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|Title:||Constraining the rate and luminosity function of Swift gamma-ray bursts||Authors:||Howell, E. J.
Coward, D. M.
|Issue Date:||2014||Journal:||MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY||Number:||444||Issue:||1||First Page:||15||Abstract:||We compute the intrinsic isotropic peak luminosity function (LF) and formation rate of long gamma-ray bursts (LGRBs) using a novel approach. We complement a standard log N-log P brightness distribution and V<SUB>max</SUB> estimations with two observation-time relations: a redshift-observation-time relation (log z-log T) and a new luminosity-observation-time relation (log L-log T). We show that this approach reduces degeneracies that exist between the rate and LF of a brightness distribution. To account for the complex triggering algorithm employed by Swift, we use recent results of Lien et al. (2014) to produce a suite of efficiency functions. Using these functions with the above methods, we show that a log L-log T method can provide good constraints on the form of the LF, particularly the high end. Using a sample of 175 peak luminosities determined from redshifts with well-defined selection criteria, our results suggest that LGRBs occur at a local rate (without beaming corrections) of [0.7 < ρ<SUB>0</SUB> < 0.8] Gpc<SUP>-3</SUP> yr<SUP>-1</SUP>. Within this range, assuming a broken power-law LF, we find best estimates for the low- and high-energy indices of -0.95 ± 0.09 and -2.59 ± 0.93, respectively, separated by a break luminosity 0.80 ± 0.43 × 10<SUP>52</SUP> erg s<SUP>-1</SUP>.||Description:||EJH acknowledges support from a UWA Research Fellowship. DMC is supported by an Australian Research Council Future Fellowship. The authors gratefully acknowledge L14 for kindly providing the data used in Section 3 and for valuable discussions in regards to modelling the detection efficiency of Swift. The authors also acknowledge the anonymous referee for a careful reading of the manuscript and for providing a number of comments and suggestions that have significantly improved the paper.||URI:||http://hdl.handle.net/20.500.12386/12138||ISSN:||0035-8711||DOI:||10.1093/mnras/stu1403||Bibcode ADS:||2014MNRAS.444...15H|
|Appears in Collections:||1.01 Articoli in rivista|
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