observations are in good agreement with calculated rates assuming that red supergiants (RSGs) explode with fiducial radii of 500 solar, explosion energies of 10^51 erg, and ejecta masses of 10 solar masses. Exploding blue supergiants and Wolf-Rayet stars are poorly constrained. We describe how such observations can be used to derive the progenitor radius, surface composition and explosion energy per unit mass of such SN events, and we demonstrate why UV observations are critical for such measurements. We use the fiducial RSG parameters to estimate the detection rate of SNe during the shock-cooling phase (100 SNe per year (~0.5 SN per deg^2), independent of host galaxy extinction, down to an NUV detection limit of 21.5 mag AB. Our pilot GALEX/PTF project thus convincingly demonstrates that a dedicated, systematic SN survey at the NUV band is a compelling method to study how massive stars end their life., See additional information including animations on http://www.weizmann.ac.il/astrophysics/ultrasat
- Published
- 2016
29. The WiggleZ Dark Energy Survey: the transition to large-scale cosmic homogeneity
- Author
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Sarah Brough, J. Berian James, Russell J. Jurek, Michael J. Drinkwater, Ted K. Wyder, Karl Forster, Michael D. Gladders, Matthew Colless, D. Christopher Martin, Morag I. Scrimgeour, Kevin A. Pimbblet, Tamara M. Davis, Ben Jelliffe, Karl Glazebrook, Scott M. Croom, Chris Blake, David Gilbank, Carlos Contreras, Howard K. C. Yee, Barry F. Madore, David Woods, Lister Staveley-Smith, Darren J. Croton, Gregory B. Poole, Warrick J. Couch, I-hui Li, Emily Wisnioski, Michael Pracy, and Rob Sharp
- Subjects
Physics ,COSMIC cancer database ,Fractal ,Scale (ratio) ,Space and Planetary Science ,Homogeneity (statistics) ,Dark energy ,Astronomy and Astrophysics ,Astrophysics ,Radius ,Fractal dimension ,Galaxy - Abstract
We have made the largest-volume measurement to date of the transition to large-scale homogeneity in the distribution of galaxies. We use the WiggleZ survey, a spectroscopic survey of over 200,000 blue galaxies in a cosmic volume of ~1 (Gpc/h)^3. A new method of defining the 'homogeneity scale' is presented, which is more robust than methods previously used in the literature, and which can be easily compared between different surveys. Due to the large cosmic depth of WiggleZ (up to z=1) we are able to make the first measurement of the transition to homogeneity over a range of cosmic epochs. The mean number of galaxies N(
- Published
- 2012
30. The WiggleZ Dark Energy Survey: joint measurements of the expansion and growth history atz< 1
- Author
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Michael Pracy, Scott M. Croom, Darren J. Croton, Rob Sharp, Sarah Brough, Gregory B. Poole, Barry F. Madore, Michael J. Drinkwater, Matthew Colless, Kevin A. Pimbblet, Warrick J. Couch, Ben Jelliffe, Chris Blake, Michael D. Gladders, Karl Glazebrook, Karl Forster, David Gilbank, Howard K. C. Yee, Carlos Contreras, Russell J. Jurek, Ted K. Wyder, Emily Wisnioski, D. Christopher Martin, David Woods, Tamara M. Davis, and I-hui Li
- Subjects
Physics ,010308 nuclear & particles physics ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Covariance ,01 natural sciences ,Galaxy ,Redshift ,Metric expansion of space ,Baryon ,Supernova ,symbols.namesake ,Space and Planetary Science ,0103 physical sciences ,Dark energy ,symbols ,010303 astronomy & astrophysics ,Hubble's law - Abstract
We perform a joint determination of the distance-redshift relation and cosmic expansion rate at redshifts z = 0.44, 0.6 and 0.73 by combining measurements of the baryon acoustic peak and Alcock-Paczynski distortion from galaxy clustering in the WiggleZ Dark Energy Survey, using a large ensemble of mock catalogues to calculate the covariance between the measurements. We find that D_A(z) = (1205 +/- 114, 1380 +/- 95, 1534 +/- 107) Mpc and H(z) = (82.6 +/- 7.8, 87.9 +/- 6.1, 97.3 +/- 7.0) km/s/Mpc at these three redshifts. Further combining our results with other baryon acoustic oscillation and distant supernovae datasets, we use a Monte Carlo Markov Chain technique to determine the evolution of the Hubble parameter H(z) as a stepwise function in 9 redshift bins of width dz = 0.1, also marginalizing over the spatial curvature. Our measurements of H(z), which have precision better than 7% in most redshift bins, are consistent with the expansion history predicted by a cosmological-constant dark-energy model, in which the expansion rate accelerates at redshift z < 0.7.
- Published
- 2012
31. The WiggleZ Dark Energy Survey: mapping the distance-redshift relation with baryon acoustic oscillations
- Author
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Michael J. Drinkwater, David Woods, Michael Pracy, Russell J. Jurek, Ben Jelliffe, Sarah Brough, Karl Glazebrook, I-hui Li, D. Christopher Martin, Tamara M. Davis, Ted K. Wyder, Scott M. Croom, Matthew Colless, Kevin A. Pimbblet, Eyal A. Kazin, Howard K. C. Yee, Rob Sharp, Michael D. Gladders, Karl Forster, Barry F. Madore, Emily Wisnioski, Darren J. Croton, Gregory B. Poole, Warrick J. Couch, Chris Blake, Carlos Contreras, Florian Beutler, David Gilbank, and David Parkinson
- Subjects
Physics ,Cosmic microwave background ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Cosmological constant ,Correlation function (astronomy) ,Galaxy ,Redshift ,Baryon ,Space and Planetary Science ,Dark energy ,Baryon acoustic oscillations ,Astrophysics::Galaxy Astrophysics - Abstract
We present measurements of the baryon acoustic peak at redshifts z = 0.44, 0.6 and 0.73 in the galaxy correlation function of the final dataset of the WiggleZ Dark Energy Survey. We combine our correlation function with lower-redshift measurements from the 6-degree Field Galaxy Survey and Sloan Digital Sky Survey, producing a stacked survey correlation function in which the statistical significance of the detection of the baryon acoustic peak is 4.9-sigma relative to a zero-baryon model with no peak. We fit cosmological models to this combined baryon acoustic oscillation (BAO) dataset comprising six distance-redshift data points, and compare the results to similar fits to the latest compilation of supernovae (SNe) and Cosmic Microwave Background (CMB) data. The BAO and SNe datasets produce consistent measurements of the equation-of-state w of dark energy, when separately combined with the CMB, providing a powerful check for systematic errors in either of these distance probes. Combining all datasets we determine w = -1.03 +/- 0.08 for a flat Universe, consistent with a cosmological constant model. Assuming dark energy is a cosmological constant and varying the spatial curvature, we find Omega_k = -0.004 +/- 0.006.
