Astronomy and Astrophysics – Astrophysics
Scientific paper
1997-04-17
Astrophys.J. 487 (1997) 73
Astronomy and Astrophysics
Astrophysics
39 pages, 14 encapsulated figures, uses LaTeX2e, Replaced Figure 2 Accepted for publication by the Astrophysical Journal. Also
Scientific paper
10.1086/304591
We present the first results of an ongoing program to investigate the kinematic characteristics of high redshift damped lya systems. Because damped lya systems are widely believed to be the progenitors of current massive galaxies, an analysis of their kinematic history allows a direct test of galaxy formation scenarios. We have collected a kinematically unbiased sample of 17 high S/N ratio, high resolution damped lya spectra taken with HIRES on the 10m W.M. Keck Telescope. Our study focuses on the unsaturated, low-ion transitions of these systems which reveal their kinematic traits. The profiles exhibit a nearly uniform distribution of velocity widths ranging from 20 - 200 km/s and a relatively high degree of asymmetry. In an attempt to explain these characteristics, we introduce several physical models, which have previously been attributed to damped lya systems, including rapidly rotating cold disks, slowly rotating hot disks, massive isothermal halos, and a hydrodynamic spherical accretion model. Using standard Monte Carlo techniques, we run sightlines through these model systems to derive simulated low-ion profiles. Comparing statistical measures of the simulated profiles with the observed profiles, we determine that the rapidly rotating cold disk model is the only tested model consistent with the data at high confidence levels. A Relative Likelihood Test of the rapidly rotating cold disk model indicates the disks must have large rotation speeds; v > 180 km/s at the 99% c.l. In turn, we demonstrate that the Cold Dark Matter Model, as developed by Kauffmann (1996), is inconsistent with the damped lya data at very high c.l. This is because the CDM Model does not predict a large enough fraction of rapidly rotating disks at z approx 2.5.
Prochaska Jason Xavier
Wolfe Arthur M.
No associations
LandOfFree
On the Kinematics of the Damped Lyman Alpha Protogalaxies 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 On the Kinematics of the Damped Lyman Alpha Protogalaxies, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and On the Kinematics of the Damped Lyman Alpha Protogalaxies will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-370918