Defining the neutron star crust meeting

I just got back from a terrific meeting in Santa Fe on the subject of the neutron star crust, and attended by a wide range of nuclear theorists and experimentalists as well as astrophysicists. There were many interesting talks, and I learned a lot; one of the overarching themes was the need for better communication between the various groups — Bob Rutledge was remarkably persistent in asking after almost every talk, "what one thing would you like the other groups represented here to take away from your work?" (to paraphrase a little). The meeting was also one of the most "wired" that I have been to, with a blog including twitter updates, and culminating in the creation of a reddit group called neutronstarstructure to collect relevant papers on the subject.
I gave a talk on some of the recent work I've been doing with determining neutron star redshifts and mass, radius from mixed H/He thermonuclear bursts, which prompted quite a response.

Defining the Neutron Star Crust: X-ray Bursts, Superbursts and Giant Flares
Measuring neutron star parameters from mixed H/He thermonuclear bursts (3.2 MB PPT or 1.5 MB PDF)

2009 has been designated the International Year of Astronomy by the International Astronomical Union (IAU) and UNESCO. I think I can speak for most astronomers when I say that we think astronomy is too much fun to keep to ourselves! There is a lot going on throughout the year, and a group here at Monash have been planning a bunch of fun and interesting activities. Check out the website iya09.monash.edu.au to find out more

A plethora of pulsars

This has been a fun few months for those interested in accretion-powered millisecond pulsars (and who isn't?) We've been observing HETE J1900.1-2455 for more than 3 years now, it has had by far the longest period of activity of any of the 8 known systems. Then, in August, IGR J00291+5934 went into outburst for the first time since it's December 2004 outburst. The X-ray flux faded shortly after, but the system unexpectedly returned to activity about a month later. To top it all off, the first-ever AMSP, SAX J1808.4-3658, also went into outburst in late September. Three AMSPs active at the same time is a terrific coincidence.

>> Read more But there's more. Back in 2007 I made some predictions for the time of the next outburst for these two systems, based on the observed outbursts to date (see the table below). These predictions were remarkably accurate, with errors of 11 and 20 days (or 0.7 and 1.7%), for the two sources. For the record, I'm now prepared to make my predictions for the next outburst for each of these systems; for SAX J1808.4-3658 on 2012 May 15 (MJD 56062) and for IGR J00291+5934 a few months later on 2012 September 23 (MJD 56193). I hope to be able to report here how these new predictions hold up!
Table: Predictions of 2008 outburst times for two AMSPs (arXiv.org:0711.4420)

	Outburst time (MJD)
Source	predicted	actual	Error (d)
IGR J00291+5934	54680	54691	11
SAX J1808.4-3658	54710	54730	20

ASA 2008, Perth WA

The annual meeting of the Astronomical Society of Australia was held this July in Perth, WA. I've never spent much time in Perth, so it was good to spend a little time over there. The UWA campus at Crawley is beautiful, right on the shore of the Swan river, and with fantastic architecture and gardens. We stayed at St. George's College, which is also very picturesque, and backs onto King's Park. The meeting was very well attended and a lot of fun. I gave an invited talk on searches for spectral features from radius-expansion bursts observed by RXTE

ASA 2008, Perth WA
ASA talk (2.9MB PDF)