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Tue Dec 07, 2004

New millisecond X-ray pulsar IGR J00291+5934

Field of IGR J00291+5934Initially identified as a new X-ray transient by ESA's INTEGRAL satellite, IGR J00291+5934 was found in RXTE observations to be a 599 Hz millisecond pulsar. Subsequent observations revealed a 2.46 hr orbit, making the source very similar to the original millisecond X-ray pulsar, SAX J1808.4-3658.

Read the paper (ApJ 622, 45L 2005)
INTEGRAL team discovery paper (Shaw et al. 2005, A&A, 432, L13)
U. Southampton press release Feb 16th 2005
New Scientist breaking news Feb 22nd 2005

Labels: 2004, /pulsars

Wed Nov 24, 2004

Analysing astronomical data under Mac OS X

Some notes relevant to astro-types thinking about migrating from other *nix platforms to OS X. People keep asking me about it.

The biggest advantage is avoiding dual-boot arrangements and and messing around with partitions etc., but still having access to commercial packages such as Microsoft Office (as well as iTunes of course!)
Astronomical data analysis packages that have been ported to OS X (not by any means complete):

  • HEAsoft comprising the FTools and XANADU packages for X-ray data analysis (RXTE, ASCA etc.)
  • CIAO for Chandra data analysis
  • SAS v6.1.0 for XMM-Newton data analysis
  • IRAF, a general purpose system for the reduction and analysis of astronomical data (see the dedicated maciraf page)
  • Karma, a "toolkit for interprocess communications, authentication, encryption, graphics display, user interface and manipulating the Karma network data structure".
Packages that have NOT as yet been ported (completely) Other essential packages: As for security, by default, OS X won't allow any connections from outside, unless you explicitly allow them. There is built-in firewall, and encryption of folder contents (FileVault) if you want either of those. As well there aren't all the nasty viruses and crap for Mac at the moment that there are for Windows (although that may change in the future if Apple significantly increases market share!)

Labels: 2004, /reference

Tue Oct 05, 2004

Australian tour 2004

Here is a talk (PDF file) that I gave to the High Energy Phenomena in Astrophysics workshop, MSO, Canberra, Australia, and later at the University of Melbourne.

Abstract: The last 10 years has seen rapid growth in our knowledge about, and understanding of, accreting neutron stars in low-mass binary systems. The fast timing capability of RXTE has enabled detection of several different classes of kHz variability, which provide clues as to the distribution of rotation speeds of neutron stars. Better numerical models and expanded thermonuclear reaction networks, in combination with extensive archived datasets, are allowing ever more detailed investigations of X-ray burst physics. The high spectral resolution of Chandra and XMM have allowed detection (in a few cases) of discrete features, from which we may deduce the properties of the neutron stars. Along with a summary of progress in these areas I hope to touch on prospects for the near future.

Labels: 2004, /meetings

Mon Sep 13, 2004

HEAD meeting 2004

Just got back from New Orleans, where I attended the eighth High-Energy Astrophysics Divisional meeting. The highlight was almost certainly the detection of 45 Hz burst oscillations in EXO 0748-676 (see also astro-ph/0409384), a much lower frequency than the previous minimum of 270 Hz (for 4U 1916-053). There was lots of other fun stuff going on, as usual. I presented two posters (links to PS files):
Thermonuclear bursts observed by RXTE: The MIT catalog
Thermonuclear bursts from millisecond X-ray pulsars

Labels: 2004, /meetings

Tue Aug 10, 2004

An X-ray Jet in CH Cygni

Analysis of archival Chandra data of the symbiotic system CH Cygni reveals faint extended emission to the south, aligned with the optical and radio jets seen in earlier HST and VLA observations. CH Cygni is only the second known white dwarf with an X-ray jet, after R Aquarii.
Read the paper (ApJL 613, L61)

Labels: 2004, /jets

Sat Jul 31, 2004

The optical counterpart of XTE J1709-267

Jonker et al. report on Chandra and CTIO observations, as well as RXTE observations revealing bursts with an unusual precursor. A similar event occurred in the well-known burster 4U 1636-536
Accepted by MNRAS 22 July 2004

Labels: 2004, /transients

Sat Jul 10, 2004

A frequency glitch in an accreting pulsar

RXTE observations reveal the 18.7 s pulsar KS 1947+30 to be in an almost circular 40.415 d orbit. We found evidence for a "glitch" - an abrupt increase in the neutron star spin frequency - previously observed only in radio pulsars and AXPs.
Read the paper (accepted by ApJ 6/11/2004)

Labels: 2004, /hmxbs

Sun Jan 04, 2004

New results from the "Clocked Burster" GS 1826-24

Analysis of the regular thermonuclear bursts from GS 1826-24 provide the best verification yet of theoretical ignition models. Solar metallicity models naturally reproduce the observed burst energies, but not the recurrence time variation.
Read the paper (ApJ 601, 466)

Labels: 2004, /thermonuclear bursts