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Full-Text Articles in Physical Sciences and Mathematics
A Spectroscopically Confirmed Excess Of 24 Μm Sources In A Super Galaxy Group At Z=0.37: Enhanced Dusty Star Formation Relative To The Cluster And Field Environment, Kim-Vy H. Tran, Amelie Saintonge, John Moustakas, Lei Bai, Anthony H. Gonzalez, Bradford P. Holden, Dennis Zaritsky, Stefan Kautsch
A Spectroscopically Confirmed Excess Of 24 Μm Sources In A Super Galaxy Group At Z=0.37: Enhanced Dusty Star Formation Relative To The Cluster And Field Environment, Kim-Vy H. Tran, Amelie Saintonge, John Moustakas, Lei Bai, Anthony H. Gonzalez, Bradford P. Holden, Dennis Zaritsky, Stefan Kautsch
Chemistry and Physics Faculty Articles
To trace how dust-obscured star formation varies with environment, we compare the fraction of 24 μm sources in a super galaxy group to the field and a rich galaxy cluster at z ~ 0.35. We draw on multi-wavelength observations that combine Hubble, Chandra, and Spitzer imaging with extensive optical spectroscopy (>1800 redshifts) to isolate galaxies in each environment and thus ensure a uniform analysis. We focus on the four galaxy groups (σ1D = 303-580 km s–1) in supergroup 1120-12 that will merge to form a galaxy cluster comparable in mass to Coma. We find …
Dynamics Of Lyman Break Galaxies And Their Host Halos, James D. Lowenthal, David C. Koo, Luc Simard, Eelco Van Kampen
Dynamics Of Lyman Break Galaxies And Their Host Halos, James D. Lowenthal, David C. Koo, Luc Simard, Eelco Van Kampen
Astronomy: Faculty Publications
We present deep two-dimensional spectra of 22 candidate and confirmed Lyman break galaxies (LBGs) at redshifts 2 < z < 4 in the Hubble Deep Field (HDF) obtained at the Keck II telescope. The targets were preferentially selected with spatial extent and/or multiple knot morphologies, and we used slitmasks and individual slits tilted to optimize measurement of any spatially resolved kinematics. Our sample is more than 1 mag fainter and is at higher redshift than the kinematic LBG targets previously studied by others. The median target magnitude was I814 = 25.3, and total exposure times ranged from 10 to 50 ks. We measure redshifts, some new, ranging from z = 0.2072 to z = 4.056, including two interlopers at z < 1, and resulting in a sample of 14 LBGs with a median redshift z = 2.424. The morphologies and kinematics of the close pairs and multiple knot sources in our sample are generally inconsistent with galaxy formation scenarios postulating that LBGs occur only at the bottom of the potential wells of massive host halos; rather, they support "collisional starburst" models with significant …
Star Formation And Mass Assembly In High Redshift Galaxies, P. Santini, A. Fontana, A. Grazian, S. Salimbeni, F. Fiore, F. Fontanot, K. Boutsia, M. Castellano, S. Cristiani, C. De Santis, S. Gallozzi, E. Giallongo, N. Menci, M. Nonino, D. Paris, L. Pentericci, E. Vanzella
Star Formation And Mass Assembly In High Redshift Galaxies, P. Santini, A. Fontana, A. Grazian, S. Salimbeni, F. Fiore, F. Fontanot, K. Boutsia, M. Castellano, S. Cristiani, C. De Santis, S. Gallozzi, E. Giallongo, N. Menci, M. Nonino, D. Paris, L. Pentericci, E. Vanzella
Astronomy Department Faculty Publication Series
Aims. The goal of this work is to infer the star formation properties and the mass assembly process of high redshift (0.3 ≤ z < 2.5) galaxies from their IR emission using the 24 μm band of MIPS-Spitzer. Methods. We used an updated version of the GOODS-MUSIC catalog, which has multiwavelength coverage from 0.3 to 24 μm and either spectroscopic or accurate photometric redshifts.We describe how the catalog has been extended by the addition of mid-IR fluxes derived from theMIPS 24 μm image.We compared two different estimators of the star formation rate (SFR hereafter). One is the total infrared emission derived from 24 μm, estimated using both synthetic and empirical IR templates. The other one is a multiwavelength fit to the full galaxy SED, which automatically accounts for dust reddening and age–star formation activity degeneracies. For both estimates, we computed the SFR density and the specific SFR. Results. We show