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IGR J16318-4848: An X-ray Source in a Dense Envelope?
Gilfanov, M. R.; Sunyaev, R. A.; Sazonov, S. Yu. +1 more
We analyze in detail the ASCA observations of the hard X-ray source IGR J16318-4848, which was recently discovered by the INTEGRAL observatory (Courvoisier et al. 2003). The source has an anomalously hard spectrum in the energy range 0.5-10 keV and is virtually undetectable below 4 keV because of strong photoabsorption (n_H L > 4 x 1023
The First Results of Observations of the Transient Pulsar SAX J2103.5+4545 by the INTEGRAL Observatory
Lutovinov, A. A.; Revnivtsev, M. G.; Molkov, S. V.
We present the preliminary results of our analysis of the observations of the X-ray pulsar SAX J2103.5+4545 by the INTEGRAL Observatory in December 2002. We mapped this region of the sky in a wide energy range, from 3 to 200 keV. The detection of the source is shown to be significant up to energies of ~100 keV. The hard X-ray flux in the energy ra…
Variability of the H_alpha and Na I D Line Profiles in the Spectrum of FU Ori
Errico, L.; Lamzin, S. A.; Vittone, A.
The variations of line profiles in the spectrum of FU Ori during several consecutive nights, from January 3 through January 8, 1999, have been traced for the first time in the entire history of studying this star. The variations of the H_alpha and Na I D line profiles are regular in pattern; at each time, the profiles of these lines were similar t…
Peculiarities of the UV Continuum Energy Distribution for T Tauri Stars
Lamzin, S. A.; Kravtsova, A. S.
In the UV spectra of BP Tau, GW Ori, T Tau, and RY Tau obtained with the Hubble Space Telescope, we detected an inflection near 2000 Angstrems in the F^clambda(lambda) curve that describes the continuum energy distribution. The inflection probably stems from the fact that the UV continuum in these stars consists of two components: the e…
Estimating the Interstellar Extinction and the Contribution from an Accretion Shock to the Formation of Emission Continuum in DS Tau and DG Tau
Kravtsova, A. S.
We analyze the UV spectra of the young stars DG Tau and DS Tau taken with the STIS spectrograph from the Hubble Space Telescope. For these stars, we found the upper limits of the interstellar extinction A_V. Their values proved to be lower than those obtained by other authors from optical observations. For DS Tau, DG Tau, and TW Hya, we also deter…
Possibilities for Detecting Extinct Radio Pulsars
Beskin, V. S.; Yeliseyeva, S. A.
We explore the possibilities for detecting pulsars that have ceased to radiate in the radio band. We consider two models: the model with hindered particle escape from the pulsar surface [first suggested by Ruderman and Sutherland (1975)] and the model with free particle escape (Arons 1981; Mestel 1999). In the model with hindered particle escape, …
Slow Solar Wind: Sources and Components of the Stream Structure at the Solar Maximum
Vladimirsky, K. V.; Lotova, N. A.; Obridko, V. N.
We study the sources and components of the solar-wind spatial stream structure at the maximum of the solar cycle 23. In our analysis, we use several independent sets of experimental data: radio-astronomical observations of scattered radiation from compact sources with the determination of the distance from the Sun to the inner boundary of the tran…