Search NASA⌕ Search

Engineering topics

Pauliny-Toth, I. I. K.

Publications and source records attributed to Pauliny-Toth, I. I. K..

6 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1982

Large scale X-ray and radio structures associated with compact extragalactic sources

Knots of X-ray emission have been detected within 20 arcmin of five compact sources initially selected from the MPIfR north polar 5 GHz survey. Two of the knots have also been detected at centimeter wavelengths and probably have nonthermal spectra. They appear to be associated with the compact sources since the probability of serendipitous discovery at the observed flux levels is low. While the apparent association may be due to colocation of the sources in a distant supercluster, it is suggested on the basis of overall alignment, and possible correlations with structures in the respective central sources, that the association may be similar to that found in extended radio sources. The observed emission may thus be due to synchrotron or inverse Compton radiation, the energy being supplied by jets from the central source.

Biermann, P.↗
NASA NTRS1981

Observations of six flat spectrum sources from the 5 GHz survey

Observations at radio, optical, and X-ray wavelengths of six sources from the Bonn-NRAO 5 GHz survey are reported. The sources were selected on the basis of their flux densities and spectral indices at 5 GHz. All have been shown to contain compact radio cores and to emit strongly at X-ray wavelengths; five are strongly polarized at optical wavelengths. The measured flux densities suggest that the sources are of comparable luminosity (per fractional bandwidth) in the X-ray and optical regions. The interpretation of these results in terms of a synchrotron-self-Compton mechanism is briefly discussed.

Biermann, P.↗
NASA NTRS1981

High-resolution observations of the QSO 3C 345 at 1.3 centimeters

High-resolution VLBI observations made at a frequency of 22.235 GHz of the quasar 3C 345 are discussed. Antennas located at the Crimean Astrophysical Observatory, USSR; Onsala, Sweden; Effelsberg, West Germany; and the Haystack Observatory, Massachusetts were employed at 4-min integration times to provide baselines ranging up to 5.5 x 10 to the 8th wavelengths. About 40% of the total flux density of 7.85 Jy, observed in November 1977, and 8.05 Jy, observed in October 1978, is found to originate in an unresolved component of the quasar core in a region less than 0.1 milliarcsec in diameter. The elongated jet-like component of the quasar is observed to contain several peaks of emission extending up to 6 milliarsec from the core which decreased in extent between the two observations.

Baath, L. B.↗
NASA NTRS1977

The compact radio sources in 4C 39.25 and 3C 345

Long-baseline interferometry of the quasars 4C 39.25 and 3C 345 at 10.65 and 14.77 GHz shows that the centimeter radio source in each object is double, with component separations of 0.0020 arcsec (4C 39.25) and 0.0013 arcsec (3C 345 at 1974.5). For each source, the separation is the same at both frequencies, as well as similar to the structure observed at 7.85 GHz (and 5.0 GHz for 4C 39.25). The spectra of the individual components are derived and shown to vary with time approximately as expected for expanding self-absorbed synchrotron sources. The magnetic fields in the components are estimated to be as high as 0.1 gauss, but the structure of the sources appears to be unrelated to the magnetic-field orientation derived from low-resolution polarization measurements. The component separation in 4C 39.25 has not changed for several years, whereas 3C 345 shows rapid expansion.

Shaffer, D. B.↗