Redshift Dependence of the Low-energy Spectral Index of Gamma-Ray Bursts Revisited
arXiv:2306.12290 · doi:10.1088/1674-4527/acf18d
Abstract
A negative correlation was found to exist between the low-energy spectral index and the redshift of gamma-ray bursts (GRBs) by Amati(2002). It was later confirmed by Geng(2013) and Gruber(2014), but the correlation was also found to be quite dispersive when the sample size was significantly expanded. In this study, we have established two even larger samples of gamma-ray bursts to further examine the correlation. One of our sample is consisted of 316 GRBs detected by the Swift satellite, and the other one is consisted of 80 GRBs detected by the Fermi satellite. It is found that there is no correlation between the two parameters for the Swift sample, but there does exist a weak negative correlation for the Fermi sample. The correlation becomes even more significant when the spectral index at the peak flux is considered. It is argued that the absence of the correlation in the Swift sample may be due to the fact that Swift has a very narrow energy response so that it could not measure the low-energy spectral index accurately enough. Further studies based on even larger GRB samples are solicited.
References in corpus (26)
- Intrinsic spectra and energetics of BeppoSAX Gamma-Ray Bursts with known redshifts
- GRB Formation Rates inferred from the Spectral Peak Energy - Luminosity Relation
- The Fermi GBM Gamma-Ray Burst Spectral Catalog: Four Years Of Data
- The Second Swift BAT Gamma-Ray Burst Catalog
- A complete sample of bright Swift Long Gamma-Ray Bursts: Sample presentation, Luminosity Function and evolution
- Cosmology with gamma-ray bursts: I. The Hubble diagram through the calibrated - correlation
- Extremely energetic Fermi Gamma-Ray Bursts obey spectral energy correlations
- Cosmological Aspects of Gamma-Ray Bursts: Luminosity Evolution and an Estimate of the Star Formation Rate at High Redshifts
- The Einstein Probe Mission
- Statistical Study of Gamma-Ray Bursts with a Plateau Phase in the X-ray Afterglow
- The Lag-Luminosity Relation in the GRB Source-Frame: An Investigation with Swift BAT Bursts
- Possible Origins of Dispersion of the Peak Energy--Brightness Correlations of Gamma-Ray Bursts
- The peak luminosity - peak energy correlation in GRBs
- Are there cosmological evolution trends on Gamma-Ray Burst features?
- Low-energy Spectra of Gamma-ray Bursts from Cooling Electrons
- Possible existence of Ep-Lp and Ep-Eiso correlations for Short Gamma-Ray Bursts with a factor 5 to 100 dimmer than those for Long Gamma-Ray Bursts
- A comprehensive statistical study on gamma-ray bursts
- Spectral and temporal analysis of the joint Swift/BAT-Fermi/GBM GRB sample
- "Double-tracking" Characteristic of the Spectral Evolution of GRB 131231A: Synchrotron Origin?
- Correlation between Peak Energy and Peak Luminosity in Short Gamma-Ray Bursts
- Distributions of Pseudo-Redshifts and Durations (Observed and Intrinsic) of Fermi GRBs
- Revisiting the Amati and Yonetoku Correlations with Swift GRBs
- On the Correlation of Low-energy Spectral Indices and Redshifts of Gamma-ray Bursts
- Standard GRB Spectral Models "Misused"?
- A Spectral Analysis of Fermi-LLE GRBs
- Probing the progenitor of high- short-duration GRB 201221D and its possible bulk acceleration in prompt emission