8211( 5) - 09/22/99 10:10 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8211 Version: 5 Check-in Date: 22-Sep-1999 10:09:04 1.Proposal Title: An Ultraviolet Census of Counterparts to Highly Luminous X-ray Sources in M31 Globular Clusters ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Bruce Margon University of Washington CoI: Dr. Scott Anderson University of Washington Y CoI: Dr. Eric Deutsch University of Washington N ------------------------------------------------------------------------------------ 5. Abstract The cores of certain globular clusters in our Galaxy contain some of the most extraordinary stars known, identified by their intense, near-Eddington limited X-ray emission. Essentially all are X-ray bursters, emitting L_x>10^4 L_\odot in a few seconds. At least one, and probably two, of these sources are the shortest binary period stars known anywhere: NGC 6624 contains a double-degenerate binary with an 11 minute orbital period. HST has enabled the optical identification and study of counterparts to a half-dozen of these sources in the Milky Way, but the systems prove to have a wide range of optical luminosities and orbital periods, with few obvious patterns emerging. However, one common characteristic of these sources is intense flux at 1400 Angstrom, a wavelength where the 10^5 cluster stars virtually disappear. The Andromeda Nebula is known to contain dozens of bright globular cluster X-ray sources. We propose here a modest, first imaging reconnaissance of globular cluster X-ray source counterparts in M 31 at 1400 Angstrom, with a goal of materially increasing the number of X-ray clusters with counterparts, and further exploring an odd dispersion of L_X/L_1400 seen in galactic clusters. ------------------------------------------------------------------------------------ 8211( 5) - 09/22/99 10:10 - [ 2] Observations Description ------------------------ X-ray source counterparts in M31 globulars are expected to be highly luminous (though apparently faint due to the large distance modulus) in the UV, and so should stand out in FUV/MAMA exposures with F25SRF2; this filter avoids geocoronal Lyman-alpha backgrounds. SHADOW time is essential however to limit OI 1304 airglow background, which might otherwise swamp the signal in F25SRF2 exposures. We suggest that highly useful data can and should be obtained outside of the SHADOW portions of each orbit, however, e.g., by switching to F25QTZ during non-SHADOW portions of the orbits. Unfortunately, RPS2 doesn't allow us to specificy both SHADOW and non-SHADOW exposures in the same orbit, so for the initial Phase II we've just indicated the SHADOW exposures. When scheduling windows become more firm, we might instead provide specific date ranges for the observations to retain the SHADOW requirement implicitly, while also specifying both F25QTZ and F25SRF2 exposures for each orbit. In order that the boundaries between SHADOW and non-SHADOW time on each orbit need not be known in advance to arbitrarily high accuracy, we have used the TIME-TAG mode to permit maximum flexibility later in data reduction in distinguishing low- from high-background intervals. Real Time Justification ----------------------- None Calibration Justification ------------------------- None Additional Comments ------------------- Shadow time essential for F25SRF2 exposures. ------------------------------------------------------------------------------------ Data Distribution Paper Products: NO Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8211( 5) - 09/22/99 10:10 - [ 3] TARGET LIST Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 NGC224-BO5 EXT-CLUSTER, GLOBULAR RA=00H 40M 20.28S+/-0.1S, J2000 V = 15.7 CLUSTER DEC=40D 43' 58.6"+/-1.0"PLATE- ID=0738 2 NGC224-BO82 EXT-CLUSTER, GLOBULAR RA=00H 42M 15.81S+/-0.1S, J2000 V = 15.4 CLUSTER DEC=41D 01' 14.8"+/-1.0"PLATE- ID=0738 3 NGC224-BO135 EXT-CLUSTER, GLOBULAR RA=00H 42M 51.96S+/-0.1S, J2000 V = 16.0 CLUSTER DEC=41D 31' 8.2"+/-1.0"PLATE- ID=0738 4 NGC224-BO225 EXT-CLUSTER, GLOBULAR RA=00H 44M 29.54S+/-0.1S, J2000 V = 14.5 CLUSTER DEC=41D 21' 35.8"+/-1.0"PLATE- ID=0738 5 NGC224-BO375 EXT-CLUSTER, GLOBULAR RA=00H 45M 45.58S+/-0.1S, J2000 V = 17.5 CLUSTER DEC=41D 39' 