Circular No. 6805 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) GRB 980109 J. in 't Zand and J. M. Muller, Space Research Organisation, Utrecht; L. Piro, L. Di Ciolo, A. Coletta, S. Rebecchi, and G. Gennaro, BeppoSAX Science Operation Center, Telespazio, Rome; M. Feroci, Istituto di Astrofisica Spaziale, CNR, Rome; and F. Frontera, Istituto Tecnologie e Studio Radiazioni Extraterrestri, CNR, Bologna, report on behalf of the BeppoSAX team: "A gamma-ray burst (Bacodine trigger 6564) has been detected by the BeppoSAX Gamma-Ray burst Monitor on Jan. 9.05024 UT. A quick-look analysis shows a single-peak gamma-ray burst lasting about 25 s with a peak intensity of 550 counts/s. The gamma-ray burst was also detected by the Wide Field Camera WFC2 with a peak flux of about 0.8 Crab. The position given by an off-line analysis is R.A. = 0h25m56s, Decl. = -63o01'.4 (equinox 2000.0). The event was detected in a part of the orbit when the satellite was in a very unfavorable attitude control configuration, resulting in a conservative 99- percent error radius of 10'. A BeppoSAX Narrow Field follow-up observation will not be performed. Observations at all wavelengths are solicited." (C) Copyright 1998 CBAT 1997 January 9 (6805) Daniel W. E. Green ////////////////////////////////////////////////////////////////////////// Circular No. 6808 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) GRB 980109 K. C. Sahu, Space Telescope Science Institute; and C. Sterken, University of Brussels, report: "The field of GRB 980109 (cf. IAUC 6805) was imaged with the European Southern Observatory's Dutch 0.91-m telescope at La Silla on Jan. 12.04 and 13.03 UT using a Gunn i filter, and on Jan. 10.11, 11.04, 12.06, and 13.06 using a V filter. The image size is about 3'.7 x 3'.7, and single images centered on the position of the GRB were taken. On Jan. 10 and 11, the observing conditions were poor, the exposure times were 20 min, and the limiting magnitude was about 18.5. These images show no new source when compared with the ESO/Digital Sky Survey fields. On Jan. 12 and 13, the exposure time was 30 min for each image, the sky was photometric, and limiting magnitude of the i images was about 21 (at least 1 mag fainter than the limiting magnitude of the DSS fields). As a result, several new sources are seen, but none of these sources has varied by more than the measurement uncertainty of about 0.2 mag during this 1-day interval. These results indicate that, if the optical counterpart were brighter than I = 20 (as in the case of GRB 970508; cf. IAUC 6654), it lies beyond 1'.5 from the center of the BeppoSAX error box." (C) Copyright 1998 CBAT 1998 January 15 (6808) Daniel W. E. Green ////////////////////////////////////////////////////////////////////////// From udalski@ogle.ctio.noao.edu Fri Jan 16 19:00:59 1998 From: udalski@ogle.ctio.noao.edu (Andrzej Udalski) GRB980109 field was observed by the OGLE collaboration with the 1.3-m Warsaw telescope at the Las Campanas Observatory, Chile on Jan. 10.06, 10.18, 11.05, 12.05 and 16.05, 1998. Ten 900 sec I-band exposures were collected. The field size was 14.2 by 14.2 arcmins covering almost entire error box. None fading or variable stellar-like object was detected up to detection limit of I ~ 21 mag and variability threshold of 0.4 mag.