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Astrophysics and Astronomy

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University of Massachusetts Amherst

2014

Articles 31 - 55 of 55

Full-Text Articles in Physical Sciences and Mathematics

The Mass Evolution Of The First Galaxies: Stellar Mass Functions And Star Formation Rates At 4 < Z < 7 In The Candels Goods-South Field, K. Duncan, C.J. Conselice, A. Mortlock, W.G. Hartley, Y. Guo, H.C. Ferguson, R. Dave, Y. Lu, J. Ownsworth, M.L.N. Ashby, A. Dekel, M. Dickinson, S. Faber, Mauro Giavalisco, N. Grogin, D. Kocevski, A. Koekemoer, R.S. Somerville, C.E. White Jan 2014

The Mass Evolution Of The First Galaxies: Stellar Mass Functions And Star Formation Rates At 4 < Z < 7 In The Candels Goods-South Field, K. Duncan, C.J. Conselice, A. Mortlock, W.G. Hartley, Y. Guo, H.C. Ferguson, R. Dave, Y. Lu, J. Ownsworth, M.L.N. Ashby, A. Dekel, M. Dickinson, S. Faber, Mauro Giavalisco, N. Grogin, D. Kocevski, A. Koekemoer, R.S. Somerville, C.E. White

Mauro Giavalisco

We measure new estimates for the galaxy stellar mass function and star formation rates for samples of galaxies at z ~ 4; 5; 6 & 7 using data in the CANDELS GOODS South-field. The deep near-infrared observations allow us to construct the stellar mass function at z > 6 directly for the first time. We estimate stellar masses for our sample by fitting the observed spectral energy distributions with synthetic stellar populations, including nebular line and continuum emission. The observed UV luminosity functions for the samples are consistent with previous observations, however we find that the observed MUV - M_ relation …

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An Empirical Model For The Star Formation History In Dark Matter Halos, Zhankui Lu, H. J. Mo, Yu Lu, Neal S. Katz, Martin D. Weinberg, Frank C. Van Den Bosch, Xiaohu Yang Jan 2014

An Empirical Model For The Star Formation History In Dark Matter Halos, Zhankui Lu, H. J. Mo, Yu Lu, Neal S. Katz, Martin D. Weinberg, Frank C. Van Den Bosch, Xiaohu Yang

Neal S. Katz

We develop an empirical approach to infer the star formation rate in dark matter haloes from the galaxy stellar mass function (SMF) at different redshifts and the local cluster galaxy luminosity function (CGLF), which has a steeper faint end relative to the SMF of local galaxies. As satellites are typically old galaxies which have been accreted earlier, this feature can cast important constraint on the formation of low-mass galaxies at high redshift. The evolution of the SMFs suggests the star formation in high-mass haloes (>1012 h−1 M⊙) has to be boosted at high redshift beyond what is expected from …

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Bayesian Inferences Of Galaxy Formation From The K-Band Luminosity And Hi Mass Functions Of Galaxies: Constraining Star Formation And Feedback, Yu Lu, H.J. Mo, Zhankui Lu, Neal S. Katz, Martin D. Weinberg Jan 2014

Bayesian Inferences Of Galaxy Formation From The K-Band Luminosity And Hi Mass Functions Of Galaxies: Constraining Star Formation And Feedback, Yu Lu, H.J. Mo, Zhankui Lu, Neal S. Katz, Martin D. Weinberg

Neal S. Katz

We infer mechanisms of galaxy formation for a broad family of semi-analytic models (SAMs) constrained by the K-band luminosity function and H I mass function of local galaxies using tools of Bayesian analysis. Even with a broad search in parameter space the whole model family fails to match to constraining data. In the best-fitting models, the star formation and feedback parameters in low-mass haloes are tightly constrained by the two data sets, and the analysis reveals several generic failures of models that similarly apply to other existing SAMs. First, based on the assumption that baryon accretion follows the dark matter …

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The Spitzer Survey Of Interstellar Clouds In The Gould Belt. Vi. The Auriga-California Molecular Cloud Observed With Irac And Mips, Hannah Broekhoven-Fiene, Brenda C. Matthews, Paul M. Harvey, R. A. Gutermuth, Tracy L. Huard, Nicholas F.H. Tothill, David Nutter, Tyler L. Bourke, James Difrancesco, Jes K. Jorgensen, Lori E. Allen, Nicholas L. Chapman, Michael M. Dunham, Bruno Merin, Jennifer Miller, Susan Terebey, Dawn E. Peterson, Karl R. Stapelfeldt Jan 2014

The Spitzer Survey Of Interstellar Clouds In The Gould Belt. Vi. The Auriga-California Molecular Cloud Observed With Irac And Mips, Hannah Broekhoven-Fiene, Brenda C. Matthews, Paul M. Harvey, R. A. Gutermuth, Tracy L. Huard, Nicholas F.H. Tothill, David Nutter, Tyler L. Bourke, James Difrancesco, Jes K. Jorgensen, Lori E. Allen, Nicholas L. Chapman, Michael M. Dunham, Bruno Merin, Jennifer Miller, Susan Terebey, Dawn E. Peterson, Karl R. Stapelfeldt

