0 Assigned ID: 2185 ----- Attempting Submission 1 (Mon Aug 26 13:00:58 GMT 2013) ----- HST Phase I Proposal 2185 (mheida_merged.pdf.apt) successfully submitted. Joint Chandra/HST Phase I 0 ----- Attempting Submission 1 (Fri Sep 27 14:47:36 GMT 2013) ----- In 2010 we reported the discovery of CXOU J122518.6+144545. A new Chandra observation in 2012 showed that it varies by more than a factor 10 in X-ray flux. This leaves us with two options: we either discovered a rare type IIn SN, or the second most luminous HLX thus far. Deeper Chandra observations combined with a new HST visit will decide between these scenarios. If CXO J1225 was a supernova, with these new data we will be able to identify the progenitor star. This will be only the second type IIn SN for which this is done. If instead the source is an HLX it is a strong candidate to contain an intermediate mass black hole. In this case the new Chandra data will give us information about its variability and the HST image will give us stronger constraints on the size of the optical source. We plan to take a deep image to observe the counterpart of the X-ray source CXO J122518.6+144545 using WFC3/UVIS. We use the F475W filter for consistency with a previous HST/ACS observation. We use the standard WFC3/UVIS box dither pattern with four dither points to remove cosmic rays and bad pixels and to optimally sample the PSF. In one orbit we can fit four 628 s exposures and overheads, which gives us a total exposure time of 2512 seconds. Default false false false false false SUPPORTED EXT-STAR ACCRETION DISK SUPERNOVA TYPE II X-RAY TRANSIENT This object was generated by the targetselector and retrieved from the SIMBAD database. J2000 J2000 g' = 26.4+/-0.1, g'-z' < 0.7, values from ACS obs in 2003, source can be fainter if it is a fading SN WFC3/UVIS Imaging No No F475W POS-TARG DITHER 0.173 LINE 0.112 false false 81.785 4 23.884 WFC3-UVIS-DITHER-BOX 1 false 1380285907610 /Users/marianne/proposals/cxo1225-chan2013/hst_phaseII/OP-cache/hst_13511_phase_II-v01.xml The scheduling data was generated by CASM 21.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 13511 :visit-id "01" :proposal-version -1 :trans-version "20130919" :date "27-Sep-2013 14:45:07.0" :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 1154992 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 13511 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 13511 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2904 :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 3239 :pcs-gap 0 ) true 1 0