Simultaneous radio and X-ray observations of MXB1837+05 /Ser X-1/
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Ulmer, M. P.↗
Engineering topics
Hjellming, R. M.
Publications and source records attributed to Hjellming, R. M..
X-ray and radio emission from the compact galaxy III Zw 2
X-rays from the compact galaxy III Zw 2 have been detected with the rotating modulation collimator on board SAS 3. The (2-10-keV) flux is (4.3 + or - 0.5) by 10 to the -11th power erg/sq cm per sec, which corresponds to a luminosity of 1.4 by 10 to the 45th power erg/s at 530 Mpc. Subsequent radio observations between 1.46 and 90 GHz were made at the NRAO Very Large Array and 36-foot (11-m) installations. The radio spectrum rises sharply toward higher frequencies and, below about 100 GHz, is indicative of a self-absorbed synchrotron spectrum from an extremely compact, rapidly evolving object.
Schnopper, H. W.↗
Discovery of an X-ray QSO
The discovery of X-ray QSO MR2251-178 at a distance of 410 Mpc is reported. The observations are based on signals (2-11 keV) from NRAO's Very Large Array (VLA) radio telescope and from two independent rotating modulation collimators (RMC). Coordinates are given and positional identification with X-ray source 2A2251-179 is made. Examination of POSS plates and redshift has given rise to speculation that MR2251-178 could actually be a Seyfert galaxy; but its high luminosity would tend to support the contention that it is, indeed, a QSO.
Ricker, G. R.↗
Further joint X-ray, infrared, and radio observations of Cygnus X-3
Observations of Cygnus X-3 have been carried out at 2.5-7.5 keV, 2.2 micrometers, 8.1 GHz, and 2.7 GHz over a two week period. The X-ray data show the periodic structure which is typical of Cyg X-3. At times the X-ray and infrared measurements show very similar periodic structure, both in phase and in shape, while at other times the infrared data show no periodic variability. The radio fluxes were unusually low during the period of observation; both the daily average radio flux levels and the spectral index remained nearly constant.
Mason, K. O.↗
The radio sources associated with Cyg X-3
Some of the conclusions derived from the data on the radio flaring of Cyg X-3 are summarized. In addition, recent data showing that Cyg X-3 has both active and quiet radio behavior are presented.
Hjellming, R. M.↗
The May 1975 transient radio event in Cyg X-1
Radio observations of Cyg X-1 (HDE 226868) taken during the period May-June 1975 at 2,695 and 8,085 MHz are presented and discussed in the context of both the previous four years of data at these frequencies and subsequent data for September-October 1975. The data show that the radio event was a transient one with a time scale of the order of a few to several weeks, and that the observed radio decay was qualitatively similar to the observed decay of the enhanced X-ray state.
Hjellming, R. M.↗
Further joint X-ray, infrared and radio observations of Cygnus X-3
Observations of Cygnus X-3 were carried out at 2.5 - 7.5 keV, 2.2 micron, 8.1 GHz and 2.7 GHz over a two week period. The X-ray data show the periodic structure which is typical of Cyg X-3. At times the X-ray and infrared measurements show very similar periodic structure, both in phase and shape, while at other times the infrared data show no periodic variability. The radio fluxes were usually low during the period of observation; both the daily average radio flux levels and spectral index remained nearly constant.
Mason, K. O.↗
Extended X-ray and radio observations of Scorpius X-1.
A 23-day observation reveals temporal variations at energies of 3-10 keV similar to those found in previous optical data. However, there is no evidence of more than one preferred intensity level or of an intensity threshold for flares. We rule out X-ray periodicities containing more than 5 per cent of the mean quiescent-period intensity with periods of from 6 minutes to 4 hours. The X-ray intensity is strongly correlated with hardness but is not correlated with radio data collected over eight days.
Canizares, C. R.↗
Detection of radio emission from GX9+1.
Detection of a variable radio source in association with the X-ray source GX9+1, using the NRAO three-element interferometer at frequencies of 2695 and 8085 MHz. This radio source appears unresolved at all spacings, and must therefore be smaller than 1 arc sec. Two other celestial X-ray sources, GX349+2 and GX340+0 were also observed for radio emission during the same period of observations of GX9+1. These two sources should be good candidates for radio emission.
Zaumen, W.↗
Physical processes in H II regions.
Physical process effect on structure of H II REGIONS, noting ionization, Lyman continuum spectral distribution and radiative transfer frequency dependence on absorptive processes
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