Robert A. Gutermuth

We present observations of the Auriga-California Molecular Cloud (AMC) at 3.6, 4.5, 5.8, 8.0, 24, 70, and 160 μm observed with the IRAC and MIPS detectors as part of the Spitzer Gould Belt Legacy Survey. The total mapped areas are 2.5 deg2 with IRAC and 10.47 deg2 with MIPS. This giant molecular cloud is one of two in the nearby Gould Belt of star-forming regions, the other being the Orion A Molecular Cloud (OMC). We compare source counts, colors, and magnitudes in our observed region to a subset of the SWIRE data that was processed through our pipeline. Using color-magnitude …

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Parametrising Star Formation Histories, Vimal Simha, David H. Weinberg, Charlie Conroy, Romeel Dave, Mark Fardal, Neal S. Katz, Benjamin D. Oppenheimer Jan 2014

Parametrising Star Formation Histories, Vimal Simha, David H. Weinberg, Charlie Conroy, Romeel Dave, Mark Fardal, Neal S. Katz, Benjamin D. Oppenheimer

Neal S. Katz

No abstract provided.

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Young Stellar Object Variability (Ysovar): Long Timescale Variations In The Mid-Infrared, L. M. Rebull, A. M. Cody, K. R. Covey, H. M. Gunther, L. A. Hillenbrand, P. Plavchan, K. Poppenhaeger, J. R. Stauffer, S. J. Wolk, R. A. Gutermuth, M. Morales-Calderon, I. Song, D. Barrado, A. Bayo, D. James, J. L. Hora, F. J. Vrba, C. Alves De Oliveira, J. Bouvier, S. J. Carey, J. M. Carpenter, F. Favata, K. Flaherty, J. Forbrich, J. Hernandez, M. J. Mccaughrean, S. T. Megeath, G. Micela, H. A. Smith, S. Terebey, N. Turner, L. Allen, D. Ardila, H. Bouy, S. Guieu Jan 2014

Young Stellar Object Variability (Ysovar): Long Timescale Variations In The Mid-Infrared, L. M. Rebull, A. M. Cody, K. R. Covey, H. M. Gunther, L. A. Hillenbrand, P. Plavchan, K. Poppenhaeger, J. R. Stauffer, S. J. Wolk, R. A. Gutermuth, M. Morales-Calderon, I. Song, D. Barrado, A. Bayo, D. James, J. L. Hora, F. J. Vrba, C. Alves De Oliveira, J. Bouvier, S. J. Carey, J. M. Carpenter, F. Favata, K. Flaherty, J. Forbrich, J. Hernandez, M. J. Mccaughrean, S. T. Megeath, G. Micela, H. A. Smith, S. Terebey, N. Turner, L. Allen, D. Ardila, H. Bouy, S. Guieu

Robert A. Gutermuth

The YSOVAR (Young Stellar Object VARiability) Spitzer Space Telescope observing program obtained the first extensive mid-infrared (3.6 and 4.5 μm) time series photometry of the Orion Nebula Cluster plus smaller footprints in 11 other star-forming cores (AFGL 490, NGC 1333, Mon R2, GGD 12-15, NGC 2264, L1688, Serpens Main, Serpens South, IRAS 20050+2720, IC 1396A, and Ceph C). There are ~29,000 unique objects with light curves in either or both IRAC channels in the YSOVAR data set. We present the data collection and reduction for the Spitzer and ancillary data, and define the "standard sample" on which we calculate statistics, …

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Discovering Extremely Compact And Metal-Poor, Star-Forming Dwarf Galaxies Out To Z ~ 0.9 In The Vimos Ultra-Deep Survey, R. Amorin, V. Sommariva, M. Castellano, A. Grazian, L. A. M. Tasca, A. Fontana, L. Pentericci, P. Cassata, B. Garilla, V. Le Brun, O. Le Fevre, D. Maccagni, R. Thomas, E. Vanzella, G Zamorani, E Zucca, S Bardelli, P Capak, L. Cassara, A Cimatti, J.G. Cuby, O. Cucciati, S. De La Torre, A. Durkalec, Mauro Giavalisco, N. P. Hathi, O. Ilbert, B. C. Lemaux, C. Moreau, S. Paltani, B. Ribeiro, M. Salvato, D. Schaerer, M. Scodeggio, M. Talia, Y. Taniguchi, L. Tresse, D. Vergani, P.W. Wang, S. Charlot, T. Contini, S. Fotopoulou, C. Lopez-Sanjuan, Y. Mellier, N. Scoville Jan 2014

Discovering Extremely Compact And Metal-Poor, Star-Forming Dwarf Galaxies Out To Z ~ 0.9 In The Vimos Ultra-Deep Survey, R. Amorin, V. Sommariva, M. Castellano, A. Grazian, L. A. M. Tasca, A. Fontana, L. Pentericci, P. Cassata, B. Garilla, V. Le Brun, O. Le Fevre, D. Maccagni, R. Thomas, E. Vanzella, G Zamorani, E Zucca, S Bardelli, P Capak, L. Cassara, A Cimatti, J.G. Cuby, O. Cucciati, S. De La Torre, A. Durkalec, Mauro Giavalisco, N. P. Hathi, O. Ilbert, B. C. Lemaux, C. Moreau, S. Paltani, B. Ribeiro, M. Salvato, D. Schaerer, M. Scodeggio, M. Talia, Y. Taniguchi, L. Tresse, D. Vergani, P.W. Wang, S. Charlot, T. Contini, S. Fotopoulou, C. Lopez-Sanjuan, Y. Mellier, N. Scoville

Mauro Giavalisco

No abstract provided.

