The very high energy (VHE; E > 100 GeV) blazar Markarian 501 (Mrk 501) has a well-studied history of extreme spectral variability and is an excellent laboratory for studying the physical processes within the jets of active galactic nuclei. However, there are few detailed multiwavelength studies of Mrk 501 during its quiescent state, due to its low

There are ubiquitous flows observed in the solar atmosphere of sub-Alfvénic speeds; however, after flaring and coronal mass ejection events flows can become Alfvénic. In this Letter, we derive an expression for the standing kink mode frequency due to siphon flow in coronal loops, valid for both low and high speed regimes. It is found that siphon

We report the detection of a type I X-ray burst in a 9ksec-long RXTE-PCA observation of the neutron star transient SAX J1747.0-2853. The burst bolometric flux was [1.7+/-0.1]x10{-8} erg/s/cm2 at the peak, on 2011-03-10 16:29:13 UTC, and the burst lasted for about 15 seconds. The blackbody temperature reached 2.4+/-0.1 keV at the peak and decayed to

Aims: We propose and explore a new diagnostic technique based upon the linear polarization emitted in Hanle-sensitive lines in disk-integrated stars where a dipolar magnetic field breaks the rotational symmetry of the resonance scattering polarization Methods: A star with a simple dipolar field and a 1-0 spectral line were used to compute

At 04:08:54 UT on 2007 October 25, the Burst Alert Telescope on-board Swift detected GRB 071025 and performed a rapid slew to the GRB location, beginning observations with the X-Ray Telescope at 146s after the trigger. The robotic IR observatory PAIRITEL consists of the 1.3-m Peters Telescope at Mt. Hopkins, Arizona, formerly used for the Two

For the first time, subelectron readout noise has been achieved with a camera dedicated to astronomical wavefront-sensing applications. The OCam system demonstrated this performance at a 1300 Hz frame rate and with 240 × 240 pixel frame size. ESO and JRA2 OPTICON jointly funded e2v Technologies to develop a custom CCD for adaptive optics (AO)