Central Bureau for Astronomical Telegrams
IAUC 6321: GRO J1744-28
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Circular No. 6321
Central Bureau for Astronomical Telegrams
INTERNATIONAL ASTRONOMICAL UNION
Postal Address: Central Bureau for Astronomical Telegrams
Smithsonian Astrophysical Observatory, Cambridge, MA 02138, U.S.A.
IAUSUBS@CFA.HARVARD.EDU or FAX 617-495-7231 (subscriptions)
BMARSDEN@CFA.HARVARD.EDU or DGREEN@CFA.HARVARD.EDU (science)
Phone 617-495-7244/7440/7444 (for emergency use only)
GRO J1744-28
P. Blanco, University of California, San Diego; C. Lidman,
European Southern Observatory (ESO); and K. Glazebrook, Anglo-
Australian Observatory, report photometry in the K band (2.2
microns) for objects in the vicinity of the radio-source candidate
for GRO J1744-28 (IAUC 6307, 6308): "These measurements were made
on a co-added image (600 s total exposure) taken on Feb. 8 UT at
the ESO 2.2-m telescope (+ IRAC2); this image provided the
preliminary K-band flux and source identifications reported on IAUC
6315. Using the same nomenclature, we have determined the
following K magnitudes: star A, 13.1; star B, 14.0; star C, 13.3;
star D, 11.3. At this wavelength, 0.0 mag corresponds to 620.0 Jy.
To aid calibration in the ongoing searches for near-infrared
variability, we also report magnitudes for three nearby isolated
stars in our image: R.A. = 17h44m34s.0, Decl. = -28o45'07" (equinox
2000.0), K = 11.86; position end figures 37s.3, 50", 11.75; 37s.6,
12", 11.88. Although our absolute fluxes have uncertainties of +/-
0.25 mag, photometry of sources A-D relative to these brighter
stars should be accurate to +/-0.1 mag, except for star B (+/-0.3
mag), which is faint and confused with star D."
G. V. Jung and B. F. Phlips, Universities Space Research
Association; J. D. Kurfess, J. E. Grove, M. S. Strickman, W. N.
Johnson, C. D. Dermer, and G. H. Share, Naval Research Laboratory
(NRL); and S. J. Sturner, NRL and National Research Council, on
behalf of the Gamma Ray Observatory OSSE team, report: "OSSE has
observed the 467-ms pulsed emission from the bursting x-ray pulsar
GRO J1744-28 (IAUC 6285), in both the steady source and during
bursts. Using the pulsar ephemeris supplied by BATSE (M. Finger,
private communication), we epoch-folded and co-added data from the
brightest 2 s of each burst in a sample of 104 bursts observed by
OSSE between Jan. 18 and 30. We find that the pulsed emission
during the bursts lags the non-bursting pulsed emission; the lag
amounts to 0.155 +/- 0.007 of a pulsar period at the peak of the
burst. The magnitude of the phase lag follows the average
intensity profile of the burst sample. This result suggests that
the burst-emitting region is physically offset from the region that
produces the persistent emission, which could be caused by
azimuthal asymmetries from accreting matter constrained to move
along different field lines."
(C) Copyright 1996 CBAT
1996 February 21 (6321) Daniel W. E. Green
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