that the two SFR indicators are roughly consistent, once the uncertainties involved are taken into account. However, they show a systematic trend, IR-based estimates exceeding the fit-based ones as the star formation rate increases. With this new catalog, we show that: a) at z > 0.3, the star formation rate is correlated well with stellar mass, and this relationship seems to steepen with redshift if one relies on IR–based estimates of the SFR; b) the contribution to the global SFRD by massive galaxies increases with redshift up to ≃ 2.5, more rapidly than for galaxies of lower mass, but appears to flatten at higher z; c) despite this increase, the most important contributors to the SFRD at any z are galaxies …
Aztec Millimetre Survey Of The Cosmos Field - Ii. Source Count Overdensity And Correlations With Large-Scale Structure, J. E. Austermann, I. Aretxaga, D. H. Hughes, Y. Kang, S. Kim, James D. Lowenthal, T. A. Perera, D. B. Sanders, K. S. Scott, N. Scoville, G. W. Wilson, M. S. Yun
Aztec Millimetre Survey Of The Cosmos Field - Ii. Source Count Overdensity And Correlations With Large-Scale Structure, J. E. Austermann, I. Aretxaga, D. H. Hughes, Y. Kang, S. Kim, James D. Lowenthal, T. A. Perera, D. B. Sanders, K. S. Scott, N. Scoville, G. W. Wilson, M. S. Yun
Astronomy: Faculty Publications
We report an overdensity of bright submillimetre galaxies (SMGs) in the 0.15 deg AzTEC/COSMOS survey and a spatial correlation between the SMGs and the optical-IR galaxy density at z ≲ 1.1. This portion of the COSMOS field shows a ∼3σ overdensity of robust SMG detections when compared to a background, or 'blank-field', population model that is consistent with SMG surveys of fields with no extragalactic bias. The SMG overdensity is most significant in the number of very bright detections (14 sources with measured fluxes S > 6 mJy), which is entirely incompatible with sample variance within our adopted blank-field number densities …
Structural Properties Of Central Galaxies In Groups And Clusters, Yc Guo, Dh Mcintosh, Hj Mo, N Katz, Fc Van Den Bosch, M Weinberg, Sm Weinmann, A Pasquali, Xh Yang
Structural Properties Of Central Galaxies In Groups And Clusters, Yc Guo, Dh Mcintosh, Hj Mo, N Katz, Fc Van Den Bosch, M Weinberg, Sm Weinmann, A Pasquali, Xh Yang
Astronomy Department Faculty Publication Series
Using a statistically representative sample of 911 central galaxies (CENs) from the Sloan Digital Sky Survey (SDSS) Data Release 4 group catalogue, we study how the structure (shape and size) of the first rank (by stellar mass) group and cluster members depends on (1) galaxy stellar mass (Mstar), (2) the global environment defined by the dark matter halo mass (Mhalo) of the host group and (3) the local environment defined by their special halocentric position. We quantify the structure of SDSS galaxies with a galfit-based pipeline that fits two-dimensional Sérsic models to the r-band image data. Through tests with simulated …
Dust-Corrected Star Formation Rates Of Galaxies. I. Combinations Of H Alpha And Infrared Tracers, Rc Kennicutt, Cn Hao, D Calzetti, J Moustakas, Da Dale, G Bendo, Cw Engelbracht, Bd Johnson, Jc Lee
Dust-Corrected Star Formation Rates Of Galaxies. I. Combinations Of H Alpha And Infrared Tracers, Rc Kennicutt, Cn Hao, D Calzetti, J Moustakas, Da Dale, G Bendo, Cw Engelbracht, Bd Johnson, Jc Lee
Astronomy Department Faculty Publication Series
We combine Hα emission-line and infrared (IR) continuum measurements of two samples of nearby galaxies to derive dust attenuation-corrected star formation rates (SFRs). We use a simple energy balance based method that has been applied previously to H II regions in the Spitzer Infrared Nearby Galaxies Survey, and extend the methodology to integrated measurements of galaxies. We find that our composite Hα + IR based SFRs are in excellent agreement with attenuation-corrected SFRs derived from integrated spectrophotometry, over the full range of SFRs (0.01-80 M sun yr-1) and attenuations (0-2.5 mag) studied. We find that the combination of Hα and …
Hubble Space Telescope/Advanced Camera For Surveys Morphology Of Ly Alpha Emitters At Redshift 5.7 In The Cosmos Field, Y Taniguchi, Et. Al.
