ar X iv : a st ro - p h / 04 01 42 8 v 1 2 1 Ja n 20 04 IS THE LOCAL BUBBLE DEAD ?

ar X iv : a st ro - p h / 04 01 12 2 v 2 1 9 Ja n 20 04 High Energy Gamma - Ray Astronomy

The physics results of high energy γ-ray astronomy are reported, emphasizing recent achievements with ground-based detectors. This includes some of the instrumental developments and latest projects. The fundamental contribution of the field to the question of Cosmic Ray origin is highlighted.

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ar X iv : a st ro - p h / 04 01 29 1 v 1 1 5 Ja n 20 04 INTEGRAL Spectrometer Analysis of GRB 030227 & GRB 030131

The spectrometer SPI on board INTEGRAL is capable of high-resolution spectroscopic studies in the energy range 20 keV to 8 MeV for GRBs which occur within the fully coded field of view (16 • corner to corner). Six GRBs occurred within the SPI field of view between October 2002 and November 2003. We present results of the analysis of the first two GRBs detected by SPI after the payload performan...

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...

ar X iv : a st ro - p h / 04 01 55 8 v 1 2 6 Ja n 20 04 Cepheids and Long Period Variables in NGC 4395

Repeated imaging observations of NGC 4395 were made with the WIYN 3.5 m and the KPNO 2.1 m telescopes. From the photometry of the resolved brighter stars in this galaxy eleven Cepheids with periods ranging between 12 and 90 days have been identified. The true distance modulus has been derived from the apparent distance moduli in g, r and i.