Multi-INstrument Burst ARchive - MINBAR

Monday, Jul 24, 2017

New burst source discovered in MINBAR data

During a collaborative visit to SRON, Netherlands MINBAR team member Jean in 't Zand identified a handful of bursts observed by RXTE from a 2008—9 transient, XTE J1812–182, that was not previously known to be a burster. We reported our discovery in Astronomer's Telegram #10567 and will shortly present a more detailed analysis via a paper.


MINBAR team members during the collaboration meeting at DTU Space, Denmark, with INTEGRAL model; from left to right, Jean in 't Zand, Celia Sanchez, Jérôme Chenevez & Duncan Galloway

The discovery took place during a visit that also took in MINBAR team members in DTU Space, Denmark. While there, we also celebrated the deployment of NICER to the International Space Station.

Friday, Mar 24, 2017

Reference bursts from MINBAR

Efforts to match observations of thermonuclear bursts to numerical simulations have been fairly limited to date, partially because of the dearth of high-quality, well characterised burst measurements. To address this issue, we have assembled a set of "reference" bursts from the MINBAR sample, featuring examples of a number of different types of bursts, presented in a paper which has just been accepted by PASA. We also hope that the observed bursts will serve as test cases for numerical codes in order to assess the variations between those codes, in order to quantify the fundamental uncertainty of burst simulations.

Read the paper arXiv:1703.07485 .

Monday, Oct 31, 2016

Burst oscillations from the MINBAR sample

Some thermonuclear burst sources exhibit temporary "burst oscillations", periodic variations in the X-ray intensity at frequencies characteristic of each source. It has been shown that these oscillations trace the neutron star spin, but much is still not known about the detailed mechanism, and many puzzles remain. UvA student Laura Ootes led a comprehensive study of the oscillations detected in the entire Rossi X-ray Timing Explorer sample, which has just been accepted for publication by ApJ. The paper presents a comprehensive comparison of the observed properties with burst oscillation models, and the results of the analysis will be incorporated into the first MINBAR data release (DR1). Although we still cannot unambiguously identify the oscillation mechanism, this analysis is going to be definitive for many years, until a new X-ray timing mission is launched.

Read the paper arXiv:1610.08995

Tuesday, September 6, 2016

MINBAR v0.8

MINBAR version 0.8 was assembled this month, including additional attribute values, notably spectral colours. Various other incremental changes have been made; for a description, and a summary of the data holdings so far, see the release notes.

Monday, Jan 12, 2015

Varying accretion rate during bursts

In a study of several hundred "photospheric radius-expansion" MINBAR bursts observed by the Rossi X-ray Timing Explorer, Monash PhD student Hauke Worpel found evidence that the accretion rate increases by a substantial amount during the burst (Worpel et al. 2013, ApJ 772, 94). As a followup, Hauke also analysed the much larger sample of almost 1800 less-intense bursts, that did not exhibit radius expansion. The additional analyses confirm the original result, and further support the interpretation that the accretion rate is increasing in response to the bursts. Interestingly, even including the amplified contribution from the persistent (accretion) emission does not result in a formally good fit to all the spectra, suggesting that the burst spectrum deviates significantly from a blackbody. Hauke's second paper was just accepted by ApJ.

Read the paper arXiv:1501.02070

Friday, June 20, 2014

MINBAR at the X-ray Universe 2014

MINBAR version 0.7 is currently under development, with additional bursts from JEM-X, along with preliminary persistent spectral fit parameters and intensities for selected JEM-X observations. For full details, see the release notes.

In the meantime, MINBAR was the subject of a presentation at the X-ray Universe 2014 meeting this week, in Dublin, Ireland. The meeting was also a good opportunity to catch up with some of the collaboration members who were also in attendance.

Click for the presentation slides.

Wednesday, December 4, 2013

MINBAR v0.6

MINBAR version 0.6 was assembled this month, including — for the first time — some 2500 events observed by INTEGRAL/JEM-X. The JEM-X data is quite incomplete, and is limited for the time being to the burst start times and likely source origin. Beginning in the new year, it is anticipated that the analysis results for these events will gradually become available and will be added to the database. For a more detailed description of the new data, and a summary of the data holdings so far, see the release notes.

In a parallel effort, the web interface has been restored, and the project webpage is back to its usual location here. I have also created preliminary observation and burst pages (for the JEM-X events only) which are linked to the web interface. Click for an example observation (showing a nice double burst from 4U 0836–429) or burst page.

Tuesday, July 16, 2013

Two steps forward, one step back

In the last few months we've continued work on the JEM-X component of the sample, but also made a lot of progress with improving access to the data. With a new home for burst data at Monash, burst.sci.monash.edu we set up the MINBAR Wiki, and also a new interface to the database, with a lot of help from the Monash e-Research Centre.
Unfortunately, in early July, the machine hosting these new services crashed, and it is still unclear whether we'll be able to recover any of the data. Most can be replaced, but it will take us a little time to bring all these components back on line. In the meantime we've reverted to the old MINBAR page, and some information can still be found on Duncan's wiki.

