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Full-Text Articles in Astrophysics and Astronomy
Contemporaneous Iue, Euve, And High-Energy Observations Of 3c 273, E. Ramos, Menas Kafatos, A. Fruscione, F. C. Bruhweiler, I. M. Mchardy, R. C. Hartman, L. G. Titarchuk, C. Von Montigny
Contemporaneous Iue, Euve, And High-Energy Observations Of 3c 273, E. Ramos, Menas Kafatos, A. Fruscione, F. C. Bruhweiler, I. M. Mchardy, R. C. Hartman, L. G. Titarchuk, C. Von Montigny
Mathematics, Physics, and Computer Science Faculty Articles and Research
We present the results of our 1994 January and 1995 January observations of the quasar 3C 273 obtained with the International Ultraviolet Explorer (IUE) and the Extreme-Ultraviolet Explorer (EUV E). These observations were part of a large multiwavelength campaign to observe 3C 273 from radio through γ-rays. Our 1995 January photometric observations with the EUV E Lexan/B Deep Survey (DS) instrument indicate strong evidence for variability, at a 99% confidence level, during the 12 day observing period. We have utilized ROSAT PSPC soft X-ray power-law models to correlate with EUV E count rates. Besides variations in the normalization level between …
Moderate-Resolution Spectroscopy Of The Lensed Quasar 2237+0305: A Search For Ca Ii Absorption Due To The Interstellar Medium In The Foreground Lensing Galaxy, P. Hintzen, S. P. Maran, A. G. Michalitsianos, C. B. Foltz, F. H. Chafee, Menas Kafatos
Moderate-Resolution Spectroscopy Of The Lensed Quasar 2237+0305: A Search For Ca Ii Absorption Due To The Interstellar Medium In The Foreground Lensing Galaxy, P. Hintzen, S. P. Maran, A. G. Michalitsianos, C. B. Foltz, F. H. Chafee, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
The gravitational lens system 2237 + 0305 consists of a low-redshift barred spiral galaxy (z = 0.0394) centered on a more distant quasar (z = 1.695). Because the lensing galaxy is nearly face on, spectroscopy of the background quasar affords a unique opportunity to study the interstellar medium in the galaxy's center and buW:. We report moderate-resolution spectroscopy of QS02237 + 0305 yielding a 3u upper limit of 72 rnA forthe rest equivalent width of Ca II K absorption d);le to gas in the intervening galaxy. Since gas in the Milky Way "thick disk" typically produces 220 mA Ca II …
The Unusual Ultraviolet Variability Of The Qso 3c 232, C. Bruhweilier, Menas Kafatos, U. J. Sofia
The Unusual Ultraviolet Variability Of The Qso 3c 232, C. Bruhweilier, Menas Kafatos, U. J. Sofia
Mathematics, Physics, and Computer Science Faculty Articles and Research
After examining ultraviolet IUE spectra of 18 QSOs with z > 0.35, we find that one object, 3C 232 (z = 0.533), stands out as exhibiting highly unusual spectral and continuum variability. The H 1-Lya shows at least 50% variability on a time scale of roughly a month, while the ultraviolet continuum exhibited approximately a factor of 2 decrease in a day. The magnitude of the UV continuum variability is reminiscent of that seen in the optically violent variables at visual wavelengths. Several spectral features at wavelengths shortward of H I-Lya in the rest frame are identified. A brief discussion COJ?lparing …
Gamma Rays From Penrose Powered Black Holes In Centaurus A, 3c 273, And Ngc 4151, Menas Kafatos
Gamma Rays From Penrose Powered Black Holes In Centaurus A, 3c 273, And Ngc 4151, Menas Kafatos
Mathematics, Physics, and Computer Science Faculty Articles and Research
Gamma-ray observations of active galaxies have important consequences for theories of the activity in their nuclei. The observations of Cen A, 3C 273, and NGC 4151 are examined under the assumption that Penrose collision processes in the ergospheres of massive black holes power their nuclei. The observed sharp break in the MeV region of the NGC 4151 spectrum cannot be due to the γ-γ pair production process. We attribute this break to the Penrose Compton scattering (PCS), in which γ-rays escape from the ergosphere as a result of Penrose processes involving electrons and lower energy X-ray photons in the ergosphere …
Penrose Pair Production As A Power Source Of Quasars And Active Galactic Nuclei, Menas Kafatos, D. Leiter
Penrose Pair Production As A Power Source Of Quasars And Active Galactic Nuclei, Menas Kafatos, D. Leiter
Mathematics, Physics, and Computer Science Faculty Articles and Research
In this paper we propose a new mechanism, Penrose pair production in massive, canonical (with a/M = 0.998) Kerr black holes, as a power source in quasars, Seyfert galaxies, radio galaxies, and BL Lac objects (i.e., what one usually refers to as active nuclei). As a working hypothesis, we postulate that massive (10^8 M0 or around this value) Kerr black holes reside in the centers of these objects. We also postulate that an accretion disk is formed. In a variety of models, hot, inner disks are expected. If the temperature is sufficiently high-as, for example, in the two-temperature model-then MeV …
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 …