8644( 7) - 05/30/01 15:13 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8644 Version: 7 Check-in Date: 30-May-2001 15:12:29 1.Proposal Title: Galaxy Recycling in Clusters ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 9 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Michael West University of Hawaii CoI: Michael Gregg University of California, Davis N ------------------------------------------------------------------------------------ 5. Abstract We propose to obtain deep WFPC2 B, V, and I images of two unusual, extended, low surface brightness plumes of material recently discovered in the Coma and Centaurus clusters. These plumes are most likely transient tidal debris resulting from the destruction of galaxies as they passed through the cores of these clusters. Over time, this debris will spread throughout the cluster potential, augmenting the intergalactic populations of stars, globular clusters, dwarf galaxies, and gas. Some of this material may also be incorporated into the halos of the central dominant galaxies. In these plumes we are witnessing the ongoing formation of the diffuse intracluster background of stellar light seen in many rich clusters, as well as the material from which cD galaxies themselves may be built. This is recycling on a cosmic scale. Determining the nature of this recycled material is key to understanding the formation and evolution of the intergalactic stellar population, as well as t he evolution of the galaxy populations in clusters. HST images of these two plumes will enable direct study of their stellar populations, specifically, the number of bright supergiants, globular clusters, and star forming regions which may be present. ------------------------------------------------------------------------------------ 8644( 7) - 05/30/01 15:13 - [ 2] Observations Description ------------------------ We will image one field in each cluster, Coma and Centaurus, using the F450W, F606W, and F814W filters. These are not the "standard" B and V filters of WFPC2, however, they have roughly twice the integrated throughputs of F439W and F555W, respectively and for this reason were used in the Hubble Deep Field observations. Holtzman et al. (1995) have shown that the transformation from F450W and F606W to Johnson B and V are not problematic. An additional benefit of the F450W filter is that its peak transmission is at 5100 Angstrom, so it will pick up OIII 5007 emission making the images somewhat more sensitive to HII regions and star formation. The main driver for the integration times is to reach below the peak of the quasi-gaussian globular cluster luminosity function (GCLF) at M_V=-7.4 with enough S/N to detect average globulars which will be unresolved at these distances. We adopt m-M=33.3 and A_ B=0.46 for Centaurus and m-M=35.0 and A_ B=0.03 for Coma. For Centaurus, th e WFPC2 Exposure Time Calculator estimates that WFPC2 will reach S/N of 10 or better in F450W for a point source globular cluster at the peak of the GCLF (V = 26) in two orbits (~ 5000s). The depth of the F450W can be more than matched in just one orbit in both F606W and F814W. To reach similar S/N at the peak of the GCLF in Coma is more difficult; not only is Coma more than twice as far, but the plume is projected on the halo of NGC4874, significantly increasing the background. We consequently scale back our goal to S/N of 5 for the peak of the GCLF (V=27.6) in Coma. The ETC then calls for an exposure of 12500s in F450W, or about 5 orbits. Somewhat better S/N, almost on a par with the Centaurus observations, is reached in 3 and 4 orbits, respectively, with F606W and F814W in Coma. We will place the PC on the regions of highest surface brightness in each plume to make best use of the higher sampling. We will subpixel dither our images to allow for CR splitting and driz zl ing to enhance the resolution. vspace0.05in STIS parallel imaging using the 50CCD and F28X50LP bandpasses is also requested. The angular size of the Centaurus plume is greater than the WFPC2 - STIS separation, so it will be possible to orient the spacecraft to use STIS to obtain deep images of a region at the other end of the plume. With two orbits in each bandpass, STIS will reach approximately 1 magnitude deeper than the corresponding V and I images from WFPC2. These observations are directly comparable to the WFPC2 primary observations, since the STIS bands can be transformed onto