Central Bureau for Astronomical Telegrams
IAUC 5895: 1993af, 1993ag, 1993ah; PSR 0823+26
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Circular No. 5895
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)
SUPERNOVAE 1993af, 1993ag, 1993ah
M. Hamuy, Cerro Tololo Interamerican Observatory; and J. Maza,
University of Chile, report the discovery of three apparent
supernovae on three 20-min unfiltered IIa-O plates taken by G.
Valladares with the CTIO Curtis Schmidt telescope. SN 1993af (mpg
about 17) was discovered by M. Wischnjewsky (University of Chile)
on a plate taken Nov. 15.30 UT; the new object is located 220" east
and 94" north of the nucleus of the spiral galaxy NGC 1808 (R.A. =
5h05m59s, Decl. = -37o34'.7, equinox 1950.0). SN 1993ag (mpg about
18.5) was discovered by R. Antezana (University of Chile) on an
exposure taken Nov. 15.33, and is located about 5" west and 6" south
of the nucleus of an anonymous galaxy at R.A. = 10h01m25s, Decl. =
-35o13'.1. SN 1993ah (mpg about 17) was discovered by Wischnjewsky
on a plate taken on Nov. 16.13, the new object being located 0".5
west and 8" north of the nucleus of the lenticular galaxy ESO
471-27 (R.A. = 23h49m15s, Decl. = -28o14'.6). Confirmation of all
three supernovae was made by L. Ho (University of California,
Berkeley) on CCD B and V images obtained on Nov. 23 with the CTIO
0.9-m telescope.
PSR 0823+26
X. Sun, Institute of High Energy Physics, Beijing; and J.
Trumper, K. Dennerl, and W. Becker, Max-Planck-Institut fur
Extraterrestrische Physik, report: "X-ray emission from the radio
pulsar PSR 0823+26 was detected with the ROSAT PSPC at count rates of
0.0015 +/- 0.0004 and 0.0009 +/- 0.0003 count/s for the broad (0.8-
2.0 keV) and hard (0.5-2.0 keV) bands at confidence levels of 5 and
6 sigma, respectively. The separation between the x-ray and radio
positions of 13" is compatible with the uncertainty of the PSPC
position. There is no other object in the vicinity of the radio
pulsar position in the SIMBAD and NED catalogues, and the Palomar Sky
Survey image also shows that there is no object evident in this
region. We conclude that this is the x-ray emission from the radio
pulsar. The low count rate does not permit a timing analysis, but
assuming a blackbody spectrum and adopting the column density (6.0
x 10E20 cmE-2) and distance (380 pc) derived from the radio
dispersion measure, the energy distribution of photons can be used to
constrain the temperature and luminosity to values close to 0.1 keV
and 1 x 10E30 erg/s. The corresponding size of the emission area
of 1 kmE2 implies that polar cap emission is dominating."
1993 November 23 (5895) Daniel W. E. Green
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