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Full-Text Articles in Physical Sciences and Mathematics

Dynamics Of Lyman Break Galaxies And Their Host Halos, James D. Lowenthal, David C. Koo, Luc Simard, Eelco Van Kampen Sep 2009

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 …


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 Jan 2009

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 …


Large Area Survey For Z=7 Galaxies In Sdf And Goods-N: Implications For Galaxy Formation And Cosmic Reionization, M Ouchi, B Mobasher, K Shimasaku, Hc Ferguson, Sm Fall, Y Ono, N Kashikawa, T Morokuma, K Nakajima, S Okamura, M Dickinson, M Giavalisco, K Ohta Jan 2009

Large Area Survey For Z=7 Galaxies In Sdf And Goods-N: Implications For Galaxy Formation And Cosmic Reionization, M Ouchi, B Mobasher, K Shimasaku, Hc Ferguson, Sm Fall, Y Ono, N Kashikawa, T Morokuma, K Nakajima, S Okamura, M Dickinson, M Giavalisco, K Ohta

Astronomy Department Faculty Publication Series

We present results of our large area survey for z'-band dropout galaxies at z = 7 in a 1568 arcmin2 sky area covering the SDF and GOODS-N fields. Combining our ultra-deep Subaru/Suprime-Cam z'- and y-band (λeff = 1 μm) images with legacy data of Subaru and Hubble Space Telescope, we have identified 22 bright z-dropout galaxies down to y = 26, one of which has a spectroscopic redshift of z = 6.96 determined from Lyα emission. The z = 7 luminosity function yields the best-fit Schechter parameters of ϕ* = 0.69+2.62−0.55 × 10−3 Mpc−3, …


Hubble Space Telescope/Advanced Camera For Surveys Morphology Of Ly Alpha Emitters At Redshift 5.7 In The Cosmos Field, Y Taniguchi, Et. Al. Jan 2009

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 Jan 2009

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 …


Mapping The Dark Matter From Uv Light At High Redshift: An Empirical Approach To Understand Galaxy Statistics, Kyoung-Soo Lee, Mauro Giavalisco, Charlie Conroy, Risa H. Wechsler, Henry C. Ferguson, Rachel S. Somerville, Mark E. Dickinson, Claudia M. Urry Jan 2009

Mapping The Dark Matter From Uv Light At High Redshift: An Empirical Approach To Understand Galaxy Statistics, Kyoung-Soo Lee, Mauro Giavalisco, Charlie Conroy, Risa H. Wechsler, Henry C. Ferguson, Rachel S. Somerville, Mark E. Dickinson, Claudia M. Urry

Astronomy Department Faculty Publication Series

We present a simple formalism to interpret the observations of two galaxy statistics, the UV luminosity function (LF) and two-point correlation functions for star-forming galaxies at z∼4, 5, and 6 in the context of Λ cold dark matter cosmology. Both statistics are the result of how star formation takes place in dark matter halos, and thus are used to constrain how UV light depends on halo properties, in particular halo mass. The two physical quantities we explore are the star formation duty cycle, and the range of UV luminosity that a halo of mass M can have (mean and …


Two Bright Submillimeter Galaxies In A Z=4.05 Protocluster In Goods-North, And Accurate Radio-Infrared Photometric Redshifts, E Daddi, H Dannerbauer, D Stern, M Dickinson, G Morrison, D Elbaz, M Giavalisco, C Mancini, A Pope, H Spinrad Jan 2009

Two Bright Submillimeter Galaxies In A Z=4.05 Protocluster In Goods-North, And Accurate Radio-Infrared Photometric Redshifts, E Daddi, H Dannerbauer, D Stern, M Dickinson, G Morrison, D Elbaz, M Giavalisco, C Mancini, A Pope, H Spinrad

Astronomy Department Faculty Publication Series

No abstract provided.