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Csi 2264: Characterizing Accretion-Burst Dominated Light Curves For Young Stars In Ngc 2264, John Stauffer, Ann Marie Cody, Anne Baglin, Silvia Alenzcar, Luisa Rebull, Lynne A. Hillenbrand, Laura Venzuti, Neal J. Turner, John Carpenter, Peter Plavchan, Krzysztof Findeisen, Sean Carey, Susan Terebey, Maria Morales-Calderon, Jerome Bouvier, Guishi Micela, Ettore Flaccomio, Inseok Song, R. A. Gutermuth, Lee Hartmann, Nuria Calvet, Barbara Whitney, David Barrado, Frederick J. Vrba, Kevin Covey, William Herbst, Gabor Furesz, Suzanne Aigrain, Fabio Favata Jan 2014

Csi 2264: Characterizing Accretion-Burst Dominated Light Curves For Young Stars In Ngc 2264, John Stauffer, Ann Marie Cody, Anne Baglin, Silvia Alenzcar, Luisa Rebull, Lynne A. Hillenbrand, Laura Venzuti, Neal J. Turner, John Carpenter, Peter Plavchan, Krzysztof Findeisen, Sean Carey, Susan Terebey, Maria Morales-Calderon, Jerome Bouvier, Guishi Micela, Ettore Flaccomio, Inseok Song, R. A. Gutermuth, Lee Hartmann, Nuria Calvet, Barbara Whitney, David Barrado, Frederick J. Vrba, Kevin Covey, William Herbst, Gabor Furesz, Suzanne Aigrain, Fabio Favata

Robert A. Gutermuth

Based on more than four weeks of continuous high cadence photometric monitoring of several hundred members of the young cluster NGC 2264 with two space telescopes, NASA’s Spitzer and the CNES CoRoT (Convection, Rotation, and planetary Transits), we provide high quality, multi-wavelength light curves for young stellar objects (YSOs) whose optical variability is dominated by short duration flux bursts, which we infer are due to enhanced mass accretion rates. These light curves show many brief – several hour to one day – brightenings at optical and near-infrared (IR) wavelengths with amplitudes generally in the range 5-50% of the quiescent value. …

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The Dependence Of Protostellar Lumosity On Environment In The Cygnus-X Star-Forming Complex, E. Kryukova, S.T. Megeath, J.L. Hora, R. A. Gutermuth, S. Bontemps, K. Kraemer, M. Hennemann, N. Schneider, Howard. A. Smith, F. Motte Jan 2014

The Dependence Of Protostellar Lumosity On Environment In The Cygnus-X Star-Forming Complex, E. Kryukova, S.T. Megeath, J.L. Hora, R. A. Gutermuth, S. Bontemps, K. Kraemer, M. Hennemann, N. Schneider, Howard. A. Smith, F. Motte

Robert A. Gutermuth

The Cygnus-X star-forming complex is one of the most active regions of low- and high-mass star formation within 2 kpc of the Sun. Using mid-infrared photometry from the IRAC and MIPS Spitzer Cygnus-X Legacy Survey, we have identified over 1800 protostar candidates. We compare the protostellar luminosity functions of two regions within Cygnus-X: CygX-South and CygX-North. These two clouds show distinctly different morphologies suggestive of dissimilar star-forming environments. We find the luminosity functions of these two regions are statistically different. Furthermore, we compare the luminosity functions of protostars found in regions of high and low stellar density within Cygnus-X and …

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A 52 Hours Vlt/Fors2 Spectrum Of A Bright Z ~ 7 Hudf Galaxy: No Lya Emission, E. Venzella, A. Fontana, L. Pentericci, M. Castellano, A. Grazian, Mauro Giavalisco, M. Nonino, S. Cristiani, G. Zamorani, C. Vignali Jan 2014

A 52 Hours Vlt/Fors2 Spectrum Of A Bright Z ~ 7 Hudf Galaxy: No Lya Emission, E. Venzella, A. Fontana, L. Pentericci, M. Castellano, A. Grazian, Mauro Giavalisco, M. Nonino, S. Cristiani, G. Zamorani, C. Vignali

Mauro Giavalisco

Aims: We aim to determine the redshift of GDS_1408, the most solid z _ 7 galaxy candidate lying in the Hubble Ultra Deep Field. Methods: We have used all the VLT spectra of GDS_1408 collected by us and two other groups with FORS2 at VLT in the last five years, for a total integration time of 52hr. The combined spectrum is the deepest ever obtained of a galaxy in the Reionization epoch. Results: We do not detect any emission line or continuum over the whole wavelength range, up to 10100Å. Based on an accurate set of simulations, we are able …

