Extended Lyα emission from a damped Lyα absorber at z = 3.115
- Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan)
- School of General Education, Shinshu University, 3-1-1, Asahi, Matsumoto, Nagano 390-8621 (Japan)
- Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku Place, Hilo, HI 96720 (United States)
- Tokyo University of Science, Tomino 102-1, Oshamambe, Hokkaido, 049-3514 (Japan)
- Department of Astronomy, School of Science, Graduate University for Advanced Studies, Mitaka, Tokyo 181-8588 (Japan)
We searched for star formation activity associated with high-z damped Lyα systems (DLAs) with the Subaru telescope. We used a set of narrow-band (NB) filters whose central wavelengths correspond to the redshifted Lyα emission lines of targeted DLA absorbers at 3 < z < 4.5. We detected one apparent NB-excess object located 3.80 arcsec (∼28 h{sub 70}{sup −1} kpc) away from the quasar SDSS J031036.84+005521.7. Follow-up spectroscopy revealed an asymmetric Lyα emission at z {sub em} = 3.115 ± 0.003, which perfectly matches the sub-DLA trough at z {sub abs} = 3.1150 with logN(H I)/cm{sup –2} = 20.05. The Lyα luminosity is estimated to be L {sub Lyα} = 1.07 × 10{sup 42} erg s{sup –1}, which corresponds to a star formation rate of 0.97 M {sub ☉} yr{sup –1}. Interestingly, the detected Lyα emission is spatially extended with a sharp peak. The large extent of the Lyα emission is remarkably one-sided toward the quasar line-of-sight and is redshifted. The observed spatially asymmetric surface brightness profile can be qualitatively explained by a model of a DLA host galaxy, assuming a galactic outflow and a clumpy distribution of H I clouds in the circumgalactic medium. This large Lyα extension, which is similar to those found in Rauch et al., could be the result of complicated anisotropic radiative transfer through the surrounding neutral gas embedded in the DLA.
- OSTI ID:
- 22348270
- Journal Information:
- Astrophysical Journal, Vol. 780, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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