Time delay and broadening of gamma ray bursts in various energy bands

1995 ◽  
Author(s):  
King-wai Lam
Keyword(s):  
Time Delay ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Energy Bands

scholarly journals Searching for Gravitationally Lensed Gamma-Ray Bursts with Their Afterglows

2022 ◽  
Vol 924 (2) ◽  
pp. 49
Author(s):  
Shengnan Chen ◽  
Xudong Wen ◽  
He Gao ◽  
Kai Liao ◽  
Liangduan Liu ◽  
...  
Keyword(s):  
Time Delay ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Archival Data ◽  
Potential Candidate ◽  
X Ray ◽  
Gamma Ray Detectors ◽  
Sky Survey ◽  
Lensing Effect ◽  
Recent Claim

Abstract Gamma-ray bursts (GRBs) at high redshifts are expected to be gravitationally lensed by objects of different mass scales. Other than a single recent claim, no lensed GRB has been detected so far by using gamma-ray data only. In this paper, we suggest that multiband afterglow data might be an efficient way to search for lensed GRB events. Using the standard afterglow model, we calculate the characteristics of the lensed afterglow lightcurves under the assumption of two popular analytic lens models: the point-mass and singular isothermal sphere models. In particular, when different lensed images cannot be resolved, their signals would be superimposed together with a given time delay. In this case, the X-ray afterglows are likely to contain several X-ray flares of similar width in linear scale and similar spectrum, and the optical afterglow lightcurve will show re-brightening signatures. Since the lightcurves from the image arriving later would be compressed and deformed in the logarithmic timescale, the larger time delay (i.e., the larger mass of the lens), the easier it is to identify the lensing effect. We analyzed the archival data of optical afterglows and found one potential candidate of the lensed GRB (130831A) with time delay ∼500 s; however, observations of this event in gamma-ray and X-ray bands seem not to support the lensing hypothesis. In the future, with the cooperation of the all-sky monitoring gamma-ray detectors and multiband sky survey projects, the method proposed in this paper would be more efficient in searching for strongly lensed GRBs.

scholarly journals A Robust Estimation of Lorentz Invariance Violation and Intrinsic Spectral Lag of Short Gamma-Ray Bursts

2022 ◽  
Vol 924 (2) ◽  
pp. L29
Author(s):  
Shuo Xiao ◽  
Shao-Lin Xiong ◽  
Yue Wang ◽  
Shuang-Nan Zhang ◽  
He Gao ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Lorentz Invariance ◽  
Propagation Speed ◽  
Gamma Ray Bursts ◽  
Energy Bands ◽  
Photon Propagation ◽  
Invariance Violation ◽  
Lorentz Invariance Violation ◽  
Spectral Lag ◽  
Wide Energy

Abstract Gamma-ray bursts (GRBs) have been identified as one of the most promising sources for Lorentz invariance violation (LIV) studies due to their cosmological distance and energetic emission in wide energy bands. However, the arrival-time difference of GRB photons among different energy bands is affected not only by the LIV effect but also by the poorly known intrinsic spectral lags. In previous studies, assumptions of spectral lag have to be made which could introduce systematic errors. In this paper, we used a sample of 46 short GRBs (SGRBs), whose intrinsic spectra lags are much smaller than long GRBs, to better constrain the LIV. The observed spectral lags are derived between two fixed energy bands in the source rest frame rather than the observer frame. Moreover, the lags are calculated with the novel Li–CCF method, which is more robust than traditional methods. Our results show that, if we consider LIV as a linear energy dependence of the photon propagation speed in the data fit, then we obtain a robust limit of E QG > 1015 GeV (95% CL). If we assume no LIV effect in the keV–MeV energy range, the goodness of data fit is equivalently as well as the case with LIV and we can constrain the common intrinsic spectral lags of SGRBs to be 1.4 ± 0.5 ms (1σ), which is the most accurate measurement thus far.

scholarly journals Time Delay between Neutrinos and Gamma-Rays in Short Gamma-Ray Bursts

2019 ◽  
Vol 871 (2) ◽  
pp. L30 ◽  
Author(s):  
A. V. Penacchioni ◽  
O. Civitarese
Keyword(s):  
Time Delay ◽  
Gamma Rays ◽  
Gamma Ray ◽  
Gamma Ray Bursts

scholarly journals Dark photon dark matter and fast radio bursts

2020 ◽  
Vol 80 (10) ◽  
Author(s):  
Ricardo G. Landim
Keyword(s):  
Dark Matter ◽  
Time Delay ◽  
Parameter Space ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Radio Bursts ◽  
Free Electrons ◽  
Weak Equivalence Principle ◽  
Dark Photon ◽  
The Standard Model