- Published
- 2011
32. The WiggleZ Dark Energy Survey: measuring the cosmic expansion history using the Alcock-Paczynski test and distant supernovae
- Author
-
Ted K. Wyder, Sarah Brough, David Woods, Ben Jelliffe, D. Christopher Martin, Tamara M. Davis, Russell J. Jurek, Chris Blake, David Gilbank, Howard K. C. Yee, Karl Forster, Scott M. Croom, Michael J. Drinkwater, Emily Wisnioski, Carlos Contreras, Matthew Colless, Kevin A. Pimbblet, Michael D. Gladders, Karl Glazebrook, I-hui Li, Barry F. Madore, Rob Sharp, Gregory B. Poole, Warrick J. Couch, and Michael Pracy
- Subjects
Physics ,COSMIC cancer database ,media_common.quotation_subject ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Measure (mathematics) ,Universe ,Redshift ,Galaxy ,Metric expansion of space ,Supernova ,Space and Planetary Science ,Dark energy ,media_common - Abstract
Astronomical observations suggest that today's Universe is dominated by a dark energy of unknown physical origin. One of the most notable consequences in many models is that dark energy should cause the expansion of the Universe to accelerate: but the expansion rate as a function of time has proven very difficult to measure directly. We present a new determination of the cosmic expansion history by combining distant supernovae observations with a geometrical analysis of large-scale galaxy clustering within the WiggleZ Dark Energy Survey, using the Alcock-Paczynski test to measure the distortion of standard spheres. Our result constitutes a robust and non-parametric measurement of the Hubble expansion rate as a function of time, which we measure with 10-15% precision in four bins within the redshift range 0.1 < z < 0.9. We demonstrate that the cosmic expansion is accelerating, in a manner independent of the parameterization of the cosmological model (although assuming cosmic homogeneity in our data analysis). Furthermore, we find that this expansion history is consistent with a cosmological-constant dark energy.
- Published
- 2011
33. The WiggleZ Dark Energy Survey: testing the cosmological model with baryon acoustic oscillations at z= 0.6
- Author
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Russell J. Jurek, David Gilbank, Chris Blake, Ted K. Wyder, Carlos Contreras, Matthew Colless, Kevin A. Pimbblet, Scott M. Croom, D. Christopher Martin, Howard K. C. Yee, Tamara M. Davis, I-hui Li, David Woods, Rob Sharp, Emily Wisnioski, Ben Jelliffe, David Parkinson, Barry F. Madore, Sarah Brough, Michael J. Drinkwater, Karl Glazebrook, Karl Forster, Michael Pracy, Warrick J. Couch, Gregory B. Poole, and Michael D. Gladders
- Subjects
Physics ,Cold dark matter ,Space and Planetary Science ,Cosmic microwave background ,Dark energy ,Spectral density ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Baryon acoustic oscillations ,Correlation function (astronomy) ,Redshift ,Galaxy - Abstract
We measure the imprint of baryon acoustic oscillations (BAOs) in the galaxy clustering pattern at the highest redshift achieved to date, z=0.6, using the distribution of N=132,509 emission-line galaxies in the WiggleZ Dark Energy Survey. We quantify BAOs using three statistics: the galaxy correlation function, power spectrum and the band-filtered estimator introduced by Xu et al. (2010). The results are mutually consistent, corresponding to a 4.0% measurement of the cosmic distance-redshift relation at z=0.6 (in terms of the acoustic parameter "A(z)" introduced by Eisenstein et al. (2005) we find A(z=0.6) = 0.452 +/- 0.018). Both BAOs and power spectrum shape information contribute toward these constraints. The statistical significance of the detection of the acoustic peak in the correlation function, relative to a wiggle-free model, is 3.2-sigma. The ratios of our distance measurements to those obtained using BAOs in the distribution of Luminous Red Galaxies at redshifts z=0.2 and z=0.35 are consistent with a flat Lambda Cold Dark Matter model that also provides a good fit to the pattern of observed fluctuations in the Cosmic Microwave Background (CMB) radiation. The addition of the current WiggleZ data results in a ~ 30% improvement in the measurement accuracy of a constant equation-of-state, w, using BAO data alone. Based solely on geometric BAO distance ratios, accelerating expansion (w < -1/3) is required with a probability of 99.8%, providing a consistency check of conclusions based on supernovae observations. Further improvements in cosmological constraints will result when the WiggleZ Survey dataset is complete.
