Central Bureau for Astronomical Telegrams
IAUC 6911: Var STAR NEAR NGC 4013 = 1989Z?; NGC 6814
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Circular No. 6911
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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VARIABLE STAR NEAR NGC 4013 = SUPERNOVA 1989Z?
D. Bettoni, Padua Astronomical Observatory, reported her
discovery of a possible supernova (mag about 12) on an unfiltered
CCD image obtained of NGC 4013 on May 18.91 UT with the 1.82-m
Asiago telescope; the star was confirmed on an image taken on May
20.02. The star lies along the dust lane, about 7" east and 8"
north of the galaxy nucleus, which is very flattened and difficult
to define because of the strong dust absorption. The position is
very similar to that of the reported SN 1989Z (cf. IAUC 5162),
which was reported more than a year after the single observation
and was never confirmed. Bettoni adds: "A spectrum taken on May 20
at the Nordic Optical Telescope by J. Hjorth and S. Benetti
indicates this to be a star of spectral type A with negligible
redshift and no P-Cyg effect. Further examination of images of
this galaxy in the literature shows that the star is absent (or
very faint) in an image taken in April 1989 with the Lowell 1.1-m
telescope (Frey et al., NASA/IPAC Extragalactic Database images),
and it is faint (mag about 17) in an image from March 1996 taken
with the 2.42-m Hawaii telescope (Tully et al. 1996, A.J. 112,
2471). It is probably a foreground variable star of as-yet-
undetermined type. I suspect that this is the same star that was
reported by Shaw on IAUC 5162."
NGC 6814
K. Mukai, Goddard Space Flight Center (GSFC), NASA, and
Universities Space Research Association; G. Madejski, GSFC and
University of Maryland; and C. Hellier, University of Keele, write:
"We have observed the Seyfert galaxy NGC 6814 with the Rossi X-ray
Timing Explorer. On May 18.54 UT, it was detected at a rate of
about 15 counts/s in 5 PCUs (subject to background uncertainties of
about 5 counts/s), or 3 x 10E-11 erg cmE-2 sE-2 at 2-10 keV. Thus,
NGC 6814 appears to be in an unusually high state, an order of
magnitude brighter than in 1993 May (1.2 x 10E-12 erg cmE-2 sE-1 at
2-10 keV; George et al. 1998, Ap.J. Supp. 114, 73), and arguably
brighter than in any previous x-ray observations. We have also
observed the magnetic cataclysmic variable, V1432 Aql (which
contaminated previous non-imaging x-ray data on the Seyfert),
located 37' away, and confirmed that cross-contamination in our
data is minimal. We will be monitoring both sources at about
4-day intervals until early September (see
http://lheawww.gsfc.nasa.gov/~mukai/v1432.html); coordinated
observations at other wavelengths are strongly encouraged."
(C) Copyright 1998 CBAT
1998 May 21 (6911) Daniel W. E. Green
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