AbstractThe nature of dark matter (DM) is still a mystery that may indicate the necessity for extensions of the Standard Model (SM). Light dark photons (DP) may comprise partially or entirely the observed DM density and existing limits for the DP DM parameter space arise from several cosmological and astrophysical sources. In the present work we investigate DP DM using cosmic transients, specifically fast radio bursts (FRBs). The observed time delay of radio photons with different energies have been used to constrain the photon mass or the Weak Equivalence Principle, for example. Due to the mixing between the visible and the DP, the time delay of photons from these cosmic transients, caused by free electrons in the intergalactic medium, can change and impact those constraints from FRBs. We use five detected FRBs and two associations of FRBs with gamma-ray bursts to investigate the correspondent variation on the time delay caused by the presence of DP DM. The result is virtually independent of the FRB used and this variation is very small, considering the still allowed DP DM parameter space, not jeopardizing current bounds on other contributions of the observed time delay.

PULSE CHARACTERIZATION OF GRBs WITH KNOWN REDSHIFT

2010 ◽  
Vol 19 (06) ◽  
pp. 997-1002 ◽  
Author(s):  
NICOLAS VASQUEZ ◽  
NOBUYUKI KAWAI
Keyword(s):  
Gamma Ray ◽  
Bimodal Distribution ◽  
Gamma Ray Bursts ◽  
Energy Evolution ◽  
Spectral Measures ◽  
Energy Bands ◽  
Decay Index ◽  
The Universe ◽  
Prompt Emission

Gamma-ray Bursts (GRBs) are one of the most promising tools in the study of cosmology. The luminosity, energy, light curve parameters and spectral measures could yield to the calibration of standard candles in the Universe. Nevertheless, cosmological and non-cosmological effects are not well understood. Aiming to clarify the possible effects, we started to study the autocorrelation function (ACF) of a sample of GRBs with known redshift in the combined band of Swift (15–150 keV) and Suzaku (50 keV–5 Mev) satellites. We first confirmed the bimodal distribution of the cosmological corrected ACF reported by Borgonovo et al., then looking at the energy evolution we found a bimodal distribution of the decay index of the ACF. For the next step we explored the intrinsic effects of the pulses within GRBs, determining the ACF of individual pulses at two different energy bands, as well as the skewness of the pulse. We found two kinds of internal effects, the increase of the asymmetry of the pulse with energy and the variability-dependence on energy. Two types of pulses are distinguished, suggesting more than one physical process during the prompt emission.

scholarly journals Bounding the time delay between high-energy neutrinos and gravitational-wave transients from gamma-ray bursts

2011 ◽  
Vol 35 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Bruny Baret ◽  
Imre Bartos ◽  
Boutayeb Bouhou ◽  
Alessandra Corsi ◽  
Irene Di Palma ◽  
...  
Keyword(s):  
Time Delay ◽  
Gravitational Wave ◽  
Gamma Ray ◽  
High Energy ◽  
Gamma Ray Bursts ◽  
High Energy Neutrinos

scholarly journals CORRELATION BETWEEN HARDNESS RATIO AND DURATION OF FERMI GAMMA-RAY BURSTS

2013 ◽  
Vol 23 ◽  
pp. 298-300
Author(s):  
FU-WEN ZHANG
Keyword(s):  
Statistical Analysis ◽  
Power Law ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Spectral Shape ◽  
Energy Bands ◽  
Hardness Ratio

Using the latest gamma-ray bursts (GRB) observed by Fermi-GBM, we perform a statistical analysis of the relation between hardness ratio (HR) and duration (ΔT) of GRBs, and find that HR and ΔT are still anti-correlated. we also find that this correlation strongly depends upon the spectral shape of GRBs and energy bands, and the bursts with the curved spectra in the typical BATSE energy bands show a tighter anti-correlation than those with the power-law spectra in the typical BAT energy bands. This might explain why the HR – ΔT correlation is not evident for Swift-BAT GRB sample as well as other GRB sample detected by instruments with a narrower/softer energy bandpass such as HETE-2.

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