- Published
- 2011
34. The WiggleZ Dark Energy Survey: the growth rate of cosmic structure since redshift z=0.9
- Author
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David Gilbank, D. Christopher Martin, Sarah Brough, Ted K. Wyder, Tamara M. Davis, Howard K. C. Yee, Barry F. Madore, Russell J. Jurek, Michael Pracy, Rob Sharp, Michael D. Gladders, Michael J. Drinkwater, Chris Blake, Carlos Contreras, Karl Glazebrook, Karl Forster, Scott M. Croom, Ben Jelliffe, Matthew Colless, Kevin A. Pimbblet, David Woods, Gregory B. Poole, Warrick J. Couch, Emily Wisnioski, and I-hui Li
- Subjects
Physics ,Supernova ,COSMIC cancer database ,Space and Planetary Science ,Dark energy ,Spectral density ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Baryon acoustic oscillations ,Astrophysics ,Galaxy ,Redshift ,Metric expansion of space - Abstract
We present precise measurements of the growth rate of cosmic structure for the redshift range 0.1 < z < 0.9, using redshift-space distortions in the galaxy power spectrum of the WiggleZ Dark Energy Survey. Our results, which have a precision of around 10% in four independent redshift bins, are well-fit by a flat LCDM cosmological model with matter density parameter Omega_m = 0.27. Our analysis hence indicates that this model provides a self-consistent description of the growth of cosmic structure through large-scale perturbations and the homogeneous cosmic expansion mapped by supernovae and baryon acoustic oscillations. We achieve robust results by systematically comparing our data with several different models of the quasi-linear growth of structure including empirical models, fitting formulae calibrated to N-body simulations, and perturbation theory techniques. We extract the first measurements of the power spectrum of the velocity divergence field, P_vv(k), as a function of redshift (under the assumption that P_gv(k) = -sqrt[P_gg(k) P_vv(k)] where g is the galaxy overdensity field), and demonstrate that the WiggleZ galaxy-mass cross-correlation is consistent with a deterministic (rather than stochastic) scale-independent bias model for WiggleZ galaxies for scales k < 0.3 h/Mpc. Measurements of the cosmic growth rate from the WiggleZ Survey and other current and future observations offer a powerful test of the physical nature of dark energy that is complementary to distance-redshift measures such as supernovae and baryon acoustic oscillations.
- Published
- 2011
35. THE KINEMATICS OF IONIZED GAS IN LYMAN-BREAK ANALOGS ATz∼ 0.2
- Author
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David R. Law, D. Christopher Martin, Antara Basu-Zych, David Schiminovich, Thiago S. Gonçalves, Ted K. Wyder, Roderik Overzier, R. Michael Rich, Ryan Mallery, and Timothy Heckman
- Subjects
Physics ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Line-of-sight ,Stellar mass ,media_common.quotation_subject ,Continuum (design consultancy) ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Kinematics ,Universe ,Galaxy ,Redshift ,Space and Planetary Science ,Dispersion (optics) ,Astrophysics::Galaxy Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics ,media_common - Abstract
We present results for 19 "Lyman Break Analogs" (LBAs) observed with Keck/OSIRIS with an AO-assisted spatial resolution of less than 200 pc. We detect satellites/companions, diffuse emission and velocity shear, all with high signal-to-noise ratios. These galaxies present remarkably high velocity dispersion along the line of sight(- 70 km s-1), much higher than standard star-forming spirals in the low-redshift universe. We artificially redshift our data to z - 2.2 to allow for a direct comparison with observations of high-z LBGs and find striking similarities between both samples. This suggests that either similar physical processes are responsible for their observed properties, or, alternatively, that it is very difficult to distinguish between different mechanisms operating in the low versus high redshift starburst galaxies based on the available data. The comparison between morphologies in the UV/optical continuum and our kinemetry analysis often shows that neither is by itself sufficient to confirm or completely rule out the contribution from recent merger events. We find a correlation between the kinematic properties and stellar mass, in that more massive galaxies show stronger evidence for a disk-like structure. This suggests a co-evolutionary process between the stellar mass build-up and the formation of morphological and dynamical sub-structure within the galaxy., Comment: 18 pages; accepted for publication in ApJ
- Published
- 2010
36. The UV-optical colour dependence of galaxy clustering in the local universe
- Author
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Yeong-Shang Loh, D. Christopher Martin, Young-Wook Lee, Mark Seibert, Patrick Morrissey, Sebastien Heinis, Luciana Bianchi, Samir Salim, Karl Forster, Susan G. Neff, Peter G. Friedman, Ted K. Wyder, R. Michael Rich, Jose Donas, Bruno Milliard, Alexander S. Szalay, Barry Y. Welsh, Timothy M. Heckman, Ryan Scranton, S. Yi, Ryan Mallery, Tom A. Barlow, Stephane Arnouts, David Schiminovich, and Barry F. Madore
- Subjects
Physics ,010308 nuclear & particles physics ,media_common.quotation_subject ,Diagram ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,01 natural sciences ,Redshift ,Galaxy ,Universe ,Luminosity ,Amplitude ,Space and Planetary Science ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Halo ,10. No inequality ,Cluster analysis ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,media_common - Abstract
We measure the UV-optical color dependence of galaxy clustering in the local universe. Using the clean separation of the red and blue sequences made possible by the NUV - r color-magnitude diagram, we segregate the galaxies into red, blue and intermediate "green" classes. We explore the clustering as a function of this segregation by removing the dependence on luminosity and by excluding edge-on galaxies as a means of a non-model dependent veto of highly extincted galaxies. We find that \xi (r_p, \pi) for both red and green galaxies shows strong redshift space distortion on small scales -- the "finger-of-God" effect, with green galaxies having a lower amplitude than is seen for the red sequence, and the blue sequence showing almost no distortion. On large scales, \xi (r_p, \pi) for all three samples show the effect of large-scale streaming from coherent infall. On scales 1 Mpc/h < r_p < 10 Mpc/h, the projected auto-correlation function w_p(r_p) for red and green galaxies fits a power-law with slope \gamma ~ 1.93 and amplitude r_0 ~ 7.5 and 5.3, compared with \gamma ~ 1.75 and r_0 ~ 3.9 Mpc/h for blue sequence galaxies. Compared to the clustering of a fiducial L* galaxy, the red, green, and blue have a relative bias of 1.5, 1.1, and 0.9 respectively. The w_p(r_p) for blue galaxies display an increase in convexity at ~ 1 Mpc/h, with an excess of large scale clustering. Our results suggest that the majority of blue galaxies are likely central galaxies in less massive halos, while red and green galaxies have larger satellite fractions, and preferentially reside in virialized structures. If blue sequence galaxies migrate to the red sequence via processes like mergers or quenching that take them through the green valley, such a transformation may be accompanied by a change in environment in addition to any change in luminosity and color.
