13456( 6) - 14-May-2014 17:16:56 - [ 1] HUBBLE SPACE TELESCOPE OBSERVING PROGRAM 13456 Version: 6 Check-in Time: 14-May-2014 17:16:56 STScI Edit Number: 3 Title Searching for 300,000 Degree Gas in the Core of the Phoenix Cluster with HST-COS ------------------------------------------------------------------------------------ Type Cycle GO 21 ------------------------------------------------------------------------------------ Investigators Contact? PI: Dr. Michael McDonald Massachusetts Institute of Technology Y CoI: Dr. Marshall Bautz Massachusetts Institute of Technology N CoI: Prof. Sylvain Veilleux University of Maryland N CoI: Prof. Andrew C. Fabian University of Cambridge N CoI: Dr. Bradford Benson University of Chicago N CoI: Dr. Eric D. Miller Massachusetts Institute of Technology N ------------------------------------------------------------------------------------ Abstract The high central density of the intracluster medium in some galaxy clusters suggests that the hot 10, 000, 000K gas should cool completely in less than a Hubble time. In these clusters, simple cooling models predict 100-1000 solar masses per year of cooling gas should fuel massive starbursts in the central galaxy. The fact that the typical central cluster galaxy is a massive, "red and dead" elliptical galaxy, with little evidence for a cool ISM, has led to the realization of the "cooling flow problem". It is now thought that mechanical feedback from the central supermassive blackhole, in the form of radio-blown bubbles, is offsetting cooling, leading to an exceptionally precise (residuals of less than 10 percent) balance between cooling and feedback in nearly every galaxy cluster in the local Universe. In the recently-discovered Phoenix cluster, where z=0.596, we observe an 800 solar mass per year starburst within the central galaxy which accounts for about 30 percent of the classical cooling prediction for this system. We speculate that this may represent the first "true" cooling flow, with the factor of 3 difference between cooling and star formation being attributed to star formation efficiency, rather than a problem with cooling. In order to test these predictions, we propose far-UV spectroscopic observations of the OVI 1032A emission line, which probes 10^5.5K gas, in the central galaxy of the Phoenix cluster. If detected at the expected levels, this would provide compelling evidence that the starburst is, indeed, fueled by runaway cooling of the intracluster medium, confirming the presence of the first, bonafide cooling flow. ------------------------------------------------------------------------------------ Observations Description ------------------------ The primary goal of this program is to obtain spectra of the OVI (1032, 1038) doublet, which will be redshifted to 1648, 1658A. Our secondary goal is to obtain broad UV continuum coverage. We are imaging two relatively diffuse/clumpy regions, neither of which are centrally peaked in UV brightness. Thus, pointing revision via ACQ/SEARCH is not possible. We instead must center on a nearby star (~60" away) and perform offsets. According to the COS users manual, such offsets should be accurate enough for our purposes. 13456( 6) - 14-May-2014 17:16:56 - [ 2] All of our observations are done in TIME-TAG mode. This temporal sampling will allow us to exclude poor quality data and get improved thermal correction and background removal. We separate our visits into 7 orbits, where each orbit uses one of four different FP-POS (1, 2, 3, 4, 2, 3, 4). This observing strategy is adopted to reduce the fixed pattern noise and fill up the wavelength hole produced by the chip gap without excessive overheads. Since our targets are faint (<0.001 cts/s), we use a BUFFER-TIME equal to the exposure time minus 110s, as suggested by Julia Duval for a similar 2012 program. We choose a central wavelength of 1577 in order to keep the OVI line (1650A) as far from the chip gap as possible. We are open to suggestions on this, if we are pushing the line into a low-sensitivity regime. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 13456( 6) - 14-May-2014 17:16:56 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 PHOENIX STAR, UNDESIGNATED RA=23H44M46.8902S +/- 0.1", J2000 V = 16.0 20.933 (GALEX NUV) DEC=-42D42'25.19" +/- 0.1" Reference Frame: ICRS ------------------------------------------------------------------------------------------------------------------------------------ 2 PHOENIX-CENT GALAXY, COOLING FLOW, RA=23H44M43.8930S +/- 0.1", J2000 V = 18.0 ER ELLIPTICAL, STARBURST DEC=-42D43'12.58" +/- 0.1" Reference Frame: ICRS Comments: Center of galaxy, to be used for COS centroiding ------------------------------------------------------------------------------------------------------------------------------------ 3 PHOENIX-NW GALAXY, COOLING FLOW, RA-OFF=-0.031S, DEC-OFF=+1.43", J2000 V = 18.0 ELLIPTICAL, STARBURST FROM 2 ------------------------------------------------------------------------------------------------------------------------------------ 