Gamma-Ray Bursts: their Nature and use as Cosmological Probes

Lead Research Organisation: University of Leicester
Department Name: Physics and Astronomy

Abstract

Gamma-ray bursts, usually known as GRBs, were originally discovered in the 1960s by orbiting military satellites, but only in 1997 was the distance to one first measured. To many astronomers' surprise it turned out to be about half way across the observable universe, which meant that GRBs are by far the most luminous objects known to science. This breakthrough was made possible by the detection of the faint, fading remnant of the GRB, a so-called afterglow, in optical light. GRBs themselves are characterised by the intense bursts of high-energy gamma-rays they produce, which only last typically a few seconds or minutes. By contrast, the afterglows, fade away over a period of days and weeks. Optical detection turned out to be critical because it provided a very accurate position for the GRB, and ultimately a spectroscopic redshift, which astronomers can easily translate into a measurement of distance. Since 1997, further research has shown that GRBs are produced when certain rare kinds of star, much more massive than the Sun, collapse at the end of their lives to form black-holes. In the process, by means we still don't understand, jets of material are ejected at velocities very close to the speed of light. These jets are the source of the flashes of gamma-rays we see, and when they crash into the tenuous gas surrounding the star, the afterglow light is produced. My research is aimed at better understanding these astonishing events, and using these ultimate cosmic light-houses to probe distant regions of the universe. The next few years promise to be a very exciting time in the GRB field thanks to the new US/UK/Italian satellite called Swift. This satellite detects around 100 GRBs per year, and rapidly transmits their positions to the ground. My own programs are largely concerned with following up these positions, to find and monitor afterglows, and to search for rare exciting types of GRBs. To do this I use the UK's RoboNet network of 3 large robotic telescopes sited at various locations around the world, along with many other powerful facilities, including the VLT and Gemini 8 m telescopes, the Hubble Space Telescope. A particularly exciting possibility is that with Swift we will discover GRBs at distances greater than any previous galaxy or quasar has been found. Since when we look across the universe we are looking backward in time, such a discovery would open a new window on the very earliest times, shortly after the Big Bang. At these distances galaxies and even quasars are expected to be rare and faint. GRBs by contrast should be bright enough to detect, and providing we can observe them quickly enough, should provide a great deal of information about the regions they occur in, and the state of matter in the universe at that time. My programmes have already contributed to discovering the two most distant GRBs to date, and have followed up one that has been tentatively claimed may be the most distant of them all. Another prime goal is to investigate the nature of so-called 'short duration' bursts. These events are very similar to the standard GRBs, but their gamma-ray flashes are briefer, often much less than a second. Only in the last year have afterglows been found for these bursts, and they seem to be a surpringly diverse population. A favourite idea is that they might be produced when two neutron-stars, extremely dense objects with masses similar to that of the Sun, but sizes only a few miles across, collide and merge with each other releasing enormous reservoirs of energy. However, it is increasingly clear that some GRBs must come from different sources, in particular giant flares from highly magnetic neutron stars in nearby galaxies. Observing GRBs is intensive and time-critical, and requires observers to be available 24 hours a day, 365 days a year. This grant would pay for a dedicated PDRA to share the burden of this effort and ensure the PI is able to effectively coordinate the followup.

Publications

10 25 50

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Huxor A (2011) Exploring the properties of the M31 halo globular cluster system The M31 halo globular cluster system in Monthly Notices of the Royal Astronomical Society

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Huxor A (2013) Three newly discovered globular clusters in NGC 6822 in Monthly Notices of the Royal Astronomical Society

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Jaunsen A. O. (2008) GRB 070306: A highly extinguished afterglow in ASTROPHYSICAL JOURNAL

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Levan A (2007) A case of mistaken identity? GRB 060912A and the nature of the long-short GRB divide* in Monthly Notices of the Royal Astronomical Society

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Levan A (2008) On the nature of the short-duration GRB 050906 ? On the nature of the short-duration GRB 050906 in Monthly Notices of the Royal Astronomical Society

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Levan A. J. (2006) The first Swift X-ray flash: The faint afterglow of XRF 050215B in ASTROPHYSICAL JOURNAL

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Levan A. J. (2013) SUPERLUMINOUS X-RAYS FROM A SUPERLUMINOUS SUPERNOVA in ASTROPHYSICAL JOURNAL

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Levan A. J. (2014) A NEW POPULATION OF ULTRA-LONG DURATION GAMMA-RAY BURSTS in ASTROPHYSICAL JOURNAL