- Published
- 2010
37. TIDAL DWARF GALAXIES AROUND A POST-MERGER GALAXY, NGC 4922
- Author
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D. Christopher Martin, Chang H. Ree, Tom A. Barlow, Jennifer M. Lotz, Ignacio Ferreras, Peter G. Friendman, Ted K. Wyder, Tim Conrow, Knut Olsen, Young-Wook Lee, Jang-Hyun Park, Sydney A. Barnes, Mark Seibert, Hyunjin Jeong, Barry F. Madore, Patrick Morrissey, Susan G. Neff, Sukyoung K. Yi, Karl Foster, Todd Small, David Schiminovich, Yun-Kyeong Sheen, and Mark Dickinson
- Subjects
Physics ,Cosmology and Nongalactic Astrophysics (astro-ph.CO) ,Stellar mass ,Star formation ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Astrophysics - Astrophysics of Galaxies ,Galaxy ,Stars ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Coma Cluster ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Tidal tail ,Astrophysics::Galaxy Astrophysics ,Astrophysics - Cosmology and Nongalactic Astrophysics ,Dwarf galaxy - Abstract
One possible channel for the formation of dwarf galaxies involves birth in the tidal tails of interacting galaxies. We report the detection of a bright UV tidal tail and several young tidal dwarf galaxy candidates in the post-merger galaxy NGC 4922 in the Coma cluster. Based on a two-component population model (combining young and old stellar populations), we find that the light of tidal tail predominantly comes from young stars (a few Myr old). The Galaxy Evolution Explorer (GALEX) ultraviolet data played a critical role in the parameter (age and mass) estimation. Our stellar mass estimates of the tidal dwarf galaxy candidates are ~ 10^{6-7} M_sun, typical for dwarf galaxies., Comment: 10 pages, 7 figures, 2 tables - Published in AJ; v2 Minor revision to match published version
- Published
- 2009
38. Quenching Star Formation in the Green Valley: The Mass Flux at Intermediate Redshifts
- Author
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D. Christopher Martin and Thiago S. Gonçalves
- Subjects
Mass flux ,Physics ,Number density ,Space and Planetary Science ,Star formation ,Magnitude (astronomy) ,Astronomy ,Astronomy and Astrophysics ,Astrophysics ,Spectral line ,Bin ,Galaxy ,Redshift - Abstract
We have obtained several hundred very deep spectra with DEIMOS/Keck in order to estimate the galactic mass flux density at intermediate redshifts (0.6 < z < 0.9) from the "blue cloud" to the red sequence across the so-called “green valley”, the intermediate region in the color-magnitude plot between those two populations. We use spectral indices (specifically Dn(4000) and Hδ, A) to determine star formation histories. Together with an independent measurement of number density of galaxies in each bin of the color-magnitude plot, one can infer the rate at which galaxies from a given sample are transiting through that bin. Measuring this value for all magnitude values, studies at lower redshift determined that the mass flux density in the green valley is comparable to both the mass build-up rate of the red sequence and the mass loss rate from the blue cloud. We show preliminary results for our intermediate redshift sample.
- Published
- 2009
39. Lyα‐Emitting Galaxies at 0.2 < z < 0.35 fromGALEXSpectroscopy
- Author
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R. Michael Rich, Barry Y. Welsh, Jean Michel Deharveng, Timothy M. Heckman, Sukyoung K. Yi, Jose Donas, Todd Small, D. Christopher Martin, Barry F. Madore, Luciana Bianchi, Karl Forster, Susan G. Neff, David Schiminovich, Patrick Morrissey, Young-Wook Lee, Mark Seibert, Bruno Milliard, Alexander S. Szalay, Tom A. Barlow, Celine Peroux, Peter G. Friedman, and Ted K. Wyder
- Subjects
Physics ,010504 meteorology & atmospheric sciences ,Stellar population ,Continuum (design consultancy) ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,01 natural sciences ,Galaxy ,Redshift ,Luminosity ,Space and Planetary Science ,0103 physical sciences ,Galaxy formation and evolution ,010303 astronomy & astrophysics ,Equivalent width ,Astrophysics::Galaxy Astrophysics ,0105 earth and related environmental sciences ,Luminosity function (astronomy) - Abstract
The GALEX (Galaxy Evolution Explorer) spectroscopic survey mode, with a resolution of about 8 A in the FUV (1350 - 1750 A) and about 20 A in the NUV (1950 - 2750 A) is used for a systematic search of Ly-a emitting galaxies at low redshift. This aims at filling a gap between high-redshift surveys and a small set of objects studied in detail in the nearby universe. A blind search of 7018 spectra extracted in 5 deep exposures (5.65 sq.deg) has resulted in 96 Ly-a emitting galaxy candidates in the FUV domain, after accounting for broad-line AGNs. The Ly-a EWs (equivalent width) are consistent with stellar population model predictions and show no trends as a function of UV color or UV luminosity, except a possible decrease in the most luminous that may be due to small-number statistics. Their distribution in EW is similar to that at z about 3 but their fraction among star-forming galaxies is smaller. Avoiding uncertain candidates, a sub-sample of 66 objects in the range 0.2 < z < 0.35 has been used to build a Ly-a LF (luminosity function). The incompleteness due to objects with significant Ly-a emission but a UV continuum too low for spectral extraction has been evaluated. A comparison with H-a LF in the same redshift domain is consistent with an average Ly-a/H-a of about 1 in about 15 % of the star-forming galaxies. A comparison with high-redshift Ly-a LFs implies an increase of the Ly-a luminosity density by a factor of about 16 from z about 0.3 to z about 3. By comparison with the factor 5 increase of the UV luminosity density in the same redshift range, this suggests an increase of the average Ly-a escape fraction with redshift.