Hubble Space Telescope/Advanced Camera For Surveys Morphology Of Ly Alpha Emitters At Redshift 5.7 In The Cosmos Field, Y Taniguchi, Et. Al.
Astronomy Department Faculty Publication Series
We present detailed morphological properties of Lyα emitters (LAEs) at z ≈ 5.7 in the COSMOS field based on Hubble Space Telescope Advanced Camera for Surveys (ACS) data. The ACS imaging in the F814W filter covered 85 LAEs of the 119 LAEs identified in the full two square degree field, and 47 LAEs of them are detected in the ACS images. Nearly half of them are spatially extended with a size larger than 0.15 arcsec (∼0.88 kpc at z = 5.7) and up to 0.4 arcsec (∼2.5 kpc at z = 5.7). The others are nearly unresolved compact objects. Two …
Expanding The Search For Galaxies At Z Similar To 7-10 With New Nicmos Parallel Fields, Alaina L. Henry, Brian Siana, Matthew A. Malkan, Matthew L.N. Ashby, Carrie R. Bridge, Ranga-Ram Chary, James W. Colbert, Mauro Giavalisco, Harry I. Teplitz, Patrick J. Mccarthy
Expanding The Search For Galaxies At Z Similar To 7-10 With New Nicmos Parallel Fields, Alaina L. Henry, Brian Siana, Matthew A. Malkan, Matthew L.N. Ashby, Carrie R. Bridge, Ranga-Ram Chary, James W. Colbert, Mauro Giavalisco, Harry I. Teplitz, Patrick J. Mccarthy
Astronomy Department Faculty Publication Series
We have carried out a search for galaxies at z ∼ 7–10 in ∼14.4 arcmin2 of new NICMOS parallel imaging taken in the Great Observatories Origins Deep Survey (5.9 arcmin2), the Cosmic Origins Survey (7.2 arcmin2), and SSA22 (1.3 arcmin2). These images reach 5σ sensitivities of J110 = 26.0–27.5 (AB), and combined they increase the amount of deep near-infrared data by more than 60% in fields where the investment in deep optical data has already been made. We find no z > 7 candidates in our survey area, consistent with the Bouwens et al. measurements at z ∼ 7 and …
Biases And Uncertainties In Physical Parameter Estimates Of Lyman Break Galaxies From Broadband Photometry, Sk Lee, R Idzi, Hc Ferguson, Rs Somerville, T Wiklind, M Giavalisco
Biases And Uncertainties In Physical Parameter Estimates Of Lyman Break Galaxies From Broadband Photometry, Sk Lee, R Idzi, Hc Ferguson, Rs Somerville, T Wiklind, M Giavalisco
Astronomy Department Faculty Publication Series
We investigate the biases and uncertainties in estimates of physical parameters of high-redshift Lyman break galaxies (LBGs), such as stellar mass, mean stellar population age, and star formation rate (SFR), obtained from broadband photometry. These biases arise from the simplifying assumptions often used in fitting the spectral energy distributions (SEDs). By combining ΛCDM hierarchical structure formation theory, semianalytic treatments of baryonic physics, and stellar population synthesis models, we construct model galaxy catalogs from which we select LBGs at redshifts z ∼ 3.4, 4.0, and 5.0. The broadband photometric SEDs of these model LBGs are then analyzed by fitting galaxy template …
The Aztec/Sma Interferometric Imaging Survey Of Submillimeter-Selected High-Redshift Galaxies, Jd Younger, Gg Fazio, Js Huang, Min Yun, Gw Wilson, Mln Ashby, Ma Gurwell, Ab Peck, Gr Petitpas, Dj Wilner, Dh Hughes, I Aretxaga, S Kim, Ks Scott, J Austermann, T Perera, Jd Lowenthal
