0 Assigned ID: 141 ----- Attempting Submission 1 (Thu Apr 10 00:16:38 GMT 2014) ----- HST Phase I Proposal 141 (BCG2261-APT.apt) successfully submitted. ----- Attempting Submission 2 (Fri Apr 11 16:43:33 GMT 2014) ----- HST Phase I Proposal 141 (BCG2261-APT.apt) successfully submitted. 0 ----- Attempting Submission 1 (Sun Mar 01 15:49:10 GMT 2015) ----- Testing for a Recoiling Supermassive Black Hole in the Giant Core of BCG 2261 We request 8 orbits for STIS spectroscopic observations of three compact knots near the center of the brightest cluster galaxy in Abell 2261 (BCG2261) to directly test for the presence of a recoiling supermassive black hole (SMBH). BCG2261's exceptionally large, flat core is thought to have been formed by scouring from a binary SMBH inspiral, with additional broadening effects caused by a recoiling SMBH after the binary's coalescence. A radio jet in the system indicates recent or current active nucleus activity, and appears to point to an origin in one of the off-center stellar concentrations (knots). All of the knots are candidates for a "cloaked" SMBH. Theory predicts that an ejected SMBH should carry a cloak of tightly bound stars with it. The stellar cloak would resemble a globular cluster or dwarf galaxy, but would have a high velocity dispersion. The presence of the off-center knots, the galactic core morphology, and the radio jet tentatively imply that one knot is likely to be cloaking a recoiling SMBH. Our proposed HST/STIS observations will test of the presence of a SMBH in the knots by seeking high-dispersion absorption lines and evidence for active nucleus emission. If any such signature is found, BCG2261 will represent the first direct observational support for three preeminent theoretical speculations: that scouring forms cores, that SMBHs may recoil after coalescence, and that recoil can strongly influence core formation and morphology. Observe compact galaxies UNRESOLVED STELLAR POPULATIONS AND GALAXY STRUCTURE 12 Regular false false false false false SUPPORTED GALAXY DWARF COMPACT MULTIPLE NUCLEI J2000 J2000 Knot 1: 22.15, Knot 2: STIS/CCD Spectroscopic No No G750L 7751 STIS/CCD Spectroscopic No No G750L 7751 The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 14046 :visit-id "01" :proposal-version -1 :trans-version "20140605" :date "19-Feb-2015 13:43:25.0" :trans-errors '(:WARNINGS 0 :ERRORS 0 :HEALTH-AND-SAFETY 0 :FATAL-ERRORS 0 :CONTINUABLE-FATALS 0) :number-of-orbits 4 :saa-model "24" :si-bright-earth-limb-angle 20.0 :data-volume 368512 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 14046 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 14046 :visit-id "01" :orbit-number 1 :pcs-time 333 :si-vis-utilization 2919 :al-overhead-at-end 0 :internal-dur-at-end 185 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14046 :visit-id "01" :orbit-number 2 :pcs-time 222 :si-vis-utilization 3035 :al-overhead-at-end 0 :internal-dur-at-end 185 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14046 :visit-id "01" :orbit-number 3 :pcs-time 222 :si-vis-utilization 3035 :al-overhead-at-end 0 :internal-dur-at-end 185 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) (Tic-Orbit :proposal-id 14046 :visit-id "01" :orbit-number 4 :pcs-time 222 :si-vis-utilization 3035 :al-overhead-at-end 0 :internal-dur-at-end 584 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3257 :pcs-gap 0 ) true 4 0 The scheduling data was generated by CASM 22.2. CASM was run in Phase II mode. 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