The Variable Warm Absorber in Circinus X-1

Norbert's paper on the faint-state observations of Cir X-1 has just been accepted to ApJ. While the P-Cygni lines (present in earlier observations when the source was brighter) were absent, we found evidence for complex absorption effects, including warm (moderately ionized) absorbers with varying column density. This Chandra observation has proved popular lately, with another paper analysing the same data posted just weeks earlier.

Read the paper arXiv:0709.3336

An X-ray jet in Circinus X-1

Sebastian did well to spot the X-ray jet in one of Norbert's 2005 zero-phase observations of the enigmatic X-ray binary Cir X-1. This source is thus the first neutron star for which an extended X-ray jet has been detected. Previously ultrarelativistic arcsecond-scale radio jets were detected by Rob Fender's group; see their 2004 Nature paper. The kinetic jet power that we infer is significantly larger than the minimum power required for the jet to inflate the large-scale radio nebula.

Read the paper (ApJ 663, L93)

Fe Kα Lines in MCVs

Aimee's paper on the Fe Kα line profiles from the accretion columns of magnetic CVs was accepted by MNRAS last month. The paper extends Jason Cullen's nonlinear Monte-Carlo code to predict the degree of broadening expected from lines arising from close to the white dwarf. We used a Chandra observation of GK Per in outburst for comparison, and while the relative line strengths in the model is not set by the physical conditions, the results were promising.

Read the paper (astro-ph/0704.1516)