SUMMARY OF PROPOSAL 42054
DR. CRAIG R. ROBINSON
UNIVERSITIES SPACE RESEARCH ASSOCIATION
AL USA 35812
HUNTSVILLE
ES-84 USRA, NASA/MSFC
E-mail: ROBINSON@SSL.MSFC.NASA.GOV Tel: 205-544-8920 Fax: 205-544-5800
Medium: 2GB8MM
Subject: X-RAY BINARIES
Title: X-RAY EMISSION FROM THE SOFT X-RAY TRANSIENT AQUILA X-1
Abstract:
The soft X-ray transient Aquila X-1, due to its proximity and low absorption, has
now been unambiguously identified several times as a source of X-rays in quiescence
with the ROSAT PSPC and HRI. The quiescent spectrum, poorly constrained, appears
distinctly different from the outburst spectrum. No observations have been obtained
of Aql X-1 with the energy range and resolution necessary to determine the
quiescent-state emission shape. We plan a single pointing. If in quiescence (highly
likely), ASCA will observe the soft X-ray components and may reveal harder emission,
as found in Cen X-4, perhaps from separate surface or shock-driven emission. If in
outburst, we will use simultaneous BATSE data, which has already shown a hard X-ray component, to model the broad-band spectrum.
Co-Is:
1 YASUO TANAKA ISAS JAPAN
(No Co-I contact data)
2 FUMIAKI NAGASE ISAS JAPAN
3 ALAN HARMON NASA/MSFC USA
4 WILLIAM PACIESAS UAH USA
5 SHUANG-NAN ZHANG USRA CHINA
6 BRAD RUBIN USRA USA
7 COLLEEN WILSON NASA/MSFC USA
8 MARCO TAVANI COLUMBIA ITALY
9 PHILIP, ERIC KAARET, FORD COLUMBIA USA
10 K. ASAI ISAS JAPAN
Target Name PRI RA Dec Time TC Off GIS SIS_Cts Obs
------------------- --- -------- -------- ---- -- --- --- ------- ---
AQUILA X-1 0 287.8208 0.5800 40 N N P 480.00000 1
REMARKS: ESTIMATED COUNT RATES ARE GIVEN IN TABLE I. THE SIS COUNT RATE ON TARGET
SUMMARY PAGE IS AN EXTRAPOLATION DURING OURBURST. IT'S LIKELY THE RATE
WILL BE LOWER (SEE PROPOSAL) REQUIRING REQUESTED TIME.