科研之友
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摘要
We report the detection at 850 m of the central source in SSA22-LAB1, the archetypal %26quot;Lyman-alpha Blob%26quot; (LAB), a 100 kpc scale radio-quiet emission-line nebula at z = 3.1. The flux density of the source, S-850 = 4.6 +/- 1.1 mJy, implies the presence of a galaxy or group of galaxies with a total luminosity of L-IR approximate to 10(12) L-circle dot. The position of an active source at the center of a similar to 50 kpc radius ring of linearly polarized Ly alpha emission detected by Hayes et al. suggests that the central source is leaking Ly alpha photons preferentially in the plane of the sky, which undergo scattering in H I clouds at a large galactocentric radius. The Ly alpha morphology around the submillimeter detection is reminiscent of a biconical outflow, and the average Ly alpha line profiles of the two %26quot;lobes%26quot; are dominated by a red peak, which is expected for a resonant line emerging from a medium with a bulk velocity gradient that is outflowing relative to the line center. Taken together, these observations provide compelling evidence that the central active galaxy (or galaxies) is responsible for a large fraction of the extended Ly alpha emission and morphology. Less clear is the history of the cold gas in the circumgalactic medium being traced by Ly alpha: is it mainly pristine material accreting into the halo that has not yet been processed through an interstellar medium (ISM), now being blown back as it encounters an outflow, or does it mainly comprise gas that has been swept-up within the ISM and expelled from the galaxy?
- 出版日期2014-9-20
