The influence of rotation and finite size of the radiation source on the orbits of dust particles around stars is analyzed. It is found that there are physical situations in which the results first derived by Robertson (Poynting-Robertson effect), corresponding to a nonrotating point-like source, cannot properly describe the dynamical behavior of

We present one new radio identification and one confirmation of two high-latitude gamma-ray sources detected by CGRO-EGRET, based on flux density measurements at 1.3 mm (Caltech Submillimeter Observatory2) and 1.3 cm (Metsähovi Research Station) of objects in the EGRET error boxes. We identify EGRET sources 10744+5438 and J1239+044l with 87GB

We have observed the accreting millisecond X-ray pulsar SAX J1808.4-3658 in its current outburst (ATel #1728, #1732, #1733) in the radio band with the Australia Telecope Compact Array (ATCA) on 2008 September 26th for about 5h (03:39 - 08:35 UT). The radio-counterpart was not detected. The 3-sigma upper-limits are 0.45 mJy/beam at 4.8 GHz and 0.72

We have used three large-scale radio surveys to study the spectral behaviour of radio sources towards Abell clusters of galaxies. Without attempting to separate genuine cluster sources from background sources, we find a steeper median spectral index within 0.5 Abell radii (r_A_) than between 0.5 and 1 r_A_ (1 r_A_=3 h_50^-1 Mpc, and H_0 = 50 h_50_

Aims:We aim to understand the real nature of the stellar overdensity at southern galactic latitudes in the region of CMa. Methods: We perform a critical re-analysis and discussion of recent results presented in the literature which interpret the CMa overdensity as the signature of an accreting dwarf galaxy or a new substructure within the Galaxy

We present the results of optical/near-IR observations carried out in the period Dec 1998-Dec 1999 at Spanish, Indian and New Zealand observatories. Most of the searches proved to be unfruitful, in spite of the rapid follow-up observations, starting 3-24 hr after the events. This indicates that a significant fraction of the bursts occur in high