[ArXiv] GRB host galaxies, Aug. 10, 2007
From arxiv/astro-ph:0708.1510v1
Connecting GRBs and galaxies: the probability of chance coincidence by Cobb and Bailyn
Without an optical afterglow, a galaxy within the 2 arc second error region of a GRB x-ray afterglow is identified as a host galaxy; however confusion can rise due to the facts that 1. the edge of a galaxy is diffused, 2. multiple sources could exist within 2 arc second error region, 3.the distance between the galaxy and the x-ray afterglow is measured by projection, and 4. lensing causes increase of brightness and position shifts. In this paper, the authors “investigated the fields of 72 GRBs in order to examine the general issue of associations between GRBs and host galaxies.”
The authors added some statistical issues on this matching GRBs and host galaxies but current knowledge and techniques seem short to tackle the problem. Yet, to prevent false discovery, the authors proposed strategic studies for the followings:
- Gamma-ray luminosity indicators
- Detection (or non-detection ) SNe (Supernova) for long-duration bursts
- Classification of associated galaxy : long-duration and short-duration bursts are associated with late-type and early-type galaxies, respectively
- Optical afterglow spectral absorption features
- Visual detection of true host galaxy as happened with GRB 060912a
- X-ray afterglow spectral emission lines, and
- Strong lensing of x-ray afterglows
As multi-wavelength studies become popular nowadays, this source matching issue across bands continuously arises where statistics can contribute the validity of source matching methods. So far, those methods are incomprehensible to statisticians.
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