An Aztec 1.1 Mm Survey Of The Goods-N Field - Ii. Multiwavelength Identifications And Redshift Distribution, El Chapin, A Pope, D Scott, I Aretxaga, Je Austermann, Rr Chary, K Coppin, M Halpern, Dh Hughes, Jd Lowenthal, Ge Morrison, Ta Perera, Ks Scott, Gw Wilson, Min Yun Jan 2009

An Aztec 1.1 Mm Survey Of The Goods-N Field - Ii. Multiwavelength Identifications And Redshift Distribution, El Chapin, A Pope, D Scott, I Aretxaga, Je Austermann, Rr Chary, K Coppin, M Halpern, Dh Hughes, Jd Lowenthal, Ge Morrison, Ta Perera, Ks Scott, Gw Wilson, Min Yun

Astronomy Department Faculty Publication Series

We present results from a multiwavelength study of 29 sources (false detection probabilities <5 per cent) from a survey of the Great Observatories Origins Deep Survey-North (GOODS-N) field at 1.1 mm using the Astronomical Thermal Emission Camera (AzTEC). Comparing with existing 850 μm Submillimetre Common-User Bolometer Array (SCUBA) studies in the field, we examine differences in the source populations selected at the two wavelengths. The AzTEC observations uniformly cover the entire survey field to a 1σ depth of ∼1 mJy. Searching deep 1.4 GHz Very Large Array (VLA) and Spitzer 3–24 μm catalogues, we identify robust counterparts for 21 1.1 mm sources, and tentative associations for the remaining objects. The redshift distribution of AzTEC sources is inferred from available spectroscopic and photometric redshifts. We find a median redshift of z= 2.7, somewhat higher than z= 2.0 for 850 μm selected sources in the same field, and our lowest redshift identification lies at a spectroscopic redshift z= 1.1460. We measure the 850 μm to 1.1 mm colour of our sources and do not find …


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 Jan 2009

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 …


Candels: The Contribution Of The Observed Galaxy Population To Cosmic Reionization, Steven L. Finkelstein, Casey Papovich, Russel E, Ryan Jr., Andreas H. Pawlik, Mark Dickinson, Henry C. Ferguson, Kristian Finlator, Anton M. Koekemoer, Mauro Giavalisco, Mauro Giavalisco, Asantha Cooray, James S. Dunlop, Sandy M. Faber, Norman A. Grogin, Dale D. Kocevski, Jeffrey A. Newman Jan 2009

Candels: The Contribution Of The Observed Galaxy Population To Cosmic Reionization, Steven L. Finkelstein, Casey Papovich, Russel E, Ryan Jr., Andreas H. Pawlik, Mark Dickinson, Henry C. Ferguson, Kristian Finlator, Anton M. Koekemoer, Mauro Giavalisco, Mauro Giavalisco, Asantha Cooray, James S. Dunlop, Sandy M. Faber, Norman A. Grogin, Dale D. Kocevski, Jeffrey A. Newman

Mauro Giavalisco

We present measurements of the specific ultraviolet luminosity density from a sample of 483 galaxies at 6 . z . 8. These galaxies were selected from new deep near-infrared Hubble Space Telescope imaging from the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey, Hubble UltraDeep Field 2009 and WFC3 Early Release Science programs. In contrast to the majority of previous analyses, which assume that the distribution of galaxy ultraviolet (UV) luminosities follows a Schechter distribution, and that the distribution continues to luminosities far below our observable limit, we investigate the contribution to reionization from galaxies which we can observe, free from …


Expanding The Search For Galaxies At Z ~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 Jan 2009

Expanding The Search For Galaxies At Z ~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

Mauro Giavalisco

We have carried out a search for galaxies at z ~ 7-10 in ~14.4 sq. arcmin of new NICMOS parallel imaging taken in the Great Observatories Origins Deep Survey (GOODS, 5.9 sq. arcmin), the Cosmic Origins Survey (COSMOS, 7.2 sq. arcmin), and SSA22 (1.3 sq. arcmin). These images reach 5 sigma 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. …


Spectroscopic Observations Of Lyman-Break Galaxies At Redshift ~ 4, 5 And 6 In The Goods-South Field, E. Vanzella, Mauro Giavalisco, M. Dickinson, S. Cristiani, M. Nonino, H. Kuntschner, P. Popesso, P, Rosati, A. Renzini, D. Stern, C. Cesarsky, H. C. Ferguson, R. A. E. Fosbury, The Goods Team Jan 2009

Spectroscopic Observations Of Lyman-Break Galaxies At Redshift ~ 4, 5 And 6 In The Goods-South Field, E. Vanzella, Mauro Giavalisco, M. Dickinson, S. Cristiani, M. Nonino, H. Kuntschner, P. Popesso, P, Rosati, A. Renzini, D. Stern, C. Cesarsky, H. C. Ferguson, R. A. E. Fosbury, The Goods Team

