We use medium- and high-resolution spectroscopy of close pairs of quasars to analyze the circumgalactic medium (CGM) surrounding 32 damped Ly
We use medium-resolution Keck/Echellette Spectrograph and Imager spectroscopy of bright quasars to study cool gas traced by Ca
- NSF-PAR ID:
- 10371354
- Publisher / Repository:
- DOI PREFIX: 10.3847
- Date Published:
- Journal Name:
- The Astrophysical Journal
- Volume:
- 936
- Issue:
- 2
- ISSN:
- 0004-637X
- Format(s):
- Medium: X Size: Article No. 171
- Size(s):
- ["Article No. 171"]
- Sponsoring Org:
- National Science Foundation
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Abstract α absorption systems (DLAs). The primary quasar sightline in each pair probes an intervening DLA in the redshift range 1.6 <z abs< 3.5, such that the secondary sightline probes absorption from Lyα and a large suite of metal-line transitions (including Oi , Cii , Civ , Siii , and Siiv ) in the DLA host galaxy’s CGM at transverse distances 24 kpc ≤R ⊥≤ 284 kpc. Analysis of Lyα in the CGM sightlines shows an anticorrelation betweenR ⊥and Hi column density (N HI) with 99.8% confidence, similar to that observed around luminous galaxies. The incidences of Cii and Siii withN > 1013cm−2within 100 kpc of DLAs are larger by 2σ than those measured in the CGM of Lyman break galaxies (Cf (N CII ) > 0.89 and ). Metallicity constraints derived from ionic ratios for nine CGM systems with negligible ionization corrections andN HI> 1018.5cm−2show a significant degree of scatter (with metallicities/limits across the range ), suggesting inhomogeneity in the metal distribution in these environments. Velocity widths of Civ λ 1548 and low-ionization metal species in the DLA versus CGM sightlines are strongly (>2σ ) correlated, suggesting that they trace the potential well of the host halo overR ⊥≲ 300 kpc scales. At the same time, velocity centroids for Civ λ 1548 differ in DLA versus CGM sightlines by >100 km s−1for ∼50% of velocity components, but few components have velocities that would exceed the escape velocity assuming dark matter host halos of ≥1012M ⊙. -
Abstract The circumgalactic medium (CGM) plays a vital role in the formation and evolution of galaxies, acting as a lifeline between galaxies and the surrounding intergalactic medium. In this study, we leverage a unique sample of quasar pairs to investigate the properties of the CGM with absorption line tomography. We present a new sample of medium-resolution Keck/ESI, Magellan/MagE, and VLT/XSHOOTER spectra of 29 quasar pairs at redshift 2 <
z < 3. We supplement the sample with additional spectra of 32 pairs from the literature, creating a catalog of 61 quasar pairs with angular separations between 1.″7 and 132.″9 and projected physical separations (r ⊥) between 14 kpc and 887 kpc. We construct a catalog of 906 metal-line absorption doublets of Civ (λλ 1548, 1550) with equivalent widths ranging from 6 m Å ≤W r ,1550≤ 2053 m Å. The best-fit linear model to the log-space equivalent width frequency distribution ( ) of the sample yields coefficients ofm = −1.44 ± 0.16 andb = −0.43 ± 0.16. To constrain the projected extent of Civ , we calculate the transverse autocorrelation function. The flattening of the autocorrelation function at lowr ⊥provides a lower limit for the coherence length of the metal enriched CGM—on the order of 200h −1comoving kpc. This physical size constraint allows us to refine our understanding of the metals in the CGM, where the extent of Civ in the CGM depends on gas flows, feedback, timescale of metal injection and mixing, and the mass of the host galaxies. -
Abstract We present results on the nature of extreme ejective feedback episodes and the physical conditions of a population of massive (
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Abstract We present the discovery of neutral gas detected in both damped Ly
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