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IAUC 7116: 4U 0115+63; 1ES 1426+428; 1999aa

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                                                  Circular No. 7116
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7244/7440/7444 (for emergency use only)


4U 0115+63
     R. B. Wilson and B. A. Harmon, Marshall Space Flight Center,
NASA; and M. H. Finger, Universities Space Research Association,
report for the Compton GRO BATSE team:  "An outburst is currently
being detected from the Be/x-ray pulsar 4U 0115+63.  Pulsations
from the source were first detected on Feb. 22 at a frequency of
0.27666170(75) Hz, assuming the binary-orbit ephemeris of Bildsten
et al. (1997, Ap.J. Suppl. 113, 367).  The rms average pulsed
fluxes in the energy range 20-50 keV on Feb. 22 and 23 were 0.132
+/- 0.030 and 0.177 +/- 0.024 keV cmE-2 sE-1, respectively.  The
source is detected by earth occultation after Feb. 18, reaching an
average intensity between Feb. 20 and 23 of 0.31 +/- 0.08 keV cmE-2
sE-1 in the band 20-50 keV."
     Corrigenda.  On IAUC 3510, 5990, 5999, 6266, 6272, 6450, and
6451, this object was erroneously given as "4U 0115+634".


1ES 1426+428
     G. Ghisellini, G. Tagliaferri, Osservatorio Astronomico di
Brera, Milan; and P. Giommi, BeppoSAX, Rome, report:  "The BL Lac
object 1ES 1426+428 was observed by BeppoSAX starting on Feb. 8.865
UT.  Preliminary results indicate a hard x-ray spectrum, with
energy spectral index about 0.85 in the band 0.1-10 keV.  The
spectrum at higher energies, up to 100 keV, shows an excess with
respect to the extrapolation from the band 2-10 keV.  The 2-10-keV
flux is about 2 x 10E-11 erg cmE-2 sE-1.  Examination of the All
Sky Monitor XTE light curve shows that the source remained in a
very active x-ray state also after the BeppoSAX observation.
Since the entire x-ray spectrum of this source is believed to be
due to the synchrotron process, we foresee an intense TeV emission.
Observations in the TeV and optical bands are strongly encouraged."


SUPERNOVA 1999aa IN NGC 2595
     Magnitude estimates:  Feb. 15.855 UT, 14.9 (D. Hanzl, Brno,
Czech Republic; CCD); 17.911, 15.0 (K. Hornoch, Lelekovice, Czech
Republic; visual); 18.897, 14.8 (Hornoch); 22.698, 15.2 (S.
Yoshida and K. Kadota, Ageo City, Japan; CCD); 23.810, 14.8
(Hornoch).

                      (C) Copyright 1999 CBAT
1999 March 1                   (7116)            Daniel W. E. Green

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