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Early Science With The Large Millimeter Telescope: Exploring The Effect Of Agn Activity On The Relationships Between Molecular Gas Dust And Star Formation, Allison Kirkpatrick, Alexandra Pope, Itziar Aretxaca, Lee Armus, Daniela Calzetti, George Helou, Alfredo Montana, Gopal Narayanan, F. Peter Schloerb, Young Shi, Olga Vega, Min Yun Jan 2014

Early Science With The Large Millimeter Telescope: Exploring The Effect Of Agn Activity On The Relationships Between Molecular Gas Dust And Star Formation, Allison Kirkpatrick, Alexandra Pope, Itziar Aretxaca, Lee Armus, Daniela Calzetti, George Helou, Alfredo Montana, Gopal Narayanan, F. Peter Schloerb, Young Shi, Olga Vega, Min Yun

Gopal Narayanan

The molecular gas, H2, that fuels star formation in galaxies is difficult to observe directly. As such, the ratio of LIR to is an observational estimate of the star formation rate compared with the amount of molecular gas available to form stars, which is related to the star formation efficiency and the inverse of the gas consumption timescale. We test what effect an IR luminous active galactic nucleus (AGN) has on the ratio in a sample of 24 intermediate redshift galaxies from the 5 mJy Unbiased Spitzer Extragalactic Survey (5MUSES). We obtain new CO(1–0) observations with the Redshift Search Receiver …

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The Vimos Ultra-Deep Survey (Vuds): Igm Transmission Towards Galaxies With 2.5, R. Thomas, O. Le Fevre, V. Le Brun, P. Cassata, B. Garilli, C. Lemaux, D. Maccagni, L. Pentericci, L.A.M. Tasca, G. Zamorani, R. Amorin, S. Bardelli, L. Cassara, M. Castellano, A. Cimatti, O. Cucciati, A. Durkalec, A. Fontana, Mauro Giavalisco, A. Grazian, N.P. Hathi, O. Ilbert, S. Paltani, B. Ribeiro, D. Schaerer, M. Scodeggio, V. Sommariva, M. Talia, L. Tresse, E. Vanzella, D. Vergani, P. Capak, S. Charlot, T. Contini, J.G. Cuby, S. De La Torre, J. Dunlop, S. Fotopoulou, A. Koekemoer, C. Lopez-Sanjuan, Y. Mellier, J. Pforr, M. Salvato, N. Scoville, Y. Taniguchi, P.W. Wang Jan 2014

The Vimos Ultra-Deep Survey (Vuds): Igm Transmission Towards Galaxies With 2.5, R. Thomas, O. Le Fevre, V. Le Brun, P. Cassata, B. Garilli, C. Lemaux, D. Maccagni, L. Pentericci, L.A.M. Tasca, G. Zamorani, R. Amorin, S. Bardelli, L. Cassara, M. Castellano, A. Cimatti, O. Cucciati, A. Durkalec, A. Fontana, Mauro Giavalisco, A. Grazian, N.P. Hathi, O. Ilbert, S. Paltani, B. Ribeiro, D. Schaerer, M. Scodeggio, V. Sommariva, M. Talia, L. Tresse, E. Vanzella, D. Vergani, P. Capak, S. Charlot, T. Contini, J.G. Cuby, S. De La Torre, J. Dunlop, S. Fotopoulou, A. Koekemoer, C. Lopez-Sanjuan, Y. Mellier, J. Pforr, M. Salvato, N. Scoville, Y. Taniguchi, P.W. Wang

Mauro Giavalisco

The observed UV rest-frame spectra of distant galaxies are the result of their intrinsic emission combined with absorption along the line of sight produced by the inter-galactic medium (IGM). Here we analyse the evolution of the mean IGM transmission Tr(Ly_alpha) and its dispersion along the line of sight for 2127 galaxies with 2.5= 4 compared to results from QSOs, but a degeneracy between dust extinction and IGM prevents to draw firm conclusions if the internal dust extinction for star-forming galaxies at z>4 takes a mean value significantly in excess of E(B-V)>0.15. Most importantly, we find a large dispersion …

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Tracing Inflows And Outlflows With Absorption Lines In Circumgalactic Gas, Amanda Brady Ford, Romeel Dave, Benjamin D. Oppenheimer, Neal S. Katz, Juna A. Kollmeier, Robert Thompson, David H. Weinberg Jan 2014

Tracing Inflows And Outlflows With Absorption Lines In Circumgalactic Gas, Amanda Brady Ford, Romeel Dave, Benjamin D. Oppenheimer, Neal S. Katz, Juna A. Kollmeier, Robert Thompson, David H. Weinberg