Cousins BVI photometry to good approximation (Gregg & Minniti 1997). The color information from the two bandpasses of STIS is essential for distinguishing globulars from redder and bluer compact background galaxies. All STIS exposures will be CRSPLIT and dithered along with the WFPC2 primary images. The Coma plume is not long enough to be observed simultaneously by STIS and WFPC2, but STIS ob servations of an additional field in Coma would nevertheless be extremely worthwhile. As our target fields are in the core of the cluster, there are many early type galaxies whose GCLF could be measured using STIS, which over the 12 orbits requested, would reach considerably deeper than previous observations of the GCLF in Coma galaxies. In 6 orbits of 50CCD and LongPass integrations, with average zodiacal light and Earthshine, the STIS ETC predicts S/N ~ 5 and 3.4 respectively, for globular clusters with V=28.6, about 1 magnitude fainter than the peak of the luminosity function. (These numbers are a pessimistic estimate as the STIS ETC uses an aperture of area 30 pixels to compute S/N; in practice, photometry through an aperture of much smaller size will substantially increase the S/N and photometric accuracy). Contamination by Galactic stars in the Coma high latitude field will not be a serious problem. Only 15 stars were found in the Hubble Deep Field (Mendez, et a l. 1997) down to well below our limiting S/N, and no more than 5-10 are expected in the proposed Coma WFPC2 fields. Centaurus is at b=22degrees, so more stars are expected, but the LSB material is narrow compared to the WFPC2 field, and any Centaurus population of bright stars and clusters will clearly follow the LSB distribution. Real Time Justification ----------------------- To place both WFPC2 and STIS on the Centaurus plume requires tight constraint on the roll angle of HST to +/- 20 degrees. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 8644( 7) - 05/30/01 15:13 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 ABELL3526B- GALAXY, TIDAL TAIL RA=12H 49M 42.7S +/- 0S, DEC=- J2000 V=+4000 V = 24.0 PLUME 41D 24' 29.0" +/- 0", PLATE- B-V = 1.0 ID=0162 Coordinate Source: GSC_SURVEY_PLATE Comments: Tidal debris in Centaurus Cluster 8644( 7) - 05/30/01 15:13 - [ 4] Visit: 01 Visit Priority: Visit Requirements: ORIENT 81D TO 81D ON HOLD On Hold Comments: Visits 3 and 4 are prefered, but this depends on visit 3 executing before July 2000. If this does not happen, then execute visits 1 and 2. Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 101 ABELL3526B- WFPC2 IMAGE WF3-FIX F814W CR-SPLIT=NO,CLOCKS=YES 1 800 S PLUME Comments: 1 of 3 F814W ------------------------------------------------------------------------------------------------------------------------------------ 103 ABELL3526B- WFPC2 IMAGE WF3-FIX F606W CR-SPLIT=NO,CLOCKS=YES 1 700 S PLUME Comments: 1 of 3 F606W ------------------------------------------------------------------------------------------------------------------------------------ 107 ABELL3526B- WFPC2 IMAGE WF3-FIX F606W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG -0.2242,-0.6720 PLUME Comments: 2 of 3 F606W ------------------------------------------------------------------------------------------------------------------------------------ 201 ABELL3526B- WFPC2 IMAGE WF3-FIX F814W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG 0.4484,-0.4484 PLUME Comments: 2 of 3 F814W ------------------------------------------------------------------------------------------------------------------------------------ 203 ABELL3526B- WFPC2 IMAGE WF3-FIX F606W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG 0.4484,-0.4484 PLUME Comments: 3 of 3 F606W ------------------------------------------------------------------------------------------------------------------------------------ 207 ABELL3526B- WFPC2 IMAGE WF3-FIX F814W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG -0.2242,-0.6720 PLUME Comments: 3 of 3 F814W ------------------------------------------------------------------------------------------------------------------------------------ 8644( 7) - 05/30/01 15:13 - [ 5] Visit: 02 Visit Priority: Visit Requirements: ON HOLD SAME ORIENT AS 01 On Hold Comments: See visit 1 ON HOLD comments. Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 101 ABELL3526B- WFPC2 IMAGE WF3-FIX F814W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG 0.6726, 0.2240 PLUME Comments: 1 of 3 F814W ------------------------------------------------------------------------------------------------------------------------------------ 103 ABELL3526B- WFPC2 IMAGE WF3-FIX F606W CR-SPLIT=NO,CLOCKS=YES 1 700 S POS TARG 0.6726, 0.2240 PLUME Comments: 1 of 3 F606W ------------------------------------------------------------------------------------------------------------------------------------ 107 ABELL3526B- WFPC2 IMAGE WF3-FIX F606W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG 0.1993, 0.6969 PLUME Comments: 2 of 3 F606W ------------------------------------------------------------------------------------------------------------------------------------ 201 ABELL3526B- WFPC2 IMAGE WF3-FIX F814W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG -0.4484, 0.4484 PLUME Comments: 2 of 3 F814W ------------------------------------------------------------------------------------------------------------------------------------ 203 ABELL3526B- WFPC2 IMAGE WF3-FIX F606W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG -0.4484, 0.4484 PLUME Comments: 3 of 3 F606W ------------------------------------------------------------------------------------------------------------------------------------ 207 ABELL3526B- WFPC2 IMAGE WF3-FIX F814W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG 0.1993, 0.6969 PLUME Comments: 3 of 3 F814W ------------------------------------------------------------------------------------------------------------------------------------ 8644( 7) - 05/30/01 15:13 - [ 6] Visit: 03 Visit Priority: Visit Requirements: ORIENT 81D TO 81D BEFORE 01-Jul-2000 On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 101 ABELL3526B- WFPC2 IMAGE WF3-FIX F814W CR-SPLIT=NO,CLOCKS=YES 1 800 S PAR 104, 106 WITH 101, PLUME 103 Comments: 1 of 3 F814W ------------------------------------------------------------------------------------------------------------------------------------ 103 ABELL3526B- WFPC2 IMAGE WF3-FIX F606W CR-SPLIT=NO,CLOCKS=YES 1 700 S PLUME Comments: 1 of 3 F606W ------------------------------------------------------------------------------------------------------------------------------------ 104 ABELL3526B- STIS/C ACCUM 50CCD MIRROR CR-SPLIT=2 1 820 S PLUME CD Comments: 1-2 of 6 50CCD ------------------------------------------------------------------------------------------------------------------------------------ 106 ABELL3526B- STIS/C ACCUM F28X50L MIRROR CR-SPLIT=2 1 820 S PLUME CD P Comments: 1-2 of 6 F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ 107 ABELL3526B- WFPC2 IMAGE WF3-FIX F606W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG -0.2242,-0.6720 PLUME PAR 108 WITH 107 Comments: 2 of 3 F606W ------------------------------------------------------------------------------------------------------------------------------------ 108 ABELL3526B- STIS/C ACCUM F28X50L MIRROR CR-SPLIT=2 1 880 S PLUME CD P Comments: 3-4 of 6 50CCD ------------------------------------------------------------------------------------------------------------------------------------ 201 ABELL3526B- WFPC2 IMAGE WF3-FIX F814W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG 0.4484,-0.4480 PLUME PAR 204, 206 WITH 201, 203 Comments: 2 of 3 F814W ------------------------------------------------------------------------------------------------------------------------------------ 203 ABELL3526B- WFPC2 IMAGE WF3-FIX F606W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG 0.4484,-0.4480 PLUME Comments: 3 of 3 F606W ------------------------------------------------------------------------------------------------------------------------------------ 204 ABELL3526B- STIS/C ACCUM 50CCD MIRROR CR-SPLIT=2 1 880 S PLUME CD Comments: 5-6 of 6 50CCD ------------------------------------------------------------------------------------------------------------------------------------ 206 ABELL3526B- STIS/C ACCUM F28X50L MIRROR CR-SPLIT=2 1 880 S PLUME CD P Comments: 3-4 of 6 F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ 207 ABELL3526B- WFPC2 IMAGE WF3-FIX F814W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG -0.2242,-0.6720 PLUME PAR 208 WITH 207 Comments: 3 of 3 F814W ------------------------------------------------------------------------------------------------------------------------------------ 8644( 7) - 05/30/01 15:13 - [ 7] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 208 ABELL3526B- STIS/C ACCUM F28X50L MIRROR