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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…

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…

The nature of ultraviolet spectra of AG Pegasi and other symbiotic stars: locations, origins, and excitation mechanisms of emission lines

Wahlgren, G. M.; Johansson, S.; Eriksson, M.

A detailed study of ultraviolet spectra of the symbiotic star AG Peg has been undertaken to derive the atomic excitation mechanisms and origin of formation for the lines common in symbiotic systems. More than 600 emission lines are observed in spectra from {IUE}, {HST} and {FUSE} of which 585 are identified. Population mechanisms and origin of for…

Warm-hot intergalactic medium contribution to baryonic matter

Sołtan, A. M.

Context: .Hydrodynamical simulations indicate that a substantial fraction of baryons in the universe remains in a diffuse component - warm-hot intergalactic medium (WHIM).
Aims: .The goal of this paper is to determine the physical properties (spatial distribution, temperature, and density) of the WHIM.
Methods: .Spatial structure of the so…

Supersoft sources in XMM-Newton Small Magellanic Cloud fields. A symbiotic and a close binary or cooling neutron star

Haberl, F.; Kahabka, P.

We report the detection and study of two faint ROSAT supersoft X-ray sources in the SMC field with XMM-Newton, RX J0059.1-7505 and RX J0059.4-7118. Due to the larger effective area of XMM-Newton we can constrain the X-ray spectra of both sources. RX J0059.1-7505 is optically identified with the symbiotic LIN 358 in the SMC. A 20 eV blackbody compo…

Mass segregation in rich LMC clusters from modelling of deep HST colour-magnitude diagrams

Santiago, B. X.; Kerber, L. O.

Aims.We used the deep colour-magnitude diagrams (CMDs) of five rich LMC clusters (NGC 1805, NGC 1818, NGC 1831, NGC 1868, and Hodge 14) observed with HST/WFPC2 to derive their present day mass function (PDMF) and its variation with position within the cluster.
Methods: .The PDMF was parameterized as a power law in the available main-sequence …

The ZZ Ceti star G 185-32: new insight from asteroseismology

Pech, D.; Vauclair, G.

One of the brightest pulsating DA white dwarfs (ZZ Ceti stars), G 185-32, shows 19 periods in its power spectrum, from 71 s to 651 s. Its short periods are among the shortest ones observed in a ZZ Ceti star. The one at 141.9 s shows an amplitude which does not vary with wavelength, in contrast with what the linear theory predicts for ℓ=1 or ℓ=2 no…