Neal S. Katz

We examine how H I and metal absorption lines within low-redshift galaxy haloes trace the dynamical state of circumgalactic gas, using cosmological hydrodynamic simulations that include a well-vetted heuristic model for galactic outflows. We categorize inflowing, outflowing, and ambient gas based on its history and fate as tracked in our simulation. Following our earlier work, showing that the ionization level of absorbers was a primary factor in determining the physical conditions of absorbing gas, we show here that it is also a governing factor for its dynamical state. Low-ionization metal absorbers (e.g. Mg II) tend to arise in gas that …

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Molecular Gas Content Of Hi Monsters And Implications To Cold Gas Content Evolution In Galaxies, Cheoljong Lee, Aeree Chung, Min S. Yun, Ryan Cybulski, Gopal Narayanan, N. Erickson Jan 2014

Molecular Gas Content Of Hi Monsters And Implications To Cold Gas Content Evolution In Galaxies, Cheoljong Lee, Aeree Chung, Min S. Yun, Ryan Cybulski, Gopal Narayanan, N. Erickson

Gopal Narayanan

No abstract provided.

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The Interstellar Medium And Feedback In The Progenitors Of The Compact Passive Galaxies At Z ~ 2, Christina C. Williams, Mauro Giavalisco, Bomee Lee, Elena Tundo, Bahram Mobasher, Hooshang Nayyeri, Henry C. Ferguson, Anton Koekemoer, Jonathan R. Trump, Paolo Cassata, Avishai Dekel, Yicheng Guo, Kyoung-Soo Lee, Laura Pentericci, Eric F. Bell, Marco Castellano, Steven L. Finkelstein, Adriano Fontana, Andrea Grazian, Norman Grogin, Dale Kocevski, David C. Koo, Ray A. Lucas, Swara Ravindranath, Paola Santini, Eros Vanzella, Benjamin J. Weiner Jan 2014

The Interstellar Medium And Feedback In The Progenitors Of The Compact Passive Galaxies At Z ~ 2, Christina C. Williams, Mauro Giavalisco, Bomee Lee, Elena Tundo, Bahram Mobasher, Hooshang Nayyeri, Henry C. Ferguson, Anton Koekemoer, Jonathan R. Trump, Paolo Cassata, Avishai Dekel, Yicheng Guo, Kyoung-Soo Lee, Laura Pentericci, Eric F. Bell, Marco Castellano, Steven L. Finkelstein, Adriano Fontana, Andrea Grazian, Norman Grogin, Dale Kocevski, David C. Koo, Ray A. Lucas, Swara Ravindranath, Paola Santini, Eros Vanzella, Benjamin J. Weiner

Mauro Giavalisco

Quenched galaxies at z>2 are nearly all very compact relative to z∼0, suggesting a physical connection between high stellar density and efficient, rapid cessation of star–formation. We present rest–frame UV spectra of Lyman–break galaxies (LBGs) at z ∼ 3 selected to be candidate progenitors of the quenched galaxies at z ∼ 2 based on their compact restframe-optical sizes and high _SFR. We compare their UV properties to those of more extended LBGs of similar mass and star–formation rate (non-candidates). We find that candidate progenitors have faster bulk ISM gas velocities and higher equivalent widths of interstellar absorption lines, implying …

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The Photon Underproduction Crisis, Juna A. Kollmeier, David H. Weinberg, Benjamin D. Oppenheimer, Francesco Haardt, Neal S. Katz, Rameel A. Dave, Mark Fardal, Piero Madau, Charles Danforth, Amanda B. Ford, Molly S. Peeples, Joseph Mcewen Jan 2014

The Photon Underproduction Crisis, Juna A. Kollmeier, David H. Weinberg, Benjamin D. Oppenheimer, Francesco Haardt, Neal S. Katz, Rameel A. Dave, Mark Fardal, Piero Madau, Charles Danforth, Amanda B. Ford, Molly S. Peeples, Joseph Mcewen

Neal S. Katz

We examine the statistics of the low-redshift Lyα forest from smoothed particle hydrodynamic simulations in light of recent improvements in the estimated evolution of the cosmic ultraviolet background (UVB) and recent observations from the Cosmic Origins Spectrograph (COS). We find that the value of the metagalactic photoionization rate (ΓHI) required by our simulations to match the observed properties of the low-redshift Lyα forest is a factor of five larger than the value predicted by state-of-the art models for the evolution of this quantity. This mismatch in ΓHI results in the mean flux decrement of the Lyα forest being overpredicted by …

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Geometry Of Star-Forming Galaxies From Sdss, 3d-Hst And Candels, A. Van Der Wel, Yu-Yen Chang, E. F. Bell, B. P. Holden, H.C. Ferguson, Mauro Giavalisco, H.W. Rix, R. Skelton, K. Whitaker, I. Momcheva, G. Brammer, S.A. Kassin, M. Martig, A. Dekel, D. Ceverino, D.C. Koo, M. Mozena, P.G. Van Dokkum, M. Franx, S.M. Faber, J. Primack Jan 2014

Geometry Of Star-Forming Galaxies From Sdss, 3d-Hst And Candels, A. Van Der Wel, Yu-Yen Chang, E. F. Bell, B. P. Holden, H.C. Ferguson, Mauro Giavalisco, H.W. Rix, R. Skelton, K. Whitaker, I. Momcheva, G. Brammer, S.A. Kassin, M. Martig, A. Dekel, D. Ceverino, D.C. Koo, M. Mozena, P.G. Van Dokkum, M. Franx, S.M. Faber, J. Primack

Mauro Giavalisco

No abstract provided.