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Littlejohns O (2012) The origin of the early-time optical emission of Swift GRB 080310? The early-time emission of GRB 080310 in Monthly Notices of the Royal Astronomical Society

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Littlejohns O (2013) Are gamma-ray bursts the same at high redshift and low redshift? in Monthly Notices of the Royal Astronomical Society

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Mackey A (2013) Young accreted globular clusters in the outer halo of M31 in Monthly Notices of the Royal Astronomical Society

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Mackey A. D. (2013) A PECULIAR FAINT SATELLITE IN THE REMOTE OUTER HALO OF M31 in ASTROPHYSICAL JOURNAL LETTERS

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Malesani D. (2009) EARLY SPECTROSCOPIC IDENTIFICATION OF SN 2008D in ASTROPHYSICAL JOURNAL LETTERS

 
Description Iceland Research Excellence Grant
Amount £2,000 (GBP)
Organisation Icelandic Centre for Research 
Sector Public
Country Iceland
Start 04/2008 
End 04/2011
 
Description Partnership in Science grant
Amount £2,830 (GBP)
Organisation British Council 
Department British Council and Platform Beta Techniek
Sector Charity/Non Profit
Country United Kingdom
Start 08/2009 
End 09/2009
 
Description STFC studentship
Amount £51,010 (GBP)
Organisation Science and Technologies Facilities Council (STFC) 
Sector Public
Country United Kingdom
Start 10/2007 
End 09/2010
 
Description GRB follow-up collaborations 
Organisation Liverpool John Moores University
Department Astrophysics Research Institute
Country United Kingdom 
Sector Academic/University 
PI Contribution My team has played a leading role in the world-wide GRB follow-up activity, which has been greatly enhanced by collaboration with these many groups. The mutual benefits are access to facilities which one wouldn't otherwise have direct access to, sharing workload during time-critical follow-up periods, scientific cross-fertilisation of ideas.
Collaborator Contribution We have collaborated with Prof Bremer's group in Bristol on studies of galaxies at very high redshifts, as selected by gamma-ray bursts.
Impact The outputs are largely the scientific papers already listed. In addition, a number of our results have generated media interest. We have supported (in the sense of helping organise, attending and speaking at etc.) meetings amongst the collaborators. These collaborations have also been vital to the work of PhD students at Leicester under my supervision.
 
Description GRB follow-up collaborations 
Organisation Max Planck Society
Department Max Planck Institute For Extraterrestrial Physics (MPE)
Country Germany 
Sector Academic/University 
PI Contribution My team has played a leading role in the world-wide GRB follow-up activity, which has been greatly enhanced by collaboration with these many groups. The mutual benefits are access to facilities which one wouldn't otherwise have direct access to, sharing workload during time-critical follow-up periods, scientific cross-fertilisation of ideas.
Collaborator Contribution We have collaborated with Prof Bremer's group in Bristol on studies of galaxies at very high redshifts, as selected by gamma-ray bursts.
Impact The outputs are largely the scientific papers already listed. In addition, a number of our results have generated media interest. We have supported (in the sense of helping organise, attending and speaking at etc.) meetings amongst the collaborators. These collaborations have also been vital to the work of PhD students at Leicester under my supervision.
 
Description GRB follow-up collaborations 
Organisation Reykjavík University
Department Department of Physics
Country Iceland 
Sector Academic/University 
PI Contribution My team has played a leading role in the world-wide GRB follow-up activity, which has been greatly enhanced by collaboration with these many groups. The mutual benefits are access to facilities which one wouldn't otherwise have direct access to, sharing workload during time-critical follow-up periods, scientific cross-fertilisation of ideas.
Collaborator Contribution We have collaborated with Prof Bremer's group in Bristol on studies of galaxies at very high redshifts, as selected by gamma-ray bursts.
Impact The outputs are largely the scientific papers already listed. In addition, a number of our results have generated media interest. We have supported (in the sense of helping organise, attending and speaking at etc.) meetings amongst the collaborators. These collaborations have also been vital to the work of PhD students at Leicester under my supervision.
 
