Central Bureau for Astronomical Telegrams

Central Bureau for Astronomical Telegrams -- Image credits

IAUC 6436: GRO J1655-40 AND GRS 1915+105; 1985T; C/1995 O1

The following International Astronomical Union Circular may be linked-to from your own Web pages, but must not otherwise be redistributed (see these notes on the conditions under which circulars are made available on our WWW site).

Read IAUC 6435  SEARCH Read IAUC 6437

View IAUC 6436 in .dvi or .ps format.
IAUC number

                                                  Circular No. 6436
Central Bureau for Astronomical Telegrams
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)
Phone 617-495-7244/7440/7444 (for emergency use only)

GRO J1655-40 AND GRS 1915+105
     B. A. Harmon, C. A. Wilson, M. McCollough, S. N. Zhang, W. S.
Paciesas, and C. R. Robinson report for the BATSE Compton
Observatory Science Team:  "The two superluminal jet sources GRO
J1655-40 and GRS 1915+105 are both being detected strongly in hard
x-rays by BATSE.  GRO J1655-40 was first detected in late May 1996,
but has gradually increased in brightness to an average around 0.6
Crab (20-100 keV) beginning about July 1.  Occasional daily
averages reach 0.9 Crab.  The spectrum is similar to that of
previous outbursts, exhibiting a power law shape to 200 keV with
photon indices of -2.3 to -2.6.  GRS 1915+105 has also become
active again in hard x-rays, and is undergoing a moderately bright
outburst (about 200 mCrab in the band 20-100 keV) which began
around July 4.  This precedes the increased radio flux by about 5
days (IAUC 6432).  Recent increases in hard x-ray flux (around
June 21 and July 4 onward) have been accompanied by spectral
softening.  The spectrum, adequately fit by a power law, has a
spectral index varying between -2.4 and -3.4."

     R. H. McNaught, Anglo-Australian Observatory, reports his
discovery of an apparent supernova on a J plate taken by F. G.
Watson on 1985 June 15 with the U.K. Schmidt telescope, confirmed
on an R/I plate pair taken with the same telescope by M. R. S.
Hawkins on 1985 June 26.  The R plates show the supernova at the
same brightness (mag about 18) on both dates; SN 1985T is slightly
fainter in I than R, relative to nearby stars.  The position of SN
1985T is R.A. = 19h03m28s.54, Decl. = -65o36'12".4 (equinox 2000.0),
which is 22" east and 21" north of the galaxy's center.  No star
appears to mag 21 at this position on U.K. Schmidt J plates taken
on 1975 June 14 and 1986 Sept. 3, or on R plates taken in
1995/1996; likewise, SN 1985T does not appear on the ESO R
(exposure number 5665) or ESO B (number 545) surveys.

     Total visual magnitude estimates:  June 24.58 UT, 5.6 (D.
Seargent, The Entrance, N.S.W., naked eye); July 8.91, 5.6 (J. D.
Shanklin, Versailles, France, 7x50 binoculars); 12.15, 5.7 (J. E.
Bortle, Stormville, NY, 10x50 binoculars); 14.28, 5.9 (C. S.
Morris, Lockwood Valley, CA, 10x50 binoculars); 15.22, 5.5 (R.
Keen, Mt. Thorodin, CO, 3x30 binoculars).

                      (C) Copyright 1996 CBAT
1996 July 16                   (6436)            Daniel W. E. Green

Read IAUC 6435  SEARCH Read IAUC 6437

View IAUC 6436 in .dvi or .ps format.

Our Web policy. Index to the CBAT/MPC/ICQ pages.

Valid HTML 4.01!