Mauro Giavalisco

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 …


Large Area Survey For Z=7 Galaxies In Sdf And Goods-N: Implications For Galaxy Formation And Cosmic Reionization, Masami Ouchi, Bahram Mobasher, Kazuhiro Shimasaku, Henry C. Ferguson, S. Michael Fall, Yoshiaki Ono, Nobunari Kashikawa, Tomoki Morokuma, Kimihiko Nakajima, Sadanori Okamura, Mark Dickinson, Mauro Giavalisco, Kouji Ohta Jan 2009

Large Area Survey For Z=7 Galaxies In Sdf And Goods-N: Implications For Galaxy Formation And Cosmic Reionization, Masami Ouchi, Bahram Mobasher, Kazuhiro Shimasaku, Henry C. Ferguson, S. Michael Fall, Yoshiaki Ono, Nobunari Kashikawa, Tomoki Morokuma, Kimihiko Nakajima, Sadanori Okamura, Mark Dickinson, Mauro Giavalisco, Kouji Ohta

Mauro Giavalisco

We present results of our large-area survey for z'-band dropout galaxies at z=7 in a 1568 arcmin^2 sky area covering the SDF and GOODS-N fields. Combining our ultra-deep Subaru/Suprime-Cam z'- and y-band (lambda_eff=1um) images with legacy data of Subaru and HST, we have identified 22 bright z-dropout galaxies down to y=26, one of which has a spectroscopic redshift of z=6.96 determined from Lya emission. The z=7 luminosity function (LF) yields the best-fit Schechter parameters of phi*=0.69 +2.62/-0.55 x10^(-3) Mpc^(-3), Muv*=-20.10 +/-0.76 mag, and alpha=-1.72 +/-0.65, and indicates a decrease from z=6 at a >95% confidence level. This decrease is beyond …


The Udf05 Follow-Up Of The Hubble Ultra Deep Field. Iii. The Luminosity Function At Z~6, Jian Su, Massimo Stiavelli, Pascal Oesch, Michele Trenti, Eddie Bergeron, Larry Bradley, Marcella Carollo, Tomas Dahlen, Henry C. Ferguson, Mauro Giavalisco, Anton Koekemoer, Simon Lilly, Ray A. Lucas, Bahram Mobasher, Nino Panagia, Cheryl Pavlovsky Jan 2009

The Udf05 Follow-Up Of The Hubble Ultra Deep Field. Iii. The Luminosity Function At Z~6, Jian Su, Massimo Stiavelli, Pascal Oesch, Michele Trenti, Eddie Bergeron, Larry Bradley, Marcella Carollo, Tomas Dahlen, Henry C. Ferguson, Mauro Giavalisco, Anton Koekemoer, Simon Lilly, Ray A. Lucas, Bahram Mobasher, Nino Panagia, Cheryl Pavlovsky

Mauro Giavalisco

In this paper, we present a derivation of the rest-frame 1400A luminosity function (LF) at redshift six from a new application of the maximum likelihood method by exploring the five deepest HST/ACS fields, i.e., the HUDF, two UDF05 fields, and two GOODS fields. We work on the latest improved data products, which makes our results more robust than those of previous studies. We use un-binned data and thereby make optimal use of the information contained in the dataset. We focus on the analysis to a magnitude limit where the completeness is larger than 50% to avoid possibly large errors in …


The Evolution Of The Galaxy Rest-Frame Ultraviolet Luminosity Function Over The First Two Billion Years, Steven L. Finkelstein, Russell E. Ryan Jr., Casey Papovich, Mark Dickinson, Mimi Song, Rachel Somerville, Herny C. Ferguson, Brett Salmon, Mauro Giavalisco, Anton M. Koekemoer, Matthew L. N. Ashby, Peter Behroozi, Marco Castellano, James S. Dunlop, Sandy M. Faber, Giovanni G. Fazio, Adriano Fontana, Norman A. Grogin, Nimish Hathi, Jason Jaacks, Dale D. Kocevski, Rachel Livermore, Ross J. Mclure, Emiliano Merlin, Bahram Mobasher, Jeffrey A. Newman, Marc Rafelski, Vithal Tilvi, S.P. Willner Jan 2009

