Astronomy and Astrophysics – Astrophysics
Scientific paper
2007-11-15
Astronomy and Astrophysics
Astrophysics
14 pages, 12 figures, matches version published in MNRAS. Discussion on polarization dependence of phase function added in App
Scientific paper
10.1111/j.1365-2966.2008.13066.x
The high-redshift Universe contains luminous Lyman Alpha (hereafter Lya) emitting sources such as galaxies and quasars. The emitted Lya radiation is often scattered by surrounding neutral hydrogen atoms. We show that the scattered Lya radiation obtains a high level of polarization for a wide range of likely environments of high-redshift galaxies. For example, the back-scattered Lya flux observed from galaxies surrounded by a superwind-driven outflow may reach a fractional polarization as high as ~40%. Equal levels of polarization may be observed from neutral collapsing protogalaxies. Resonant scattering in the diffuse intergalactic medium typically results in a lower polarization amplitude (<7%), which depends on the flux of the ionizing background. Spectral polarimetry can differentiate between Lya scattering off infalling gas and outflowing gas; for an outflow the polarization should increase towards longer wavelengths while for infall the opposite is true. Our numerical results suggest that Lya polarimetry is feasible with existing instruments, and may provide a new diagnostic of the distribution and kinematics of neutral hydrogen around high-redshift galaxies. Moreover, polarimetry may help suppress infrared lines originating in the Earth's atmosphere, and thus improve the sensitivity of ground-based observations to high-redshift Lya emitting galaxies outside the currently available redshift windows.
Dijkstra Mark
Loeb Abraham
No associations
LandOfFree
The Polarization of Scattered Lyman Alpha Radiation Around High-Redshift Galaxies does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with The Polarization of Scattered Lyman Alpha Radiation Around High-Redshift Galaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and The Polarization of Scattered Lyman Alpha Radiation Around High-Redshift Galaxies will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-214528