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IAUC 4635: GX 1+4; 1988P; SU UMa; 3C 279

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IAUC number

                                                  Circular No. 4635
Central Bureau for Astronomical Telegrams
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
TWX 710-320-6842 ASTROGRAM CAM    Telephone 617-495-7244/7440/7444

GX 1+4
     E. Gotthelf, J. Halpern, and A. Szentgyorgyi, Columbia
University, write:  "An optical spectrum of the x-ray pulsar GX 1+4
obtained using a grism/CCD spectrograph on the Shane 3-m telescope
at Lick Observatory on July 8 UT by R. Becker and D. Helfand
suggests a change in activity of this system.  Comparison with
published spectra (Davidsen et al. 1977, Ap.J. 211, 866) reveals
an absence of previously observed high-excitation forbidden lines.
In particular, the [Fe VII] 608.7-nm line is at least 6 times weaker
than previously reported and the [Fe VII] 572.1-nm, [Fe X] 637.4-nm,
and [O III] 495.9- and 500.7-nm lines are undetected, while the strong
H-alpha and the He I 587.6-, 667.8-, and 706.5-nm lines remain at their
previously reported flux levels to within 15 percent.  We speculate
that the absence of the high-excitation lines is correlated with
the low x-ray state as reported by Makishima et al. (1988, Nature
333, 746)."

     C. Pollas, Observatoire de la Cote d'Azur, writes concerning
the report by Filippenko and Schachter (IAUC 4630):  "Palomar Sky
Survey prints show a faint, diffuse, probable H II region at
approximately the same position as the probable supernova 1988P,
at mag ~ 20-21 on the blue print (~ 20 on the red print).  Our
June 9 (IIIa-J) and 14 (IIa-O) plates show the SN candidate to be
significantly (> 2 mag) brighter than this.  On June 18.96 UT, C.
Buil and E. Thouvenot found SN 1988P at mag 19-19.2 (0.6-m telescope
+ unfiltered CCD, Pic du Midi Observatory)."

     P. Schmeer, Bischmisheim, West Germany, telexes that this object
is undergoing an outburst typical of a supermaximum, as indicated
by the following visual magnitude estimates:  July 25.96 UT, [12.7;
30.98, 11.9; 31.96, 11.5; Aug. 1.09, 11.6; 4.10, 11.5.

3C 279
     A. C. Sadun, Agnes Scott College, reports the following
magnitudes:  May 24 UT, V = 13.58 (0.6-m telescope, Capilla Peak
Observatory, University of New Mexico); May 25.169, V = 11.51 (Capilla
Peak); June 16, V = 13.6, B-V = +0.5 (Table Mountain Observatory
0.6-m telescope).

1988 August 6                  (4635)            Daniel W. E. Green

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