From quai@cbatmpc.harvard.edu Fri Jun 5 21:11:17 1998 Return-Path: Received: [ from aip.de by abrixas.obs.aip.de (8.8.7/8.8.7) with SMTP id VAA31216 for ; Fri, 5 Jun 1998 21:11:16 +0200 (MET DST)] Received: from cfa.harvard.edu by marlowe (4.1/SMI-4.2-apr170795) id AA16370; Fri, 5 Jun 98 21:11:02 +0200 Received: from cbatmpc.harvard.edu (cbatmpc.harvard.edu [131.142.10.57]) by cfa.harvard.edu (8.8.5/8.7.3) with SMTP id PAA30578 for ; Fri, 5 Jun 1998 15:11:01 -0400 (EDT) Received: by cbatmpc.harvard.edu (SMI-8.6/SMI-SVR4) id PAA28671; Fri, 5 Jun 1998 15:11:00 -0400 Date: Fri, 5 Jun 1998 15:11:00 -0400 From: quai@cbatmpc.harvard.edu (IAUC mailing list) Message-Id: <199806051911.PAA28671@cbatmpc.harvard.edu> To: iau-circulars@aip.de Subject: IAUC 6933: SGR 1900+14; XTE J2012+381; XTE J1748-288 Status: RO Circular No. 6933 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 Phone 617-495-7244/7440/7444 (for emergency use only) SGR 1900+14 B. R. Oppenheimer, J. S. Bloom, S. S. Eikenberry, and K. Matthews, California Institute of Technology, communicate: "We have obtained narrowband 2.2-micron images of the proposed infrared counterpart to SGR 1900+14 (Vrba et al. 1996, Ap.J. 468, 225) on June 3.486 UT, 4.1 days after the recent bursting activity reported on IAUC 6929. Differential photometry of stars 'A' and 'B' (the double M stars) and star 'C' of Vrba et al. yields m_A-m_B = +0.4 +/- 0.1 and m_A-m_C = +4.5 +/- 0.2 mag, consistent with the measurements of Vrba et al. Over the course of 10 min (ten separate frames), no variability was detected in the double M stars to a limit of 0.1 mag." XTE J2012+381 P. Callanan and J. McCarthy, University College, Cork; and M. Garcia and J. McClintock, Harvard-Smithsonian Center for Astrophysics, report: "Observations of the XTE J2012+381 error region (IAUC 6920, 6927) were performed using the Cerro Tololo 1.5-m telescope (+ CIRIM detector) on June 1.36, 2.35, 3.35, and 4.36 UT. The J and K magnitudes of the object near the radio position (IAUC 6924) were 15.0 +/- 0.1 and 14.3 +/- 0.1, respectively. No variability at more than the 10-percent level was observed in the J and K bands between each night. Closer inspection of those images with a FWHM of < 1" reveals an apparent southeast-northwest elongation of this object, indicating that this is a composite image of two stars about 1" apart. This confirms the detection of the faint red companion to USNO 1275.13846761 found by Hynes and Roche (IAUC 6932). As the position of the northwest star is consistent with the improved radio position (IAUC 6932), it may be the true counterpart to the x-ray source. Further observations, especially in conditions of good seeing, are encouraged." XTE J1748-288 B. A. Harmon, M. L. McCollough, C. A. Wilson, S. N. Zhang, and W. S. Paciesas, Marshall Space Flight Center, report for the BATSE Team: "This x-ray transient is being detected with BATSE, with the following average daily fluxes in the bands 20-30 and 50-70 keV: June 3, 150 +/- 65 and 160 +/- 45 mCrab; June 4, 450 +/- 70 and 280 +/- 45 mCrab. There was no detection on June 2 (< 75 mCrab). The spectrum extends to at least 100 keV and softened significantly between June 3 (power-law photon number index -2.2 +/- 0.3) and June 4 (index -2.9 +/- 0.1)." (C) Copyright 1998 CBAT 1998 June 5 (6933) Daniel W. E. Green