A Test on Different Types of the Time Curve of Hardness Ratio of Gamma-Ray Bursts based on the Curvature Effect

2008 ◽  
Vol 8 (4) ◽  
pp. 451-464 ◽  
Author(s):  
Lan-Wei Jia
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Curvature Effect ◽  
Time Curve ◽  
Different Types ◽  
Hardness Ratio

scholarly journals Asymmetry in Supernovae

2011 ◽  
Vol 7 (S279) ◽  
pp. 261-268
Author(s):  
Keiichi Maeda
Keyword(s):  
Spherical Symmetry ◽  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Core Collapse ◽  
Late Time ◽  
Innermost Part ◽  
Optical Emissions ◽  
Standard Candle ◽  
Different Types ◽  
Bipolar Type

AbstractAsymmetry in the innermost part of the supernova (SN) ejecta is a key to understanding their explosion mechanisms. Late-time spectroscopy is a powerful tool to investigate the issue. We show what kind of geometry is inferred for different types of SNe – core-collapse SNe Ib/c, those associated with Gamma-Ray Bursts (GRBs), and thermonuclear SNe Ia –, and discuss implications for the explosion mechanisms, observational diversities, and cosmological applications. For SNe Ib/c, the data show the clear deviation from spherical symmetry, and they are most consistent with the bipolar-type explosion as the characteristic geometry. Detailed modeling of optical emissions from SN 1998bw associated with GRB980425 indicates that this SN was in the extreme end of the bipolar explosion, suggesting that the explosion mechanisms of canonical SNe Ib/c and GRB-SNe are different. The situation is different for SNe Ia. Late-time spectra indicate the deviation from spherical symmetry, but for SNe Ia the explosion is asymmetric between two hemispheres, i.e., one-sided explosions. The diversities arising from different viewing directions can nicely explain (a part of) observational diversities of SNe Ia, and correcting this effect may improve the standard-candle calibration of SNe Ia for cosmology.

scholarly journals The diversity of GRBs and their SNe: Observations from the 10.4m GTC

2017 ◽  
Vol 12 (S331) ◽  
pp. 39-44
Author(s):  
Antonio de Ugarte Postigo ◽  
Christina Thöne ◽  
Zach Cano ◽  
David Alexander Kann ◽  
Luca Izzo ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Massive Stars ◽  
Gamma Ray Bursts ◽  
Compact Objects ◽  
The Past ◽  
Photometric And Spectroscopic Observations ◽  
Long Duration ◽  
Different Types ◽  
Short Grbs

AbstractObserving the supernovae (SNe) associated to the different types of gamma-ray bursts (GRBs) is one of the few means to study their progenitors. In the past years, it has become clear that GRB-like events are more heterogeneous than previously thought. There is a marked difference between long GRBs, which are produced by the collapse of very massive stars and are normally associated with broad-lined type Ic SNe, and short bursts, which occur when two compact objects merge and that, at least in some cases, can produce an associated kilonova. Moreover, the SNe associated with different sub-types of long GRBs are also seen to differ, especially those associated with ultra-long duration GRBs. To address this issue in a systematic way we started an observing programme in 2010 at the 10.4m GTC telescope. Here we present some results of our programme, including the detection of 12 new GRB-SNe. Highlights of our sample are the discovery of the first spectroscopic SN associated with a highly energetic (Eγ, iso ~ 1054 erg) “cosmological” burst (GRB 130427A), the study of the SN associated with a shock-breakout GRB (GRB 140606B) and the SN associated with the peculiar ultra-long GRB 101225A at z = 0.85. The sample includes also the follow-up of several short GRBs in search for kilonovae emission (GRB 130603B and GRB 160821B are important examples). Amongst our latest results we present the photometric and spectroscopic observations of the SNe associated with GRB 150818A and GRB 161219B.

Sequences in the Hardness Ratio-Peak Energy Plane of Gamma-Ray Bursts

2005 ◽  
Vol 5 (2) ◽  
pp. 151-158 ◽  
Author(s):  
Xiao-Hong Cui ◽  
En-Wei Liang ◽  
Rui-Jing Lu
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Peak Energy ◽  
Hardness Ratio ◽  
Energy Plane

Swift-BAT results on the prompt emission of short bursts

2007 ◽  
Vol 365 (1854) ◽  
pp. 1281-1291 ◽  
Author(s):  
Scott D Barthelmy
Keyword(s):  
Gamma Ray ◽  
Gamma Ray Bursts ◽  
Extended Phase ◽  
Hardness Ratio ◽  
Prompt Emission ◽  
Extended Emission

This is a brief review of short hard bursts (SHBs) from previous missions and from Swift-BAT; in particular, a review of the developing class of gamma-ray bursts which are similar to SHBs in that they have the short hard initial spike (0.1 to a few seconds), but that they also have a long extended phase of soft emission (50–200 s). Further, we suggest that a class of events discovered by Horvath in the T90 versus hardness ratio plane is this SHB with extended emission.

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