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Physical Properties of a 2003 April Quiescent Streamer
Raymond, J. C.; Uzzo, M.; Ko, Y. -K. +2 more
In 2003 April, the Ultraviolet Coronagraph Spectrometer (UVCS) on board the Solar and Heliospheric Observatory (SOHO) observed a quiescent streamer in an effort to derive the physical plasma parameters across the streamer and as a function of height (from 1.75 to 5.0 Rsolar). Values for the electron temperature, proton and O5+
Filling the infrared gap: ISO observations of 1 Jy BL Lacertae objects
Giommi, P.; Ábrahám, P.; Moór, A. +2 more
Aims.The large majority of BL Lacertae objects belonging to the 1 Jy sample, the class prototype for radio-selected sources, are thought to emit most of their synchrotron power in the far infrared band. Ironically, this spectral region is very sparsely sampled, with only a minority of the objects having IRAS data (most of them being upper limits o…
GMRT observations of the field of INTEGRAL X-ray sources - I
Durouchoux, P.; Manchanda, R. K.; Pandey, M. +2 more
Since its launch the INTEGRAL observatory has discovered a variety of hard X-ray sources in the Galactic plane. Using GMRT, we have made repeated observations of these sources to search for the radio counterparts of seventeen of them at low frequencies. The source positions were taken from the various ATEL and IAUC announcements reporting their di…
Comparison of the Variations of CMEs and ICMEs with those of other Solar and Interplanetary Parameters During Solar Cycle 23
Kane, R. P.
This paper examines the variations of coronal mass ejections (CMEs) and interplanetary CMEs (ICMEs) during solar cycle 23 and compares these with those of several other indices. During cycle 23, solar and interplanetary parameters had an increase from 1996 (sunspot minimum) to ∼2000, but the interval 1998-2002 had short-term fluctuations. Sunspot …
The Unusual Spectrum of the Ultraluminous X-Ray Source M82 X-1
Misra, R.; Agrawal, V. K.
The results of a spectral analysis, using XMM-Newton and Chandra data of the brightest ultraluminous X-ray source in the nearby galaxy M82, are presented. The spectrum of M82 X-1 was found to be unusually hard (photon spectral index Γ~1) with a sharp cutoff at ~6 keV. The disk blackbody emission model requires a nonphysically high temperature. Ins…
Chemical abundances of 32 mildly metal-poor stars
Zhao, G.; Zhang, H. W.
Context: .The formation scenario of the Galactic thick disk is an unresolved problem. Chemical abundances in long-lived dwarf stars of the thin and thick disks provide information of the Galactic disk formation.Aims.We present photospheric abundances of the O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Ni, and Ba elements for 32 mildly metal-poor star…
Thermal emission of spherical spinning ring particles. The standard model
Leyrat, C.; Ferrari, C.
A simple new thermal model was developed to study the effects of the spherical shape of ring particles, of their finite thermal inertia, and of their spinning properties on the rings thermal emission. Ring particles are assumed to be scattered in a monolayer,
a structure that might exist at least in the population of large particles embedded …Accurate photometry of extended spherically symmetric sources
Gieles, M.; de Grijs, R.; Anders, P.
We present a new method to derive reliable photometry of extended spherically symmetric sources from HST images (WFPC2, ACS/WFC and NICMOS/NIC2 cameras), extending existing studies of point sources and marginally resolved sources. We develop a new approach to accurately determine intrinsic sizes of extended spherically symmetric sources, such as s…
Mission operations for the new Rosetta
Ferri, Paolo
The International Rosetta Mission, a cornerstone mission of the European Space Agency Scientific Programme, was scheduled for launch in January 2003 on Ariane 5, but it missed its 19 days launch window due to the suspension of Ariane 5 launches following the failure of flight 517 in December 2002. The search for a new mission opportunity started i…
Hubble Space Telescope Faint Object Spectrograph Spectral Mapping of V2051 Ophiuchi in a Low State
Saito, R. K.; Baptista, R.
We report a study of the spectra and structure of the accretion disk of the dwarf nova V2051 Ophiuchi while the star was in an unusual faint brightness state during 1996. The differences between the UV resonant lines and continuum disk surface brightness distributions indicate a vertically extended disk with the emission from these lines arising f…