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IAUC 6488: GX 1+4 AND GRS 1915+105; C/1996 P2

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                                                  Circular No. 6488
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
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)
Phone 617-495-7244/7440/7444 (for emergency use only)


GX 1+4 AND GRS 1915+105
     P. C. Agrawal, B. Paul, A. R. Rao, M. N. Vahia, and J. S.
Yadav, Tata Institute of Fundamental Research, Mumbai; and T. M. K.
Marar, S. Seetha and K. Kasturirangan, ISRO Satellite Centre,
Bangalore, report:  "The x-ray pulsar GX 1+4 was observed with the
Indian X-ray Astronomy Instrument onboard the IRS-P3 satellite
launched from India on Mar. 21.  The instrument consists of three
identical, coaligned, multilayer proportional counters collimated
to a 2 deg x 2 deg field-of-view, with an effective area of about
1200 cmE2.  GX 1+4 was observed during July 10-19 and again on Aug.
16-17.  It was detected with an average countrate of about 90
counts/s (equivalent to 90 mCrab) in the band 2-18 keV during this
period.  X-ray pulsations were weak and detectable only on July 13,
Aug. 16, and 17, the pulse fraction then being 7 +/- 3.5, 20 +/- 5,
and 6 +/- 2 percent, respectively.  The pulses were very broad,
with a duty cycle of about 80 percent on Aug. 16 and 17 and 60
percent on July 13.  The upper limit on the pulsed fraction for all
the other days is 4 percent.  The superluminal x-ray transient GRS
1915+105 was detected with the same instrument on July 24, 25, and
27 as a bright source with an average countrate of about 760
counts/s (760 mCrab) in the band 2-18 keV.  Timing analysis
revealed rapid intensity variations on a timescale of 0.1-0.5 s by
a factor of up to 3.  Strong quasiperiodic oscillations (QPOs) were
detected on all days with a QPO frequency in the range 0.62-0.82
Hz; the QPOs were detected in all three detectors separately.  The
frequency was found to change slowly over a period of hours, and
the QPO fraction varied in the range 10-20 percent.  No hourly or
longer-term variations were detected."


COMET C/1996 P2 (RUSSELL-WATSON)
     Ephemeris continuation to IAUC 6465 (elements MPC 27882):

1996 TT     R. A. (2000) Decl.   Delta     r    Elong. Phase    m1
Oct. 14     1 12.15   -35 56.4   2.499   3.289  135.9   12.2   13.2
     24     1 05.58   -35 21.8   2.632   3.373  131.4   12.8   13.4
Nov.  3     1 00.40   -34 23.9   2.783   3.457  125.7   13.5   13.6
     13     0 56.93   -33 07.4   2.951   3.542  119.3   14.1   13.8
     23     0 55.32   -31 36.9   3.134   3.628  112.4   14.6   14.1
Dec.  3     0 55.49   -29 57.0   3.329   3.713  105.3   14.8   14.3
     13     0 57.32   -28 11.2   3.533   3.799   98.1   14.9   14.5
     23     1 00.62   -26 22.7   3.743   3.885   90.9   14.7   14.8

                      (C) Copyright 1996 CBAT
1996 October 12                (6488)            Daniel W. E. Green

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