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IAUC 7103: XTE J1723-376; AB Aur; 1998S, 1998aq, 1998bu, 1998es, 1999D, 1999E

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                                                  Circular No. 7103
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Mailstop 18, Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
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Phone 617-495-7244/7440/7444 (for emergency use only)


XTE J1723-376
     F. E. Marshall, Goddard Space Flight Center (GSFC); and C. B.
Markwardt, National Academy of Sciences/National Research Council
and GSFC, on behalf of the RXTE Science Operations Center, report
the discovery of a transient x-ray source with quasiperiodic
oscillations (QPO) at 816 Hz with an rms amplitude of 5 percent.
The transient was first seen on Jan. 25.21 UT during a scan with
the PCA on RXTE, with a 2-10-keV flux of 1.5 x 10E-9 erg cmE-2
sE-1.  The QPO were detected during a pointed observation at Jan.
31.1, when the flux was 1.2 x 10E-9 erg cmE-2 sE-1.  The best-fit
source position is R.A. = 17h23m.6, Decl. = -37o39' (equinox
2000.0), with an estimated uncertainty of 2'.  Additional RXTE
observations are planned.


AB AURIGAE
     N. M. Ashok and T. Chandrasekhar, Physical Research Laboratory
(PRL), Ahmedabad; and H. C. Bhatt and P. Manoj, Indian Institute of
Astrophysics (IIA), Bangalore, report:  "AB Aur (HD 31293), the
prototype and one of the brightest Herbig Ae/Be stars, presently
seems to have entered an unusually inactive phase.  A near-infrared
spectrum taken with the 1.2-m telescope (+ Nearinfrared
Imager/Spectrometer + 256x256 HgCdTe NICMOS3 array) at the PRL's
Mt. Abu Observatory on Jan. 9 shows that the Paschen beta  line is
marginally in absorption and the Brackett gamma emission is absent.
Optical linear polarization measurements of AB Aur, made with a
polarimeter on the IIA 1-m telescope at Kavalur on Jan. 15, show
that its degree of polarization (P(V) = 0.8 +/- 0.1 percent, theta
= 70 +/- 3 deg) is now at its highest.  The photometric magnitudes
were V = 7.0 +/- 0.1 on Jan. 15; and J = 7.2 +/- 0.15, H = 6.4 +/-
0.15, K = 6.0 +/- 0.15 on Jan. 9.  While its visual magnitude is at
its brightest, the infrared J, H, K magnitudes are at their
faintest level, indicating substantial decrease in the
near-infrared caused by circumstellar dust."


SUPERNOVAE 1998S, 1998aq, 1998bu, 1998es, 1999D, 1999E
     Unfiltered CCD magnitude estimates by L. Kiss, K. Sarneczky,
and E. Barat, Piszkesteto, Konkoly Observatory:  SN 1998S in NGC
3877, Jan. 23.138 UT, 18.0 +/- 0.4; SN 1998aq in NGC 3982, Jan.
21.999, 19.6 +/- 0.4; SN 1998bu in NGC 3368, Jan. 21.985, 17.7 +/-
0.3; SN 1998es in NGC 632, Jan. 21.706, 15.8 +/- 0.2; SN 1999D in
NGC 3690, Jan. 21.992, 16.6 +/- 0.3; SN 1999E, Jan. 23.156, 16.7
+/- 0.3.

                      (C) Copyright 1999 CBAT
1999 February 2                (7103)            Daniel W. E. Green

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