Astronomy and Astrophysics – Astrophysics
Scientific paper
2002-06-17
Astron.J. 125 (2003) 32
Astronomy and Astrophysics
Astrophysics
45 pages, 25 figures, final version. AJ, accepted
Scientific paper
10.1086/344945
The effective optical depth in the Ly-alpha forest region of 1061 low-resolution QSO spectra drawn from the SDSS database decreases with decreasing redshift over the range 2.5 < z < 4. Although the evolution is relatively smooth, tau_eff ~ (1+z)^{3.8 pm 0.2}, at z ~ 3.2 the effective optical depth decreases suddenly, by about ten percent with respect to this smoother evolution. It climbs back to the original smooth scaling again by z ~ 2.9. We describe two techniques, one of which is new, for quantifying this evolution which give consistent results. A variety of tests show that the feature is not likely to be a consequence of how the QSO sample was selected, nor the result of flux calibration or other systematic effects. Other authors have argued that, at this same epoch, the temperature of the IGM also shows a departure from an otherwise smooth decrease with time. These features in the evolution of the temperature and the optical depth are signatures of the reionization of He II.
Bernardi Marco
Brinkmann John
Burles Scott
Connolly Andrew J.
Frieman Josh
No associations
LandOfFree
A feature at z ~ 3.2 in the evolution of the Ly-alpha forest optical depth 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 A feature at z ~ 3.2 in the evolution of the Ly-alpha forest optical depth, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and A feature at z ~ 3.2 in the evolution of the Ly-alpha forest optical depth will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-366961