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IAUC 8056: XTE J1720-318; 2002ka; 2002jy

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                                                  Circular No. 8056
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)
CBAT@CFA.HARVARD.EDU (science)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)


XTE J1720-318
     C. B. Markwardt, University of Maryland and Goddard Space
Flight Center (GSFC); and J. H. Swank, GSFC, write: "The best x-ray
position of the transient XTE J1720-318, derived from RXTE PCA
scans on Jan. 15.06 UT, is R.A. = 17h20m00s, Decl. = -31o44'.8
(equinox 2000.0).  The estimated systematic uncertainty is 0'.5,
consistent with the radio position (IAUC 8054).  The x-ray flux
declined 30 percent between Jan. 14 and 19, from a maximum of 1.0 x
10**-8 erg cm**-2 s**-1 (2-10 keV).  The soft spectrum and low
high-frequency variability are consistent with the high soft states
of black-hole candidates."
     D. Kato and T. Nagata, Nagoya University, on behalf of the
InfraRed Survey Facility (IRSF)/Simultaneous three-color InfraRed
Imager for Unbiased Survey (SIRIUS) team of Nagoya University and
the National Astronomical Observatory of Japan; T. Kato and M.
Uemura, Kyoto University; and H. Yamaoka, Kyushu University, report
on near-infrared (J, H, K_s) imaging of the field of the x-ray
transient XTE J1720-318 (IAUC 8050) with the IRSF (which consists
of the Nagoya-South African Astronomical Observatory 1.4-m
telescope + SIRIUS) at Sutherland on Jan. 18.1 and 19.1 UT.  A
likely infrared counterpart was detected at R.A. = 17h19m59s.00,
Decl. = -31o45'01".2 (equinox 2000.0; about 150 2MASS reference
stars; rms error 0".2), located within 1".7 of the proposed radio
counterpart (IAUC 8054).  The new object is invisible on public
2MASS images; any definite identification would require further
follow-up observations, since the brightness of the new object is
close to the limiting magnitudes of the 2MASS survey.  Magnitudes
for the likely infrared counterpart of XTE J1720-318 are:  Jan.
18.1, J = 16.73 +/- 0.02, H = 15.91 +/- 0.03, K_s = 15.31 +/- 0.03;
19.1, 16.68 +/- 0.02, 15.80 +/- 0.03, 15.27 +/- 0.05.


SUPERNOVA 2002ka
     W. M. Wood-Vasey, Lawrence Berkeley National Laboratory,
reports that prediscovery NEAT observations of SN 2002ka (cf. IAUC
8038), taken with the NEAT 1.2-m reflector at Haleakala, yield
unfiltered magnitudes of 15.7 on 2002 Dec. 13.7 UT and 15.8 on Dec.
19.1.


SUPERNOVA 2002jy IN NGC 477
     Unfiltered CCD magnitude estimates by T. Vanmunster, Landen,
Belgium:  2002 Dec. 26.817 UT, 15.9; 2003 Jan. 8.733, 16.6.

                      (C) Copyright 2003 CBAT
2003 January 24                (8056)            Daniel W. E. Green

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