GRB as luminosity indicator

GRB Variability-Luminosity Correlation Confirmed

Recently, Guidorzi et al. (2005) expanded the size of the sample of GRBs for which variabilities and peak luminosities have been measured, from 11 to 32. They confirm the existence of a correlation, but find a dramatically different relationship between L and V than had originally been found. We find that this is the result of improper statistical methodology. When we fit a model to the data th...

The Globular Cluster Luminosity Function as a Distance Indicator : Dynamical

The dynamical evolution of the globular cluster systems in galaxies is predicted, based on the standard dynamical theory normalized to the example of the Milky Way. The major processes varying with the galactocentric distance are the tidal shocks and dynamical friction. Our simple model explains, on a quantitative basis, the observed diierences of the inner and outer populations of globular clu...

Mid-infrared luminosity as an indicator of the total infrared luminosity of galaxies

The infrared (IR) emission plays a crucial role for understanding the star formation in galaxies hidden by dust. We first examined four estimators of the IR luminosity of galaxies, LFIR (Helou et al. 1988), LTIR (Dale et al. 2001a), revised version of LTIR (Dale & Helou 2002) (we denote LTIR2), and LIR (Sanders & Mirabel 1996) by using the observed SEDs of well-known galaxies. We found that LIR...

Multiple regression of GRB luminosity on light-curve properties

Statistical relations between the luminosity L of gamma-ray burster (GRBs) and several of their other observable properties have been discovered. Four of these properties are considered here: the spectral lag; a measure of the light-curve variability; peak energy and the minimum light-curve rise time. Data are taken from a tabulation by Schaefer. Log–log regression of L on various combinations ...

Implications of Lag-luminosity Relationship for Unified Grb Paradigms