QUENCHED COLD ACCRETION OF A LARGE-SCALE METAL-POOR FILAMENT DUE TO VIRIAL SHOCKING IN THE HALO OF A MASSIVE z = 0.7 GALAXY

Journal Article · Tue Nov 20 04:00:00 EST 2012 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/760/1/68· OSTI ID:22086266

Churchill, Christopher W; Holtzman, Jon; Nielsen, Nikole M; Trujillo-Gomez, Sebastian ^[1]; Kacprzak, Glenn G; Spitler, Lee R ^[2]; Steidel, Charles C ^[3]

---

1. Department of Astronomy, New Mexico State University, MSC 4500, Las Cruces, NM 88003 (United States)
2. Centre for Astrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122 (Australia)
3. Department of Astronomy, California Institute of Technology, MS 105-24, Pasadena, CA 91125 (United States)

Using HST/COS/STIS and HIRES/Keck high-resolution spectra, we have studied a remarkable H I absorbing complex at z = 0.672 toward the quasar Q1317+277. The H I absorption has a velocity spread of {Delta}v = 1600 km s{sup -1}, comprises 21 Voigt profile components, and resides at an impact parameter of D = 58 kpc from a bright, high-mass (log M {sub vir}/M {sub Sun} {approx_equal} 13.7) elliptical galaxy that is deduced to have a 6 Gyr old, solar metallicity stellar population. Ionization models suggest the majority of the structure is cold gas surrounding a shock-heated cloud that is kinematically adjacent to a multi-phase group of clouds with detected C III, C IV, and O VI absorption, suggestive of a conductive interface near the shock. The deduced metallicities are consistent with the moderate in situ enrichment relative to the levels observed in the z {approx} 3 Ly{alpha} forest. We interpret the H I complex as a metal-poor filamentary structure being shock heated as it accretes into the halo of the galaxy. The data support the scenario of an early formation period (z > 4) in which the galaxy was presumably fed by cold-mode gas accretion that was later quenched via virial shocking by the hot halo such that, by intermediate redshift, the cold filamentary accreting gas is continuing to be disrupted by shock heating. Thus, continued filamentary accretion is being mixed into the hot halo, indicating that the star formation of the galaxy will likely remain quenched. To date, the galaxy and the H I absorption complex provide some of the most compelling observational data supporting the theoretical picture in which accretion is virial shocked in the hot coronal halos of high-mass galaxies.

• OSTI ID: 22086266
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 760; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ABSORPTION
ABSORPTION SPECTRA
ASTRONOMY
ASTROPHYSICS
CARBON IONS
FILAMENTS
GALACTIC EVOLUTION
GALAXIES
HYDROGEN IONS
IMPACT PARAMETER
INTERFACES
IONIZATION
LYMAN LINES
MASS
OXYGEN IONS
QUASARS
RED SHIFT
SHOCK HEATING
STAR ACCRETION