- Published
- 2008
40. Hubble Space TelescopeMorphologies of Local Lyman Break Galaxy Analogs. I. Evidence for Starbursts Triggered by Merging
- Author
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Stéphane Charlot, Jennifer M. Lotz, David Schiminovich, Antara Basu-Zych, Roderik Overzier, Barry F. Madore, Mark Seibert, Alessandra Aloisi, Guinevere Kauffmann, Timothy M. Heckman, D. Christopher Martin, R. Michael Rich, and Charles G. Hoopes
- Subjects
Physics ,education.field_of_study ,Star formation ,Population ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,Galaxy ,Redshift ,Stars ,Star cluster ,Space and Planetary Science ,education ,Lyman-break galaxy ,Astrophysics::Galaxy Astrophysics ,Luminosity function (astronomy) - Abstract
Heckman et al. (2005) used the Galaxy Evolution Explorer (GALEX) UV imaging survey to show that there exists a rare population of nearby compact UV-luminous galaxies (UVLGs) that closely resembles high redshift Lyman break galaxies (LBGs). We present HST images in the UV, optical, and Ha, and resimulate them at the depth and resolution of the GOODS/UDF fields to show that the morphologies of UVLGs are also similar to those of LBGs. Our sample of 8 LBG analogs thus provides detailed insight into the connection between star formation and LBG morphology. Faint tidal features or companions can be seen in all of the rest-frame optical images, suggesting that the starbursts are the result of a merger or interaction. The UV/optical light is dominated by unresolved (~100-300 pc) super starburst regions (SSBs). A detailed comparison with the galaxies Haro 11 and VV 114 at z=0.02 indicates that the SSBs themselves consist of diffuse stars and (super) star clusters. The structural features revealed by the new HST images occur on very small physical scales and are thus not detectable in images of high redshift LBGs, except in a few cases where they are magnified by gravitational lensing. We propose, therefore, that LBGs are mergers of gas-rich, relatively low-mass (~10^10 Msun) systems, and that the mergers trigger the formation of SSBs. If galaxies at high redshifts are dominated by SSBs, then the faint end slope of the luminosity function is predicted to have slope alpha~2. Our results are the most direct confirmation to date of models that predict that the main mode of star formation in the early universe was highly collisional.
- Published
- 2008
41. The Detection of M Dwarf UV Flare Events in the GALEX Data Archives
- Author
-
Tom A. Barlow, Stanley E. Browne, Jonathan Wheatley, David Schiminovich, Susan G. Neff, Todd Small, Mark Seibert, Ted K. Wyder, D. Christopher Martin, Karl Forster, Peter G. Friedman, Barry Y. Welsh, Oswald H. W. Siegmund, R. Michael Rich, Patrick Morrissey, and Andrew A. West
- Subjects
Photon ,Astrophysics::High Energy Astrophysical Phenomena ,Extreme ultraviolet lithography ,Software tool ,media_common.quotation_subject ,FOS: Physical sciences ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,medicine.disease_cause ,law.invention ,law ,medicine ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Galaxy Astrophysics ,media_common ,Physics ,Astrophysics (astro-ph) ,Astronomy and Astrophysics ,Stars ,Space and Planetary Science ,Sky ,Magnitude (astronomy) ,Astrophysics::Earth and Planetary Astrophysics ,Ultraviolet ,Flare - Abstract
We present the preliminary results from implementing a new software tool that enables inspection of time-tagged photon data for the astronomical sources contained within individual GALEX ultraviolet images of the sky. We have inspected the photon data contained within 1802 GALEX images to reveal rapid, short-term (, Accepted for the Astrophysical Journal Supplement, GALEX Special Issue
- Published
- 2007
42. The Calibration and Data Products of GALEX
- Author
-
Peter G. Friedman, Jose Donas, Patrick Morrissey, Barry F. Madore, Mark Seibert, R. Michael Rich, Young-Wook Lee, David Schiminovich, Susan G. Neff, Stéphane Arnouts, Tom A. Barlow, Ted K. Wyder, Todd Small, Barry Y. Welsh, Karl Forster, Timothy M. Heckman, Tim Conrow, Sukyoung K. Yi, Tamás Budavári, Bruno Milliard, Alexander S. Szalay, Luciana Bianchi, and D. Christopher Martin
- Subjects
Physics ,Data processing ,Pipeline (computing) ,media_common.quotation_subject ,Detector ,Astronomy and Astrophysics ,Field of view ,Galaxy ,Space and Planetary Science ,Sky ,Calibration ,Microchannel plate detector ,Remote sensing ,media_common - Abstract
We describe the calibration status and data products pertaining to the GR2 and GR3 data releases of the Galaxy Evolution Explorer (GALEX). These releases have identical pipeline calibrations that are significantly improved over the GR1 data release. GALEX continues to survey the sky in the far-ultraviolet (FUV, ~154 nm) and near-ultraviolet (NUV, ~232 nm) bands, providing simultaneous imaging with a pair of photon-counting, microchannel plate, delay line readout detectors. These 1.25° field of view detectors are well suited to ultraviolet observations because of their excellent red rejection and negligible background. A dithered mode of observing and photon list output pose complex requirements on the data processing pipeline, entangling detector calibrations, and aspect reconstruction algorithms. Recent improvements have achieved photometric repeatability of 0.05 and 0.03 m_(AB) in the FUV and NUV, respectively. We have detected a long-term drift of order 1% FUV and 6% NUV over the mission. Astrometric precision is of order 0.5" rms in both bands. In this paper we provide the GALEX user with a broad overview of the calibration issues likely to be confronted in the current release. Improvements are likely as the GALEX mission continues into an extended phase with a healthy instrument, no consumables, and increased opportunities for guest investigations.
