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IAUC 7993: 2002gi, 2002gj, 2002gk, 2002gl, 2002gm; SAX J1808.4-3658

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                                                  Circular No. 7993
Central Bureau for Astronomical Telegrams
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
URL http://cfa-www.harvard.edu/iau/cbat.html  ISSN 0081-0304
Phone 617-495-7440/7244/7444 (for emergency use only)

SUPERNOVAE 2002gi, 2002gj, 2002gk, 2002gl, 2002gm
     Further to IAUC} 7977, on behalf of the Supernova Cosmology
Project, R. Knop, Vanderbilt University, reports the discovery of
five supernovae at the Cerro Tololo 4-m telescope (+ Mosaic camera)
during May 6-8, via subtraction of reference images taken Apr.
15-17 (when the 3-sigma limit on each magnitude was R = 24.0,
except limiting mag I = 24.6 for 2002gi).  Spectroscopy and
redshifts (given to 0.001 for host galaxies, to 0.01 for
supernovae) were obtained during May 8-15 with Gemini North (+
GMOS) on Mauna Kea (2002gm) and with the Very Large Telescope (+
FORS1, FORS2) at Paranal (remaining objects).  Photometry of 2002gi
was obtained with the Hubble Space Telescope (+ ACS); the other
supernovae were followed in R and I bands with the WIYN 3.5-m
telescope at Kitt Peak and the 3.5-m Telescopio Nazionale Galileo
and 4.2-m William Herschel Telescope at La Palma.  Each supernova
is within 1" of its host galaxy's center, except for 2002gj (1".5

SN       2002 UT     R.A. (2000.0) Decl.      Mag.      z     Type
2002gi   May  7    13 57 12.3   + 4 33 17    24.1 I   0.912    Ia
2002gj        7    15 36 25.5   + 9 28 18    22.9 R   0.44     I
2002gk        7    15 37 07.5   + 9 36 19    21.3 R   0.21     Ia
2002gl        7    15 43 24.4   + 7 53 58    23.3 R   0.511    Ia
2002gm        8    15 46 57.0   + 8 12 37    22.3 R   0.49     Ia

SAX J1808.4-3658
     C. B. Markwardt, University of Maryland and Goddard Space
Flight Center; J. M. Miller, Harvard-Smithsonian Center for
Astrophysics; and R. Wijnands, University of St. Andrews, report a
new outburst of the millisecond accreting pulsar SAX J1808.4-3658
(cf. IAUC} 7369).  In RXTE PCA scans of the Galactic center on Oct.
13.279 UT, an x-ray source whose position is consistent with SAX
J1808.4-3658 was detected with a flux of 65 mCrab (2-10 keV).  On
Oct. 9.5, the PCA flux was < 0.5 mCrab.  Two minutes of pointed
data detected x-ray pulsations at the frequency 400.953 +/- 0.008
Hz (barycentered).  This frequency is consistent with the known
pulsar spin frequency and orbital Doppler modulation.  The RXTE ASM
instrument detected the source on Oct. 14.30 and 14.37 at fluxes of
105 and 76 mCrab, respectively.  In its 1998 outburst, the source
also exhibited fast radio and optical transients, so
multiwavelength observing is encouraged.

                      (C) Copyright 2002 CBAT
2002 October 15                (7993)            Daniel W. E. Green

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