HIGH DUST DEPLETION IN TWO INTERVENING QUASAR ABSORPTION LINE SYSTEMS WITH THE 2175 A EXTINCTION BUMP AT z {approx} 1.4

Journal Article · Wed Dec 01 04:00:00 EST 2010 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/724/2/1325· OSTI ID:21474459

Peng, Jiang; Hongyan, Zhou; Tinggui, Wang ^[1]; Jian, Ge ^[2]; Prochaska, J Xavier ^[3]

---

1. Key Laboratory for Research in Galaxies and Cosmology, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, Anhui 230026 (China)
2. Astronomy Department, University of Florida, 211 Bryant Space Science Center, P.O. Box 112055, Gainesville, FL 32611 (United States)
3. University of California Observatories-Lick Observatory, University of California, Santa Cruz, CA 95064 (United States)

We present the column densities of heavy elements and dust depletion studies in two strong Mg II absorption systems at z {approx} 1.4 displaying the 2175 A dust extinction feature. Column densities are measured from low-ionization absorption lines using an Apparent Optical Depth Method on the Keck/ESI spectra. We find that the dust depletion patterns resemble that of cold diffuse clouds in the Milky Way (MW). The values, [Fe/Zn] {approx}-1.5 and [Si/Zn]<-0.67, are among the highest dust depletion measured for quasar absorption line systems. In another 2175 A absorber at z = 1.64 toward the quasar SDSS J160457.50+220300.5, Noterdaeme et al. reported a similar dust depletion measurement ([Fe/Zn] = -1.47 and [Si/Zn] = -1.07) and detected C I and CO absorption lines on its VLT/UVES spectrum. We conclude that heavy dust depletion (i.e., a characteristic of cold dense clouds in MW) is required to produce a pronounced 2175 A extinction bump.

• OSTI ID: 21474459
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 724; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION
ABUNDANCE
COSMIC RADIO SOURCES
DUSTS
GALAXIES
IONIZATION
MILKY WAY
QUASARS
SORPTION
SPECTRA