The Evolution Of The Galaxy Rest-Frame Ultraviolet Luminosity Function Over The First Two Billion Years, Steven L. Finkelstein, Russell E. Ryan Jr., Casey Papovich, Mark Dickinson, Mimi Song, Rachel Somerville, Herny C. Ferguson, Brett Salmon, Mauro Giavalisco, Anton M. Koekemoer, Matthew L. N. Ashby, Peter Behroozi, Marco Castellano, James S. Dunlop, Sandy M. Faber, Giovanni G. Fazio, Adriano Fontana, Norman A. Grogin, Nimish Hathi, Jason Jaacks, Dale D. Kocevski, Rachel Livermore, Ross J. Mclure, Emiliano Merlin, Bahram Mobasher, Jeffrey A. Newman, Marc Rafelski, Vithal Tilvi, S.P. Willner

Mauro Giavalisco

No abstract provided.


The Unusual Niv]-Emitter Galaxy Gds J033218.92-275302.7: Star Formation Or Agn-Driven Winds From A Massive Galaxy At Z=5.56, E. Vanzella, A. Grazian, M. Hayes, L. Pentericci, D. Schaerer, M. Dickinson, S. Cristiani, Mauro Giavalisco, A. Verhamme, M. Nonino, P. Rosati Jan 2009

The Unusual Niv]-Emitter Galaxy Gds J033218.92-275302.7: Star Formation Or Agn-Driven Winds From A Massive Galaxy At Z=5.56, E. Vanzella, A. Grazian, M. Hayes, L. Pentericci, D. Schaerer, M. Dickinson, S. Cristiani, Mauro Giavalisco, A. Verhamme, M. Nonino, P. Rosati

Mauro Giavalisco

Aims: We investigate the nature of the source GDS J033218.92-275302.7at redshift ~ 5.56. Methods: The SED of the source is well sampled by 16 bands photometry, from UV-optical, near infrared and mid-infrared (MID-IR).The detection of signal in the MID-IR Spitzer/IRAC bands 5.8, 8.0 um -- where the nebular emission contribution is less effective -- suggests the presence of a Balmer break, signature of an underlying stellar population formed at earlier epochs. The optical spectrum shows a clear Lya emission line together with semi-forbidden NIV] 1483.3-1486.5 also in emission. Results: From the SED fitting and the Lya modelling it turns out …


Hst/Acs Morphology Of Lyman Alpha Emitters At Redshift 5.7 In The Cosmos Field, Y. Taniguchi, T. Murayama, N. Z. Scoville, S. S. Sasaki, T. Nagao, Y. Shioya, T. Saito, Y. Ideue, A. Nakajima, K. Matsuoka, D. B. Sanders, B. Mobasher, H. Aussel, P. Capak, M. Salvato, K. Koekemoer, C. Carilli, A. Cimatti, R. S. Ellis, B. Garilli, Mauro Giavalisco, O. Ilbert, C. D. Impey, M. G. Kitzbilcher, O. Le Fevre, H. J. Mccracken, C. Scarlata, E. Schinnerer, V. Smolcic, S. Tribiano, J. R. Trump Jan 2009

Hst/Acs Morphology Of Lyman Alpha Emitters At Redshift 5.7 In The Cosmos Field, Y. Taniguchi, T. Murayama, N. Z. Scoville, S. S. Sasaki, T. Nagao, Y. Shioya, T. Saito, Y. Ideue, A. Nakajima, K. Matsuoka, D. B. Sanders, B. Mobasher, H. Aussel, P. Capak, M. Salvato, K. Koekemoer, C. Carilli, A. Cimatti, R. S. Ellis, B. Garilli, Mauro Giavalisco, O. Ilbert, C. D. Impey, M. G. Kitzbilcher, O. Le Fevre, H. J. Mccracken, C. Scarlata, E. Schinnerer, V. Smolcic, S. Tribiano, J. R. Trump

Mauro Giavalisco

We present detailed morphological properties of Lyman alpha emitters (LAEs) at z~ 5.7 in the COSMOS field, based on {\it 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) up to 0.4 arcsec (~2.5 kpc at z=5.7). The others are nearly unresolved compact objects. Two LAEs show double-component structures, …