42.5"+/-1.0"PLATE- ID=0738 6 NGC224-BO386 EXT-CLUSTER, GLOBULAR RA=00H 46M 26.98S+/-0.1S, J2000 V = 15.6 CLUSTER DEC=42D 01' 52.7"+/-1.0"PLATE- ID=0738 8211( 5) - 09/22/99 10:10 - [ 4] Visit: 01 Visit Priority: Visit Requirements: 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 ------------------------------------------------------------------------------------------------------------------------------------ 111 NGC224-BO5 STIS/F TIME-TA F25SRF2 MIRROR BUFFER-TIME=2000 1 1750 S SHADOW UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 121 NGC224-BO5 STIS/F TIME-TA F25SRF2 MIRROR BUFFER-TIME=2000 1 1890 S SHADOW UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 8211( 5) - 09/22/99 10:10 - [ 5] Visit: 02 Visit Priority: Visit Requirements: 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 ------------------------------------------------------------------------------------------------------------------------------------ 211 NGC224-BO82 STIS/F TIME-TA F25SRF2 MIRROR BUFFER-TIME=2000 1 1750 S SHADOW UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 221 NGC224-BO82 STIS/F TIME-TA F25SRF2 MIRROR BUFFER-TIME=2000 1 1890 S SHADOW UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 8211( 5) - 09/22/99 10:10 - [ 6] Visit: 03 Visit Priority: Visit Requirements: 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 ------------------------------------------------------------------------------------------------------------------------------------ 311 NGC224-BO13 STIS/F TIME-TA F25SRF2 MIRROR BUFFER-TIME=2000 1 1750 S SHADOW 5 UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 321 NGC224-BO13 STIS/F TIME-TA F25SRF2 MIRROR BUFFER-TIME=2000 1 1890 S SHADOW 5 UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 8211( 5) - 09/22/99 10:10 - [ 7] Visit: 04 Visit Priority: Visit Requirements: 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 ------------------------------------------------------------------------------------------------------------------------------------ 411 NGC224-BO22 STIS/F TIME-TA F25SRF2 MIRROR BUFFER-TIME=2000 1 1750 S SHADOW 5 UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 421 NGC224-BO22 STIS/F TIME-TA F25SRF2 MIRROR BUFFER-TIME=2000 1 1890 S SHADOW 5 UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 8211( 5) - 09/22/99 10:10 - [ 8] Visit: 05 Visit Priority: Visit Requirements: 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 ------------------------------------------------------------------------------------------------------------------------------------ 511 NGC224-BO37 STIS/F TIME-TA F25SRF2 MIRROR BUFFER-TIME=2000 1 1750 S SHADOW 5 UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 521 NGC224-BO37 STIS/F TIME-TA F25SRF2 MIRROR BUFFER-TIME=2000 1 1890 S SHADOW 5 UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 8211( 5) - 09/22/99 10:10 - [ 9] Visit: 06 Visit Priority: Visit Requirements: 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 ------------------------------------------------------------------------------------------------------------------------------------ 611 NGC224-BO38 STIS/F TIME-TA F25SRF2 MIRROR BUFFER-TIME=2000 1 1750 S SHADOW 6 UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 621 NGC224-BO38 STIS/F TIME-TA F25SRF2 MIRROR BUFFER-TIME=2000 1 1890 S SHADOW 6 UV-MAM G A ------------------------------------------------------------------------------------------------------------------------------------ 8211( 5) - 09/22/99 10:10 - [ 10] Summary Form for Proposal 8211 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F25SRF2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/FUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes TIME-TAG ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BUFFER-TIME=2000 ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements SHADOW ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR ------------------------------------------------------------------------------------------------------------------------------------ Target Names NGC224-BO5 NGC224-BO82 NGC224-BO135 NGC224-BO225 NGC224-BO375 NGC224-BO386 ------------------------------------------------------------------------------------------------------------------------------------