4 PHOENIX-SE GALAXY, COOLING FLOW, RA-OFF=+0.039S, DEC-OFF=-0.83", J2000 V = 18.0 ELLIPTICAL, STARBURST FROM 2 ------------------------------------------------------------------------------------------------------------------------------------ 13456( 6) - 14-May-2014 17:16:56 - [ 4] Visit: 01 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 PHOENIX-CEN COS/NUV ACQ/IMA PSA MIRRORA 1 580 S (580 TER GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 PHOENIX-SE COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=1204, FLASH=YES, 1 1469 S G FP-POS=1, EXTENDED=YES (1469 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 PHOENIX-SE COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S SAME POS AS 2 G FP-POS=2, EXTENDED=YES (3047 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 PHOENIX-SE COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S SAME POS AS 2 G FP-POS=3, EXTENDED=YES (3047 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 PHOENIX-SE COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S SAME POS AS 2 G FP-POS=4, EXTENDED=YES (3047 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 PHOENIX-SE COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S SAME POS AS 2 G FP-POS=2, EXTENDED=YES (3047 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 PHOENIX-SE COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S SAME POS AS 2 G FP-POS=3, EXTENDED=YES (3047 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 PHOENIX-SE COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S SAME POS AS 2 G FP-POS=4, EXTENDED=YES (3047 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ PHOENIX-CENTER 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE PHOENIX-SE 2 COS/FUV TIME-TA PSA G160M 1577 none none none none 1 N/A G PHOENIX-SE 3 COS/FUV TIME-TA PSA G160M 1577 none none none none 2 N/A G PHOENIX-SE 4 COS/FUV TIME-TA PSA G160M 1577 none none none none 3 N/A G PHOENIX-SE 5 COS/FUV TIME-TA PSA G160M 1577 none none none none 4 N/A G PHOENIX-SE 6 COS/FUV TIME-TA PSA G160M 1577 none none none none 5 N/A G 13456( 6) - 14-May-2014 17:16:56 - [ 5] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ PHOENIX-SE 7 COS/FUV TIME-TA PSA G160M 1577 none none none none 6 N/A G PHOENIX-SE 8 COS/FUV TIME-TA PSA G160M 1577 none none none none 7 N/A G 13456( 6) - 14-May-2014 17:16:56 - [ 6] Visit: 02 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 PHOENIX COS/NUV ACQ/SEA PSA MIRRORA CENTER=BRIGHTEST, SCAN-SIZE=3, 1 100 S (100 RCH STEP-SIZE=1.767 S) ------------------------------------------------------------------------------------------------------------------------------------ 2 PHOENIX COS/NUV ACQ/IMA PSA MIRRORA 1 46 S (46 GE S) ------------------------------------------------------------------------------------------------------------------------------------ 3 PHOENIX COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=1204, FLASH=YES, 1 1314 S POS TARG G FP-POS=1, EXTENDED=YES (1314 S) -8.476723689658884, -55.98962938415026 ------------------------------------------------------------------------------------------------------------------------------------ 4 PHOENIX COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S POS TARG G FP-POS=2, EXTENDED=YES (3047 S) -8.476723689658884, -55.98962938415026 ------------------------------------------------------------------------------------------------------------------------------------ 5 PHOENIX COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S POS TARG G FP-POS=3, EXTENDED=YES (3047 S) -8.476723689658884, -55.98962938415026 ------------------------------------------------------------------------------------------------------------------------------------ 6 PHOENIX COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S POS TARG G FP-POS=4, EXTENDED=YES (3047 S) -8.476723689658884, -55.98962938415026 ------------------------------------------------------------------------------------------------------------------------------------ 7 PHOENIX COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S POS TARG G FP-POS=2, EXTENDED=YES (3047 S) -8.476723689658884, -55.98962938415026 ------------------------------------------------------------------------------------------------------------------------------------ 8 PHOENIX COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S POS TARG G FP-POS=3, EXTENDED=YES (3047 S) -8.476723689658884, -55.98962938415026 ------------------------------------------------------------------------------------------------------------------------------------ 9 PHOENIX COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S POS TARG G FP-POS=4, EXTENDED=YES (3047 S) -8.476723689658884, -55.98962938415026 ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ PHOENIX 1 COS/NUV ACQ/SEA PSA MIRRORA none none none none 1 N/A RCH 13456( 6) - 14-May-2014 17:16:56 - [ 7] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ PHOENIX 2 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE PHOENIX 3 COS/FUV TIME-TA PSA G160M 1577 none none none none 1 N/A G PHOENIX 4 COS/FUV TIME-TA PSA G160M 1577 none none none none 2 N/A G PHOENIX 5 COS/FUV TIME-TA PSA G160M 1577 none none none none 3 N/A G PHOENIX 6 COS/FUV TIME-TA PSA G160M 1577 none none none none 4 N/A G PHOENIX 7 COS/FUV TIME-TA PSA G160M 1577 none none none none 5 N/A G PHOENIX 8 COS/FUV TIME-TA PSA G160M 1577 none none none none 6 N/A G PHOENIX 9 COS/FUV TIME-TA PSA G160M 1577 none none none none 7 N/A G 13456( 6) - 14-May-2014 17:16:56 - [ 8] Visit: 52 Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exp | Target | Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Num | Name | Config | Mode | or FOV |Element |Waveln.