1999A&AS..138..449C


C.D.S. - SIMBAD4 rel 1.7 - 2019.09.23CEST07:59:47

1999A&AS..138..449C - Astron. Astrophys., Suppl. Ser., 138, 449-450 (1999/September-0)

Optical observations of GRB afterglows: GRB 970508 and GRB 980326 revisited.

CASTRO-TIRADO A.J. and GOROSABEL J.

Abstract (from CDS):

Since January 1997, we have monitored 15 GRB fields, detecting 6 optical/IR afterglows. We have revisited GRB 970508 and GRB 980326. For GRB 970508, we derive a power-law decay exponent α=-1.19 (R-band). The luminosity of the host galaxy L relative to the characteristic luminosity L* is in the range 0.06-0.15, i.e. a dwarf galaxy. For GRB 980326, we derive a power-law decay exponent α=-1.7, taking into account the new upper limit for the host as R≥27.3 provided by Bloom & Kulkarni (1998, GCN, 161). This implies one of the fastest GRB optical decays ever measured. The fact that only about 50% of optical transients have been found within the γ/X-ray error boxes, suggest that either considerable intrinsic absorption is present or that some optical transients display a very fast decline. We also propose that the ``secondary maximum" detected on 17 Apr. 1998 could be explained in the context of the ``SN-like" light curves 2-3 weeks after the GRB, as recently suggested by Woosley (1999A&AS..138..499W).

Abstract Copyright:

Journal keyword(s): methods: observational - gamma-rays: bursts

Simbad objects: 6

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Number of rows : 6

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2019
#notes
1 GRB 970616 gB 01 18 48.0 -05 26 18           ~ 49 0
2 GRB 970508 gB 06 53 49.2 +79 16 19           ~ 835 1
3 GRB 980326 gB 08 36 34.3 -18 51 24           ~ 255 0
4 GRB 970111 gB 15 28 15.0 +19 36 18           ~ 137 0
5 4B 970815 gB 16 06 54.0 +81 30 34           ~ 54 0
6 GRB 970828 gB 18 08 31.6 +59 18 51           ~ 334 1

    Equat.    Gal    SGal    Ecl

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2019.09.23-07:59:47

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