The Aztec/Sma Interferometric Imaging Survey Of Submillimeter-Selected High-Redshift Galaxies, Jd Younger, Gg Fazio, Js Huang, Min Yun, Gw Wilson, Mln Ashby, Ma Gurwell, Ab Peck, Gr Petitpas, Dj Wilner, Dh Hughes, I Aretxaga, S Kim, Ks Scott, J Austermann, T Perera, Jd Lowenthal
Astronomy Department Faculty Publication Series
We present results from a continuing interferometric survey of high-redshift submillimeter galaxies (SMGs) with the Submillimeter Array, including high-resolution (beam size ~2 arcsec) imaging of eight additional AzTEC 1.1 mm selected sources in the COSMOS field, for which we obtain six reliable (peak signal-to-noise ratio (S/N) >5 or peak S/N >4 with multiwavelength counterparts within the beam) and two moderate significance (peak S/N >4) detections. When combined with previous detections, this yields an unbiased sample of millimeter-selected SMGs with complete interferometric follow up. With this sample in hand, we (1) empirically confirm the radio-submillimeter association, (2) examine the submillimeter morphology—including …
The Aztec/Sma Interferometric Imaging Survey Of Submillimeter-Selected High-Redshift Galaxies, Joshua D. Younger, Giovanni G. Fazio, Jia Sheng Huang, Min S. Yun, Grant W. Wilson, Matthew L.N. Ashby, Mark A. Gurwell, Alison B. Peck, Glen R. Petitpas, David J. Wilner, David H. Hughes, Itziar Aretxaga, Sungeun Kim, Kimberly S. Scott, Jason Austermann, Thushara Perera, James D. Lowenthal
The Aztec/Sma Interferometric Imaging Survey Of Submillimeter-Selected High-Redshift Galaxies, Joshua D. Younger, Giovanni G. Fazio, Jia Sheng Huang, Min S. Yun, Grant W. Wilson, Matthew L.N. Ashby, Mark A. Gurwell, Alison B. Peck, Glen R. Petitpas, David J. Wilner, David H. Hughes, Itziar Aretxaga, Sungeun Kim, Kimberly S. Scott, Jason Austermann, Thushara Perera, James D. Lowenthal
Astronomy: Faculty Publications
We present results from a continuing interferometric survey of high-redshift submillimeter galaxies (SMGs) with the Submillimeter Array, including high-resolution (beam size ∼ 2 arcsec) imaging of eight additional AzTEC 1.1 mm selected sources in the COSMOS field, for which we obtain six reliable (peak signal-to-noise ratio (S/N) >5 or peak S/N >4 with multiwavelength counterparts within the beam) and two moderate significance (peak S/N >4) detections. When combined with previous detections, this yields an unbiased sample of millimeter-selected SMGs with complete interferometric follow up. With this sample in hand, we (1) empirically confirm the radio-submillimeter association, (2) examine the submillimeter …
The Dynamics Of Satellite Disruption In Cold Dark Matter Haloes, Jh Choi, Md Weinberg, N Katz
The Dynamics Of Satellite Disruption In Cold Dark Matter Haloes, Jh Choi, Md Weinberg, N Katz
Astronomy Department Faculty Publication Series
We investigate the physical mechanisms of tidal heating and satellite disruption in cold dark matter host haloes using N-body simulations based on cosmological initial conditions. We show the importance of resonant shocks and resonant torques with the host halo to satellite heating. A resonant shock (torque) couples the radial (tangential) motion of a satellite in its orbit to its phase space. For a satellite on a circular orbit, an inner Lindblad resonance (ILR)-like resonance dominates the heating and this heating results in continuous satellite mass loss. We estimate the requirements for simulations to achieve these dynamics using perturbation theory. Both …
