QUASARS PROBING QUASARS. VIII. THE PHYSICAL PROPERTIES OF THE COOL CIRCUMGALACTIC MEDIUM SURROUNDING z ∼ 2–3 MASSIVE GALAXIES HOSTING QUASARS

Journal Article · Sat Oct 01 04:00:00 EDT 2016 · Astrophysical Journal, Supplement Series

DOI:https://doi.org/10.3847/0067-0049/226/2/25· OSTI ID:22661036

Lau, Marie Wingyee; Prochaska, J. Xavier ^[1]

---

1. Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)

We characterize the physical properties of the cool T  ∼ 10{sup 4} K circumgalactic medium (CGM) surrounding z  ∼ 2–3 quasar host galaxies, which are predicted to evolve into present-day massive ellipticals. Using a statistical sample of 14 quasar pairs with projected separation <300 kpc and spectra of high dispersion and high signal-to-noise ratio, we find extreme kinematics with low metal ion lines typically spanning ≈500 km s{sup −1}, exceeding any previously studied galactic population. The CGM is significantly enriched, even beyond the virial radius, with a median metallicity [M/H] ≈ −0.6. The α /Fe abundance ratio is enhanced, suggesting that halo gas is primarily enriched by core-collapse supernovae. The projected cool gas mass within the virial radius is estimated to be 1.9 × 10{sup 11} M {sub ⊙} ( R {sub ⊥}/160 kpc){sup 2}, accounting for ≈1/3 of the baryonic budget of the galaxy halo. The ionization state of CGM gas increases with projected distance from the foreground quasars, contrary to expectation if the quasar dominates the ionizing radiation flux. However, we also found peculiarities not exhibited in the CGM of other galaxy populations. In one absorption system, we may be detecting unresolved fluorescent Ly α emission, and another system shows strong N v lines. Taken together, these anomalies suggest that transverse sightlines are—at least in some cases—possibly illuminated. We also discovered a peculiar case where detection of the C ii fine-structure line implies an electron density >100 cm{sup −3} and sub-parsec-scale gas clumps.

• OSTI ID: 22661036
• Journal Information: Astrophysical Journal, Supplement Series, Journal Name: Astrophysical Journal, Supplement Series Journal Issue: 2 Vol. 226; ISSN 0067-0049; ISSN APJSA2
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION
GALAXIES
GALAXY CLUSTERS
GRAVITATIONAL COLLAPSE
PHYSICAL PROPERTIES
PROBES
QUASARS
SUPERNOVAE