We are in the process of obtaining a complete sample of exploratory X-ray observations of broad absorption line (BAL) QSOs from the Large Bright Quasar Survey (LBQS). This survey is composed of short (5– 7 ks) Chandra ACIS-S3 observations designed to significantly constrain X-ray fluxes and hardness ratios. Our sample avoids the selection biases of some previous surveys while providing X-ray da...

Two broad absorption features were discovered in the Chandra/ACIS spectrum of the isolated neutron star 1E1207.4-5209 (Sanwal et al. 2002). Expanding on our previous paper (Hailey & Mori 2002), we describe the atomic physics methodology which leads to the identification of this neutron star’s atmospheric composition. The solution of Schrödinger’s equation in an intense magnetic field combined w...

We present Chandra ACIS-I and ACIS-S observations (∼200 ks in total) of the X-ray luminous elliptical galaxy NGC 4636, located in the outskirts of the Virgo cluster. A soft band (0.5-2 keV) image shows the presence of a bright core in the center surrounded by an extended X-ray corona and two pronounced quasi-symmetric, 8 kpc long, arm-like features. Each of this features defines the rim of an e...

We report the results of a programme of dual-epoch Chandra ACIS-S observations of five ultraluminous X-ray sources (ULXs) in nearby spiral galaxies. All five ULXs are detected as unresolved, point-like X-ray sources by Chandra, though two have faded below the 10 erg s luminosity threshold used to first designate these sources as ULXs. Using this same criterion, we detect three further ULXs with...

We present new observations on PKS 2155-304 with the Chandra Low Energy Transmission Grating Spectrometer (LETG), using the Advanced CCD Imaging Spectrometer (ACIS). We confirm the detection of an absorption line plausibly identified as O VIII Lyα from the warm-hot intergalactic medium associated with a small group of galaxies along the line of sight, as originally reported by Fang et al. 2002 ...

Context. The outer Galaxy, where the environmental conditions are different from the solar neighborhood, is a laboratory in which it is possible to investigate the dependence of star formation process on the environmental parameters. Aims. We investigate the X-ray properties of NGC 1893, a young cluster (∼1–2 Myr) in the outer part of the Galaxy (galactic radius ≥11 kpc) where we expect differe...

The satellite-based cloud condensation nuclei (CCN) proxies used to quantify the aerosol-cloud interactions (ACIs) are column integrated and do not guarantee vertical co-location of aerosols clouds. This has encouraged use height-resolved measurements spaceborne lidars for ACI studies led advancements in lidar-based CCN retrieval algorithms. In this study, we present a comparison between number...