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 Jan 2009

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 …


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 Jan 2009

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 Jan 2009

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 …


Galaxies In A Simulated Lambda Cdm Universe - Ii. Observable Properties And Constraints On Feedback, D Keres, N Katz, R Dave, M Fardal, Dh Weinberg Jan 2009

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 …


Erasing Dark Matter Cusps In Cosmological Galactic Halos With Baryons, Emilio Romano-Diaz, Isaac Shlosman, Yehuda Hoffman, Clayton Heller Oct 2008

Erasing Dark Matter Cusps In Cosmological Galactic Halos With Baryons, Emilio Romano-Diaz, Isaac Shlosman, Yehuda Hoffman, Clayton Heller

Department of Physics and Astronomy Faculty Publications

We study the central dark matter (DM) cusp evolution in cosmologically grown galactic halos. Numerical models with and without baryons (baryons+DM, hereafter BDM model, and pure DM, PDM model, respectively) are advanced from identical initial conditions, obtained using the Constrained Realization method. The DM cusp properties are contrasted by a direct comparison of pure DM and baryonic models. We find a divergent evolution between the PDM and BDM models within the inner few × 10 kpc region. The PDM model forms an R−1 cusp as expected, while the DM in the BDM model forms a larger isothermal cusp R …


The Physical Scale Of The Far-Infrared Emission In The Most Luminous Submillimeter Galaxies, Jd Younger, Gg Fazio, Dj Wilner, Mln Ashby, R Blundell, Ma Gurwell, Js Huang, D Iono, Ab Peck, Gr Petitpas, Ks Scott, Gw Wilson, Min Yun Jan 2008

The Physical Scale Of The Far-Infrared Emission In The Most Luminous Submillimeter Galaxies, Jd Younger, Gg Fazio, Dj Wilner, Mln Ashby, R Blundell, Ma Gurwell, Js Huang, D Iono, Ab Peck, Gr Petitpas, Ks Scott, Gw Wilson, Min Yun

Astronomy Department Faculty Publication Series

We present high-resolution submillimeter interferometric imaging of two of the brightest high-redshift submillimeter galaxies known: GN 20 and AzTEC1 at 0.8'' and 0.3'' resolution, respectively. Our data—the highest resolution submillimeter imaging of high-redshift sources accomplished to date—were collected in three different array configurations: compact, extended, and very extended. We derive angular sizes of 0.6'' and 1.0'' for GN 20 and 0.3'' and 0.4'' for AzTEC1 from modeling their visibility functions as a Gaussian and an elliptical disk, respectively. Because both sources are B-band dropouts, they likely lie within a relatively narrow redshift window around z ~ 4, which indicates …


Star Formation Rates In Lyman Break Galaxies: Radio Stacking Of Lbgs In The Cosmos Field And The Sub-Mu Jy Radio Source Population, Cl Carilli, N Lee, P Capak, E Schinnerer, Ks Lee, H Mccraken, Min Yun, N Scoville, V Smolcic, M Giavalisco, A Datta, Y Taniguchi, Cm Urry Jan 2008

Star Formation Rates In Lyman Break Galaxies: Radio Stacking Of Lbgs In The Cosmos Field And The Sub-Mu Jy Radio Source Population, Cl Carilli, N Lee, P Capak, E Schinnerer, Ks Lee, H Mccraken, Min Yun, N Scoville, V Smolcic, M Giavalisco, A Datta, Y Taniguchi, Cm Urry

Astronomy Department Faculty Publication Series

We present an analysis of the radio properties of large samples of Lyman break galaxies (LBGs) at z ~ 3, 4, and 5 from the COSMOS field. The median stacking analysis yields a statistical detection of the z ~ 3 LBGs (U-band dropouts), with a 1.4 GHz flux density of 0.90 ± 0.21 μJy. The stacked emission is unresolved, with a size <1, or a physical size <8 kpc. The total star formation rate implied by this radio luminosity is 31 ± 7 M yr−1, based on the radio-FIR correlation in low-redshift star-forming galaxies. The star formation rate derived from a similar analysis of the UV luminosities is 17 M yr−1, without any correction for …