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The Cos-Halos Survey: Physical Conditions And Baryonic Mass In The Low-Redshift Circumgalactic Medium, Jessica K. Werk, J. Xavier Prochaska, Jason Tumlinson, Molly S. Peeples, Todd M. Tripp, Andrew J. Fox, Nicolas Lehner, Christopher Thom, John M. O'Meara, Amanda Brady Ford, Rongmon Bordoloi, Neal S. Katz, Nicolas Tejos, Benjamin D. Oppenheimer, Romeel Dave, David H. Weinberg Jan 2014

The Cos-Halos Survey: Physical Conditions And Baryonic Mass In The Low-Redshift Circumgalactic Medium, Jessica K. Werk, J. Xavier Prochaska, Jason Tumlinson, Molly S. Peeples, Todd M. Tripp, Andrew J. Fox, Nicolas Lehner, Christopher Thom, John M. O'Meara, Amanda Brady Ford, Rongmon Bordoloi, Neal S. Katz, Nicolas Tejos, Benjamin D. Oppenheimer, Romeel Dave, David H. Weinberg

Neal S. Katz

We analyze the physical conditions of the cool, photoionized (T ~104 K) circumgalactic medium (CGM) using the COS-Halos suite of gas column density measurements for 44 gaseous halos within 160 kpc of L ~ L* galaxies at z ~ 0.2. These data are well described by simple photoionization models, with the gas highly ionized (n H II /n H gsim 99%) by the extragalactic ultraviolet background. Scaling by estimates for the virial radius, R vir, we show that the ionization state (tracked by the dimensionless ionization parameter, U) increases with distance from the host galaxy. The ionization parameters imply a …

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Ysovar: Mid-Ir Variability In The Star Forming Region Lynds 1688, H. M. Gunther, A. M. Cody, K. R. Covey, L. A. Hillenbrand, P. Plavchan, K. Poppenhaeger, L. M. Rebull, J. R. Stauffer, S. J. Wolk, L. Allen, A. Bayo, R. A. Gutermuth, J. L. Hora, H.Y.A. Meng, M. Morales-Calderon, J. R. Parks, Inseok Song Jan 2014

Ysovar: Mid-Ir Variability In The Star Forming Region Lynds 1688, H. M. Gunther, A. M. Cody, K. R. Covey, L. A. Hillenbrand, P. Plavchan, K. Poppenhaeger, L. M. Rebull, J. R. Stauffer, S. J. Wolk, L. Allen, A. Bayo, R. A. Gutermuth, J. L. Hora, H.Y.A. Meng, M. Morales-Calderon, J. R. Parks, Inseok Song

Robert A. Gutermuth

The emission from young stellar objects (YSOs) in the mid-infrared (mid-IR) is dominated by the inner rim of their circumstellar disks. We present IR data from the Young Stellar Object VARiability (YSOVAR) survey of ~800 objects in the direction of the Lynds 1688 (L1688) star-forming region over four visibility windows spanning 1.6 yr using the Spitzer Space Telescope in its warm mission phase. Among all light curves, 57 sources are cluster members identified based on their spectral energy distribution and X-ray emission. Almost all cluster members show significant variability. The amplitude of the variability is larger in more embedded YSOs. …

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The Vimos Ultra-Deep Survey (Vuds): ~10,000 Galaxies With Spectroscopic Redshifts To Study Galaxy Assembly At Early Epochs 2 < Z ≈ 6, O. Le Fevre, L.A.M. Tasca, P. Cassata, B. Garilli, V. Le Brun, D. Maccagni, L. Pentericci, R. Thomas, E. Vanzella, G. Zamorani, E. Zucca, R. Amorin, S. Bardelli, P. Capak, L. Cassara, M. Castellano, A. Cimatti, J.G. Cuby, O. Cucciati, S. De La Torre, A Durkalec, A. Fontana, Mauro Giavalisco, A. Grazian, N.P. Hathi, O. Ilbert, B.C. Lemaux, C. Moreau, S. Paltani, B. Ribeiro, M. Salvato, D. Schaerer, M. Scodeggio, V. Sommariva, M. Talia, Y. Taniguchi, L. Tresse, D. Vergani, P.W. Wang, S. Charlot, T. Contini, S. Fotopoulou, C. Lopez-Sanjuan, Y. Mellier, N. Scoville Jan 2014

