COSMIC DUST IN Mg ii ABSORBERS

Mg ii absorbers induce reddening on background quasars. We measure this effect and infer the cosmic density of dust residing in these systems to be Ω ≈ 2 × 10−6, in units of the critical density of the universe, which is comparable to the amount of dust found in galactic disks or about half the amount inferred to exist outside galaxies. We also estimate the neutral hydrogen abundance in Mg ii clouds to be Ω ≈ 1.5 × 10−4, which is approximately 5% of hydrogen in stars in galaxies. This implies a dust-to-gas mass ratio for Mg ii clouds of about 1/100, which is similar to the value for normal galaxies. This would support the hypothesis of the outflow origin of Mg ii clouds, which are intrinsically devoid of stars and hence have no sources of dust. Considerations of the dust abundance imply that the presence of Mg ii absorbers around galaxies lasts effectively for a few Gyr. High-redshift absorbers allow us to measure the rest-frame extinction curve to 900 Å, at which the absorption by the Lyman edge dominates over scattering by dust in the extinction opacity.

[1]  R. Simcoe,et al.  A SURVEY OF Mg ii ABSORPTION AT 2 < z < 6 WITH MAGELLAN/FIRE. I. SAMPLE AND EVOLUTION OF THE Mg ii FREQUENCY , 2012, 1201.3919.

[2]  Nmsu,et al.  THE H i MASS DENSITY IN GALACTIC HALOS, WINDS, AND COLD ACCRETION AS TRACED BY Mg ii ABSORPTION , 2011, 1111.3359.

[3]  P. Hewett,et al.  Dusty Mg ii absorbers: population statistics, extinction curves and gamma‐ray burst sightlines , 2011, 1106.0692.

[4]  M. Fukugita.  Global amount of dust in the universe , 2011, 1103.4191.

[5]  A. Weyant,et al.  THE PITTSBURGH SLOAN DIGITAL SKY SURVEY Mg ii QUASAR ABSORPTION-LINE SURVEY CATALOG , 2011, 1103.1626.

[6]  D. L. Clements,et al.  SPIRE imaging of M 82: Cool dust in the wind and tidal streams , 2010, 1005.1526.

[7]  V. Wild,et al.  Probing star formation across cosmic time with absorption line systems , 2009, 0912.3263.

[8]  A. Szalay,et al.  GALEX–SDSS CATALOGS FOR STATISTICAL STUDIES , 2009, 0904.1392.

[9]  M. Fukugita,et al.  Measuring the galaxy–mass and galaxy–dust correlations through magnification and reddening , 2009, 0902.4240.

[10]  W. Keel,et al.  AN EXTENDED DUST DISK IN A SPIRAL GALAXY: AN OCCULTING GALAXY PAIR IN THE ACS NEARBY GALAXY SURVEY TREASURY , 2009 .

[11]  B. M'enard,et al.  On the H I content, dust-to-gas ratio and nature of Mg II absorbers , 2008, 0803.0745.

[12]  G. Richards,et al.  Lensing, reddening and extinction effects of Mg ii absorbers from z= 0.4 to 2 , 2007, 0706.0898.

[13]  S. Driver,et al.  The Millennium Galaxy Catalogue: the B-band attenuation of bulge and disc light and the implied cosmic dust and stellar mass densities , 2007, 0704.2140.

[14]  D. Turnshek,et al.  The Environments of Ultrastrong Mg II Absorbers , 2006, astro-ph/0610760.

[15]  Tristan L. Smith,et al.  Average extinction curves and relative abundances for quasi-stellar object absorption-line systems at 1 ≤zabs < 2 , 2006, astro-ph/0601279.

[16]  D. Turnshek,et al.  Damped Lyα Systems at z < 1.65: The Expanded Sloan Digital Sky Survey Hubble Space Telescope Sample , 2006 .

[17]  D. Turnshek,et al.  Mg II Absorption Systems in Sloan Digital Sky Survey QSO Spectra , 2005 .

[18]  R. Nichol,et al.  The Fourth Data Release of the Sloan Digital Sky Survey , 2005 .

[19]  Institute for Astronomy,et al.  Outflows in Infrared-Luminous Starbursts at z < 0.5. II. Analysis and Discussion , 2005, astro-ph/0506611.

[20]  S. Veilleux,et al.  Galactic Winds , 2005, astro-ph/0504435.

[21]  A. Szalay,et al.  The Galaxy Evolution Explorer: A Space Ultraviolet Survey Mission , 2004, astro-ph/0411302.

[22]  D. Turnshek,et al.  Mg II Absorption Systems in SDSS QSO Spectra , 2004, astro-ph/0410493.

[23]  M. Fukugita,et al.  The Cosmic Energy Inventory , 2004, astro-ph/0406095.

[24]  J. Young,et al.  CO Luminosity Functions For FIR and B-band Selected Galaxies and the First Estimate for Omega_{HI+H2} , 2002, astro-ph/0209413.

[25]  N. Bond,et al.  High-Redshift Superwinds as the Source of the Strongest Mg II Absorbers: A Feasibility Analysis , 2001, astro-ph/0108062.

[26]  J. Weingartner,et al.  Dust Grain-Size Distributions and Extinction in the Milky Way, Large Magellanic Cloud, and Small Magellanic Cloud , 2001 .

[27]  J. Weingartner,et al.  Dust Grain Size Distributions and Extinction in the Milky Way, LMC, and SMC , 2000, astro-ph/0008146.

[28]  Walter A. Siegmund,et al.  The Sloan Digital Sky Survey: Technical Summary , 2000, astro-ph/0006396.

[29]  T. Heckman,et al.  Absorption-Line Probes of Gas and Dust in Galactic Superwinds , 2000, astro-ph/0002526.

[30]  Jr.,et al.  The Global Schmidt law in star forming galaxies , 1997, astro-ph/9712213.

[31]  T. Heckman,et al.  Hubble Space Telescope Observations of QSO Absorption Lines Associated with Starburst Galaxy Outflows , 1996 .

[32]  C. Steidel,et al.  Quasar Absorbing Galaxies at z ≲ 1: Deep Imaging and Spectroscopy in the Field of 3C 336 , 1996, astro-ph/9610230.

[33]  S. E. Persson,et al.  Field Galaxy Evolution Since Z 1 from a Sample of QSO Absorption-Selected Galaxies , 1994, astro-ph/9410025.

[34]  K. Lanzetta,et al.  EVOLUTION OF THE GASEOUS CONTENT OF THE UNIVERSE , 1993 .

[35]  C. Steidel,et al.  Mg II absorption in the spectra of 103 QSOs : implications for the evolution of gas in high-redshift galaxies , 1992 .

[36]  ApJ in press Preprint typeset using L ATEX style emulateapj v. 10/09/06 OPTICAL PROPERTIES AND SPATIAL DISTRIBUTION OF MGII ABSORBERS FROM SDSS IMAGE STACKING , 2007 .

[37]  John E. Davis,et al.  Sloan Digital Sky Survey: Early Data Release , 2002 .

[38]  J. Young,et al.  CO LUMINOSITY FUNCTIONS FOR FIR AND B-BAND SELECTED GALAXIES AND THE FIRST ESTIMATE FOR ΩHI+H2 , 2002 .

[39]  M. O’Hara,et al.  Summary and Implications , 1995 .