scholarly journals The Surroundings of Gamma-Ray Bursts: Constraints on Progenitors

2005 ◽  
Vol 192 ◽  
pp. 441-450
Author(s):  
Roger A. Chevalier

SummaryThe association of a supernova with a gamma-ray burst (GRB 030329) implies a massive star progenitor, which is expected to have an environment formed by pre-burst stellar winds. Although some sources are consistent with the expected wind environment, many are not, being better fit by a uniform density environment. One possibility is that this is a shocked wind, close to the burst because of a high interstellar pressure and a low mass loss density. Alternatively, there is more than one kind of burst progenitor, some of which interact directly with the interstellar medium. Another proposed environment is a pulsar wind bubble that has expanded inside a supernova, which requires that the supernova precede the burst.

1999 ◽  
Vol 16 (1) ◽  
pp. 106-112 ◽  
Author(s):  
Fabian Walter

AbstractHigh resolution HI observations of nearby dwarf galaxies (most of which are situated in the M81 group at a distance of about 3·2 Mpc) reveal that their neutral interstellar medium (ISM) is dominated by hole-like features most of which are expanding. A comparison of the physical properties of these holes with the ones found in more massive spiral galaxies (such as M31 and M33) shows that they tend to reach much larger sizes in dwarf galaxies. This can be understood in terms of the galaxy's gravitational potential. The origin of these features is still a matter of debate. In general, young star forming regions (OB-associations) are held responsible for their formation. This picture, however, is not without its critics and other mechanisms such as the infall of high velocity clouds, turbulent motions or even gamma ray bursters have been recently proposed. Here I will present one example of a supergiant shell in IC 2574 which corroborates the picture that OB associations are indeed creating these structures. This particular supergiant shell is currently the most promising case to study the effects of the combined effects of stellar winds and supernova explosions which shape the neutral interstellar medium of (dwarf) galaxies.


2015 ◽  
Vol 804 (1) ◽  
pp. 51 ◽  
Author(s):  
A. Cucchiara ◽  
M. Fumagalli ◽  
M. Rafelski ◽  
D. Kocevski ◽  
J. X. Prochaska ◽  
...  

1999 ◽  
Vol 193 ◽  
pp. 218-226
Author(s):  
Georges Meynet

Stellar winds contribute together with supernovae explosions to the chemical enrichment of the interstellar medium. We recall how the metallicity dependence of the stellar winds implies a metallicity dependence of the stellar yields. We show that an increase of the initial angular velocity has different effects than an increase of the mass loss rates. Wolf-Rayet stars appear as important sources of 19F and 26Al. They are the favoured candidates for the 22Ne anomaly observed in the Galactic cosmic ray sources. They may also have injected into the proto-solar nebula short-lived radionuclides as 26Al, 36Cl, 41Ca, 107Pd and 205Pb.


2011 ◽  
Vol 7 (S279) ◽  
pp. 75-82
Author(s):  
Paolo A. Mazzali

AbstractThe properties of the Supernovae discovered in coincidence with long-duration Gamma-ray Bursts and X-Ray Flashes are reviewed, and compared to those of SNe for which GRBs are not observed. The SNe associated with GRBs are of Type Ic, they are brighter than the norm, and show very broad absorption lines in their spectra, indicative of high expansion velocities and hence of large explosion kinetic energies. This points to a massive star origin, and to the birth of a black hole at the time of core collapse. There is strong evidence for gross asymmetries in the SN ejecta. The observational evidence seems to suggest that GRB/SNe are more massive and energetic than XRF/SNe, and come from more massive stars. While for GRB/SNe the collapsar model is favoured, XRF/SNe may host magnetars.


Author(s):  
D Watson ◽  
J.P.U Fynbo ◽  
C.C Thöne ◽  
J Sollerman

There is strong evidence that long-duration gamma-ray bursts (GRBs) are produced during the collapse of a massive star. In the standard version of the collapsar model, a broad-lined and luminous Type Ic core-collapse supernova (SN) accompanies the GRB. This association has been confirmed in observations of several nearby GRBs. Recent observations show that some long-duration GRBs are different. No SN emission accompanied the long-duration GRBs 060505 and 060614 down to limits fainter than any known Type Ic SN and hundreds of times fainter than the archetypal SN 1998bw that accompanied GRB 980425. Multi-band observations of the early afterglows, as well as spectroscopy of the host galaxies, exclude the possibility of significant dust obscuration. Furthermore, the bursts originated in star-forming galaxies, and in the case of GRB 060505, the burst was localized to a compact star-forming knot in a spiral arm of its host galaxy. We find that the properties of the host galaxies, the long duration of the bursts and, in the case of GRB 060505, the location of the burst within its host, all imply a massive stellar origin. The absence of an SN to such deep limits therefore suggests a new phenomenological type of massive stellar death.


2008 ◽  
Vol 4 (S252) ◽  
pp. 271-281 ◽  
Author(s):  
Jorick S. Vink

AbstractWe discuss the role of mass loss for the evolution of the most massive stars, highlighting the role of the predicted bi-stability jump that might be relevant for the evolution of rotational velocities during or just after the main sequence. This mechanism is also proposed as an explanation for the mass-loss variations seen in the winds from Luminous Blue Variables (LBVs). These might be relevant for the quasi-sinusoidal modulations seen in a number of recent transitional supernovae (SNe), as well as for the double-throughed absorption profile recently discovered in the Hα line of SN 2005gj. Finally, we discuss the role of metallicity via the Z-dependent character of their winds, during both the initial and final (Wolf-Rayet) phases of evolution, with implications for the angular momentum evolution of the progenitor stars of long gamma-ray bursts (GRBs).


1989 ◽  
Vol 120 ◽  
pp. 146-151
Author(s):  
A. Talavera ◽  
A.I. Gomez de Castro

The contribution of A supergiant stars to the return of mass and energy to the interstellar medium is not very important. Abbott (1982) analised a sample of early stars and concluded that B and A supergiants provided less than 8 % of the mass input to the ISM by stellar winds. However, A-type supergiants are important in the framework of the stellar winds-mass loss phenomenology since they are located at the boundary between hot and cool stars, where radiative acceleration may not be sufficiently efficient to drive the wind.


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