The Radio–to–X-Ray Spectrum of GRB 970508 on 1997 May 21.0 UT

Galama, T. J.; Wijers, R. A. M. J.; Bremer, M.; Groot, P.; Strom, R. G.; Kouveliotou, C.; Paradijs, J. van

doi:10.1086/311425

Cited by 115 publications

(126 citation statements)

References 24 publications

Supporting

Mentioning

104

Contrasting

Unclassified

Order By: Relevance

“…In spite of considerable uncertainties in the spectral slopes deduced from observations (Galama et al 1998a), the results shown in Fig. 3 are satisfactory: the observed crossing of the A complementary analysis to that in the previous paragraph is the study of an AG's optical spectrum at a fixed time at which the injection bend is crossing the observed frequency range, or is nearby.…”

Section: Evidence For An Injection Bendsupporting

confidence: 58%

“…The first column is the bend frequency ν 0 b at t = 0, computed with Eq. (14) and the optical AG parameters Galama et al (1998a). of Table 3 (the density n p is extracted from the measured x ∞ with use of Eq.…”

Section: Evidence For An Injection Bendmentioning

confidence: 99%

“…determine γ(t) and δ(t), and the density n p deduced 4 from x ∞ and the reference N CB and R max . The data are gathered by Galama et al (1998a) from observations in the U, B, V, R c and I c bands (Castro-Tirado et al 1998;Galama et al 1998b;Metzger et al 1997;Sokolov et al 1998;Zharikov et al 1998), by Chary et al (1998) for K band results, and by Pian et al (1998) for the H band.…”

Section: Evidence For An Injection Bendmentioning

confidence: 99%

See 2 more Smart Citations

On the radio afterglow of gamma ray bursts

Dado

Dar

Rújula

2003

A&A

View full text Add to dashboard Cite

Abstract. We use the cannonball (CB) model of gamma ray bursts (GRBs) to predict the spectral and temporal behaviour of their radio afterglows (AGs). A single simple expression describes the AGs at all times and frequencies; its high-frequency limit reproduces the successful CB model predictions for optical and X-ray AGs. We analyze all of the observed radio AGs of GRBs with known redshifts, including those of the exceptionally close-by GRB 980425. We also study in detail the timeevolution of the AGs' spectral index. The agreement between theory and observations is excellent, even though the CB model is extremely frugal in the number of parameters required to explain the radio observations. We propose to use the scintillations in the radio AGs of GRBs to verify and measure the hyperluminal speed of their jetted CBs, whose apparent angular velocity is of the same order of magnitude as that of galactic pulsars, consistently measured directly, or via scintillations.

show abstract

Section: Evidence For An Injection Bendsupporting

confidence: 58%

Section: Evidence For An Injection Bendmentioning

confidence: 99%

Section: Evidence For An Injection Bendmentioning

confidence: 99%

See 1 more Smart Citation

On the radio afterglow of gamma ray bursts

Dado

Dar

Rújula

2003

A&A

View full text Add to dashboard Cite

show abstract

“…GRB 970508 was also the Ðrst GRB for which a radio counterpart was detected Galama et al 1998b). The broadband (radio to X-ray) spectrum of the afterglow (Waxman, Kulkarni, & Frail 1998 ;Galama et al 1998a) provided strong support for the synchrotron-emitting shock model for afterglows (see, e.g., Sari, Piran, & Narayan 1998).…”

