Central Bureau for Astronomical Telegrams
IAUC 6048: X-RAY N IN Sco; 1994W
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Circular No. 6048
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
Telephone 617-495-7244/7440/7444 (for emergency use only)
TWX 710-320-6842 ASTROGRAM CAM EASYLINK 62794505
MARSDEN@CFA or GREEN@CFA (.SPAN, .BITNET or .HARVARD.EDU)
X-RAY NOVA IN SCORPIUS
J. F. Schachter, Smithsonian Astrophysical Observatory, reports:
"We note that virtually the entire quoted BATSE error circle
(IAUC 6046) lies in the Scorpius OB1 association (Perry et al. 1991,
A.Ap. Suppl. 90, 195). A known Einstein Slew Survey x-ray source
not associated with any known O or B star, 1ES 1649-403 (Elvis et
al. 1992, Ap.J. Suppl. 80, 257), lies just at the northwest corner
of Scorpius OB1 and is only 0.47 deg from the quoted BATSE position.
The epoch for our detection was that of the Einstein IPC (1978-
1981). The position of the 1ES source is R.A. = 16h49m07s, Decl. =
-40o20'.4 (equinox 1950.0; 90-percent-confidence error radius of
1'.2). Its unabsorbed flux in the band 0.2-4 keV, assuming a 5-keV
bremsstrahlung spectrum and column density of about 10E22 cmE-2, is
(1.80 +/- 0.44) x 10E-11 erg cmE-2 sE-1. Assuming a distance of 2
kpc, the estimated quiescent luminosity is about 10E34 erg sE-1.
Archival ROSAT PSPC data (during 1991 Feb.-Mar.) show a strong
source near the position of 1ES 1649-403 (although the image's
proximity to an opaque support structure makes a precise determination
of the offset difficult). The two evident ROSAT sources in
the BATSE error circle are associated with early-type stars. We
suggest that 1ES 1649-403 could be the BATSE source seen in
quiescence. Imaging observations at Cerro Tololo are planned in the
next few days."
SUPERNOVA 1994W IN NGC 4041
C. M. Gaskell, Department of Physics and Astronomy, University
of Nebraska, writes: "The descriptions of the spectrum of SN 1994W
(IAUC 6046) closely match the appearance of SN 1984E in spectra
taken by me at maximum light. The narrow hydrogen lines in SN
1984E disappeared within a few weeks, presumably when the blast
wave overtook the circumstellar shell (Henry and Branch 1987, PASP
99, 112; Gaskell and Keel 1988, in Supernova 1987A in the Large
Magellanic Cloud, Cambridge, p. 13). Close monitoring of SN 1994W
would be worthwhile to see if its narrow lines suffer a similar fate."
Further visual magnitude estimates (cf. IAUC 6044): Aug. 3.90
UT, 13.6 (G. Cortini and M. Villi, Mt. Colombo, Italy); 7.23, 13.5
(C. E. Spratt, Victoria, BC, Canada).
1994 August 8 (6048) Daniel W. E. Green
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