Related papers: Quasar 2175 {\AA} dust absorbers I: metallicity, d…
We present the cold neutral content (H I and C I gas) of 13 quasar 2175 \AA$ $ dust absorbers (2DAs) at $z$ = 1.6 - 2.5 to investigate the correlation between the presence of the UV extinction bump with other physical characteristics. These…
We present the column densities of heavy-elements and dust depletion studies in twostrong Mg~II absorption systems at $z\sim1.4$ displaying the 2175-{\AA} dust extinction feature. Column densities are measured from low-ionization absorption…
We present, for the first time, a systematic study of quasar-associated 2175 \AA\ dust absorbers using spectroscopic data from the Sloan Digital Sky Survey (SDSS) Data Release 16 (DR16). By analyzing the optical spectra and multi-band…
We report detections of 39 2175-{\AA} dust extinction bump candidates associated with strong Mg II absorption lines at z$\sim$ 1--1.8 on quasar spectra in Sloan Digital Sky Survey (SDSS) DR3. These strong Mg II absorption line systems are…
We report discoveries of 165 new quasar Ca II absorbers from the Sloan Digital Sky Survey (SDSS) Data Release 7 and 12. Our Ca II rest frame equivalent width distribution supports the weak and strong subpopulations, split at…
We report the detection of a strong Milky Way-type 2175 \AA$ $ extinction bump at $z$ = 2.1166 in the quasar spectrum towards SDSS J121143.42+083349.7 from the Sloan Digital Sky Survey (SDSS) Data Release 10. We conduct follow up…
We report Keck/ESI and VLT/UVES observations of three super-damped Lyman-alpha quasar absorbers with H I column densities log N(HI) >= 21.7 at redshifts z=2-2.5. All three absorbers show similar metallicities (-1.3 to -1.5 dex), and dust…
We report on a dusty Mg~II absorber associated with the quasar SDSSJ003545.13+011441.2 (hereafter J0035+0114) at $z$=1.5501, which is the strongest one among the three Mg~II absorbers along the sight line of quasar. The two low redshift…
CaII 3934,3969 absorbers, which are likely to be a subset of damped Lyman alpha systems, are the most dusty quasar absorbers known, with an order of magnitude more extinction in E(B-V) than other absorption systems. There is also evidence…
To investigate the properties of dust in the nuclear region of quasars, we explored the extinction curves of the iron low-ionization broad absorption line (FeLoBAL) quasar SDSS J163004.29+311957.6 and its two analogues. The parameterized…
We report spectroscopic observations with the Multiple Mirror Telescope for 11 damped Lyman-alpha absorbers (DLAs) or strong DLA candidates at 0.1 < z < 1.5, including several absorbers discovered in the Sloan Digital Sky Survey. In…
The 2175{\AA} bump is a prominent absorption feature at ultraviolet (UV) wavelengths in dust extinction and attenuation curves. Understanding the relative strength of this feature is important for accurate dust corrections at both low- and…
We present the results of a search for cold gas at high redshift along QSO lines-of-sight carried out without any a priori assumption on the neutral atomic-hydrogen (HI) content of the absorbers. To do this, we systematically looked for…
We have discovered two dusty intervening MgII absorption systems at z~1.3 in the Sloan Digital Sky Survey (SDSS) database. The overall spectra of both QSOs are red (u-K>4.5 mag) and are well modelled by the composite QSO spectrum reddened…
We present a new determination of the dust content and near-ultraviolet/optical extinction curves associated with a sample of ~8300 strong (equivalent width > 1A) Mg II absorbers, with redshifts 0.4<z<2.2, identified in Sloan Digital Sky…
The broad absorption bump at 2175 angstrom due to dust, which is ubiquitous in the Galaxy and is seen in the Magellanic clouds, is also seen in a composite spectrum of Mg II absorbers. The composite absorber spectrum is obtained by taking…
The strongest spectroscopic dust extinction feature in the Milky Way, the broad absorption bump at 2175 \AA, is generally believed to be caused by aromatic carbonaceous materials -- very likely a mixture of Polycyclic Aromatic Hydrocarbon…
We present results from a mini-survey of dust spectral features arising in galaxies at redshifts $0.5 < z < 1.2$ in our James Webb Space Telescope (JWST) mid-infrared spectra of physically-unrelated background quasars. We analyze the JWST…
Quasar absorption systems not only affect the way quasars are selected, but also serve as key probes of galaxies, providing insight into their chemical evolution and interstellar medium (ISM). Recently, a method based on Gaia astrometric…
We study metal depletion due to dust in the interstellar medium (ISM) to infer the properties of dust grains and characterize the metal and dust content of galaxies, down to low metallicity and intermediate redshift z. We provide metal…