Diffuse Far-UV Line Emission from the Low-Redshift Lyman Break Galaxy Analog KISSR242

Abstract

We present new ultraviolet (UV) observations of the luminous compact blue galaxy KISSR242, obtained with the HST-COS. We identify multiple resolved sub-arcsecond near-UV sources within the COS aperture. The far-UV spectroscopic data show strong outflow absorption lines, consistent with feedback processes related to an episode of massive star-formation. OI, CII, and SiII--SiIV are observed with a mean outflow velocity v_{out} = -60 km/s. We also detect faint fine-structure emission lines of singly ionized silicon for the first time in a low-redshift starburst galaxy. These emissions have been seen previously in deep Lyman break galaxy surveys at z ~ 3. The SiII* lines are at the galaxy rest velocity, and they exhibit a quantitatively different line profile from the absorption features. These lines have a width of ~ 75 km/s, too broad for point-like emission sources such as the HII regions surrounding individual star clusters. The size of the SiII* emitting region is estimated to be ~ 250 pc. We discuss the possibility of this emission arising in overlapping super star cluster HII regions, but find this explanation to be unlikely in light of existing far-UV observations of local star-forming galaxies. We suggest that the observed SiII* emission originates in a diffuse warm halo populated by interstellar gas driven out by intense star-formation and/or accreted during a recent interaction that may be fueling the present starburst episode in KISSR242.

ApJL accepted. 6 pages, 3 figures, 2 tables

References in corpus (6)

• A Search for Extended Ultraviolet Disk (XUV-disk) Galaxies in the Local Universe
• The Direct Detection of Lyman-Continuum Emission from Star-forming Galaxies at z~3
• Physical Conditions in a Young, Unreddened, Low Metallicity Galaxy at High Redshift
• A High-Resolution Survey of Low-Redshift QSO Absorption Lines: Statistics and Physical Conditions of O VI Absorbers
• The Low-z Intergalactic Medium. III. HI and Metal Absorbers at z<0.4
• Luminous Compact Blue Galaxies up to z~1 in the HST Ultra Deep Field: I. Small galaxies, or blue centers of massive disks?

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