8401( 1) - 02/19/99 11:29 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8401 Version: 1 Check-in Date: 19-Feb-1999 11:28:44 1.Proposal Title: Archival Support for HST Service Observations of GRB 990123 ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle AR 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Shri Kulkarni Caltech CoI: S. G. Djorgovski Caltech N CoI: J. S. Bloom Caltech N ------------------------------------------------------------------------------------ 5. Abstract This program provides Archival Research Funding to the DD ToO observations of the remarkable new gamma-ray burst, GRB 990123. It is the brightest GRB detected by SAX. In rapid succession, the optical and radio afterglow to this GRB were discovered (Odewahn, Kulkarni, Djorgovski, et al.), and a redshift of z >= 1.61 (Kelson et al.) to the GRB measured. At this redshift, the implied isotropic energy release is greater than $2 \times 10^{54}$ erg in gamma-rays alone, an order of magnitude higher than for the already extreme GRB 971214 and more than the rest mass energy of a neutron star. In addition, the burst is interesting for the discovery of the first prompt optical emission of a GRB by the ROTSE-I team. As noted by the Caltech group, the pre-burst POSS-II images show a bright foreground galaxy close (< 2 arcsec) to the position of the optical transient. Absorption lines from two intervening systems (z=0.21 and z=0.29) have been detected in a spectrum obtained by the Nordic Optical Telescope group, which could indicate a foreground gravitational lens. If lensing is weak, the energetics of this GRB would make it the brightest object in the Universe detected to date. If the GRB is lensed and the magnification is high, measurements of time delay in the multiple images of the afterglow could be used to measure H_0 with an accuracy of better than 10%. High resolution observations by HST are essential to resolve the environment of the GRB. The urgency of the observation is motivated by the fact that the afterglow is fading. To maximize the scientific benefit to the community of this unique event, we are observing the GRB with HST as a service and will make the data immediately available with no proprietary period. ------------------------------------------------------------------------------------ 8401( 1) - 02/19/99 11:29 - [ 2] Observations Description ------------------------ None Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Paper Products: NO Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8401( 1) - 02/19/99 11:29 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 GRB990123 STAR, GAMMA RAY BURSTER RA=15H 25M 30.34S +/- .5", J2000 V = 23.0+/-0.7 DEC=44D 45' 59.1" +/- .5" 8401( 1) - 02/19/99 11:29 - [ 4] Summary Form for Proposal 8401 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category AR ------------------------------------------------------------------------------------------------------------------------------------