CR-SPLIT=2 1 830 S PLUME CD P Comments: 5-6 of 6 F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ 8644( 7) - 05/30/01 15:13 - [ 8] Visit: 04 Visit Priority: Visit Requirements: SAME ORIENT AS 03 AFTER 03 BY 300 D TO 425 D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 101 ABELL3526B- WFPC2 IMAGE WF3-FIX F814W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG 0.6726, 0.2240 PLUME PAR 104, 106 WITH 101, 103 Comments: 1 of 3 F814W ------------------------------------------------------------------------------------------------------------------------------------ 103 ABELL3526B- WFPC2 IMAGE WF3-FIX F606W CR-SPLIT=NO,CLOCKS=YES 1 700 S POS TARG 0.6726, 0.2240 PLUME Comments: 1 of 3 F606W ------------------------------------------------------------------------------------------------------------------------------------ 104 ABELL3526B- STIS/C ACCUM 50CCD MIRROR CR-SPLIT=2 1 820 S PLUME CD Comments: 1-2 of 6 50CCD ------------------------------------------------------------------------------------------------------------------------------------ 106 ABELL3526B- STIS/C ACCUM F28X50L MIRROR CR-SPLIT=2 1 820 S PLUME CD P Comments: 1-2 of 6 F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ 107 ABELL3526B- WFPC2 IMAGE WF3-FIX F606W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG 0.1993, 0.6969 PLUME PAR 108 WITH 107 Comments: 2 of 3 F606W ------------------------------------------------------------------------------------------------------------------------------------ 108 ABELL3526B- STIS/C ACCUM F28X50L MIRROR CR-SPLIT=2 1 880 S PLUME CD P Comments: 3-4 of 6 50CCD ------------------------------------------------------------------------------------------------------------------------------------ 201 ABELL3526B- WFPC2 IMAGE WF3-FIX F814W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG 0.4484,-0.4484 PLUME PAR 204, 206 WITH 201, 203 Comments: 2 of 3 F814W ------------------------------------------------------------------------------------------------------------------------------------ 203 ABELL3526B- WFPC2 IMAGE WF3-FIX F606W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG 0.4484,-0.4484 PLUME Comments: 3 of 3 F606W ------------------------------------------------------------------------------------------------------------------------------------ 204 ABELL3526B- STIS/C ACCUM 50CCD MIRROR CR-SPLIT=2 1 880 S PLUME CD Comments: 5-6 of 6 50CCD ------------------------------------------------------------------------------------------------------------------------------------ 206 ABELL3526B- STIS/C ACCUM F28X50L MIRROR CR-SPLIT=2 1 880 S PLUME CD P Comments: 3-4 of 6 F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ 207 ABELL3526B- WFPC2 IMAGE WF3-FIX F814W CR-SPLIT=NO,CLOCKS=YES 1 800 S POS TARG 0.1993, 0.6969 PLUME PAR 208 WITH 207 Comments: 3 of 3 F814W ------------------------------------------------------------------------------------------------------------------------------------ 8644( 7) - 05/30/01 15:13 - [ 9] Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 208 ABELL3526B- STIS/C ACCUM F28X50L MIRROR CR-SPLIT=2 1 830 S PLUME CD P Comments: 5-6 of 6 F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ 8644( 7) - 05/30/01 15:13 - [ 10] Summary Form for Proposal 8644 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures WF3-FIX 50CCD F28X50LP ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 STIS/CCD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters CR-SPLIT=NO CLOCKS=YES CR-SPLIT=2 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 81D TO 81D ON HOLD POS TARG -0.2242,-0.6720 POS TARG 0.4484,-0.4484 ON HOLD SAME ORIENT AS 01 POS TARG 0.6726, 0.2240 POS TARG 0.1993, 0.6969 POS TARG -0.4484, 0.4484 ORIENT 81D TO 81D BEFORE 01-Jul-2000 PAR 104, 106 WITH 101, 103 POS TARG -0.2242,-0.6720 PAR 108 WITH 107 POS TARG 0.4484,-0.4480 PAR 204, 206 WITH 201, 203 POS TARG 0.4484,-0.4480 POS TARG -0.2242,-0.6720 PAR 208 WITH 207 SAME ORIENT AS 03 AFTER 03 BY 300 D TO 425 D POS TARG 0.6726, 0.2240 PAR 104, 106 WITH 101, 103 POS TARG 0.1993, 0.6969 PAR 108 WITH 107 POS TARG 0.4484,-0.4484 PAR 204, 206 WITH 201, 203 POS TARG 0.1993, 0.6969 PAR 208 WITH 207 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F814W F606W MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names ABELL3526B-PLUME ------------------------------------------------------------------------------------------------------------------------------------