Evidence For A Population Of High-Redshift Submillimeter Galaxies From Interferometric Imaging, Joshua D. Younger, Giovanni G. Fazio, Jia Sheng Huang, Min S. Yun, Grant W. Wilson, Matthew L.N. Ashby, Mark A. Gurwell, Kamson Lai, Alison B. Peck, Glen R. Petitpas, David J. Wilner, Daisuke Iono, Kotaro Kohno, Ryohei Kawabe, David H. Hughes, Itziar Aretxaga, Tracy Webb, Alejo Martínez-Sansigre, Sungeun Kim, Kimberly S. Scott, Jason Austermann, Thushara Perera, James Lowenthal, Eva Schinnerer, Vernesa Smolčić Dec 2007

Evidence For A Population Of High-Redshift Submillimeter Galaxies From Interferometric Imaging, Joshua D. Younger, Giovanni G. Fazio, Jia Sheng Huang, Min S. Yun, Grant W. Wilson, Matthew L.N. Ashby, Mark A. Gurwell, Kamson Lai, Alison B. Peck, Glen R. Petitpas, David J. Wilner, Daisuke Iono, Kotaro Kohno, Ryohei Kawabe, David H. Hughes, Itziar Aretxaga, Tracy Webb, Alejo Martínez-Sansigre, Sungeun Kim, Kimberly S. Scott, Jason Austermann, Thushara Perera, James Lowenthal, Eva Schinnerer, Vernesa Smolčić

Astronomy: Faculty Publications

We have used the Submillimeter Array to image a flux-limited sample of seven submillimeter galaxies, selected by the AzTEC camera on the JCMT at 1.1 mm, in the COSMOS field at 890 μm with ∼2″ resolution. All of the sources - two radio-bright and five radio-dim - are detected as single point sources at high significance (>6 σ), with positions accurate to ∼0.2″ that enable counterpart identification at other wavelengths observed with similarly high angular resolution. All seven have IRAC counterparts, but only two have secure counterparts in deep HST ACS imaging. As compared to the two radio-bright sources …


Structure Formation Inside Triaxial Dark Matter Halos: Galactic Disks, Bulges, And Bars, Clayton Heller, Isaac Shlosman, Evangelie Athanassoula Dec 2007

Structure Formation Inside Triaxial Dark Matter Halos: Galactic Disks, Bulges, And Bars, Clayton Heller, Isaac Shlosman, Evangelie Athanassoula

Department of Physics and Astronomy Faculty Publications

We investigate formation and evolution of galactic disks immersed in assembling live DM halos. Models have been evolved from cosmological initial conditions and represent the collapse of an isolated density perturbation. The baryons include gas participating in star formation (SF) and stars with the energy feedback onto the ISM. We find that (1) the triaxial halo figure tumbling is insignificant and the angular momentum (J) is channeled into the internal circulation, while the baryonic collapse is stopped by the centrifugal barrier; (2) density response of the (disk) baryons is out of phase with DM, thus washing out the …


Evolution Of Stellar Bars In Live Axisymmetric Halos: Recurrent Buckling And Secular Growth, Inma Martinez-Valpuesta, Isaac Shlosman, Clayton Heller Jan 2006

Evolution Of Stellar Bars In Live Axisymmetric Halos: Recurrent Buckling And Secular Growth, Inma Martinez-Valpuesta, Isaac Shlosman, Clayton Heller

Department of Physics and Astronomy Faculty Publications

Evolution of stellar bars in disk galaxies is accompanied by dynamical instabilities and secular changes. Following the vertical buckling instability, the bars are known to weaken dramatically and develop a pronounced boxy/ peanut shape when observed edge-on. Using high-resolution N-body simulations of stellar disks embedded in live axisymmetric dark matter halos, we have investigated the long-term changes in the bar morphology, specifically the evolution of the bar size, its vertical structure, and the exchange of angular momentum. We find that following the initial buckling, the bar resumes its growth from deep inside the corotation radius and follows the ultraharmonic resonance …


Co (J = 4 → 3) And 650 Micron Continuum Observations Of The Z = 0.93 Hyperluminous Infrared Galaxy Fsc 15307+3252, Min S. Yun, N Z. Scoville Nov 1998

Co (J = 4 → 3) And 650 Micron Continuum Observations Of The Z = 0.93 Hyperluminous Infrared Galaxy Fsc 15307+3252, Min S. Yun, N Z. Scoville

