ar X iv : a st ro - p h / 02 01 46 4 v 1 2 9 Ja n 20 02 α - process elements in the Galaxy : a possible GAIA contribution

ar X iv : a st ro - p h / 02 01 05 0 v 1 4 J an 2 00 2 Probing the evolution of massive galaxies with the K 20 survey ⋆

The motivations and the status of the K20 survey are presented. The first results on the evolution of massive galaxies and the comparison with the predictions of the currently competing scenarios of galaxy formation are also discussed.

ar X iv : a st ro - p h / 99 02 06 2 v 1 4 F eb 1 99 9 SOURCES OF RELATIVISTIC JETS IN THE GALAXY

ar X iv : a st ro - p h / 02 01 31 6 v 1 1 8 Ja n 20 02 New Approach to Sgr A * Problem

The hypothesis that radiation of Sgr A* is caused by accretion onto a supermassive compact object without the events horizon is studied. The main equations of the accretion and a relativistic equation of the trasfer radiation are obtained. The synchrotron spectrum in the vicinity of the maximum is considered.

ar X iv : a st ro - p h / 02 01 47 6 v 1 2 9 Ja n 20 02 The Most Luminous Galaxies

Ultraluminous galaxies in the local universe (z≤0.2) emit the bulk of their energy in the mid and far-infrared. The multiwavelength approach to these objects has shown that they are advanced mergers of gas-rich spiral galaxies. Galaxy-galaxy collisions took place on all cosmological time-scales, and nearby mergers serve as local analogs to gain insight into the physical processes that lead to t...

ar X iv : a st ro - p h / 04 01 02 0 v 1 4 Ja n 20 04 Optical and X - ray Observations of the Afterglow to XRF 030723

The X-ray-flash XRF 030723 was detected by the HETE satellite and rapidly disseminated, allowing for an optical transient to be detected ∼ 1 day after the burst. We discuss observations in the optical with Magellan, which confirmed the fade of the optical transient. In a 2-epoch ToO observation with Chandra, we discovered a fading X-ray source spatially coincident with the optical transient. We...