Journal
ASTROPHYSICAL JOURNAL
Volume 743, Issue 2, Pages -Publisher
IOP PUBLISHING LTD
DOI: 10.1088/0004-637X/743/2/207
Keywords
galaxies: evolution; intergalactic medium; quasars: absorption lines
Categories
Funding
- NASA [NAS5-26555, NNX08AJ31G, NNX08AJ44G]
- NASA through a grant from the Space Telescope Science Institute [HST-GO-11741]
- NASA [100940, NNX08AJ31G, 100420, NNX08AJ44G] Funding Source: Federal RePORTER
Ask authors/readers for more resources
We present UV and optical observations from the Cosmic Origins Spectrograph on the Hubble Space Telescope and Keck of a z = 0.27395 Lyman limit system (LLS) seen in absorption against the QSO PG1630+377. We detect Hi absorption with log N(H I) = 17.06 +/- 0.05 as well as Mg II, C III, Si III, and O VI in this system. The column densities are readily explained if this is a multi-phase system, with the intermediate and low ions arising in a very low metallicity ([Mg/H] = -1.71 +/- 0.06) photoionized gas. We identify via Keck spectroscopy and Large Binocular Telescope imaging a 0.3L* star-forming galaxy projected 37 kpc from the QSO at nearly identical redshift (z = 0.27406 and Delta v = -26 km s(-1)) with near solar metallicity ([O/H] = -0.20 +/- 0.15). The presence of very low metallicity gas in the proximity of a near-solar metallicity, sub-L* galaxy strongly suggests that the LLS probes gas infalling onto the galaxy. A search of the literature reveals that such low-metallicity LLSs are not uncommon. We found that 50% (4/8) of the well-studied z less than or similar to 1 LLSs have metallicities similar to the present system and show sub-L* galaxies with rho < 100 kpc in those fields where redshifts have been surveyed. We argue that the properties of these primitive LLSs and their host galaxies are consistent with those of cold mode accretion streams seen in galaxy simulations.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available