high-energy group | MoCA | GOTO | MINBAR | MIT/RXTE burst catalog | HEAT | vcard | CV | wiki

Wed Sep 17, 2014

MoCA vacation scholarships

Fancy a vacation project with a difference? The Monash Centre for Astrophysics is offering a number of vacation projects for (southern) summer 2014—15. Whether you're interested in core collapse supernovae, thermonuclear bursts, X-ray transients or star formation, there's a project for you. Apply before October 13, 2014

Labels: 2014, /opportunities

Wed Aug 06, 2014

Physics of Neutron stars 2014

The Physics of Neutron Stars meeting is held approximately every three years, and honors prominent Soviet physicist Yakov Zel'dovich. The conference talks and posters covered a very wide range of topics relevant to neutron stars, from pulsar emission mechanisms to magnetars and supernova explosions. I gave a talk on observations of thermonuclear bursts. The organisers offered a cultural program including excursions to prominent attractions in this beautiful city; I chose to visit the Catherine Palace and park, with a boat ride of the extensive canal network to follow. Very nice conference in a terrific venue.

Observations of X-ray bursters (4.3 MB PDF)

Labels: 2014, /meetings

Mon Jul 28, 2014

ASA's Annual Science Meeting @ Macquarie U.

The Astronomical Society of Australia held its Annual Scientific Meeting at Macquarie University in Sydney, NSW this month. A notable inclusion to the program was the presentation, on Tuesday, of the draft reports to the National Committee for Astronomy for the Decadal Plan 2016—2025. Eleven working groups (including the group I chair, WG1.4: High energy and fundamental astrophysics) have been consulting broadly via community meetings since February, and this week offered the first opportunity for broad community review of, and feedback for, the draft reports. The session went very well and there is (I believe) a sense that the level of community interaction in this process has been extremely inclusive, so that all stakeholders have been represented. I also gave a talk on the Friday describing a new project aimed at closing the loop between thermonuclear burst observations, modelling, and nuclear experiments, which for the moment I've given the acronym NAGA*. An unusual inclusion in the social program was the opening of an art exhibition, Fields of Vision: Art and Astronomy which was a very civilized addition. The dinner, at the lovely Curzon hall, was terrific.

* Need A Good Acronym

Labels: 2014, /meetings

Thu Jun 26, 2014

Catching a gravitational wave

Gravitational waves are incredibly feeble, and it doesn't help when the source of the waves is also moving about in the sky, for example in a binary orbit around a companion. That's the case for Scorpius X-1, thought to be the best candidate for persistent gravitational waves among the class of accreting neutron stars. Measurements to improve the precision of the orbital parameters can help in turn to improve the sensitivity of future gravitational wave searches. A Monash media story accompanying our recent paper reporting such measurements for Sco X-1 was also reported in ifl science and phys.org

Labels: 2014, /press

Mon Jun 23, 2014

Influence of accretion geometry on bursts

One of the interesting outcomes of our ISSI international team on thermonuclear bursts was the work by Juri Poutanen (U. Turku) and his then-student Jari Kajava (now an ESAC research fellow), showing that the spectral evolution during the burst proceeded in characteristically different ways, depending upon the persistent spectral state of the source at the time of the burst. The persistent X-rays from burst sources arises from accretion, and these sources are found in two broad states: hard and soft, which are thought to indicate different physical conditions in the accretion flow. Juri's paper (arXiv.org:1405.2663) concerned the well-known burster and transient 4U 1608—52, while a companion paper led by Jari (arXiv.org:1406.0322) extended this analysis to 10 other sources. Those who study bursts are increasingly concerned with the interaction of bursts and the accretion environment, and these results are helping to determine just how these two phenomena are relatied. Juri's paper was just accepted by MNRAS, and Jari's paper has been submitted.

Read the papers arXiv:1405.2663 & arXiv:1406.0322

Labels: 2014, /thermonuclear bursts

Thu Feb 06, 2014

Australian Astronomy Decadal Plan 2016—25

Every ten years the Australian astronomy community collaborates to produce a plan covering the next decade. The National Committee for Astronomy kicked the planning for the period 2016—25 off last year, and teams of working groups are already busy preparing their submissions. As part of the process, there will be a series of "town-hall" style meetings to allow interested individuals and groups to provide input to the planning process. The first such meeting will be held next Friday, 14th February, here at Monash, and will cover working groups 1.2 (stars and planets) and 1.4 (high energy and fundamental astrophysics, which I chair). Please come along and have your say about the future direction of astronomy in Australia!

For more information see the Decadal Plan web site

Labels: 2014, /meetings

Mon Jan 06, 2014

Improved precision on Sco X-1 orbital parameters

Sco X-1 field with Uhuru Our program Precision Ephemeridies for Gravitational wave Searches (PEGS) posted it's first result this month, with the publication of refined orbital parameters for the X-ray binary Sco X-1. This remarkable source was the first X-ray binary ever discovered, and it's 19 hr orbital period was already known to unusually high precision thanks to 89 years of photometric observations. Thanks to new spectroscopic measurements from 2011, analysed by Monash PhD student Shakya Premachandra,we made a significantly more precise measurement, and also projected the uncertainties (including the effects of additional observations) forward into the Advanced LIGO/Virgo observing epoch. The paper is out this month in the Astrophysical Journal.

Read the paper

Labels: 2014, /gravitational waves