Swift discovered GRB 050713A and slewed promptly to begin observing with its narrow-field instruments 72.6 s after the burst onset, while the prompt gamma-ray emission was still detectable in the BAT. Simultaneous emission from two flares is detected in the BAT and XRT. This burst marks just the second time that the BAT and XRT have simultaneously

Aims:To check whether the polar angle distribution of QSOs around nearby spiral galaxies is isotropic or not. Methods: A statistical analysis of the polar angle distribution of large samples of QSOs from the SDSS survey and Monte Carlo simulations to calculate their significance are carried out. Results: There is a clear excess of QSOs near the

Due to an error at the Press, the header to column (8) of Table 1 is incorrect. This column head should read log([O I/Hα), not log([O III/Hα). The Press sincerely regrets this error.

In 2005 and 2006, the MAGIC telescope observed very high energy gamma-ray emission from the distant BL Lac object PG 1553+113. The overall significance of the signal was 8.8 σ for 18.8 hr of observation time. The light curve shows no significant flux variations on a daily timescale; the flux level during 2005 was, however, significantly higher

We present results from a series of follow-up observations of a subsample of the representative SAURON survey elliptical (E) and lenticular (S0) galaxies using the OASIS integral-field spectrograph. These observations focus on the central 10 " x 10 ", with roughly double the spatial resolution of the SAURON observations. This increased spatial

We study X-ray fluorescent emission and monochromatic scattering from the surfaces of asteroids and other atmosphereless solar-system objects using numerical Monte Carlo simulations. X-ray observations allow the assessment of the elemental composition and structure of the surface. We assume that the model regolith consists of close-packed spherical