The RXTE has been monitoring the new transient X-ray source MAXI J1409-619 since its discovery on October 20, 2010 (Yamaoka et al 2010, ATEL # 2959) . We analyzed the observations of this source performed on December 11, 2010 during the current re-brightening of the source (Ueno et al 2010, ATEL # 3067). The observation lasted for a total exposure

We report on the detection, from observations obtained with the Apache Point Observatory Galactic Evolution Experiment spectroscopic survey, of a metal-poor ([Fe/H] = -1.3 dex) field giant star with an extreme Mg-Al abundance ratio ([Mg/Fe] = -0.31 dex; [Al/Fe] = 1.49 dex). Such low Mg/Al ratios are seen only among the second-generation population

Hubble Space Telescope Near-Infrared Camera and Multiobject Spectrometer (NICMOS) observations of six brown dwarf candidates in the Pleiades open cluster are presented. One of them, namely CFHT-Pl-18, is clearly resolved as a binary with an angular separation of 0.33". The very low density of contaminating background stars in our images and the

We report the discovery of twin kilohertz quasi-periodic oscillations (kHz QPOs) in the X-ray flux of XTE J1807-294, the fourth accreting millisecond pulsar (AMP). This is the second AMP exhibiting twin kHz QPOs. In contrast to the first case, SAX J1808.4-3658, the frequency separation Δν between these kHz QPOs is consistent with the pulse

High-cadence observations by the slit-jaw (SJ) optics system of the sounding rocket experiment known as the Chromospheric Lyman Alpha Spectropolarimeter (CLASP) reveal ubiquitous intensity disturbances that recurrently propagate in either the chromosphere or the transition region or both at a speed much higher than the speed of sound. The CLASP/SJ

We report on an ongoing study of disk galaxy merger simulations and their implications for the Fundamental Plane (FP) of elliptical galaxies.