The Vimos Ultra-Deep Survey (Vuds): ~10,000 Galaxies With Spectroscopic Redshifts To Study Galaxy Assembly At Early Epochs 2 < Z ≈ 6, O. Le Fevre, L.A.M. Tasca, P. Cassata, B. Garilli, V. Le Brun, D. Maccagni, L. Pentericci, R. Thomas, E. Vanzella, G. Zamorani, E. Zucca, R. Amorin, S. Bardelli, P. Capak, L. Cassara, M. Castellano, A. Cimatti, J.G. Cuby, O. Cucciati, S. De La Torre, A Durkalec, A. Fontana, Mauro Giavalisco, A. Grazian, N.P. Hathi, O. Ilbert, B.C. Lemaux, C. Moreau, S. Paltani, B. Ribeiro, M. Salvato, D. Schaerer, M. Scodeggio, V. Sommariva, M. Talia, Y. Taniguchi, L. Tresse, D. Vergani, P.W. Wang, S. Charlot, T. Contini, S. Fotopoulou, C. Lopez-Sanjuan, Y. Mellier, N. Scoville

Mauro Giavalisco

We present the VIMOS Ultra Deep Survey (VUDS), a spectroscopic redshift survey of ~10 000 very faint galaxies to study the main phase of galaxy assembly in 2 < z ≃ 6. The survey covers 1 deg2 in three separate fields: COSMOS, ECDFS, and VVDS-02h, with the selection of targets based on an inclusive combination of photometric redshifts and colour properties. Spectra covering 3650 < λ < 9350 Å are obtained with VIMOS on the ESO-VLT with integration times of 14h. Here we present the survey strategy, target selection, data processing, and the redshift measurement process with an emphasis on the specific methods used to adapt to this high-redshift range. We discuss the spectra quality and redshift reliability and derive a success rate in redshift measurement of 91%, or 74% by limiting the dataset to the most reliable measurements, down to a limiting magnitude iAB = 25. Measurements are performed all the way down to iAB = 27. The mean redshift of the main sample is z ~ 3 and extends over a broad redshift range mainly in 2 < z < 6. At 3 < z < 5, the galaxies cover a wide range of luminosities −23 < MNUV < −20.5, stellar mass 109M⊙ < M∗ < 1011M⊙, and star formation rates 1M⊙/yr < SFR < 103M⊙/yr. We discuss the spectral properties of galaxies using individual as well asstacked spectra. The comparison between spectroscopic and photometric redshifts as well as colour selection demonstrate the effectiveness of our selection scheme. From about ~ 90% of the data analysed so far, we expect to assemble >6000 galaxies with reliable spectroscopic redshifts in 2 < z < 6 when complete. This makes the VUDS the largest survey at these redshifts and offers the opportunity for unprecedented studies of the star-forming galaxy population and its distribution in large-scale structures during the main phase of galaxy assembly.

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The Cos-Dwarfs Survey: The Carbon Reservoir Around Sub-L Galaxies, Rongmon Bordoloi, Jason Tumlinson, Jessica K. Werk, Benjamin D. Oppenheimer, Molly S. Peeples, J. Xavier Prochaska, Todd M. Tripp, Neal S. Katz, Romeel Dave, Andrew J. Fox, Christopher Thom, Amanda Brady Ford, David H. Weinberg, Joseph N. Burchett, Juna A. Kollmeier Jan 2014

The Cos-Dwarfs Survey: The Carbon Reservoir Around Sub-L Galaxies, Rongmon Bordoloi, Jason Tumlinson, Jessica K. Werk, Benjamin D. Oppenheimer, Molly S. Peeples, J. Xavier Prochaska, Todd M. Tripp, Neal S. Katz, Romeel Dave, Andrew J. Fox, Christopher Thom, Amanda Brady Ford, David H. Weinberg, Joseph N. Burchett, Juna A. Kollmeier

Neal S. Katz

We report new observations of circumgalactic gas from the COS-Dwarfs survey, a systematic investigation of the gaseous halos around 43 low-mass z ≤ 0.1 galaxies using background QSOs observed with the Cosmic Origins Spectrograph. From the projected one-dimensional and two-dimensional distribution of C iv absorption, we find that C iv is detected out to ≈100 kpc (corresponding roughly to ≈0.5 Rvir) of the host galaxies. The C iv absorption strength falls off radially as a power law, and beyond ≈0.5 Rvir, no C iv absorption is detected above our sensitivity limit of ≈50–100 mÅ. We find a tentative correlation between …

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Connecting X-Ray And Infrared Variability Among Young Stellar Objects: Ruling Out Potential Sources Of Disk Fluctuations, K.M. Flaherty, J. Muzerolle, S.J. Wolk, G. Rieke, R. A. Gutermuth, Z. Balog, W. Herbst, S.T. Mageath, E. Furlan Jan 2014

Connecting X-Ray And Infrared Variability Among Young Stellar Objects: Ruling Out Potential Sources Of Disk Fluctuations, K.M. Flaherty, J. Muzerolle, S.J. Wolk, G. Rieke, R. A. Gutermuth, Z. Balog, W. Herbst, S.T. Mageath, E. Furlan

Robert A. Gutermuth

Variability in the infrared emission from disks around pre-main-sequence stars over the course of days to weeks appears to be common, but the physical cause of the changes in disk structure are not constrained. Here we present coordinated monitoring of one young cluster with the Spitzer and Chandra space telescopes aimed at studying the physical source of the variability. In fall 2011 we obtained 10 epochs of Chandra ACIS photometry over a period of 30 days with a roughly 3 day cadence contemporaneous with 20 epochs of Spitzer [3.6], [4.5] photometry over 40 days with a roughly 2 day cadence …

