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IAUC 7096: GRB 990123; 1999J; R CrB

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                                                  Circular No. 7096
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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GRB 990123
     R. Lachaume and O. Guyon, Institut d'Astrophysique, Paris,
report their locating the optical candidate at the expected
position (cf. IAUC 7094, 7095) on two 30-min CCD exposures with the
1.2-m telescope of the Observatoire de Haute Provence, yielding the
following magnitudes (from nine USNO A2.0 catalogue stars), with
1-sigma uncertainties of +/- 0.15 mag:  Jan. 24.15 UT, B = 18.40;
24.17, R = 19.45.
     E. Ofek and E. M. Leibowitz, Tel Aviv University, write: "From
four CCD frames of the object taken at the Wise Observatory between
Jan. 24.0617 and 24.1162 UT, we have determined an average R
magnitude of 19.87 +/- 0.2, with calibration based on four USNO
A2.0 stars.  The decay parameter in the R band over that time
interval is -1.9 +/- 0.1.  On Jan. 24.0625, the color index of the
object was B-R = -0.48 +/- 0.25."
     D. D. Kelson, Department of Terrestrial Magnetism, Carnegie
Institution of Washington; G. D. Illingworth, University of
California at Santa Cruz (UCSC); M. Franx, University of Leiden; D.
Magee, UCSC; and P. G. van Dokkum, Kapteyn Astronomical Institute,
Groningen, report: "Three 10-min spectra were taken of the proposed
optical counterpart to GRB 990123 (IAUC 7094) with the Keck II 10-m
telescope on Jan. 24.6 UT.  The spectra show the following
ultraviolet absorption lines:  Fe II (234.4, 237.5, and 238.3 nm),
Fe II (258.7 and 260.0 nm), Mg II (279.6 and 280.3 nm), and Mg I
(285.2 nm).  The redshift is z = 1.61.  No strong emission lines
were detected between 460 and 920 nm."

     Further to the item on IAUC 7087 regarding the variable in the
Large Magellanic Cloud, A. Becker writes that on Jan. 17.672 UT, it
appeared to be near maximum brightness at R = 16.8, V = 17.
Discussions between Becker and P. Garnavich (Center for Astrophysics)
suggest that the spectrum seems to be most consistent with a
peculiar type-Ia supernova, similar to SN 1991T.  Garnavich finds a
redshift of 10 000 +/- 2000 km/s.  The spectrum is available at

     Visual magnitude estimates:  1998 Dec. 5.24 UT, 7.9 (A.
Pereira, Cabo da Roca, Portugal); 1999 Jan. 5.23, 7.5 (Pereira);
14.17, 8.0 (K. Hornoch, Lelekovice, Czech Rep.); 18.27, 8.5
(Pereira); 21.25, 9.3 (P. Schmeer, Bischmisheim, Germany); 23.25,
9.5 (Pereira); 23.25, 9.7 (Schmeer).

                      (C) Copyright 1999 CBAT
1999 January 24                (7096)            Daniel W. E. Green

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