- Published
- 2007
43. GALEX UV Color Relations for Nearby Early‐Type Galaxies
- Author
-
Ted K. Wyder, Alessandro Boselli, Timothy M. Heckman, Bruno Milliard, Alexander S. Szalay, Samuel Boissier, Barry Y. Welsh, Samir Salim, R. Michael Rich, D. Christopher Martin, Sukyoung K. Yi, David Schiminovich, Young-Wook Lee, Tom A. Barlow, Luciana Bianchi, Stephane Charlot, Barry F. Madore, Jose Donas, Patrick Morrissey, Susan G. Neff, Armando Gil de Paz, Karl Forster, Jean Michel Deharveng, Mark Seibert, Todd Small, Peter G. Friedman, 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), Beaussier, Catherine, 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
Astrofísica ,Physics ,010504 meteorology & atmospheric sciences ,Star formation ,Astrophysics (astro-ph) ,FOS: Physical sciences ,Velocity dispersion ,Astronomy and Astrophysics ,Blanketing ,Astrophysics ,01 natural sciences ,Full sample ,Galaxy ,Early type ,[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] ,Photometry (optics) ,[PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] ,Space and Planetary Science ,0103 physical sciences ,Electricidad ,010303 astronomy & astrophysics ,Lenticular galaxy ,0105 earth and related environmental sciences - Abstract
We use GALEX/optical photometry to construct color-color relationships for early-type galaxies sorted by morphological type. We have matched objects in the GALEX GR1 public release and the first IR1.1 internal release, with the RC3 early-type galaxies having a morphological type -5.5, Comment: 25 pages, 5 figures, accepted for publication in ApJS (abstract abridged), typos corrected in section 2.1
- Published
- 2007
44. GALEX Ultraviolet Photometry of Globular Clusters in M31: Three‐Year Results and a Catalog
- Author
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Peter G. Friedman, David Schiminovich, Tom A. Barlow, Kyungsook Lee, Jaehyon Rhee, Patrick Morrissey, Jose Donas, Barry F. Madore, Soo-Chang Rey, Sangmo Tony Sohn, Barry Y. Welsh, Chul Chung, Ted K. Wyder, D. Christopher Martin, Suk-Jin Yoon, Young-Wook Lee, R. Michael Rich, Timothy M. Heckman, Todd Small, Bruno Milliard, Alexander S. Szalay, Mark Seibert, Luciana Bianchi, Karl Forster, Susan G. Neff, Sukyoung K. Yi, 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 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), and Beaussier, Catherine
- Subjects
Physics ,education.field_of_study ,010308 nuclear & particles physics ,Star formation ,Milky Way ,Astrophysics (astro-ph) ,Population ,FOS: Physical sciences ,Astronomy and Astrophysics ,Astrophysics ,01 natural sciences ,[PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] ,Galactic halo ,Photometry (optics) ,Stars ,[PHYS.ASTR.CO] Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO] ,Space and Planetary Science ,Globular cluster ,0103 physical sciences ,Galaxy formation and evolution ,education ,010303 astronomy & astrophysics - Abstract
We present ultraviolet (UV) photometry of M31 globular clusters (GCs) found in 23 Galaxy Evolution Explorer (GALEX) images covering the entirety of M31. We detect 485 and 273 GCs (and GC candidates) in the near-ultraviolet (NUV; 2267 A) and far-ultraviolet (FUV; 1516 A), respectively. Comparing M31 data with those of Galactic GCs in the UV with the aid of population models, we find that the age ranges of old GCs in M31 and the Galactic halo are similar. Three metal-rich ([Fe/H]>-1) GCs in M31 produce significant FUV flux making their FUV-V colors unusually blue for their metallicities. These are thought to be analogs of the two peculiar Galactic GCs NGC 6388 and NGC 6441 with extended blue HB stars. Based on the models incorporating helium enriched subpopulations in addition to the majority of the population that have a normal helium abundance, we suggest that even small fraction of super-helium-rich subpopulations in GCs can reproduce the observed UV bright metal-rich GCs. Young clusters in M31 show distinct UV and optical properties from GCs in Milky Way. Population models indicate that their typical age is less than ~ 2 Gyrs. A large fraction of young GCs have the kinematics of the thin, rapidly rotating disk component. However, a subset of the old GCs also shares the thin-disk kinematics of the younger clusters. The existence of young GCs on the outskirts of M31 disk suggests the occurrence of a significant recent star formation in the thin-disk of M31. Old thin-disk GCs may set constraints on the epoch of early formation of the M31 thin-disk. We detect 12 (10) intermediate-age GC candidates in NUV (FUV). We suggest that some of spectroscopically identified intermediate-age GCs may not be truly intermediate in age, but rather older GCs that possess developed HB., 43 pages, 14 figures, accepted for the GALEX special issue of ApJS
- Published
- 2007
45. The Diverse Properties of the Most Ultraviolet‐Luminous Galaxies Discovered by GALEX
- Author
-
Charles G. Hoopes, Luciana Bianchi, Peter G. Friedman, Patrick Morrissey, Stéphane Charlot, Bruno Milliard, D. Christopher Martin, Alexander S. Szalay, Jose Donas, Barry F. Madore, Samir Salim, Karl Forster, Mark Seibert, Guinevere Kauffmann, Young-Wook Lee, Susan G. Neff, Ted K. Wyder, Timothy M. Heckman, David Schiminovich, Sukyoung K. Yi, Todd Small, Christy Tremonti, Barry Y. Welsh, and R. Michael Rich
- Subjects
Physics ,education.field_of_study ,Brightness ,Stellar mass ,010308 nuclear & particles physics ,Population ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,01 natural sciences ,Galaxy ,Redshift ,Luminosity ,Space and Planetary Science ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Surface brightness ,education ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,Dwarf galaxy - Abstract