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Stellar Masses From The Candels Survey: The Goods-South And Uds Field, P. Satini, H.C. Ferguson, A Fontana, B. Mobasher, G. Barro, M. Castellano, S.L. Finkelstein, A. Grazian, L.T. Hsu, B. Lee, S.K. Lee, J. Pforr, M. Salvato, T. Wiklind, S. Wuyts, O. Almaini, M.C. Cooper, A. Galametz, B. Weiner, R. Amorin, K. Boutsia, C.J. Conselice, T. Dahlen, M.C. Cooper, Mauro Giavalisco, N.A. Grogin, Y. Guo, N.P. Hathi, D. Kocevski, A.M. Koekemoer, P. Kurczynski, E. Merlin, A. Mortlock, J.A. Newman, D. Paris, L. Pentericci, R. Simons, S.P. Willner Jan 2014

Stellar Masses From The Candels Survey: The Goods-South And Uds Field, P. Satini, H.C. Ferguson, A Fontana, B. Mobasher, G. Barro, M. Castellano, S.L. Finkelstein, A. Grazian, L.T. Hsu, B. Lee, S.K. Lee, J. Pforr, M. Salvato, T. Wiklind, S. Wuyts, O. Almaini, M.C. Cooper, A. Galametz, B. Weiner, R. Amorin, K. Boutsia, C.J. Conselice, T. Dahlen, M.C. Cooper, Mauro Giavalisco, N.A. Grogin, Y. Guo, N.P. Hathi, D. Kocevski, A.M. Koekemoer, P. Kurczynski, E. Merlin, A. Mortlock, J.A. Newman, D. Paris, L. Pentericci, R. Simons, S.P. Willner

Mauro Giavalisco

We present the public release of the stellar mass catalogs for the GOODS-S and UDS fields obtained using some of the deepest near-IR images available, achieved as part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) project. We combine the effort from ten different teams, who computed the stellar masses using the same photometry and the same redshifts. Each team adopted their preferred fitting code, assumptions, priors, and parameter grid. The com- bination of results using the same underlying stellar isochrones reduces the systematics associated with the fitting code and other choices. Thanks to the availability of different …

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The Neutral Hydrogen Content Of Galaxies In Cosmological Hydrodynamic Simulations, Romeel Dave, Neal S. Katz, Benjamin D. Oppenheimer, Juna A. Kollmeier, David H. Weinberg Jan 2014

The Neutral Hydrogen Content Of Galaxies In Cosmological Hydrodynamic Simulations, Romeel Dave, Neal S. Katz, Benjamin D. Oppenheimer, Juna A. Kollmeier, David H. Weinberg

Neal S. Katz

We examine the global H I properties of galaxies in quarter billion particle cosmological simulations using GADGET-2, focusing on how galactic outflows impact H I content. We consider four outflow models, including a new one (ezw) motivated by recent interstellar medium simulations in which the wind speed and mass loading factor scale as expected for momentum-driven outflows for larger galaxies and energy-driven outflows for dwarfs (σ < 75 km s−1). To obtain predicted H I masses, we employ a simple but effective local correction for particle self-shielding and an observationally constrained transition from neutral to molecular hydrogen. Our ezw simulation produces an H I mass function whose faint-end slope of −1.3 agrees well with observations from the Arecibo Fast Legacy ALFA survey; other models agree less well. Satellite galaxies have a bimodal distribution in H I fraction versus halo mass, with smaller satellites and/or those in larger haloes more often being H I deficient. At a given stellar mass, H I content correlates with the star formation rate and inversely correlates with metallicity, as expected if driven by stochasticity in the accretion rate. To higher redshifts, massive H I galaxies disappear and the mass function steepens. The global cosmic H I density conspires to remain fairly constant from z ∼ 5 → 0, but the relative contribution from smaller galaxies increases with redshift.

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The Relation Between Star Formation Rate And Stellar Mass For Galaxies At 3.5 < Z < 6.5 In Candels, Brett Salmon, Casey Papovich, Steven L. Finkelstein, Vithal Tilvi, Kristian Flinator, Peter Behroozi, Tomas Dahlen, Romeel Dave, Avishai Dekel, Mark Dickinson, Henry C. Ferguson, Mauro Giavalisco, James Long, Yu Lu, Bahram Mobasher, Naveen Reddy, Rachel S. Somerville, Risa H. Wechsler Jan 2014

The Relation Between Star Formation Rate And Stellar Mass For Galaxies At 3.5 < Z < 6.5 In Candels, Brett Salmon, Casey Papovich, Steven L. Finkelstein, Vithal Tilvi, Kristian Flinator, Peter Behroozi, Tomas Dahlen, Romeel Dave, Avishai Dekel, Mark Dickinson, Henry C. Ferguson, Mauro Giavalisco, James Long, Yu Lu, Bahram Mobasher, Naveen Reddy, Rachel S. Somerville, Risa H. Wechsler

Mauro Giavalisco

No abstract provided.

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