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IAUC 5851: GRO J1008-57; GRO J0422+32; R CrB

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                                                  Circular No. 5851
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)


GRO J1008-57
     Y. Tanaka, Institute of Space and Astronautical Science, on
behalf of the ASCA Team, communicates:  "The hard x-ray transient
pulsar GRO J1008-57 (IAUC 5836, 5838) was observed with ASCA between
Aug. 5.57 and 6.17 UT.  The source was detected with an average
intensity of about 20 mCrab in the range 1-10 keV.  The source
position was determined to be R.A. = 10h09m46s, Decl. = -58o17'38"
(equinox 2000.0; error radius 1').  The intensity was modulated
with a period of 93.6 s, which is consistent with that reported by
the Gamma Ray Observatory.  The x-ray pulse profile has a double-
peak structure with a well-defined, sharp intensity minimum and a
less prominent secondary minimum.  The spectrum is hard and can be
represented by a power law with a photon index of about 1 and a
significant absorption measure of about 1.3 x 10E22 cmE-2.  The energy
flux is about 6 x 10E-10 erg cmE-2 sE-1 in the range 2-10 keV."


GRO J0422+32
     Tanaka also reports: "Following the notices of an optical flux
increase of GRO J0422+32 (IAUC 5842), we performed an x-ray
observation of the source with ASCA on Aug. 26 UT.  We found an x-ray
source at the position of the previously identified optical counterpart
of GRO J0422+32 with an intensity of about 1 mCrab, or about 2
x 10E-11 erg cmE-2 sE-1 in the range 0.5-10 keV.  The spectrum is
apparently featureless and represented by a power law with a slope
(photon index) of about 1.6."
     D. W. Hoard and S. Wachter, University of Washington; and P.
Garnavich, Dominion Astrophysical Observatory, communicate:  "
Further CCD photometry of the optical counterpart of the soft x-ray
transient GRO J0422+32 has been obtained at the Manastash Ridge
Observatory. The preliminary V magnitudes (+/- 0.06) are:  Aug.
17.45 UT, 15.43; 18.45, 15.40; 19.44, 15.37; 22.43, 15.32; 23.43,
15.23; 24.38, 15.31."


R CORONAE BOREALIS
     This variable has begun to fade in brightness, as indicated by
the following visual magnitude estimates:  Aug. 5.89 UT, 6.0 (A.
Pereira, Cabo da Roca, Portugal); 18.88, 6.0 (Pereira); 23.13, 6.1
(W. G. Dillon, Missouri City, TX); 27.15, 6.4 (Dillon); 27.87, 6.6
(Pereira); 28.83, 6.7 (H. Bengtsson, Hisings Backa, Sweden); 29.9,
6.9 (M. Tombelli, Montelupo, Italy).


1993 August 30                 (5851)            Daniel W. E. Green

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