| Parameters |Exp| (Total) | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 PHOENIX-CEN COS/NUV ACQ/IMA PSA MIRRORA 1 580 S (580 TER GE S) ------------------------------------------------------------------------------------------------------------------------------------ 2 PHOENIX-NW COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=1204, FLASH=YES, 1 1469 S G FP-POS=1, EXTENDED=YES (1469 S) ------------------------------------------------------------------------------------------------------------------------------------ 3 PHOENIX-NW COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S SAME POS AS 2 G FP-POS=2, EXTENDED=YES (3047 S) ------------------------------------------------------------------------------------------------------------------------------------ 4 PHOENIX-NW COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S SAME POS AS 2 G FP-POS=3, EXTENDED=YES (3047 S) ------------------------------------------------------------------------------------------------------------------------------------ 5 PHOENIX-NW COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S SAME POS AS 2 G FP-POS=4, EXTENDED=YES (3047 S) ------------------------------------------------------------------------------------------------------------------------------------ 6 PHOENIX-NW COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S SAME POS AS 2 G FP-POS=2, EXTENDED=YES (3047 S) ------------------------------------------------------------------------------------------------------------------------------------ 7 PHOENIX-NW COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S SAME POS AS 2 G FP-POS=3, EXTENDED=YES (3047 S) ------------------------------------------------------------------------------------------------------------------------------------ 8 PHOENIX-NW COS/FUV TIME-TA PSA G160M 1577 BUFFER-TIME=2937, FLASH=YES, 1 3047 S SAME POS AS 2 G FP-POS=4, EXTENDED=YES (3047 S) ------------------------------------------------------------------------------------------------------------------------------------ Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ PHOENIX-CENTER 1 COS/NUV ACQ/IMA PSA MIRRORA none none none none 1 N/A GE PHOENIX-NW 2 COS/FUV TIME-TA PSA G160M 1577 none none none none 1 N/A G PHOENIX-NW 3 COS/FUV TIME-TA PSA G160M 1577 none none none none 2 N/A G PHOENIX-NW 4 COS/FUV TIME-TA PSA G160M 1577 none none none none 3 N/A G PHOENIX-NW 5 COS/FUV TIME-TA PSA G160M 1577 none none none none 4 N/A G PHOENIX-NW 6 COS/FUV TIME-TA PSA G160M 1577 none none none none 5 N/A G 13456( 6) - 14-May-2014 17:16:56 - [ 9] Sub Exposures ------------------------------------------------------------------------------------------------------------------------------------ Target | Exp |Instr | Oper. | Aper |Spectral|Cent.|Primary |Secondary |Iteration |CR-SPLIT |Orbit |Duration Name | Num |Config | Mode | or FOV |Element |Wave.|Pattern Pos |Pattern Pos |Num |Num |Number | ------------------------------------------------------------------------------------------------------------------------------------ PHOENIX-NW 7 COS/FUV TIME-TA PSA G160M 1577 none none none none 6 N/A G PHOENIX-NW 8 COS/FUV TIME-TA PSA G160M 1577 none none none none 7 N/A G 13456( 6) - 14-May-2014 17:16:56 - [ 10] Summary Form for Proposal 13456 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures PSA ------------------------------------------------------------------------------------------------------------------------------------ Configurations COS/FUV, COS/NUV ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/IMAGE, ACQ/SEARCH, TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=1204, BUFFER-TIME=2937, CENTER=BRIGHTEST, EXTENDED=YES, FLASH=YES, FP-POS=1, FP-POS=2, FP-POS=3, FP-POS=4, SCAN-SIZE=3, STEP-SIZE=1.767 ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements POS TARG -8.476723689658884, -55.98962938415026, SAME POS AS 2 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements G160M, MIRRORA ------------------------------------------------------------------------------------------------------------------------------------ Target Names PHOENIX, PHOENIX-CENTER, PHOENIX-NW, PHOENIX-SE ------------------------------------------------------------------------------------------------------------------------------------