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Related papers: GRB Variability-Luminosity Correlation Confirmed

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A new analysis of the variability of the spectral slope of PG QSOs has been performed, on the basis of recent literature data in the B and R photometric bands. Preliminary results confirm our previous findings concerning the increase of…

Astrophysics · Physics 2007-05-23 Dario Trevese , Fausto Vagnetti

We derive a new peak lag vs. peak luminosity relation in gamma-ray burst (GRB) pulses. We demonstrate conclusively that GRB spectral lags are pulse rather than burst properties and show how the lag vs. luminosity relation determined from…

Astrophysics · Physics 2009-11-13 Jon Hakkila , Timothy W. Giblin , Jay P. Norris , P. Chris Fragile , Jerry T. Bonnell

We present a Monte Carlo analysis of the recently introduced variability indices $\tau$ (Tompkins 1999) and $I$ (Zhang et al. 2000 & Torres et al. 2001) for $\gamma$-ray sources. We explore different variability criteria and prove that…

Astrophysics · Physics 2009-11-06 Diego F. Torres , M. E. Pessah , Gustavo E. Romero

The correlations between the rest frame peak of the EF_E spectrum of GRBs Epeak and their isotropic energy (E_iso) or luminosity (L_iso) could have several implications for the understanding of the GRB prompt emission. These correlations…

High Energy Astrophysical Phenomena · Physics 2015-05-20 Giancarlo Ghirlanda

We compile 23 Gamma-ray Bursts (GRBs) and 21 blazars with estimated Doppler factors, and the Doppler factors of GRBs are estimated from their Lorentz factors by assuming their jet viewing angles \theta->0 degree. Using the conventional…

High Energy Astrophysical Phenomena · Physics 2015-05-30 Qingwen Wu , Yuan-Chuan Zou , Xinwu Cao , Ding-Xiong Wang , Liang Chen

The principal goal of this paper is to use attempts at reconciling the Swift long gamma-ray bursts (LGRBs) with the star formation history (SFH) to compare the predictions of $\Lambda$CDM with those in the $R_{\rm h}=ct$ Universe. In the…

High Energy Astrophysical Phenomena · Physics 2015-06-16 Jun-Jie Wei , Xue-Feng Wu , Fulvio Melia , Da-Ming Wei , Long-Long Feng

We study the effects of the beaming-induced luminosity function on statistics of observed GRBs, assuming the cosmological scenario. We select and divide the BATSE 4B data into 588 long bursts (T$_{90}>2.5$ sec) and 149 short bursts…

Astrophysics · Physics 2009-10-31 Chunglee Kim , Heon-Young Chang , Insu Yi

New theoretical evaluations of the RGB luminosity function 'bump' and the ZAHB luminosity covering the range of metallicities typical of galactic globular cluster are presented. The variation of the theoretical RGB bump and ZAHB levels due…

Astrophysics · Physics 2015-06-24 S. Cassisi , M. Salaris

If $\gamma$-ray bursts (GRBs) are accompanied by gravitational wave bursts (GWBs) the correlated output of two gravitational wave detectors evaluated in the moments just prior to a GRB will differ from that evaluated at times not associated…

General Relativity and Quantum Cosmology · Physics 2010-01-06 Lee Samuel Finn , Soumya D. Mohanty , Joseph D. Romano

It was well known that most of gamma-ray bursts (GRBs) are dominated by positive spectral lags, while a small fraction of GRBs show negative lags. However, Wei et al. firstly identified a well-defined transition from positive lags to…

High Energy Astrophysical Phenomena · Physics 2023-01-25 Wen-Qiang Liang , Rui-Jing Lu , Cheng-Feng Peng , Wen-Hao Chen

We search for the long-term variability of the \gamma-ray sky in the energy range E > 1 GeV with 168 weeks of Fermi-LAT data. We perform a full sky blind search for regions with variable flux looking for deviations from uniformity. We bin…

High Energy Astrophysical Phenomena · Physics 2015-06-03 M. S. Pshirkov , G. I. Rubtsov

In this paper, we examine the spacial distribution of gamma-ray bursts (GRBs) using a sample of 373 objects. We subdivide the GRB data into two redshift intervals over the redshift range $0<z< 6.7$. We measure the two-point correlation…

Cosmology and Nongalactic Astrophysics · Physics 2015-07-07 Ming-Hua Li , Hai-Nan Lin

Gamma rays from extragalactic sources are attenuated by pair-production interactions with diffuse photons of the extragalactic background light (EBL). Gamma-ray bursts (GRBs) are a source of high-redshift photons above 10 GeV, and could be…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-14 Rudy C. Gilmore , Francisco Prada , Joel R. Primack

In this paper, we continue to build support for the proposal to use gamma-ray bursts (GRBs) as standard candles in constructing the Hubble Diagram at redshifts beyond the current reach of Type Ia supernova observations. We confirm that…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Jun-Jie Wei , Xue-Feng Wu , Fulvio Melia

Gamma-ray bursts (GRB) are extremely energetic events and produce highly diverse light curves. Light curves are believed to be resulting from internal shocks reflecting the activities of the GRB central engine. Hence their temporal studies…

High Energy Astrophysical Phenomena · Physics 2015-06-12 Narayana P. Bhat

We collect the 2LAC and MOJAVE quasi-simultaneous data to investigate the radio-gamma connection of blazars. The cross sample contains 166 sources. The statistic analysis based on this sample confirms positive correlations between these two…

High Energy Astrophysical Phenomena · Physics 2014-09-03 Fan Xu-Liang , Bai Jin-Ming , Liu Hong-Tao , Chen Liang , Liao Neng-Hui

Gamma-ray bursts (GRBs) are intense, short-lived bursts of gamma-ray radiation observed up to a high redshift ($z \sim 10$) due to their luminosities. Thus, they can serve as cosmological tools to probe the early Universe. However, we need…

We present a spectral analysis for a sample of redshift known GRBs observed with {\em Fermi}/GBM. Together with the results derived from our systematical spectral energy distribution modeling with the leptonic models for a {\em Fermi}/LAT…

High Energy Astrophysical Phenomena · Physics 2015-06-22 Fen Lyu , En-Wei Liang , Yun-Feng Liang , Xue-Feng Wu , Jin Zhang , Xiao-Na Sun , Rui-Jing Lu , Bing Zhang

We find that dim gamma-ray bursts (GRBs) are softer than bright GRBs, as indicated on average by data from the Burst and Transient Source Experiment (BATSE) on board the Compton Gamma Ray Observatory. We show that this correlation is…

Since late 2007, we have been monitoring a large sample of known and likely gamma-ray-loud blazars at 15 GHz twice per week with the Owens Valley Radio Observatory (OVRO) 40 m Telescope. Our initial sample included the 1158 sources above…

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