HOST GALAXIES AS GAMMA-RAY BURST DISTANCE INDICATORS Page: 2 of 4
This article is part of the collection entitled: Office of Scientific & Technical Information Technical Reports and was provided to UNT Digital Library by the UNT Libraries Government Documents Department.
Extracted Text
The following text was automatically extracted from the image on this page using optical character recognition software:
Host Galaxies As Gamma-Ray Burst Distance
Indicators
David Band', Raul Jimenez2, and Tsvi Piran3
X-2, Los Alamos National Laboratory, Los Alamos, NM 87505, USA
2 Dept. of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854, USA
3 Hebrew University, Jerusalem, Israel
Abstract. We calculate the distributions of the total burst energy, the peak luminosity
and the X-ray afterglow energy using burst observations and distances to the associated
host galaxies. To expand the sample, we include redshift estimates for host galaxies
without spectroscopic redshifts. The methodology requires a model of the host galaxy
population; we find that in the best model the burst rate is proportional to the host
galaxy luminosity at the time of the burst.
1 Introduction
The first few bursts with afterglows, host galaxies and spectroscopic redshifts
demonstrated that most, if not all, classical bursts occur at cosmological dis-
tances. As the sample of such bursts grows, we can address fundamental char-
acteristics of the burst population. Here we calculate the distributions of the
total gamma-ray energy emitted, the peak luminosity, and the energy of the X-
ray afterglow. The average values of these quantities set fundamental physical
constraints on burst models, while the widths of the distributions indicate the
variability these models must permit.
To estimate the distribution of these different intrinsic intensities requires
both the apparent intensity of the burst and the distance to the burst. We fit
spectra to BATSE data, where available, to calculate the energy fluence and
the peak luminosity. The distance is obtained from the spectroscopic redshift, if
observed, or from a redshift probability distribution derived from the host galaxy
brightness. We include bursts without spectroscopic redshifts out of a desire to
use all available data. The number of bursts with spectroscopic redshifts has
increased since we began this project, and the inclusion of bursts without such
redshifts is not as compelling, although the methodology will again be useful if
the determination of spectroscopic redshifts does not keep up with the discovery
of host galaxies. The redshift probability distribution requires a model of the
host galaxy population, which we choose using a sample of bursts with both a
spectroscopic redshift and a host galaxy brightness. This host galaxy population
model is intrinsically interesting since it depends on the type of progenitor.
2 Methodology
We present the methodology for determining the distribution of the gamma-
ray energy, but the approach is easily generalized to the distributions of the
Upcoming Pages
Here’s what’s next.
Search Inside
This article can be searched. Note: Results may vary based on the legibility of text within the document.
Tools / Downloads
Get a copy of this page or view the extracted text.
Citing and Sharing
Basic information for referencing this web page. We also provide extended guidance on usage rights, references, copying or embedding.
Reference the current page of this Article.
BAND, D. & AL, ET. HOST GALAXIES AS GAMMA-RAY BURST DISTANCE INDICATORS, article, January 1, 2001; New Mexico. (https://digital.library.unt.edu/ark:/67531/metadc725716/m1/2/: accessed April 18, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.