We report on the properties of a sample of ultraviolet-luminous galaxies (UVLGs) selected by matching the Galaxy Evolution Explorer (GALEX) All-Sky Imaging and Medium Imaging Surveys with the Sloan Digital Sky Survey third data release. The overlap between these two surveys is roughly 450 deg^2. Of 25,362 galaxies (with SDSS spectroscopy) in the range 0.0 < z < 0.3 detected by GALEX, there are 215 galaxies with L > 2 × 10^(10) L_☉ at 1530 Å (observed wavelength). The properties of this population are well correlated with ultraviolet surface brightness. We find that the galaxies with low UV surface brightness are primarily large spiral systems with a mixture of old and young stellar populations, while the high surface brightness galaxies consist primarily of compact starburst systems, with an approximate boundary at a surface brightness of I_(1530) = 10^8 L_☉ kpc^(−2). The large galaxies appear to be the high-luminosity tail of the galaxy star formation function and owe their large luminosity to their large surface area. In terms of the behavior of surface brightness with luminosity, size with luminosity, the mass-metallicity relation, and other parameters, the compact UVLGs clearly depart from the trends established by the full sample of galaxies. The subset of compact UVLGs with the highest surface brightness (I_(1530) > 10^9 L_☉ kpc^(−2); "supercompact UVLGs") have characteristics that are remarkably similar to Lyman break galaxies at higher redshift. They are much more luminous (and thus have much higher star formation rates) than typical local ultraviolet-bright starburst galaxies and blue compact dwarf galaxies. They have metallicities that are systematically lower than normal galaxies of the same stellar mass, indicating that they are less chemically evolved. In all these respects, they are the best local analogs for Lyman break galaxies.
- Published
- 2007
46. Noise and dark performance for FIREBall-2 EMCCD delta-doped CCD detector
- Author
-
Erika T. Hamden, Gillian Kyne, D. Christopher Martin, Nicole Lingner, Patrick Morrissey, and Siegmund, Oswald H. W.
- Subjects
Physics ,Galactic astronomy ,business.industry ,Astrophysics::High Energy Astrophysical Phenomena ,Detector ,Waveform shaping ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Cryocooler ,Noise (electronics) ,Photon counting ,Optics ,Optoelectronics ,business ,Astrophysics::Galaxy Astrophysics ,Voltage ,Dark current - Abstract
The Faint Intergalactic-medium Redshifted Emission Balloon (FIREBall-2) is an experiment designed to observe low density emission from HI, CIV, and OVI in the circum-galactic medium around low-redshift galaxies. To detect this diffuse emission, we use a high-efficiency photon-counting EMCCD as part of FIREBall-2's detector. The flight camera system includes a custom printed circuit board, a mechanical cryo-cooler, zeolite and charcoal getters, and a Nüvü controller, for fast read-out speeds and waveform shaping. Here we report on overall detector system performance, including pressure and temperature stability. We describe dark current and CIC measurements at several temperatures and substrate voltages, with the flight set-up.
- Published
- 2015
47. Deep GALEX UV Survey of the Kepler Field I: Point Source Catalog
- Author
-
Emanuele Bertone, James D. Neill, D. Christopher Martin, Manuel Olmedo, Eric E. Mamajek, Miguel Chavez, and James P. Lloyd
- Subjects
010504 meteorology & atmospheric sciences ,FOS: Physical sciences ,01 natural sciences ,Kepler Input Catalog ,0103 physical sciences ,010303 astronomy & astrophysics ,Instrumentation and Methods for Astrophysics (astro-ph.IM) ,Solar and Stellar Astrophysics (astro-ph.SR) ,0105 earth and related environmental sciences ,Physics ,Earth and Planetary Astrophysics (astro-ph.EP) ,White dwarf ,Astronomy ,Astronomy and Astrophysics ,Planetary system ,Horizontal branch ,Astrophysics - Astrophysics of Galaxies ,Exoplanet ,Galaxy ,Stars ,Photometry (astronomy) ,Astrophysics - Solar and Stellar Astrophysics ,13. Climate action ,Space and Planetary Science ,Astrophysics of Galaxies (astro-ph.GA) ,Astrophysics - Instrumentation and Methods for Astrophysics ,Astrophysics - Earth and Planetary Astrophysics - Abstract
We report observations of a deep near-ultraviolet (NUV) survey of the Kepler field made in 2012 with the Galaxy Evolution Explorer (GALEX) Complete All-Sky UV Survey Extension (CAUSE). The GALEX-CAUSE Kepler survey (GCK) covers 104 square degrees of the Kepler field and reaches limiting magnitude NUV=22.6 at 3{\sigma}. Analysis of the GCK survey has yielded a catalog of 669,928 NUV sources, of which 475,164 are cross-matched with stars in the Kepler Input Catalog (KIC). Approximately 327 of 451 confirmed exoplanet host stars and 2614 of 4696 candidate exoplanet host stars identified by Kepler have NUV photometry in the GCK survey. The GCK catalog should enable the identification and characterization of UV-excess stars in the Kepler field (young solar-type and low-mass stars, chromospherically active binaries, white dwarfs, horizontal branch stars, etc.), and elucidation of various astrophysics problems related to the stars and planetary systems in the Kepler field., Comment: Accepted for publication in ApJ. 10 pages, 10 figures
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- 2015
- Full Text
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48. TheGALEXUltraviolet Variability Catalog