Comparison Of H Alpha And Uv Star Formation Rates In The Local Volume: Systematic Discrepancies For Dwarf Galaxies, Jc Lee, Ag De Paz, C Tremonti, Rc Kennicutt, S Salim, M Bothwell, D Calzetti, J Dalcanton, D Dale, C Engelbracht, Sjjg Funes, B Johnson, S Sakai, E Skillman, L Van Zee, F Walter, D Weisz
Comparison Of H Alpha And Uv Star Formation Rates In The Local Volume: Systematic Discrepancies For Dwarf Galaxies, Jc Lee, Ag De Paz, C Tremonti, Rc Kennicutt, S Salim, M Bothwell, D Calzetti, J Dalcanton, D Dale, C Engelbracht, Sjjg Funes, B Johnson, S Sakai, E Skillman, L Van Zee, F Walter, D Weisz
Astronomy Department Faculty Publication Series
Using a complete sample of ~300 star-forming galaxies within 11 Mpc of the Milky Way, we evaluate the consistency between star formation rates (SFRs) inferred from the far ultraviolet (FUV) non-ionizing continuum and Hα nebular emission, assuming standard conversion recipes in which the SFR scales linearly with luminosity at a given wavelength. Our analysis probes SFRs over 5 orders of magnitude, down to ultra-low activities on the order of ~10-4 M sun yr-1. The data are drawn from the 11 Mpc Hα and Ultraviolet Galaxy Survey (11HUGS), which has obtained Hα fluxes from ground-based narrowband imaging, and UV fluxes from …
The Chandra Cosmos Survey. I. Overview And Point Source Catalog, M Elvis, F Civano, C Vignali, S Puccetti, F Fiore, N Cappelluti, Tl Aldcroft, A Fruscione, G Zamorani, A Comastri, M Brusa, R Gilli, T Miyaji, F Damiani, Am Koekemoer, A Finoguenov, H Brunner, Cm Urry, J Silverman, V Mainieri, G Hasinger, R Griffiths, M Carollo, H Hao, L Guzzo, A Blain, D Calzetti, C Carilli, P Capak, S Ettori, G Fabbiano, C Impey, S Lilly, B Mobasher, M Rich, M Salvato, Db Sanders, E Schinnerer, N Scoville, P Shopbell, Je Taylor, Y Taniguchi, M Volonteri
The Chandra Cosmos Survey. I. Overview And Point Source Catalog, M Elvis, F Civano, C Vignali, S Puccetti, F Fiore, N Cappelluti, Tl Aldcroft, A Fruscione, G Zamorani, A Comastri, M Brusa, R Gilli, T Miyaji, F Damiani, Am Koekemoer, A Finoguenov, H Brunner, Cm Urry, J Silverman, V Mainieri, G Hasinger, R Griffiths, M Carollo, H Hao, L Guzzo, A Blain, D Calzetti, C Carilli, P Capak, S Ettori, G Fabbiano, C Impey, S Lilly, B Mobasher, M Rich, M Salvato, Db Sanders, E Schinnerer, N Scoville, P Shopbell, Je Taylor, Y Taniguchi, M Volonteri
Astronomy Department Faculty Publication Series
The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, Chandra program that has imaged the central 0.5 deg2 of the COSMOS field (centered at 10 h , +02 o ) with an effective exposure of ~160 ks, and an outer 0.4 deg2 area with an effective exposure of ~80 ks. The limiting source detection depths are 1.9 × 10–16 erg cm–2 s–1 in the soft (0.5-2 keV) band, 7.3 × 10–16 erg cm–2 s–1 in the hard (2-10 keV) band, and 5.7 × 10–16 erg cm–2 s–1 in the full (0.5-10 keV) band. Here we describe the strategy, design, …
Uv Continuum Slope And Dust Obscuration From Z Similar To 6 To Z Similar To 2: The Star Formation Rate Density At High Redshift, R. J. Bouwens, G. D. Illingworth, M. Franx, R.-R. Chary, G. R. Meurer, C. J. Conselice, H. Ford, M. Giavalisco, P. Van Dokkum
