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IAUC 7101: RX J0052.1-7319, XTE J0111.2-7317; 1998co; 1999B

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                                                  Circular No. 7101
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 617-495-7244/7440/7444 (for emergency use only)

RX J0052.1-7319 AND XTE J0111.2-7317
     G. L. Israel and L. Stella, Osservatorio Astronomico, Rome; S.
Covino and S. Campana, Osservatorio Astronomico di Brera, Milan;
and S. Mereghetti, Istituto Fisica Cosmica e Tecnologie Relative,
CNR, Milan, report the discovery with the Danish 1.54-m telescope
at the European Southern Observatory of the optical counterparts of
the two recently discovered x-ray pulsar transients in the Small
Magellanic Cloud:  "We have identified the likely optical
counterpart of RX J0052.1-7319 (IAUC 7081):  a B-type star with R =
14.54 +/- 0.03 and V-R = +0.08 +/- 0.04 that is located at R.A. =
0h52m14s.0, Decl. = -73o19'18" (equinox 2000.0; estimated
uncertainty 1").  A 1000-s optical spectrum taken on Jan. 19 (range
350-900 nm, resolution 1.1 nm) shows an H-alpha emission line (EW =
1.2 nm), clearly indicating the Be nature of the star.  Within the
10"-radius x-ray error circle, there is another object (R = 16.05
+/- 0.05) that does not show any emission lines.  The field of XTE
J0111.2-7317 (IAUC 7048), a currently active x-ray pulsar
transient, was observed with the same instrument on Jan. 19,
revealing two bright stars within the 30" error circle (IAUC 7062);
the fainter one is a B-type star (R = 15.29 +/- 0.03, V-R = +0.06
+/- 0.04) located at R.A. = 1h11m08s.4, Decl. = -73o16'46" (1"
uncertainty).  A 1000-s spectrum (range 350-900 nm, resolution 1.4
nm) revealed strong H-alpha and H-beta emission lines (EW = 2.1 and
0.1 nm, respectively), indicating that this source is the likely
counterpart of the x-ray transient.  The brighter star (R = 14.30
+/- 0.03) does not show any emission lines.  No other objects
brighter than R = 17.3 are found within the error circle.  Another
B-type star (R = 14.55 +/- 0.03, V-R = +0.05 +/- 0.04), located at
R.A. = 1h11m25s.9, Decl. = -73o17'27" (30" outside the x-ray error
circle), shows strong H-alpha and H-beta emission lines (EW = 3.6
and 0.3 nm, respectively)".

SUPERNOVA 1998co IN NGC 7131
     Corrigendum.  The following position by E. Prosperi from a CCD
frame taken on Jan. 26.736 UT corrects that on IAUC 7083, line 4:
R.A. = 21h47m36s.24, Decl. = -13o10'52".3.

     Unfiltered CCD magnitude estimates:  Jan. 21.716 UT, 17.3 +/-
0.2 (L. Kiss, K. Sarneczky, and E. Barat, Piszkesteto, Konkoly
Observatory); 21.88, 17.3 (S. Moretti, S. Tomaselli, and G.
Cortini, Forli, Italy).

                      (C) Copyright 1999 CBAT
1999 February 1                (7101)            Daniel W. E. Green

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