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R. Michael Rich, Young-Wook Lee, Stanley E. Browne, Barry F. Madore, David Schiminovich, Tom A. Barlow, Y. I. Byun, Oswald H. W. Siegmund, Kenneth Heafield, Roger F. Malina, Todd Small, Susan G. Neff, Peter G. Friedman, Patrick N. Jelinsky, Luciana Bianchi, Ted K. Wyder, Bruno Milliard, Alexander S. Szalay, Timothy M. Heckman, Jonathan Wheatley, Jose Donas, D. Christopher Martin, Mark Seibert, Barry Y. Welsh, Karl Forster, Patrick Morrissey, and Samir Salim
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Physics ,010504 meteorology & atmospheric sciences ,Astronomy and Astrophysics ,Astrophysics ,Limiting ,RR Lyrae variable ,medicine.disease_cause ,01 natural sciences ,law.invention ,Stars ,Amplitude ,Space and Planetary Science ,law ,0103 physical sciences ,medicine ,Galaxy formation and evolution ,Satellite ,010303 astronomy & astrophysics ,Ultraviolet ,0105 earth and related environmental sciences ,Flare - Abstract
We present version 1.0 of the NASA Galaxy Evolution Explorer (GALEX) ultraviolet variability (GUVV) catalog, which contains information on 84 time-variable and transient sources gained with simultaneous near-ultraviolet (NUV) and far-ultraviolet (FUV) photometric observations. These time-variable sources were serendipitously revealed in the various 12 diameter star fields currently being surveyed by the GALEX satellite in two ultraviolet bands (NUV 1750–2750 A, FUV 1350–1750 A) with limiting AB magnitudes of 23–25. The largest amplitude variable objects currently detected by GALEX are M dwarf flare stars, which can brighten by 5–10 mag in both the NUV and FUV bands during short-duration (
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- 2005
49. Ultraviolet Morphology and Star Formation in the Tidal Tails of NGC 4038/39
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J. E. Hibbard, Luciana Bianchi, David A. Thilker, R. Michael Rich, David Schiminovich, C. Kevin Xu, Susan G. Neff, Mark Seibert, S. Lauger, D. Burgarella, Tom A. Barlow, Yong-Ik Byun, Jose Donas, Karl Forster, Peter G. Friedman, Timothy M. Heckman, Patrick N. Jelinsky, Young-Wook Lee, Barry F. Madore, Roger F. Malina, D. Christopher Martin, Bruno Milliard, Patrick Morrissey, Oswald H. W. Siegmund, Todd Small, Alex S. Szalay, Barry Y. Welsh, and Ted K. Wyder
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Physics ,Morphology (linguistics) ,010504 meteorology & atmospheric sciences ,Star formation ,Astronomy and Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics ,01 natural sciences ,Space and Planetary Science ,0103 physical sciences ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Halo ,010303 astronomy & astrophysics ,Astrophysics::Galaxy Astrophysics ,0105 earth and related environmental sciences ,Dwarf galaxy - Abstract
We present GALEX FUV (1530 A) and NUV (2310 A) observations of the archetypal merging system NGC 4038/39, ``The Antennae". Both tails are relatively bright in the UV, especially in the vicinity of the Tidal Dwarf Galaxy candidates at the end of the southern tail. The UV light generally falls within the optically delineated tails, although the UV light is considerably more structured, with a remarkably similar morphology to the tidal HI. The UV colors suggest that there has been continuing star formation within the tidal tails, even outside the previously studied Tidal Dwarf regions. Within the inner disk regions, there are interesting UV features which appear to be related to the extended soft X-ray loops and halo recently discovered by CHANDRA.
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- 2005
50. The Ultraviolet Galaxy Luminosity Function in the Local Universe from GALEX Data
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R. Michael Rich, Tamás Budavári, D. Christopher Martin, Stephane Arnouts, David Schiminovich, Patrick Jelinsky, Ted K. Wyder, Bruno Milliard, Alexander S. Szalay, Tom A. Barlow, Oswald H. W. Siegmund, Timothy M. Heckman, Yong-Ik Byun, Marie Treyer, Susan G. Neff, Peter G. Friedman, Karl Forster, Luciana Bianchi, Young-Wook Lee, Jose Donas, Barry Y. Welsh, Patrick Morrissey, Roger F. Malina, Todd Small, and Barry F. Madore
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2dF Galaxy Redshift Survey ,Physics ,010504 meteorology & atmospheric sciences ,Star formation ,media_common.quotation_subject ,Extinction (astronomy) ,Astronomy and Astrophysics ,Astrophysics ,01 natural sciences ,Redshift ,Galaxy ,Universe ,Luminosity ,Space and Planetary Science ,0103 physical sciences ,010303 astronomy & astrophysics ,0105 earth and related environmental sciences ,Luminosity function (astronomy) ,media_common - Abstract
We present the results of a determination of the galaxy luminosity function at ultraviolet wavelengths at redshifts of $z=0.0-0.1$ from GALEX data. We determined the luminosity function in the GALEX FUV and NUV bands from a sample of galaxies with UV magnitudes between 17 and 20 that are drawn from a total of 56.73 deg^2 of GALEX fields overlapping the b_j-selected 2dF Galaxy Redshift Survey. The resulting luminosity functions are fainter than previous UV estimates and result in total UV luminosity densities of 10^(25.55+/-0.12) ergs s^-1 Hz^-1 Mpc^-3 and 10^(25.72+/-0.12) ergs s^-1 Hz^-1 Mpc^-3 at 1530 Ang. and 2310 Ang., respectively. This corresponds to a local star formation rate density in agreement with previous estimates made with H-alpha-selected data for reasonable assumptions about the UV extinction.
- Published
- 2005
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