Astronomy and Astrophysics – Astrophysics
Scientific paper
2005-10-13
Astrophys.J.649:37-47,2006
Astronomy and Astrophysics
Astrophysics
Accepted for Publication in ApJ, 11 emulateapj pages with 6 figures, together with a companion paper
Scientific paper
10.1086/506244
We model the spectra and surface brightness distributions for the Lyman alpha (Lya) radiation expected from protogalaxies that are caught in the early stages of their assembly. We use the results of a companion paper to characterize the radiation emerging from spherically collapsing gas clouds. We then modify the intrinsic spectra to incorporate the effect of subsequent resonant scattering in the intergalactic medium (IGM). Using these models, we interpret a number of recent observations of extended Lya blobs (LABs) at high redshift. We suggest, based on the angular size, energetics, as well as the relatively shallow surface brightness profiles, and double-peaked spectra, that several of these LABs may be associated with collapsing protogalaxies. We suggest two follow-up observations to diagnose the presence of gas infall. High S/N spectra of LABs should reveal a preferential flattening of the surface brightness profile at the red side of the line. Complementary imaging of the blobs at redshifted Balmer alpha wavelengths should reveal the intrinsic Lya emissivity and allow its separation from radiative transfer effects. We show that Lya scattering by infalling gas can reproduce the observed spectrum of Steidel et al's LAB2 as accurately as a recently proposed outflow model. Finally, we find similar evidence for infall in the spectra of point-like Lyman alpha emitters. The presence of scattering by the infalling gas implies that the intrinsic Lya luminosities, and derived quantities, such as the star-formation rate, in these objects may have been underestimated by about an order of magnitude.
Dijkstra Mark
Haiman Zoltan
Spaans Marco
No associations
LandOfFree
Lyman Alpha Radiation From Collapsing Protogalaxies II: Observational Evidence for Gas Infall 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 Lyman Alpha Radiation From Collapsing Protogalaxies II: Observational Evidence for Gas Infall, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Lyman Alpha Radiation From Collapsing Protogalaxies II: Observational Evidence for Gas Infall will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-222079