Central Bureau for Astronomical Telegrams
IAUC 3254: SN IN MCG -5-9-22; X-RAY EMISSION FROM HB3; OBJECT IN FIELD OF 2S 1702-363
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Circular No. 3254
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM Telephone 617-864-5758
SUPERNOVA IN MCG -5-9-22
V. M. Blanco, Cerro Tololo Interamerican Observatory, communicates
that F. Schweizer and M. Phillips have discovered a supernova
15" east and 10" north of the nucleus of the fourteenth-magnitude
galaxy MCG -5-9-22 (R.A. = 3h40m07s, Decl. = -28o01'.2, equinox 1950.0).
The supernova lies in a spiral arm and was of blue magnitude 18.5 +/-
1.0 on Aug. 14.4 UT. R. I. Klein and R. A. Chevalier, Kitt Peak
National Observatory, note that the galaxy lies 2o to the south-southeast
of the position of an x-ray burst observed on Feb. 2,
which they attribute to a type II supernova (cf. Klein and
Chevalier 1978, Astrophys. J. 223, L109). However, HEAO-2 experimenters
F. Cordova and G. Garmire, California Institute of Technology,
inform us that the centroid of the error box for the x-ray transient
- not necessarily burstlike in character - is at R.A. = 3h36m11s,
Decl. = -25o46'.1 (equinox 1950.0); the corners of the error box (3-sigma)
are located at R.A. = 3h22m56s, Decl. = -26o19'.2; 3h48m05s, -24o23'.6;
3h49m18s, -25o08'.6; 3h24m00s, -27o05'.0, apparently precluding
identification with the supernova. The x-ray transient was detected on
Feb. 2.74 and 2.81 UT at an observed intensity of (4.8 +/- 0.7) x
10**-11 erg cm**-2 s**-1 on each occasion; on Feb. 1 and 3 there was no
x-ray emission at a 1-sigma level of 1.2 x 10**-11 erg cm**-2 s**-1
X-RAY EMISSION FROM HB3
C. M. F. Galas, University of Calgary; and I. R. Tuohy and G.
Garmire, California Institute of Technology, report the discovery
of soft x-ray emission from the supernova remnant HB3 by the HEAO-A2
low-energy detectors. The preliminary flux in the energy range
0.6 to 2.2 keV is (6.4 +/- 0.7) x 10**-11 erg cm**-2 s**-1. No flux was
detected below 0.6 keV. The error box is centered in the northwest
part of the supernova remnant and includes the optical filaments
which may be associated with HB3. There is no evidence for any
angular extension of the source.
OBJECT IN FIELD OF 2S 1702-363
I. S. Glass and N. W. Feast, South African Astronomical
Observatory, report: "Continued observation of the infrared object in
the 2S 1702-363 field shows it to have brightened 0.76 magnitude at
J and less at longer wavelengths in 100 days. We think it is
probably a Mira variable with about six magnitudes of visual absorption."
1978 August 15 (3254) Daniel W. E. Green
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