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Full-Text Articles in Astrophysics and Astronomy
Cygnus A At 99 Ghz: Observations Of The Three Principal Components And The Interpretation Of The Central Source, R. W. Hobbs, S. P. Maran, Menas Kafatos, L. W. Brown
Cygnus A At 99 Ghz: Observations Of The Three Principal Components And The Interpretation Of The Central Source, R. W. Hobbs, S. P. Maran, Menas Kafatos, L. W. Brown
Mathematics, Physics, and Computer Science Faculty Articles and Research
The three principal emission components of Cygnus A have been observed at 99 GHz, the highest frequency at which radio measurements of this source have been accomplished. The observations show no definite indication of a high-frequency cutoff in the spectrum of the compact central component, which perhaps may be attributed to an optically thin synchrotron source that peaks at a frequency of several hundred GHz.
The Central, Compact Source In The Cygnus A Galaxy, Menas Kafatos
The Central, Compact Source In The Cygnus A Galaxy, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
Single, optically thin, component models as well as double, optically thick at low frequencies, component models have been examined in trying to explain the central source in the nucleus of Cygnus A. In the course of exploring those models, it is found that this compact radio source may be quite similar to other compact and variable sources in Seyfert galaxies and quasars. Double component models generally do better because they fit the X-rays, and there is a good chance that the X-rays arise in the central source; these models can naturally explain variability which may already have been detected in …
Mass Loss And Oh Maser Emission From Mira Variables, A. G. Michalitsianos, Menas Kafatos
Mass Loss And Oh Maser Emission From Mira Variables, A. G. Michalitsianos, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
We have estimated the mass, radius, and luminosity of 26 Mira variables that are known OH sources of radio emission at 1612 MHz. The time-independent solution of Salpeter's stellar wind equation and a period-density relation are used to solve for basic stellar parameters, with the aid of the terminal expansion velocity of the OH maser cloud. Masses obtained from these calculations are consistent with other estimated values for masses of Mira variables. Good agreement is obtained when comparing the rate of mass loss as determined from Reimers's semiempirical relation to estimates of the mass loss rate as deduced from theoretical …
Penrose Pair Production In Massive, Extreme Kerr Black Holes, D. Leiter, Menas Kafatos
Penrose Pair Production In Massive, Extreme Kerr Black Holes, D. Leiter, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
We show that in the case of very massive (M > 108 M0 ) Kerr black holes with extreme ranges of angular momentum 1 ≥ a/M > 0.998, the possibility of photon-induced Penrose pair production (PPP) in the ergosphere is very plausible. The pairs that escape the ergosphere are very high energy and on the order of the GeV rest mass of the Penrose accreted protons which participate in the photon-induced pair production process. Application of this model to the case of quasistellar objects (QSOs) is shown to lead to reasonable predictions about their masses, lifetimes, and luminosities. The physical mechanism is …