Uv Continuum Slope And Dust Obscuration From Z Similar To 6 To Z Similar To 2: The Star Formation Rate Density At High Redshift, R. J. Bouwens, G. D. Illingworth, M. Franx, R.-R. Chary, G. R. Meurer, C. J. Conselice, H. Ford, M. Giavalisco, P. Van Dokkum
Astronomy Department Faculty Publication Series
We provide a systematic measurement of the rest-frame UV continuum slope β over a wide range in redshift (z ∼ 2–6) and rest-frame UV luminosity (0.1 L*z = 3 to 2 L*z = 3) to improve estimates of the star formation rate (SFR) density at high redshift. We utilize the deep optical and infrared data (Advanced Camera for Surveys/NICMOS) over the Chandra Deep Field-South and Hubble Deep Field-North Great Observatories Origins Deep Survey fields, as well as the UDF for our primary UBVi "dropout" Lyman Break Galaxy sample. We also use strong lensing clusters to …
Deep U Band And R Imaging Of Goods-South: Observations, Data Reduction And First Results, M Nonino, M Dickinson, P Rosati, A Grazian, N Reddy, S Cristiani, M Giavalisco, H Kuntschner, E Vanzella, E Daddi, Rae Fosbury, C Cesarsky
Deep U Band And R Imaging Of Goods-South: Observations, Data Reduction And First Results, M Nonino, M Dickinson, P Rosati, A Grazian, N Reddy, S Cristiani, M Giavalisco, H Kuntschner, E Vanzella, E Daddi, Rae Fosbury, C Cesarsky
Astronomy Department Faculty Publication Series
We present deep imaging in the U band covering an area of 630 arcmin2 centered on the southern field of the Great Observatories Origins Deep Survey (GOODS). The data were obtained with the VIMOS instrument at the European Southern Observatory (ESO) Very Large Telescope. The final images reach a magnitude limit Ulim ≈ 29.8 (AB, 1σ, in a 1'' radius aperture), and have good image quality, with full width at half-maximum ≈08. They are significantly deeper than previous U-band images available for the GOODS fields, and better match the sensitivity of other multiwavelength GOODS photometry. The deeper U …
Spectroscopic Observations Of Lyman Break Galaxies At Redshifts Similar To 4, 5, And 6 In The Goods-South Field, E Vanzella, M Giavalisco, M Dickinson, S Cristiani, M Nonino, H Kuntschner, P Popesso, P Rosati, A Renzini, D Stern, C Cesarsky, Hc Ferguson, Rae Fosbury
Spectroscopic Observations Of Lyman Break Galaxies At Redshifts Similar To 4, 5, And 6 In The Goods-South Field, E Vanzella, M Giavalisco, M Dickinson, S Cristiani, M Nonino, H Kuntschner, P Popesso, P Rosati, A Renzini, D Stern, C Cesarsky, Hc Ferguson, Rae Fosbury
Astronomy Department Faculty Publication Series
We report on observations of Lyman-break galaxies (LBGs) selected from the Great Observatories Origins Deep Survey at mean redshift z~4, 5 and 6, obtained with FORS2 spectrograph at the ESO-VLT.This program has yielded spectroscopic identifications for 114 galaxies of which 51 are at z~4, 31 at z~5, and 32 at z~6. The adopted selection criteria are effective, identifying galaxies at the expected redshift with minimal foreground contamination. Once selection effects are properly accounted for, the rest-frame UV spectra of the higher-redshift LBGs appear to be similar to their counterparts at z~3. As at z~3, LBGs at z~4 and z~5 show …
