THE NATURE OF DAMPED LYMAN-α AND Mg II ABSORBERS EXPLORED THROUGH THEIR DUST CONTENTS
Abstract
We estimate the abundance of dust in damped Lyman-α absorbers (DLAs) by statistically measuring the excess reddening they induce on their background quasars. We detect systematic reddening behind DLAs consistent with the SMC-type reddening curve and inconsistent with the Milky Way type. We find that the derived dust-to-gas ratio is, on average, inversely proportional to the column density of neutral hydrogen, implying that the amount of dust is constant, regardless of the column density of hydrogen. It means that the average metallicity is inversely proportional to the column density of hydrogen, unless the average dust-to-metal ratio varies with the hydrogen column density. This indicates that the prime origin of metals seen in DLAs is not by in situ star formation, with which Z∼N{sub H} {sub I}{sup +0.4} is expected from the empirical star formation law, contrary to our observation. We interpret the metals observed in absorbers to be deposited dominantly from nearby galaxies by galactic winds ubiquitous in intergalactic space. When extrapolating the relation between dust-to-gas ratio and H I column density to lower column density, we find a value that is consistent with what is observed for Mg II absorbers.
- Authors:
-
- Kavli Institute for the Physics and Mathematics of the Universe, University of Tokyo, Kashiwa 277-8583 (Japan)
- Publication Date:
- OSTI Identifier:
- 22364323
- Resource Type:
- Journal Article
- Journal Name:
- Astrophysical Journal
- Additional Journal Information:
- Journal Volume: 799; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; ABSORPTION SPECTRA; DENSITY; DIAGRAMS; HYDROGEN; INTERGALACTIC SPACE; LYMAN LINES; MAGNESIUM IONS; METALLICITY; METALS; MILKY WAY; QUASARS; STARS; STELLAR WINDS
Citation Formats
Fukugita, Masataka, and Ménard, Brice. THE NATURE OF DAMPED LYMAN-α AND Mg II ABSORBERS EXPLORED THROUGH THEIR DUST CONTENTS. United States: N. p., 2015.
Web. doi:10.1088/0004-637X/799/2/195.
Fukugita, Masataka, & Ménard, Brice. THE NATURE OF DAMPED LYMAN-α AND Mg II ABSORBERS EXPLORED THROUGH THEIR DUST CONTENTS. United States. https://doi.org/10.1088/0004-637X/799/2/195
Fukugita, Masataka, and Ménard, Brice. 2015.
"THE NATURE OF DAMPED LYMAN-α AND Mg II ABSORBERS EXPLORED THROUGH THEIR DUST CONTENTS". United States. https://doi.org/10.1088/0004-637X/799/2/195.
@article{osti_22364323,
title = {THE NATURE OF DAMPED LYMAN-α AND Mg II ABSORBERS EXPLORED THROUGH THEIR DUST CONTENTS},
author = {Fukugita, Masataka and Ménard, Brice},
abstractNote = {We estimate the abundance of dust in damped Lyman-α absorbers (DLAs) by statistically measuring the excess reddening they induce on their background quasars. We detect systematic reddening behind DLAs consistent with the SMC-type reddening curve and inconsistent with the Milky Way type. We find that the derived dust-to-gas ratio is, on average, inversely proportional to the column density of neutral hydrogen, implying that the amount of dust is constant, regardless of the column density of hydrogen. It means that the average metallicity is inversely proportional to the column density of hydrogen, unless the average dust-to-metal ratio varies with the hydrogen column density. This indicates that the prime origin of metals seen in DLAs is not by in situ star formation, with which Z∼N{sub H} {sub I}{sup +0.4} is expected from the empirical star formation law, contrary to our observation. We interpret the metals observed in absorbers to be deposited dominantly from nearby galaxies by galactic winds ubiquitous in intergalactic space. When extrapolating the relation between dust-to-gas ratio and H I column density to lower column density, we find a value that is consistent with what is observed for Mg II absorbers.},
doi = {10.1088/0004-637X/799/2/195},
url = {https://www.osti.gov/biblio/22364323},
journal = {Astrophysical Journal},
issn = {0004-637X},
number = 2,
volume = 799,
place = {United States},
year = {Sun Feb 01 00:00:00 EST 2015},
month = {Sun Feb 01 00:00:00 EST 2015}
}