Please find attached our submission of "Pinpointing the location and host of the candidate tidal disruption Swift J1112.3-8238" -2010539603 Assigned ID: 541 ----- Attempting Submission 1 (Fri Apr 11 15:53:13 GMT 2014) ----- Please find attached our first submission of 13869 -2087936811 ----- Attempting Submission 1 (Mon Jul 21 13:55:08 GMT 2014) ----- Multiwavelength observations over the past few years have revealed a new class of high energy transient. These systems persist as bright gamma-ray sources for days, with luminosities in excess of the Eddington limit for a 10^10 solar mass black hole. They are accompanied by bright, long-lived (months to years) X-ray emission, and rather fainter, but still clearly detectable optical and IR counterparts. They are suggested to arise from the tidal disruption of stars in the nuclei of their host galaxies, which create a powerful relativistic outflow. In the first case (Swift J1644+57) astrometry ties the transient to nucleus of its host galaxy, while in a second (Swift J2058.4+0516) the host is exceptionally faint making (H~26.5) such tests challenging . However, other models have been postulated, such as the collapse of a giant star, where the outer envelope forms a disc that powers the observed transients, akin to a scaled-up gamma-ray burst. A key distinguishing feature between the two progenitors is their expected locations. Tidal disruptions are nuclear, while GRB-like events are consistent with the nuclei of their hosts only 1/6 of the time. Here we propose observations of an event recently uncovered in an archival search. These will resolve its host galaxy and provide a precise location on the host. An IR visit will also provide a colors, and an estimate of the stellar and (through the bulge mass -- black hole mass relation) black hole mass. These data will provide the key astrometric and photometric evidence to disentagle competing models for these events, and will greatly aid the development of a definitive understanding of this new class of transient. Our proposal is to obtain observations of the candidate relativistic tidal disruption event Swift J1112-8238. To do this we will obtain a single orbit of observations using WFC3 (IR and UVIS). For both observations we specify a somewhat restricted range of roll angles in order to avoid diffraction spikes from the relatively proximate (6"), bright (R~16.5, H~13) star. The Galactic lattitude of the source is moderate so there are additional bright sources in the field. However, inspection of archival imaging suggests that diffraction spikes from these should not reach the source position. For the IR observations we will obtain a standard 4 point dither pattern, and the STEP non-destructive read sequences for maximum dynamic range (to allow for astrometry with the bright stars in non-saturated images). FOr the UVIS observations we will also obtain the standard 4-point dither pattern, and will utilize UVIS2. We have include a POSTARG offset that places the source towards the corner of the chip in order to minimize the impact of CTE. AGN/QUASARS Default false false false false false SUPPORTED GALAXY ACCRETION DISK HIGH REDSHIFT GALAXY This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 i '= 23.2+/-0.1 , r' = 23.8+/-0.1, z' = 23.0 +/- 0.1 WFC3/UVIS Imaging No No F606W WFC3/IR Imaging No No F160W POS-TARG DITHER 0.572 LINE 0.365 false false 74.653 4 18.528 WFC3-IR-DITHER-BOX-MIN 1 false POS-TARG DITHER 0.173 LINE 0.112 false false 81.785 4 23.884 WFC3-UVIS-DITHER-BOX 2 false The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. 1405886123179 /Users/levan/hst_c22/OP-cache/13869_v1-v01.xml (Tic-Visit :proposal-id 13869 :visit-id "01" :proposal-version -1 :trans-version "20140605" :date "20-Jul-2014 20:55:23.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 1 :saa-model "29" :si-bright-earth-limb-angle 20.0 :data-volume 1921008 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13869 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13869 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 3285 :al-overhead-at-end 116 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3619 :pcs-gap 0 ) true 1 0