0 0 ----- Attempting Submission 1 (Sat Oct 09 21:34:50 GMT 2021) ----- The Massive Relic Galaxy NGC 5872 A potentially powerful approach to study early galaxy formation is through massive relic galaxies (MRGs) which are local analogs of the high-redshift "red nuggets" thought to represent progenitors of today's early-type galaxies. When a luminous hot halo is present, X-ray observations of the diffuse hot gas of MRGs provide the most viable means to measure the gravitating mass profile, and X-rays afford a powerful direct approach to study cooling and AGN feedback. Here we propose a joint Chandra -HST observation of NGC 5872, a very massive MRG, to map its inner mass profile (<~R_e), especially by measuring the stellar mass-to-light ratio, and to examine the magnitude of AGN feedback through image analysis and the radial profile of the ratio of the cooling and free-fall times. Our HST observations are designed to measure the surface brightness profile of galaxy NGC 5872 accurately. The data will be used together with Chandra observations to model the galaxy's mass distribution including stellar mass, hot gas, and dark matter. We will use WFC3 with both UVIS and IR cameras. Our IR F160W exposures will include four dithered RAPID mode exposures to obtain high dynamic range imaging of the galaxy's central region, with the IRSUB512 subarray. Then, four dithered full-frame IR exposures will be obtained using the WFC3-IR-DITHER-BOX-UVIS pattern in order to obtain deeper imaging out to large radius. Finally, we will obtain two UVIS F814W images using the UVIS-GAP-LINE pattern to dither across the CCD gap. The F814W data will provide higher angular resolution of the galaxy's nuclear region than the IR data, which will enable measurement of the galaxy's stellar profile at the smallest radii and also enable detection of dust lanes or a dust disk if present. This exposure plan efficiently fills a single orbit with no time lost to buffer dump overheads. Dr. David Buote has expertise in Chandra ACIS data analysis and the study of the X-ray emission from elliptical galaxies. He led two recent papers on CEGs/MRGs that are the subject of this proposal. Dr. Aaron Barth, co-author of these two recent papers, has expertise in HST WFC3 and ALMA analysis and the study of black holes, AGN and galactic structure. In particular, Dr. Barth's experience with the analysis of HST surface brightness profiles of galaxies will be essential for the measurement and interpretation of the stellar mass profiles using both near-IR and X-ray data. 6 false false false false false false false false SUPPORTED GALAXY ELLIPTICAL YES J2000 H=9.521 +/- 0.018 mag, I=11.30 +/- 0.11 POS-TARG MOSAIC DITHER 4 2.414 WFC3-UVIS-DITHER-BOX false 81.785 true 0.112 0.173 2 85.759 POS-TARG WFC3-UVIS-GAP-LINE 23.884 4 false POS-TARG DITHER DITHER 4 23.02 WFC3-IR-DITHER-BOX-MIN 35.212 false 74.653 true 0.365 89.287 0.572 4 0.713 POS-TARG WFC3-IR-DITHER-BOX-UVIS 18.528 6 false POS-TARG DITHER 0.572 LINE 0.365 false false 74.653 4 18.528 WFC3-IR-DITHER-BOX-MIN 8 false /private/var/folders/bl/1t52zcq144lbxcy6s2dg90900000gn/T/OPVisit17473446955822890699.xml The scheduling data was generated by CASM 29.2. CASM was run in Phase II mode. (Tic-Visit :proposal-id 16836 :visit-id "01" :proposal-version -1 :trans-version "20210514" :date "09-Oct-2021 14:27:26.0" :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 1755424 :tdrss-contact-duration 0 :coron NIL ) (Tic-Obset :proposal-id 16836 :visit-id "01" :obset-id "01" :pcs-mode "FGS" ) (Tic-Orbit :proposal-id 16836 :visit-id "01" :orbit-number 1 :pcs-time 383 :si-vis-utilization 2766 :al-overhead-at-end 125 :internal-dur-at-end 668 :dark-offset NIL :dark-utilization 0 :max-dark-utilization 1920 :low-sky "N" :pcs-visibility 3149 :pcs-gap 0 ) true 1 0