We report an outburst of a black hole X-ray binary, V4641 Sgr in 2004 July. We succeeded in performing time-series photometry during the outburst, which showed repetitive short flares having a timescale of 10 min. Even after the outburst, it remained active for 17 d, as observed after an outburst in 2002. In conjunction with a low X-ray flux, we

We investigate the structural, kinematical and spectrophotometric properties of `E+A' galaxies - those with strong Balmer absorption lines but no significant [OII] emission - using numerical simulations combined with stellar population synthesis codes. We particularly focus on the two-dimensional (2D) distributions of line-of-sight velocity

Following the recent report of a possible radio counterpart to the X-ray transient IGR J17098-3628 (ATEL #490), we re-investigated our Magellan I-band exposures obtained on 2005 April 9 UT (see ATEL #478). The frames show a point source located at R.A.(J2000)=17:09:45.93, DEC(J2000)= -36:27:58.2 in the 2MASS reference frame (0.2" uncertainty). This

In this paper we present photometric redshift estimates for a sample of X-ray selected sources detected in the wide-field ( 2 deg^2), bright [ f_X(0.5{-}8 keV)≈10-14 erg s-1 cm-2] XMM-Newton/2dF survey. Unlike deeper X-ray samples comprising a large fraction of sources with colours dominated by the host galaxy, our bright survey primarily probes

Extensive optical and infrared photometry as well as low and high resolution spectroscopy are used as inputs in deriving robust estimates of the reddening, distance and nature of the progenitor of V838 Mon, the 2002 outbursting event that produced a most spectacular light-echo. The reddening affecting V838 Mon is found to obey the R_V=3.1 law and

Within the framework of the quantum theory of polarized line formation, in the limit of complete frequency redistribution and of the collisionless regime, we derive explicit formulae describing the statistical equilibrium and the radiative emission of a multiterm atom with hyperfine structure, in the presence of an external magnetic field. The