Page 1 PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID 2248c Report Date: 09-May-96:16:58 Version: ********** Check-in Date: ********** 1.Proposal Title: ULTRAVIOLET SPECTROSCOPY OF LOW MASS X-RAY BINARIES ------------------------------------------------------------------------------------ 2. Scientific Category 3. Proposal For 4. Proposal Type 5. Continuation ID STAR GO Sub Category ------------------------------------------------------------------------------------ 6. Principal Investigator Institution Country Telephone Dr. Paul Barr ESA, ESTEC NETHERLAND +31-1719-84365 DR. ------------------------------------------------------------------------------------ 7. Abstract We propose to use the HST FOS to study the UV spectra of threelow-mass X-ray binaries (LMXRB). Our goals are to investigate the physical structure of their accretion disks and investigate the effects of X-ray heating in these systems. Studies of their UV spectra will lead to; -constraints on the accretion disk thickness and the effects of X-ray heating from comparison of the UV and X-ray luminosities, and from the studies of the UV spectral shape; -a probe of the sites of UV line emission. Possible locations for the emission line region are the accretion disk itself and the irradiated photosphere of the companion star. Only space-borne instrumentation can study the far UV spectra of these objects. Most LMXRB are too faint to have been observed with IUE. Only five have been studied with IUE and only Cen X-4 (in outburst) and Sco X-1 have yielded data of even moderate signal-to-noise ratio. It is highly desirable to extend this sample to include LMXRB of various types - bursters, dippers, accretion disk corona and 'normal' bulge sources - to search for systematic differences between them. The HST is uniquely suitable for obtaining moderate resolution UV spectra of these objects. ------------------------------------------------------------------------------------ 8. Scientific Key Words: X-RAY STAR, NEUTRON STAR; BLACK HOLE; SPECTROSCOPY; UV ------------------------------------------------------------------------------------ 9. Est obs time (hours) pri: 9.60 par: 0 10. Num targs pri: 3 par: 0 ------------------------------------------------------------------------------------ 11. Instruments requested: FOS ------------------------------------------------------------------------------------ ------------------------------------------------------------------------------------ Page 2 I. GENERAL FORM Proposal 2248c PI: Dr. Paul Barr Proposal Title: ULTRAVIOLET SPECTROSCOPY OF LOW MASS X-RAY BINARIES ------------------------------------------------------------------------------------ 1. Proposers: Proposers Institution Country ESA ------------------------------------------------------------------------------------ Dr. N. E. White ESA, ESTEC NETHERLANDS X Dr. M. Gottwald MPE GARCHING GERMANY X Dr. A. Pollock ESA, ESTEC NETHERLANDS X Dr. I. Howarth LONDON, UNIVERSITY COLLEGE UK X Dr. Michiel Van Der Klis AMSTERDAM UNIVERSITY NETHERLANDS X Dr. Paul Barr ESA, ESTEC NETHERLANDS X ------------------------------------------------------------------------------------ 3. Description of proposed observations. Our aim is to obtain high-quality UV spectra between 1150A and 3300A of three low-mass X-ray binaries using the HST FOS.For each target we propose to perform one exposure in each of the three gratings, G130H, G190H and G270H, with a resolving power R of 1300. In the 1150-2000A region we require rather high signal -to-noise ratio (S/N of 60 per pixel) in order to accurately measure the equivalent widths of rather weak emission lines such as e.g. OIV,OV,NIII, CIII ; our requirement longward of 2000A is not so strict (S/N of 20 per pixel) since we are interested principally in the UV continuum shape. We propose to observe one X-ray dipper/Accretion disk Corona(ADC) source, one burster and one 'normal' bulge source. ------------------------------------------------------------------------------------ 4. Justification of need for HST observations. Only two low mass X-ray binaries have been observed at even moderate signal-to- noise ratio and another three at very low exposure levels, with all other LMXRB are too weak to observable with IUE. Observations at ultraviolet wavelengths are essential both to determine the bolometric luminosity of the accretion disks in LMXRB, and to study the resonance lines from highly ionised ions that are diagnostics of the role of X-ray heating. Thus, observations from space-borne telescopes are necessary. These observations can only be performed with the HST due to the dimness of these systems. ------------------------------------------------------------------------------------ 11. Address Information Name: PAUL BARR Category: PI Institution: SPACE SCIENCE DEPT. ESA Address: ESTEC, POSTBUS299 City: NOORDWIJK 2200AG State: Zip Code: Country: NETHERLANDS Telephone: Telex (or e-mail): ------------------------------------------------------------------------------------ TARGET LIST a) Fixed Targets ID = 2248c [ 3] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial |Acqui|FLX| Flux data No | Name | Description | Position |Eqnx | Vel. |Prblm|REF| | | | | | | | | ------------------------------------------------------------------------------------------------------------------------------------ 1 4U1728-16 STAR; RA = 17H 31M 44.16S +/- J2000 1 V = 16.6 GX9+9 LMXRB; 0.4", 2 B-V = 0.0, U-B = -0.5, E(B-V)=-0.3 X-RAY BINARY; DEC = -16D 57M 40.7S +/- 0.4" ------------------------------------------------------------------------------------------------------------------------------------ 2 4U1735-44 STAR RA = 17H 38M 58.34S +/- 0.4" J2000 1 V = 17.7 X-RAY BINARY , 2 B-V = 0.2, U-B = -0.8, E(B-V)=-0.3 LMXRB DEC = -44D 27M 02.1S +/- 0.4" ------------------------------------------------------------------------------------------------------------------------------------ 3 4U1822-37 STAR RA = 18H 25M 46.76S +/- J2000 1 V = 16.3 X-RAY BINARY 0.4", 2 B-V = 0.0 LMXRB DEC = -37D 06M 20.2S +/- 0.4" ------------------------------------------------------------------------------------------------------------------------------------ EXPOSURE LOGSHEET ID = 2248c [ 4] ------------------------------------------------------------------------------------------------------------------------------------ 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |10 | 11 | 12 |13 |14| 15 ------------------------------------------------------------------------------------------------------------------------------------ Line | Seq | Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | S/N |Flx|Pr| Special Number | Name | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| |Rel. Time|Ref| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 1 4U1728-16 FOS/BL ACQ/ 4.3 MIRROR BRIGHT=210000 001 11S 1 01 ONBOARD ACQ FOR 2 BINARY CYCLE 1 ------------------------------------------------------------------------------------------------------------------------------------ 2 4U1728-16 FOS/BL ACCUM 1.0 G130H 1150- 001 5760S 1 01 CYCLE 1 1608 ------------------------------------------------------------------------------------------------------------------------------------ 3 4U1728-16 FOS/RD ACQ/ 4.3 MIRROR BRIGHT=330000 001 11S 1 01 ONBOARD ACQ FOR 4 BINARY CYCLE 1 ------------------------------------------------------------------------------------------------------------------------------------ 4 4U1728-16 FOS/RD ACCUM 1.0 G190H 1650- 001 3456S 1 01 CYCLE 1 2311 ------------------------------------------------------------------------------------------------------------------------------------ 5 4U1728-16 FOS/RD ACCUM 1.0 G270H 2230- 001 749S 1 01 CYCLE 1 3281 ------------------------------------------------------------------------------------------------------------------------------------ 6 4U1735-44 FOS/BL ACQ/ 4.3 MIRROR BRIGHT=66000 001 11S 1 01 ONBOARD ACQ FOR 7 BINARY CYCLE 1 ------------------------------------------------------------------------------------------------------------------------------------ 7 4U1735-44 FOS/BL ACCUM 1.0 G130H 1150- 001 4300S 1 01 CYCLE 1 1608 ------------------------------------------------------------------------------------------------------------------------------------ 8 4U1735-44 FOS/RD ACQ/ 4.3 MIRROR BRIGHT=140000 001 11S 1 01 ONBOARD ACQ FOR 9 BINARY CYCLE 1 ------------------------------------------------------------------------------------------------------------------------------------ 9 4U1735-44 FOS/RD ACCUM 1.0 G190H 1650- 001 8064S 1 01 CYCLE 1 2311 ------------------------------------------------------------------------------------------------------------------------------------ 10 4U1735-44 FOS/RD ACCUM 1.0 G270H 2230- 001 1440S 1 01 CYCLE 1 3281 ------------------------------------------------------------------------------------------------------------------------------------ 11 4U1822-37 FOS/BL ACQ/ 4.3 MIRROR BRIGHT=330000 001 11S 1 01 ONBOARD ACQ FOR 12 BINARY CYCLE 1 ------------------------------------------------------------------------------------------------------------------------------------ 12 4U1822-37 FOS/BL ACCUM 1.0 G130H 1150- 001 1498S 1 01 CYCLE 1 1608 ------------------------------------------------------------------------------------------------------------------------------------ 13 4U1822-37 FOS/RD ACQ/ 4.3 MIRROR BRIGHT=330000 001 11S 1 01 ONBOARD ACQ FOR 14 BINARY CYCLE 1 ------------------------------------------------------------------------------------------------------------------------------------ 14 4U1822-37 FOS/RD ACCUM 1.0 G190H 1650- 001 980S 1 01 CYCLE 1 2311 ------------------------------------------------------------------------------------------------------------------------------------ 15 4U1822-37 FOS/RD ACCUM 1.0 G270H 2230- 001 260S 1 01 CYCLE 1 3281 ------------------------------------------------------------------------------------------------------------------------------------ Summary Form for Proposal 2248c [ 5] Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Configurations FOS/BL FOS/RD ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ/BINARY ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters BRIGHT=210000 BRIGHT ------------------------------------------------------------------------------------------------------------------------------------ Proposal for GO ------------------------------------------------------------------------------------------------------------------------------------ S/C Hours 9.60 ------------------------------------------------------------------------------------------------------------------------------------ Scientific Category STAR ------------------------------------------------------------------------------------------------------------------------------------ Scientific Sub-category ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements ONBOARD ACQ FOR 2; CYCLE 1 ONBOARD ACQ FOR 4; CYCLE 1 ONBOARD ACQ FOR 7; CYCLE 1 ONBOARD ACQ FOR 9; CYCLE 1 ONBOARD ACQ FOR 12; CYCLE 1 ONBOARD ACQ FOR 14; CYCLE 1 ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G130H G190H G270H ------------------------------------------------------------------------------------------------------------------------------------ Target Names 4U1728-16 GX9+9 4U1735-44 4U1822-37 ------------------------------------------------------------------------------------------------------------------------------------