Tuesday, May 7, 2013

MINBAR News

  1. JEM-X data status
  2. Next MINBAR telecon
  3. New MINBAR web interface - testers please
  4. Goplan site expiry - advice on renewal?


1. JEM-X data status and MINBAR telecon
Work continues intermittently on the JEM-X burst search, and we now have what we think is a fairly robust algorithm for burst searches. Further data analysis has been delayed to some extent by an problem with the spectral response at low energies, but there may already be a (at least partial) fix for this issue. This week Jérôme, Celia and I had a pretty productive teleconference to discuss our progress and the next steps.

2. Next MINBAR telecon
We decided to meet again in a few weeks, and I invite the other MINBAR members to what hopefully will become a regular event. The next telecon will be on
** 21st May 2013 ** from 1000 to 1100 UT (1200-1300 CET; 2000-2100 AET)
Please let me know if you wish to listen in and or contribute. We will connect by Skype where possible or phone otherwise.

3. New MINBAR web interface - testers please
With members of the Monash e-Research Centre I've been building on Laurens' Python interface to produce a new version of the MINBAR web site, with enhanced functionality. It's been quite a time-consuming exercise, but the basic functionality is now ready for some detailed testing. You can access the new interface here:
astrodev.its.monash.edu.au/astroburst
This is currently restricted to collaboration members.
Please have a play around with the filter/search capability and let me know of any issues, or suggestions on how we can improve it. If you do experience issues, please describe as clearly as possible the steps leading up to the problem so we can reproduce them here.
Note that lightcurve plotting and downloading is not yet implemented; shortly we will have a plot page for each burst (where good data exists).

4. Goplan site expiry - advice on renewal?
The license for the Goplan project management site we've had for a few years has now expired, and I'm debating whether or not to renew it. We now have a new server at Monash with a dedicated virtual machine for burst data:
burst.sci.monash.edu
(ultimately this will be where the MINBAR burst interface will live). Please let me know what you think about switching to a wiki for our project files, rather than the Goplan site. The proposed location would be
burst.sci.monash.edu/wiki/index.php?n=MINBAR.Home
and would be publicly available to view, but editable only by collaboration members.

Friday, August 17, 2012

MINBAR progress & web interface

Work over the last few months has focussed on the search for, and verification of, burst candidates in the INTEGRAL/JEM-X data. This has coincided with the move of DTU Space to the main DTU campus in Lyngby, Denmark. Needless to say the move has resulted in some disruption and delays in the work!
Last month also saw the visit to Monash of MINBAR team member Laurens Keek, now at NSCL, MSU. Much use was made of the preliminary version of the database, and Laurens also set up his web interface locally (Monash access only).

Monday, January 9, 2012

Acknowledging MINBAR

Shortly we plan to publish a paper presenting the entire dataset comprising MINBAR, but already, scientific results are beginning to emerge. Below is some suggested text to acknowledge the results in the meantime; please also include the URL of this page http://burst.sci.monash.edu/minbar somewhere in the text.

This paper utilizes preliminary analysis results from the Multi-INstrument Burst ARchive (MINBAR), which is supported under the Australian Academy of Science's Scientific Visits to Europe program, and the Australian Research Council's Discovery Projects and Future Fellowship funding schemes.

Monday, March 28, 2011

MINBAR at ISSI

I presented a progress report on MIN(i)BAR at the first of two meetings at the International Space Science Institute in Bern, on the subject of thermonuclear bursts. We had a very productive meeting and set some important tasks to help us better understand our observations of these events. The MINBAR data served as the basis for a catalogue of intermediate-duration bursts, one of the deliverables for the ISSI team.

Wednesday, July 21, 2010

MINBAR at COSPAR10

Today I'm exhibiting a poster describing the MINBAR project and our progress to date as part of COSPAR10 event E13. If you're at COSPAR the poster can be found to the right of the exit near the stairs going up to the CCB area on the first floor. Please stop by and check it out!

Monday, July 19, 2010

Introducing MINBAR

The MINBAR project commenced in 2007 when I visited SRON for three weeks to work with Jean in 't Zand and his then-student, Laurens Keek. This visit was made possible thanks to the generous support of the Australian Academy of Science via their Scientific Visits to Europe program. Here is the project summary:

Thermonuclear bursts occur when accumulated H/He fuel ignites on the surface of neutron stars. These events can reveal information about the interior properties and composition, both of which are very poorly understood and thus are high-priority international research areas. Extensive samples of >1000 bursts have been accumulated over the last 10 years by the Dutch/Italian BeppoSAX and NASA's RXTE X-ray satellites. I propose to combine these samples and thereby quantify global burst behaviour over a broad range of conditions. This work will result in the most extensive dataset ever with which to probe the neutron star interior.

Around that time I discovered that the JEM-X cameras onboard ESA's INTEGRAL satellite had been built just next door, at the Danish Space Research Institute, so I arranged a visit and brought Jerome Chenevez onto the team. Some years later, we are still working on this, but hope to have our first public release of results within the next 12 months. Stay tuned!

URL: http://burst.sci.monash.edu/minbar/index.html
5th September 2017