----- Attempting Submission 1 (Wed Jul 02 18:50:37 GMT 2008) ----- Assigned ID: 815 ----- Attempting Submission 1 (Sat Mar 08 00:06:35 GMT 2008) ----- Unraveling the Mysterious Origin of GRB 070125 We propose a modest (2 WFC3 orbits) HST program to ascertain the origin of the mysterious gamma-ray burst GRB 070125. With a duration of 60 s and a high local (i.e. parsec scale) circum-burst density, GRB 070125 resembles a canonical (i.e. massive-star progenitor) long-duration event. However, we have strong evidence that GRB 070125 exploded in the halo of its host galaxy, far away from the bulk of massive star formation. The UV detection of a compact, star-forming cluster would confirm our original hypothesis that GRB 070125 exploded in a tidal tail formed by galaxy interactions (analogous to the Tadpole and Antenna galaxies) at z = 1.54. Alternatively, the absence of ongoing star formation and the presence of an old stellar population would require a novel explosion process unassociated with massive stars. While the former would open a new path to study star formation and galaxy interactions at high redshift, the latter would require a re-thinking of one of the fundamental tenets of GRB astronomy: the 1:1 mapping between duration and progenitor system.
One orbit of WFC3/UVIS (F336W) + one orbit of WFC3/IR (F110W) imaging. UNRESOLVED STELLAR POPULATIONS AND GALAXY STRUCTURE 12 false 0.0 0.0 false false false false false SUPPORTED EXT-STAR GAMMA RAY BURSTER HALO TIDAL TAIL J2000 07 51 17.7670 +31 09 4.11 J2000 WFC3/UVIS Imaging No No F336W WFC3/IR Imaging No No F110W POS-TARG DITHER 0.173 LINE 0.112 false false 81.785 4 23.884 WFC3-UVIS-DITHER-BOX 1 false POS-TARG DITHER 0.572 LINE 0.365 false false 74.653 4 18.528 WFC3-IR-DITHER-BOX-MIN 2 false The scheduling data was generated by CASM 17.2. CASM was run in Phase II mode. /private/tmp/OPVisit7521.xml (Tic-Visit :proposal-id 11717 :visit-id "01" :proposal-version -1 :trans-version "20080624" :date "02-Jul-2008 11:43:30.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 2 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 2269168 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 11717 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 11717 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2912 :al-overhead-at-end 116 :internal-dur-at-end 32 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3283 :pcs-gap 0 ) (Tic-Orbit :proposal-id 11717 :visit-id "01" :orbit-number 2 :pcs-time 195 :si-vis-utilization 3040 :al-overhead-at-end 0 :internal-dur-at-end 535 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3283 :pcs-gap 0 ) true 2 0