Central Bureau for Astronomical Telegrams

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IAUC 7392: 2000bg; XTE J1118+480

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                                                  Circular No. 7392
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)
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Phone 617-495-7244/7440/7444 (for emergency use only)


SUPERNOVA 2000bg IN NGC 6240
     Y. Sato and W. D. Li, University of California at Berkeley, on
behalf of the Lick Observatory Supernova Search (cf. IAUC 6627,
7126), report the discovery with the 0.8-m Katzman Automatic
Imaging Telescope (KAIT) of an apparent supernova on unfiltered
images taken on Apr. 1.5 and 2.5 UT, both with mag about 17.4.  SN
2000bg is located at R.A. = 16h52m58s.13, Decl. = +2 23'50".5
(equinox 2000.0), which is 11".4 west and 12".0 south of the
nucleus of NGC 6240.  An unfiltered image taken on Mar. 23.5 showed
nothing at the position of the new object (limiting mag about 19.0).


XTE J1118+480
     M. Garcia, W. Brown, M. Pahre, and J. McClintock, Harvard-
Smithsonian Center for Astrophysics; P. Callanan, University
College, Cork; and P. Garnavich, University of Notre Dame, report:
"Optical spectroscopy of XTE J1118+480 on Mar. 31 UT reveals a
spectrum typical of an x-ray nova in outburst (e.g., Shrader et al.
1994, Ap.J. 434, 698).  A series of spectra obtained with the F.L.
Whipple Observatory (FLWO) 1.5-m telescope (+ FAST spectrograph)
show the following emissions, equivalent widths, and FWHM (accurate
to 10 percent):  H-alpha, 0.19 nm, 2200 km/s; H-beta, 0.01, --; He
II 468.6-nm, 0.12, 2690.  The H-alpha FWHM that we find in this
x-ray nova is approximately equal to the largest seen in quiescent
blackhole x-ray novae.  The H-alpha line shows two blueward
absorption features, and the H-beta line shows redward and blueward
absorption features.  The Na D 589.0-nm line has an equivalent
width of 0.004 nm, indicating very low interstellar absorption.
The column density out of the plane in this direction (Dickey and
Lockman 1990, Ann. Rev. Astron. Ap. 28, 215) corresponds to E(B-V)
about 0.024.  Differential V-band photometry from the FLWO 1.2-m
telescope, relative to the USNO-A2.0 star at R.A. = 11h18m40s.65,
Decl. = +48o03'25".8 (equinox 2000.0; V = 10.91) yields magnitudes
of 12.80(0.1) and 13.05(0.1) on Mar. 31.151 and 31.396,
respectively.  The surprisingly low x-ray-to-optical flux ratio
(i.e., V about 13, F_x about 40 mCrab; cf. IAUC 7389) may be due to
a nearly edge-on viewing angle."
     G. Masi, Ceccano, Italy, provides the following position for
the optical counterpart to XTE J1118+480 (cf. IAUC 7390) from ten
co-added 25-s unfiltered CCD images:  R.A. = 11h18m10s.85, Decl. =
+48o02'12".9 (equinox 2000.0; twelve USNO-A2.0 reference stars,
mean residual 0".2); the star's magnitude was 13.0 on Apr. 1.825 UT
(limiting mag about 18).

                      (C) Copyright 2000 CBAT
2000 April 3                   (7392)            Daniel W. E. Green

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