Had a great week at the Institute for Nuclear Theory in Seattle, WA while attending the IReNA-INT Joint Workshop on Thermal and Magnetic Evolution of Neutron Stars. This workshop brought together theoretical and observational astrophysicists, with nuclear experimenters and theorists, and covered a wide range of topics of relevance to understanding neutron stars. I kicked things off on Monday talking about some of the exciting new observations of thermonuclear bursts that have happened over the last couple of years.

I really like the INT's approach to bring researchers together in small, focussed workshops to help encourage progress. A relaxed schedule — with afternoons free for general discussion and pop-up talks — is ideal. And even though the in-person interactions are most valuable, the organisers encouraged on-line presentations and participation, which is mandatory IMO for modern meetings. (I'd presented twice before to INT workshops, but both times remotely). I really appreciate the support of IReNA which made my attendance possible.

Labels: 2024, meetings

Just got back from a wonderful visit to the International Space Science Insitute in Bern. A really productive 3 weeks, working with colleagues Maurizio Falanga (also ISSI Director) and Zhaosheng Li, also visiting from Xiangtan U.. Some good discussions about thermonuclear bursts and work with data from China's HXMT-Insight telescope.

Also spent plenty of time working on the beansp code and made some really significant improvements to the code, which hopefully should be reported soon in a paper.

It wasn't all work though and I inadvertently timed my visit to include ISSI's annual dinner at the lovely Bellevue Palace, a wonderful night. I also enjoyed two weekends of glorious (although cold) weather, biking through the Aare and Rhône valleys, and of course all the glorious food. Particular thanks to my ISSI hosts for making me feel at home!

Labels: 2024, visits

Had a fantastic time in Leiden this week attending the Extreme Matter in Extreme Stars, hosted by the always-brilliant Lorentz Center. The meeting sought to bring together neutron star theorists and observers, with nuclear physics theorists and experimenters, as well as people interested in gravitational-wave sources involving neutron stars. Really nice program with only a few review talks but plenty of opportunity for discussion and short "pop-up" talks, and great attendance by ECRs. To put our money where our mouths are we were tasked with writing a "white paper" or similar intended to bridge the information/assumption gaps between these various communities. A week is only enough to really make a start and so our work will continue remotely; stay tuned!

Labels: 2024, meetings

GOTO team members Tom Killestein and Lisa Kelsey have done an incredible job developing and managing our "flagship" outreach program, Kilonova Seekers, launched with great fanfare back in 2023. The project provides candidate transients detected by GOTO and asks users to play "spot the difference" in distingushing genuine transients (or source variability) from various kinds of artifacts that crop up in our differencing procedure. Tom & Lisa wrote up their work for MNRAS and the paper has now been published. Accompanying the paper were press releases from Portsmouth, Turku, Leicester and even Monash, the latter also acknowledging the contribution of Monash PhD student Sergey Belkin. Although it was not possible to include all our contributing volunteer scientists in the author list, they are acknowledged in the paper's appendix A; all 4.5 pages of them! Keep up the great work

Labels: 2024, outreach

Brendan O'Brien runs the amazing Astrophiz series of podcasts, in which he interviews astrophysicists about their work. I met him briefly at the Transients Down Under meeting in January, and and he later arranged an interview which has now been published as Explosive Neutron Stars. If you prefer another source for your podcasts, try Audible, Soundcloud, Apple Podcasts or YouTube. Do yourself a favour — give it a listen!

Labels: 2024, outreach

Almost 20 years ago I made the first attempt to match thermonuclear bursts with the predictions of Andrew Cumming's "settle" code, for the well-known accretion-powered millisecond pulsar SAX J1808.4—3658. The code was written in IDL and kind of clunky, but worked (after a fashion).

Adelle Goodwin took up the reins for her undergrad, and later PhD work, updating both the settle code and translating my crusty IDL code into Python. Over that time we (with Tom Hilder and others) also attempted to apply the code to additional sources, but could never quite get it to work.

With the expert help of the ADACS team, via a project led by Adelle, we have made substantial corrections and improvements to the matching code, now known as beansp (the "p" is silent). In a new paper submitted to MNRAS, we have now successfully applied the code to a second system, IGR J17498—2921. This (also) 401 Hz pulsar went into outburst in 2011 and exhibited a series of bursts, which we matched with settle to infer a very low H-fraction and metallicity. We also constrain the system inclination and find suggestions for a massive (around twice the mass of our sun) neutron star.

Hopefully the code will be applied to additional systems in the near future!

Labels: 2024, thermonuclear bursts