Analysis of gamma-ray burst duration distribution using mixtures of skewed distributions

Abstract

Two classes of GRBs have been confidently identified thus far and are prescribed to different physical scenarios -- NS-NS or NS-BH mergers, and collapse of massive stars, for short and long GRBs, respectively. A third, intermediate in duration class, was suggested to be present in previous catalogs, such as BATSE and $Swift$, based on statistical tests regarding a mixture of two or three log-normal distributions of $T_{90}$. However, this might possibly not be an adequate model. This paper investigates whether the distributions of $\log T_{90}$ from BATSE, $Swift$, and $Fermi$ are described better by a mixture of skewed distributions rather than standard Gaussians. Mixtures of standard normal, skew-normal, sinh-arcsinh and alpha-skew-normal distributions are fitted using a maximum likelihood method. The preferred model is chosen based on the Akaike information criterion. It is found that mixtures of two skew-normal or two sinh-arcsinh distributions are more likely to describe the observed duration distribution of $Fermi$ than a mixture of three standard Gaussians, and that mixtures of two sinh-arcsinh or two skew-normal distributions are models competing with the conventional three-Gaussian in the case of BATSE and $Swift$. Based on statistical reasoning, existence of a third (intermediate) class of GRBs in $Fermi$ data is rejected, and it is shown that other phenomenological models may describe the observed $Fermi$, BATSE, and $Swift$ duration distributions at least as well as a mixture of standard normal distributions.

9 pages, 7 figures, 3 tables; matches the version accepted by MNRAS. arXiv admin note: text overlap with arXiv:1602.02363

References in corpus (9)

• Revisiting the Long/Soft-Short/Hard Classification of Gamma-Ray Bursts in the Fermi Era
• Further Study of the Gamma-Ray Bursts Duration Distribution
• Classification of Swift's gamma-ray bursts
• An analysis of the durations of Swift Gamma-Ray Bursts
• Statistical Study of Observed and Intrinsic Durations among BATSE and Swift/BAT GRBs
• Analysis of Fermi gamma-ray burst duration distribution
• Classification of BeppoSAX's Gamma-Ray Bursts
• On the limit between short and long GRBs
• Distinguishing short and long $Fermi$ gamma-ray bursts

Cited by in corpus (26)

• The Ep,i - Eiso correlation: type I gamma-ray bursts and the new classification method
• Gamma Ray Burst Prompt correlations
• Analysis of the duration--hardness ratio plane of gamma-ray bursts using skewed distributions
• A Comprehensive Power Spectral Density Analysis of Astronomical Time Series. II. The Swift/BAT Long Gamma-Ray Bursts
• Testing the anisotropy in the angular distribution of $Fermi$/GBM gamma-ray bursts
• Distributions of Pseudo-Redshifts and Durations (Observed and Intrinsic) of Fermi GRBs
• Classifying GRB170817A / GW170817 in a Fermi duration - hardness plane
• Multivariate analysis of BATSE gamma-ray burst properties using skewed distributions
• Two Dimensional Classification of the Swift/BAT GRBs
• Analysis of the observed and intrinsic durations of $Swift$/BAT gamma-ray bursts
• On the Connection of Gamma-Ray Bursts and X-Ray Flashes in the BATSE and RHESSI Databases
• Distinguishing short and long $Fermi$ gamma-ray bursts
• Graph-based clustering of gamma-ray bursts
• GRB Optical and X-ray Plateau Properties Classifier Using Unsupervised Machine Learning
• Multidimensional analysis of Fermi GBM gamma-ray bursts
• Statistical properties of Fermi GBM GRBs' spectra
• Can the Cosmological Dilation Explain the Skewness in the Gamma-Ray Burst Duration Distribution?
• Distribution of gamma-ray bursts on the t90-hardness ratio plane and their classification revisited
• Scanning the Universe for Large-Scale Structures using Gamma-Ray Bursts
• Confirmation of Binary Clustering in Gamma-Ray Bursts through an Integrated $p$-value from Multiple Nonparametric Tests of Hypotheses
• How does the shape of gamma-ray bursts' pulses affect the duration distribution?
• Gamma-ray burst taxonomy: looking for the third class on the spectral peak energy-duration plane in the rest frame
• Generalizing the normality: a novel towards different estimation methods for skewed information
• Gamma-ray bursts: A brief survey of the diversity
• Some statistical remarks on GRBs jointly detected by Fermi and Swift satellites
• Search for Astrophysical Transients on Limiting Time Scales and Their Classification Based on INTEGRAL Data