The Growth Of Central And Satellite Galaxies In Cosmological Smoothed Particle Hydrodynamics Simulations, V Simha, Dh Weinberg, R Dave, Oy Gnedin, N Katz, D Keres
The Growth Of Central And Satellite Galaxies In Cosmological Smoothed Particle Hydrodynamics Simulations, V Simha, Dh Weinberg, R Dave, Oy Gnedin, N Katz, D Keres
Astronomy Department Faculty Publication Series
We examine the accretion and merger histories of central and satellite galaxies in a smoothed particle hydrodynamics (SPH) cosmological simulation that resolves galaxies down to 7 × 109 M⊙. Most friends-of-friends haloes in the simulation have a distinct central galaxy, typically 2–5 times more massive than the most massive satellite. As expected, satellites have systematically higher assembly redshifts than central galaxies of the same baryonic mass, and satellites in more massive haloes form earlier. However, contrary to the simplest expectations, satellite galaxies continue to accrete gas and convert it to stars; the gas accretion declines steadily over …
Aztec Millimetre Survey Of The Cosmos Field - Ii. Source Count Overdensity And Correlations With Large-Scale Structure, Je Austermann, I Aretxaga, Dh Hughes, Y Kang, S Kim, Jd Lowenthal, Ta Perera, Db Sanders, Ks Scott, N Scoville, Gw Wilson, Min Yun
Aztec Millimetre Survey Of The Cosmos Field - Ii. Source Count Overdensity And Correlations With Large-Scale Structure, Je Austermann, I Aretxaga, Dh Hughes, Y Kang, S Kim, Jd Lowenthal, Ta Perera, Db Sanders, Ks Scott, N Scoville, Gw Wilson, Min Yun
Astronomy Department Faculty Publication Series
We report an overdensity of bright submillimetre galaxies (SMGs) in the 0.15 deg2 AzTEC/COSMOS survey and a spatial correlation between the SMGs and the optical-IR galaxy density at z≲ 1.1. This portion of the COSMOS field shows a ∼3σ overdensity of robust SMG detections when compared to a background, or ‘blank-field’, population model that is consistent with SMG surveys of fields with no extragalactic bias. The SMG overdensity is most significant in the number of very bright detections (14 sources with measured fluxes S1.1 mm > 6 mJy), which is entirely incompatible with sample variance within our adopted …
Galaxies In A Simulated Lambda Cdm Universe - Ii. Observable Properties And Constraints On Feedback, D Keres, N Katz, R Dave, M Fardal, Dh Weinberg
Galaxies In A Simulated Lambda Cdm Universe - Ii. Observable Properties And Constraints On Feedback, D Keres, N Katz, R Dave, M Fardal, Dh Weinberg
Astronomy Department Faculty Publication Series
We compare the properties of galaxies that form in a cosmological simulation without strong feedback to observations of the z= 0 galaxy population. We confirm previous findings that models without strong feedback overproduce the observed galaxy baryonic mass function, especially at the low- and high-mass extremes. Through post-processing we investigate what kinds of feedback would be required to reproduce the statistics of observed galaxy masses and star formation rates. To mimic an extreme form of ‘preventive’ feedback, such as a highly efficient active galactic nucleus ‘radio mode’, we remove all baryonic mass that was originally accreted from shock-heated gas …