6123( 0) - 07/18/95 20:12 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 6123 Version: ********** Check-in Date: ********** 1.Proposal Title: Resolving the Luminous O III Lambda 5007 Sources in the Early-Types Galaxies of Virgo ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Cycle Interstellar Medium GO 5 ------------------------------------------------------------------------------------ 5. Investigators Contact? PI: Robin Ciardullo The Pennsylvania State University CoI: George Jacoby Kitt Peak National Observatory N ------------------------------------------------------------------------------------ 6. Abstract Observations of over 3000 planetary nebulae in the Local Group, M81, NGC 5128, and galaxies in Leo I, Coma I, Triangulum, Fornax, and Virgo show that the O III Lambda 5007 planetary nebula luminosity function has an extremely sharp cutoff at bright magnitudes. However, O III surveys of Virgo Cluster ellipticals have turned up 9 objects that are significantly brighter than this cutoff. While about half of these objects might be explained by the superposition of two, separate bright sources (optical doubling), the three most luminous objects are ~ 1 mag brighter than any planetary nebula discovered anywhere. We propose to image these over- luminous objects with the F502N filter and the Planetary Camera of the Hubble Space Telescope. If HST resolves these objects into H II regions, then we will have direct evidence of star formation in the early-type galaxies of Virgo. If HST does not resolve the sources, then we will be forced to conclude that either a young stellar population exists in the Virgo ellipticals, or that there exists, in addition to classical PN, a completely different population of O III Lambda 5007 sources. ------------------------------------------------------------------------------------ 6123( 0) - 07/18/95 20:12 - [ 2] Observations Description ------------------------ We are proposing to image 3 over-luminous O III Lambda 5007 sources in the Virgo Cluster with the F502N filter of the Planetary Camera. Despite being described as over-luminous, these objects are all extremely faint, with total O III Lambda 5007 fluxes of between 1.8 * 10^16 and 2.6 * 10^16 ergs cm^-2 s^-1. According to the WFPC2 Instrument Handbook (1994), these fluxes correspond to counts rates of between 370 and 540 counts per hour. Using the point spread functions and CCD characteristics given in the WFPC2 manual, we have created model image profiles for our O III Lambda 5007 sources. We find that we can reliably discriminate between a point source and a source that extends over 3 pixels (0sec point 14, or 10 pc at the distance of Virgo) with ~ 500 counts, and that resolving small structures becomes extremely difficult with less than 300 counts. (The background sky and galaxy were neglected in these models; however, these should be negligible in the narrow-band filter.) We therefore need approximately 2 orbits per object. Real Time Justification ----------------------- None. Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ Data Distribution Media: 8MM Blocking Factor: 10 Ship To: PI_Address Ship Via: UPS Email: , ------------------------------------------------------------------------------------ 6123( 0) - 07/18/95 20:12 - [ 3] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4382-PN1 EXT-MEDIUM, Planetary RA=12H 22M 47.94S +/- 0.07S, 1950.0 V=25.2 +/- 0.1 Nebula DEC= 18D 25' 18.59" +/- 1.0" B-V=1.0 +/- 0.2 2 NGC4486-PN1 EXT-MEDIUM, Planetary RA=12H 28M 17.53S +/- 0.07S, 1950.0 V=25.6 +/- 0.1 Nebula DEC= 12D 37' 31.94" +/- 1.0" B-V=1.0 +/- 0.2 3 NGC4406-PN1 EXT-MEDIUM, Planetary RA=12H 23M 41.28S +/- 0.07S, 1950.0 V=25.6 +/- 0.1 Nebula DEC= 13D 14' 17.09" +/- 1.0" B-V=1.0 +/- 0.2 6123( 0) - 07/18/95 20:12 - [ 4] Visit: 01 Visit Requirements: ORIENT 140D TO 260D On Hold Comments: Additional Comments: We would like to get the roll angle as close to 200D as possible, to maximize our science. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4382-PN1 WFPC2 IMAGE PC1 F502N 1 4980S ------------------------------------------------------------------------------------------------------------------------------------ 6123( 0) - 07/18/95 20:12 - [ 5] Visit: 02 Visit Requirements: ORIENT 120D TO 240D On Hold Comments: Additional Comments: We would like to get our roll angle as close as possible to 180D, to maximize our science. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4486-PN1 WFPC2 IMAGE PC1 F502N 1 4980S ------------------------------------------------------------------------------------------------------------------------------------ 6123( 0) - 07/18/95 20:12 - [ 6] Visit: 03 Visit Requirements: ORIENT 315D TO 95D On Hold Comments: Additional Comments: We would like to get our roll angle as close to 45D as possible to maximize our science. Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC4406-PN1 WFPC2 IMAGE PC1 F502N 1 4980S ------------------------------------------------------------------------------------------------------------------------------------ 6123( 0) - 07/18/95 20:12 - [ 7] Summary Form for Proposal 6123 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations WFPC2 ------------------------------------------------------------------------------------------------------------------------------------ Opmodes IMAGE ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category Interstellar Medium ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ORIENT 140D TO 260D ORIENT 120D TO 240D ORIENT 315D TO 95D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements F502N ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC4382-PN1 NGC4486-PN1 NGC4406-PN1 ------------------------------------------------------------------------------------------------------------------------------------