Description GRB follow-up collaborations 
Organisation Space Telescope Science Institute
Country United States 
Sector Academic/University 
PI Contribution My team has played a leading role in the world-wide GRB follow-up activity, which has been greatly enhanced by collaboration with these many groups. The mutual benefits are access to facilities which one wouldn't otherwise have direct access to, sharing workload during time-critical follow-up periods, scientific cross-fertilisation of ideas.
Collaborator Contribution We have collaborated with Prof Bremer's group in Bristol on studies of galaxies at very high redshifts, as selected by gamma-ray bursts.
Impact The outputs are largely the scientific papers already listed. In addition, a number of our results have generated media interest. We have supported (in the sense of helping organise, attending and speaking at etc.) meetings amongst the collaborators. These collaborations have also been vital to the work of PhD students at Leicester under my supervision.
 
Description GRB follow-up collaborations 
Organisation University of Amsterdam
Department Department of Astrophysics
Country Netherlands 
Sector Academic/University 
PI Contribution My team has played a leading role in the world-wide GRB follow-up activity, which has been greatly enhanced by collaboration with these many groups. The mutual benefits are access to facilities which one wouldn't otherwise have direct access to, sharing workload during time-critical follow-up periods, scientific cross-fertilisation of ideas.
Collaborator Contribution We have collaborated with Prof Bremer's group in Bristol on studies of galaxies at very high redshifts, as selected by gamma-ray bursts.
Impact The outputs are largely the scientific papers already listed. In addition, a number of our results have generated media interest. We have supported (in the sense of helping organise, attending and speaking at etc.) meetings amongst the collaborators. These collaborations have also been vital to the work of PhD students at Leicester under my supervision.
 
Description GRB follow-up collaborations 
Organisation University of Bristol
Department School of Physics
Country United Kingdom 
Sector Academic/University 
PI Contribution My team has played a leading role in the world-wide GRB follow-up activity, which has been greatly enhanced by collaboration with these many groups. The mutual benefits are access to facilities which one wouldn't otherwise have direct access to, sharing workload during time-critical follow-up periods, scientific cross-fertilisation of ideas.
Collaborator Contribution We have collaborated with Prof Bremer's group in Bristol on studies of galaxies at very high redshifts, as selected by gamma-ray bursts.
Impact The outputs are largely the scientific papers already listed. In addition, a number of our results have generated media interest. We have supported (in the sense of helping organise, attending and speaking at etc.) meetings amongst the collaborators. These collaborations have also been vital to the work of PhD students at Leicester under my supervision.
 
Description GRB follow-up collaborations 
Organisation University of California, Berkeley
Department Department of Astronomy
Country United States 
Sector Academic/University 
PI Contribution My team has played a leading role in the world-wide GRB follow-up activity, which has been greatly enhanced by collaboration with these many groups. The mutual benefits are access to facilities which one wouldn't otherwise have direct access to, sharing workload during time-critical follow-up periods, scientific cross-fertilisation of ideas.
Collaborator Contribution We have collaborated with Prof Bremer's group in Bristol on studies of galaxies at very high redshifts, as selected by gamma-ray bursts.
Impact The outputs are largely the scientific papers already listed. In addition, a number of our results have generated media interest. We have supported (in the sense of helping organise, attending and speaking at etc.) meetings amongst the collaborators. These collaborations have also been vital to the work of PhD students at Leicester under my supervision.
 
Description GRB follow-up collaborations 
Organisation University of Copenhagen
Department Dark Cosmology Centre
Country Denmark 
Sector Academic/University 
PI Contribution My team has played a leading role in the world-wide GRB follow-up activity, which has been greatly enhanced by collaboration with these many groups. The mutual benefits are access to facilities which one wouldn't otherwise have direct access to, sharing workload during time-critical follow-up periods, scientific cross-fertilisation of ideas.
Collaborator Contribution We have collaborated with Prof Bremer's group in Bristol on studies of galaxies at very high redshifts, as selected by gamma-ray bursts.
Impact The outputs are largely the scientific papers already listed. In addition, a number of our results have generated media interest. We have supported (in the sense of helping organise, attending and speaking at etc.) meetings amongst the collaborators. These collaborations have also been vital to the work of PhD students at Leicester under my supervision.
 
Description GRB follow-up collaborations 
Organisation University of Hertfordshire
Department School of Physics and Astronomy
Country United Kingdom 
Sector Academic/University 
PI Contribution My team has played a leading role in the world-wide GRB follow-up activity, which has been greatly enhanced by collaboration with these many groups. The mutual benefits are access to facilities which one wouldn't otherwise have direct access to, sharing workload during time-critical follow-up periods, scientific cross-fertilisation of ideas.
Collaborator Contribution We have collaborated with Prof Bremer's group in Bristol on studies of galaxies at very high redshifts, as selected by gamma-ray bursts.
Impact The outputs are largely the scientific papers already listed. In addition, a number of our results have generated media interest. We have supported (in the sense of helping organise, attending and speaking at etc.) meetings amongst the collaborators. These collaborations have also been vital to the work of PhD students at Leicester under my supervision.
 