Section: Introductionmentioning

confidence: 69%

Hubble Space TelescopeObservations of the Host Galaxy of GRB 970508

Fruchter

Pian²,

Gibbons

et al. 2000

ApJ

Self Cite

View full text Add to dashboard Cite

We report on observations of the Ðeld of GRB 970508 made in 1998 early August, 454 days after outburst, with the STIS CCD camera on board the Hubble Space T elescope (HST ). The images, taken in open Ðlter (50CCD) mode, clearly reveal the presence of a galaxy that was overwhelmed in earlier (1997 June) HST images by emission from the optical transient (OT). The galaxy is regular in shape : after correcting for the HST /STIS PSF, it is well Ðtted by an exponential disk with a scale length of 0A .046and an ellipticity of 0.70^0.07. All observations are marginally consistent with a continuouŝ 0A .006 decline in OT emission as t~1.3 beginning 2 days after outburst ; however, we Ðnd no direct evidence in the late-time HST image for emission from the OT, and the surface brightness proÐle of the galaxy is most regular if we assume that the OT emission is negligible, suggesting that the OT may have faded more rapidly at late times than is predicted by the power-law decay. Due to the wide bandwidth of the STIS clear mode, the estimated magnitude of the galaxy is dependent on the galaxy spectrum that is assumed. Using colors obtained from late-time ground-based observations to constrain the spectrum, we Ðnd V \ 25.4^0.15, a few tenths of a magnitude brighter than earlier ground-based estimates that were obtained by observing the total light of the galaxy and the OT and then subtracting the estimated OT brightness, assuming that it fades as a single power law. This again suggests that the OT may have faded faster at late time than the power law predicts. The position of the OT agrees with that of the isophotal center of the galaxy to which, at the galaxy redshift z \ 0.83, corresponds to an o †set from the 0A .01, center of the host of pc. This remarkable agreement raises the possibility that the gamma-ray burst [70 may have been associated with either an active galactic nucleus or a nuclear starburst.

show abstract

“…Some examples are: GRB 970228: α X = 1.06 ± 0.12 (Costa et al 1997). GRB 970508: α O = 1.12 ± 0.07 (Galama et al 1998c); α X = 1.11 ± 0.06 (Galama et al 1998c). GRB 990123: α O = 1.29 ± 0.23 (Holland et al 1999a).…”

Section: The Distribution Of Fitted Parametersmentioning

confidence: 99%

On the optical and X-ray afterglows of gamma ray bursts

Dado

Dar

Rújula

2002

A&A

256

View full text Add to dashboard Cite

Abstract. We severely criticize the consuetudinary analysis of the afterglows of gamma-ray bursts (GRBs) in the conical-ejection fireball scenarios. We argue that, instead, recent observations imply that the long-duration GRBs and their afterglows are produced by highly relativistic jets of cannonballs (CBs) emitted in supernova explosions. The CBs are heated by their collision with the supernova shell. The GRB is the boosted surface radiation the CBs emit as they reach the transparent outskirts of the shell. The exiting CBs further decelerate by sweeping up interstellar matter (ISM). The early X-ray afterglow is dominated by thermal bremsstrahlung from the cooling CBs, the optical afterglow by synchrotron radiation from the ISM electrons swept up by the CBs. We show that this model fits simply and remarkably well all the measured optical afterglows of the 15 GRBs with known redshift, including that of GRB 990123, for which unusually prompt data are available. We demonstrate that GRB 980425 was a normal GRB produced by SN1998bw, with standard X-ray and optical afterglows. We find that the very peculiar afterglow of GRB 970508 can be explained if its CBs encountered a significant jump in density as they moved through the ISM. The afterglows of the nearest 8 of the known-redshift GRBs show various degrees of evidence for an association with a supernova akin to SN1998bw. In all other cases such an association, even if present, would have been undetectable with the best current photometric sensitivities. This gives strong support to the proposition that most, maybe all, of the long-duration GRBs are associated with supernovae. Although our emphasis is on optical afterglows, we also provide an excellent description of X-ray afterglows.

show abstract

The Radio–to–X-Ray Spectrum of GRB 970508 on 1997 May 21.0 UT

Cited by 115 publications

References 24 publications

On the radio afterglow of gamma ray bursts

On the radio afterglow of gamma ray bursts

Hubble Space TelescopeObservations of the Host Galaxy of GRB 970508

On the optical and X-ray afterglows of gamma ray bursts

Contact Info

Product

Resources

About