Min S. Yun

We report the results of our CO J = 4 → 3 line and rest-frame 650 μm continuum observations of the z = 0.93 hyperluminous infrared galaxy FSC 15307+3252 using the Owens Valley Millimeter Array. No line or continuum emission was detected, but the derived limits provide a useful constraint on the temperature, emissivity, and mass of the cold dust associated with FSC 15307+3252 and its molecular gas content. The 3 σ upper limit on the velocity-integrated CO (4-3) line flux is 1.6 Jy km s-1 (for ΔV = 300 km s-1). This corresponds to a surprisingly small total molecular …


Co J = 3-2 Emission In The Radio Galaxy 53w002 At Z = 2.394, N Z. Scoville, Min S. Yun, R A. Windhorst, W C. Keel, L Armus Aug 1997

Co J = 3-2 Emission In The Radio Galaxy 53w002 At Z = 2.394, N Z. Scoville, Min S. Yun, R A. Windhorst, W C. Keel, L Armus

Min S. Yun

We report a sensitive search for redshifted CO J = 3-2 emission from the weak radio galaxy 53W002 at z = 2.394. Maps at resolutions of 3'' and 235 km s-1 show a significant emission peak within 0farcs5 of the optical and radio continuum peaks. The measured narrowband flux is approximately 10 times the extrapolated centimeter-wavelength nonthermal radio continuum expected at 101.9 GHz and exhibits a spectral profile implying a 540 km s-1 width (FWHM) at a systemic redshift z = 2.394 ± 0.001 for CO (3-2). This emission has a total integrated flux of 1.51 ± 0.2 Jy km …


The Nature Of Compact Galaxies In The Hubble Deep Field. Ii. Spectroscopic Properties And Implications For The Evolution Of The Star Formation Rate Density Of The Universe, Rafael Guzmán, Jesús Gallego, David C. Koo, Andrew C. Phillips, James D. Lowenthal, S. M. Faber, Garth D. Illingworth, Nicole P. Vogt Jan 1997

The Nature Of Compact Galaxies In The Hubble Deep Field. Ii. Spectroscopic Properties And Implications For The Evolution Of The Star Formation Rate Density Of The Universe, Rafael Guzmán, Jesús Gallego, David C. Koo, Andrew C. Phillips, James D. Lowenthal, S. M. Faber, Garth D. Illingworth, Nicole P. Vogt

Astronomy: Faculty Publications

We present a spectroscopic study of 51 compact field galaxies with redshifts z < 1.4 and apparent magnitudes I < 23.74 in the flanking fields of the Hubble Deep Field. These galaxies are compact in the sense that they have small apparent half-light radii (r ≤ 0″.5) and high surface brightnesses (μ ≤ 22.2 mag arcsec ). The spectra, taken at the Keck telescope, show emission lines in 88% of our sample, and only absorption lines in the remaining 12%. Emission-line profiles are roughly Gaussian with velocity widths that range from the measurement limit of σ ∼ 35 km s to 150 km s . Rest frame [O II] λ3727 equivalent widths range from 5 to 94 Å, yielding star formation rates (SFRs) of ∼0.1 to 14 M yr . The analysis of various line diagnostic diagrams reveals that ∼60% of compact emission-line galaxies have velocity widths, excitations, Hβ luminosities, SFRs, and mass-to-light ratios characteristic of young star-forming H II galaxies. The remaining 40% form a more heterogeneous class of evolved starbursts, similar to local starburst disk galaxies. We find that, although the compact galaxies at z > 0.7 have similar SFRs per unit mass to those at z < 0.7, they are on average ∼10 times more massive. Our sample implies a lower limit for the global comoving SFR density of ∼0.004 M yr Mpc at z = 0.55, and ∼0.008 M yr Mpc at z = 0.85 (assuming Salpeter IMF, H = 50 km s Mpc , and q = 0.5). These values, when compared to estimates for a sample of local compact galaxies selected in a similar fashion, support a history of the universe in which the SFR density declines by a factor ∼10 from z = 1 to today. From the comparison with the SFR densities derived for magnitude-limited samples of field galaxies, we conclude that compact emission-line galaxies, though only ∼20% of the general field population, may contribute as much as ∼45% to the global SFR of the universe at 0.4 < z < 1. © 1997. The American Astronomical Society. All rights reserved. 814 1/2 I814 ⊙ ⊙ ⊙ 0 o -2 -1 -1 -1 -1 -3 -1 -3 -1 -1