Description GRB follow-up collaborations 
Organisation University of Warwick
Department Department of Physics
Country United Kingdom 
Sector Academic/University 
PI Contribution My team has played a leading role in the world-wide GRB follow-up activity, which has been greatly enhanced by collaboration with these many groups. The mutual benefits are access to facilities which one wouldn't otherwise have direct access to, sharing workload during time-critical follow-up periods, scientific cross-fertilisation of ideas.
Collaborator Contribution We have collaborated with Prof Bremer's group in Bristol on studies of galaxies at very high redshifts, as selected by gamma-ray bursts.
Impact The outputs are largely the scientific papers already listed. In addition, a number of our results have generated media interest. We have supported (in the sense of helping organise, attending and speaking at etc.) meetings amongst the collaborators. These collaborations have also been vital to the work of PhD students at Leicester under my supervision.
 
Description Astronomical Society, Cambridge 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Primary Audience Public/other audiences
Results and Impact Talk and power-point show on the high redshift universe, which generated much interest.

Much discussion with participants.
Year(s) Of Engagement Activity 2008
 
Description Astronomical Society, Derby 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Primary Audience Public/other audiences
Results and Impact Talk entitled the biggest bangs in the universe, which generated much discussion.

Lengthy Q&A session
Year(s) Of Engagement Activity 2009
 
Description Astronomical Society, Leicester 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Primary Audience Public/other audiences
Results and Impact Talk by grant-funded post-doc on his research. Very interactive audience.

Much discussion after talk.
Year(s) Of Engagement Activity 2009
 
Description Astronomical Society, Letchworth 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Primary Audience Public/other audiences
Results and Impact Discussed record-breaking gamma-ray burst 090423, which generated much interest/discussion.

Usual Q&A session
Year(s) Of Engagement Activity 2009
 
Description Astronomical Society, Letchworth 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Primary Audience Public/other audiences
Results and Impact Talk on gamma-ray bursts

Length Q&A session
Year(s) Of Engagement Activity 2008
 
Description GRB 080319B 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Primary Audience Public/other audiences
Results and Impact We put out a press release about our contribution to the discovery and study of the brightest light source ever seen in the Universe (GRB080319B). This appeared on many news web sites around the world.

Lots of discussion on-line.
Year(s) Of Engagement Activity 2008
 
Description GRB 090423 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Primary Audience Public/other audiences
Results and Impact The press-releases on our work were picked up by media world-wide. I gave many interviews to radio stations (including radio 4 and radio 5 in UK), web-site maintainers, newspaper and magazine journalists etc.

A great deal of on-line discussion about our work.

As noted above, story picked up by many media, so I can't give a full response from the drop-down menu in question 5.9
Year(s) Of Engagement Activity 2009
 
Description Heart of England Astronomical Society 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Primary Audience Public/other audiences
Results and Impact Talked on record-breaking gamma-ray burst 090423, which generated much interest.

Lengthy Q&A session
Year(s) Of Engagement Activity 2009
 
Description Inaugural lecture 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Primary Audience Public/other audiences
Results and Impact Talk given to members of the public, which was well received.

Lots of post-talk discussions and questions
Year(s) Of Engagement Activity 2008
 
Description Manchester Instititute of Physics 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Primary Audience Public/other audiences
Results and Impact Talk and power-point show on results from the Hubble Space Telescope, with an emphasis on work in which I had been involved. This generated much interest and audience participation.

Lengthy Q&A session with audience following talk
Year(s) Of Engagement Activity 2007
 
Description Photographic exhibition 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? Yes
Primary Audience Public/other audiences
Results and Impact I was one of the astronomers selected for portrait and highlighting their work, as part of a photographic exhibition funded by STFC and RAS as part of the international year of astronomy. Exhibition toured the country and was on web.

For example, see website http://www.maxalexander.com/astronomy/
Year(s) Of Engagement Activity 2009
 
Description School visit to department 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Primary Audience Schools
Results and Impact Gave a talk on science research, and careers in science. Pupils particularly interested in what degree courses would be most useful if they wanted to follow a career in research.

School sent note of thanks for talk.
Year(s) Of Engagement Activity 2009