Quasar 2175 Å dust absorbers I: metallicity, depletion pattern, and kinematics

Abstract

We present 13 new 2175 Å dust absorbers at z_abs = 1.0 - 2.2 towards background quasars from the Sloan Digital Sky Survey. These absorbers are examined in detail using data from the Echelle Spectrograph and Imager (ESI) on the Keck II telescope. Many low-ionization lines including Fe II, Zn II, Mg II, Si II, Al II, Ni II, Mn II, Cr II, Ti II, and Ca II are present in the same absorber which gives rise to the 2175 Å bump. The relative metal abundances (with respect to Zn) demonstrate that the depletion patterns of our 2175 Å dust absorbers resemble that of the Milky Way clouds although some are disk-like and some are halo-like. The 2175 Å dust absorbers have significantly higher depletion levels compared to literature Damped Lyman-α absorbers (DLAs) and subDLAs. The dust depletion level indicator [Fe/Zn] tends to anti-correlate with bump strengths. The velocity profiles from the Keck/ESI spectra also provide kinematical information on the dust absorbers. The dust absorbers are found to have multiple velocity components with velocity widths extending from ~100 to ~ 600 km/s, which are larger than those of most DLAs and subDLAs. Assuming the velocity width is a reliable tracer of stellar mass, the host galaxies of 2175 Å dust absorbers are expected to be more massive than DLA/subDLA hosts. Not all of the 2175 Å dust absorbers are intervening systems towards background quasars. The absorbers towards quasars J1006+1538 and J1047+3423 are proximate systems that could be associated with the quasar itself or the host galaxy.

arXiv comment27 pages, 32 figures, 31 tables; Accepted for publication in MNRAS

References in corpus (43)

• Maps of Dust IR Emission for Use in Estimation of Reddening and CMBR Foregrounds
• The Sloan Digital Sky Survey: Technical Summary
• The chemical composition of the Sun
• The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III
• Interstellar Dust Grains
• SDSS-III: Massive Spectroscopic Surveys of the Distant Universe, the Milky Way Galaxy, and Extra-Solar Planetary Systems
• The Baryon Oscillation Spectroscopic Survey of SDSS-III
• A Quantitative Comparison of SMC, LMC, and Milky Way UV to NIR Extinction Curves
• The Sloan Digital Sky Survey Quasar Catalog V. Seventh Data Release
• A Unified Representation of Gas-Phase Element Depletions in the Interstellar Medium
• An Analysis of the Shapes of Interstellar Extinction Curves. V. The IR-Through-UV Curve Morphology
• Wind from the black-hole accretion disk driving a molecular outflow in an active galaxy
• ESI, a new Keck Observatory echellette spectrograph and imager
• On the Kinematics of the Damped Lyman Alpha Protogalaxies
• The SDSS-III Baryon Oscillation Spectroscopic Survey: Quasar Target Selection for Data Release Nine
• Damped Lyman alpha absorbers at high redshift -- large disks or galactic building blocks?
• Velocity-Metallicity Correlation for high-z DLA Galaxies: Evidence for a Mass-Metallicity Relation?
• Damped Lyman Alpha Systems in Galaxy Formation Simulations
• Dusty Structure Around Type-I Active Galactic Nuclei: Clumpy Torus Narrow Line Region and Near-Nucleus Hot Dust
• The JHU-SDSS metal absorption line catalog: redshift evolution and properties of Mg II absorbers
• The First Positive Detection of Molecular Gas in a GRB Host Galaxy
• Dust Extinction in High-z Galaxies with GRB Afterglow Spectroscopy - The 2175Å Feature at z=2.45
• Mass-metallicity relation from z=5 to the present: Evidence for a transition in the mode of galaxy growth at z=2.6 due to the end of sustained primordial gas infall
• The Fundamental Plane of Damped Lyman Alpha Systems
• Dust and Diffuse Interstellar Bands in the z_a = 0.524 Absorption System toward AO 0235+164
• On the Nature of Velocity Fields in High z Galaxies
• Metal Abundances and Ionization in QSO Intrinsic Absorbers
• The ESO UVES Advanced Data Products Quasar Sample - VI. Sub-Damped Lyman-$\alpha$ Metallicity Measurements and the Circum-Galactic Medium
• The properties of the 2175AA extinction feature discovered in GRB afterglows
• The Metal-Strong Damped Lyman-alpha Systems
• Detections of the 2175 ÅDust Feature at 1.4z 1.5 from the Sloan Digital Sky Survey
• Disentangling microlensing and differential extinction in the double QSO HE0512-3329
• Detection of the 2175Å~ extinction feature and 21-cm absorption in two MgII systems at z~1.3
• The nature of proximate damped Lyman alpha systems
• A MIKE + UVES survey of Sub-Damped Lyman-Alpha Systems at z<1.5
• Hubble Space Telescope Observations of Sub-Damped Lyman-alpha Absorbers at z < 0.5, and Implications for Galaxy Chemical Evolution
• The Composite Spectrum of BOSS Quasars Selected for Studies of the Lyman-alpha Forest
• Towards Detecting The 2175-Å Dust Feature Associated With Strong High Redshift Mg ßII Absorption Lines
• Cold gas and a Milky Way-type 2175 Å bump in a metal-rich and highly depleted absorption system
• Neutral atomic-carbon QSO absorption-line systems at z>1.5: Sample selection, HI content, reddening, and 2175 A extinction feature
• A Metal-Strong and Dust-Rich Damped \lya Absorption System toward the Quasar SDSS J115705.52+615521.7
• The extended High A(V) Quasar Survey: Searching for dusty absorbers toward mid-infrared selected quasars
• Seven broad absorption line quasars with excess broad band absorption near 2250 Å

Cited by in corpus (15)

• Cool Outflows in Galaxies and their Implications
• The Dust Attenuation Law in Galaxies
• The IRX-$\beta$ relation of high-redshift galaxies
• Dust in the Wind: Composition and Kinematics of Galaxy Outflows at the Peak Epoch of Star Formation
• Cold gas in the early Universe. Survey for neutral atomic-carbon in GRB host galaxies at 1 < z < 6 from optical afterglow spectroscopy
• Universe opacity and CMB
• Quasar 2175 Å dust absorbers II: Correlation analysis and relationship with other absorption line systems
• On the dust properties of high redshift molecular clouds and the connection to the 2175 Å extinction bump
• Revealing the host galaxy of a quasar 2175 Å dust absorber at z = 2.12
• Discovery of Metastable He I* $\lambda$10830 Mini-broad Absorption Lines and Very Narrow Paschen $\alpha$ Emission Lines in the ULIRG Quasar IRAS F11119+3257
• Gravitationally Lensed Quasar SDSS J1442+4055: Redshifts of Lensing Galaxies, Time Delay, Microlensing Variability, and Intervening Metal System at z ~ 2
• Newly discovered Ca II absorbers in the early universe: statistics, element abundances and dust
• An Intercomparison Study of Two Proximate Damped Ly$\alpha$ Systems with Residual Flux upon the Ly$\alpha$ Absorption Trough toward Quasars
• The 2175 Å~ Bump Features in FeLoBAL Quasars: One Indicator of MW-like Dust in the Nuclear Region of Quasar
• Studying Quasar Absorber Host Galaxy Properties Using Image Stacking Technique