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Vertical pressure profile of Titan—observations of the PPI/HASI instrument

Harri, Ari-Matti; Mäkinen, Teemu; Siili, Tero +2 more

The Huygens entry probe descended through the atmosphere of Titan and provided an excellent set of observations of the atmosphere and the surface of Titan. During the 150-min descent the Huygens Atmospheric Structure Instrument (HASI) observed a comprehensive set of variables, including pressure, temperature, density and atmospheric electricity. T…

Surface-brightness fluctuations in stellar populations. IAC-star models for the optical and near-IR wavelengths

Marín-Franch, A.; Aparicio, A.

Aims.A new theoretical calibration of surface-brightness fluctuations (SBF) for single age, single metallicity stellar populations is presented for the optical and near-IR broad-band filters, as well as for the HST WFPC2 and ACS filters.
Methods: .The IAC-star code is used. Two Padua and the Teramo stellar evolution libraries have been conside…

Chlorine in the Galactic Interstellar Medium: Revised f-Values with the Far Ultraviolet Spectroscopic Explorer and the Space Telescope Imaging Spectrograph

York, D. G.; Sonnentrucker, P.; Friedman, S. D.

Cl I is the atomic species most directly coupled to molecular hydrogen due to its chemistry. Its weakest lines are thereby probably the best tracer of optically thick H₂ components in diffuse clouds. We report on the empirical determination of the oscillator strengths for four Cl I absorption lines predicted to be weak and often detecte…

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 R_solar). 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 …