Fast Breaking Comment by Alex Blustin

Alex Blustin answers a few questions about this month's fast breaking paper in the field of Space Science. The author has also sent along images of their work.

From •>>October 2006
Article Title: Swift panchromatic observations of the bright gamma-ray burst GRB 050525a
Authors: Blustin, AJ;Band, D;Barthelmy, S;Boyd, P;Capalbi, M;Holland, ST;Marshall, FE;Mason, KO;Perri, M;Poole, T;Roming, P;Rosen, S;Schady, P;Still, M;Zhang, B;Angelini, L;Barbier, L;Beardmore, A;Breeveld, A;Burrows, DN;Cummings, JR;Canizzo, J;Campana, S;Chester, MM;Chincarini, G;Cominsky, LR;Cucchiara, A;de Pasquale, M;Fenimore, EE;Gehrels, N;Giommi, P;Goad, M;Gronwall, C;Grupe, D;Hill, JE;Hinshaw, D;Hunsberger, S;Hurley, KC;Ivanushkina, M;Kennea, JA;Krimm, HA;Kumar, P;Landsman, W;La Parola, V;Markwardt, CB;McGowan, K;Meszaros, P;Mineo, T;Moretti, A;Morgan, A;Nousek, J;O'Brien, PT;Osborne, JP;Page, K;Page, MJ;Palmer, DM;Parsons, AM;Rhoads, J;Romano, P;Sakamoto, T;Sato, G;Tagliaferri, G;Tueller, J;Wells, AA;White, NE
Journal: ASTROPHYS J
Volume: 637
Issue: 2
Page: 901-913
Year: Part 1 FEB 1 2006
* Univ Coll London, Mullard Space Sci Lab, Dept Space & Climate Phys, Holmbury St Mary, Dorking RH5 6NT, Surrey, England.
* Univ Coll London, Mullard Space Sci Lab, Dept Space & Climate Phys, Dorking RH5 6NT, Surrey, England.
* NASA, Goddard Space Flight Ctr, Greenbelt, MD 20771 USA.
* ASI Sci Data Ctr, I-00044 Frascati, Rome, Italy.
* Penn State Univ, Dept Astron & Astrophys, Davey Lab 525, University Pk, PA 16802 USA.
* Univ Nevada, Dept Phys, Las Vegas, NV 89154 USA.
* Univ Leicester, Dept Phys & Astron, Leicester LE1 7RH, Leics, England.
* INAF Osservatorio Astron Brera, I-23807 Merate, Italy.
* Sonoma State Univ, Dept Phys & Astron, Rohnert Pk, CA 94928 USA.
* Los Alamos Natl Lab, Los Alamos, NM 87545 USA.
* Univ Calif Berkeley, Space Sci Lab, Berkeley, CA 94720 USA.
* Univ Texas, Dept Astron, Austin, TX 78712 USA.
* INAF Ist Astrofis Spaziale & Cosm, I-90146 Palermo, Italy.
* Space Telescope Sci Inst, Baltimore, MD 21218 USA.
* Inst Space & Astronaut Sci, Kanagawa 2298510, Japan.

Why do you think your paper is highly cited?

This paper describes the observations by the Swift satellite of a bright, nearby—at a redshift of 0.61—Gamma-Ray Burst (GRB) and its aftermath. We got excellent data at gamma-ray, X-ray, UV, and optical wavelengths, with the most comprehensive information at that time on the decay of the afterglow in the X-rays and multiple UV and optical bands. The paper provides a definitive view of a canonical GRB, setting stringent constraints on theoretical models of GRB afterglows.

Does it describe a new discovery, methodology or synthesis of knowledge?

“We obtained the first ever measurement of how the ultraviolet light emitted as part of a Gamma-Ray Burst (GRB) event fades away. This is important in understanding the nature and evolution of the GRB explosion, as well as the environment in which the event takes place.”

We obtained the first ever measurement of how the ultraviolet light emitted as part of a GRB event fades away. This is important in understanding the nature and evolution of the GRB explosion, as well as the environment in which the event takes place.

Could you summarize the significance of your paper in layman’s terms?

A GRB is a very brief flash of gamma-rays from deep space, usually followed by a fading afterglow at a wide range of wavelengths. They originate in explosions in distant galaxies, either due to the death of a massive star, or to the collisions of compact objects such as neutron stars or black holes.

The amount of energy given out in a few seconds by one of these explosions is equivalent to the total amount of energy given out by the Sun over its entire lifetime, making them the most powerful explosions since the Big Bang.

Since they can occur anywhere on the sky at any time, NASA’s Swift mission was designed to monitor 1/6 of the sky for new GRBs with its wide-angle gamma-ray telescope, and to re-point itself automatically to observe new bursts with its narrow-field X-ray and UV/optical telescopes.

The burst we observed was relatively nearby in cosmic terms—in a galaxy 8,400,000,000 light-years away—and probably originated in the collapse of a massive star. For the first time, we were able to observe the fading of the afterglow in UV light.

Comparing the optical/UV and X-ray afterglow decays and taking into account what we learn from the initial gamma-ray emission, we determined the opening angle of the fast-moving jet of matter shot out by the explosion, and the changing energy output across the different wavelengths showed us how the initial fireball cooled.

How did you become involved in this research, and were any problems encountered along the way?

Swift Mission Operations are based at Penn State University in the US, with responsibilities for instrument-specific science and engineering tasks being distributed among several institutes in the US and Europe. I managed Swift science operations at UCL’s Mullard Space Science Laboratory (UK) for the first two years of the mission. During this time I took part in both the analysis of the real-time science data from Swift, and also the calibration of the UV/Optical telescope on board.

Due to the unpredictable nature of GRBs and the semi-autonomous operation of the satellite, no other mission has been run like this before—it relies on teams of scientists in the US, UK, and Italy being on-call to deal with bursts and instrumental issues as they arise, under a lot of time pressure. It has been a steep learning curve right from the beginning, as the teams gained experience and worked out how to do things the hard way.

The project demands a high level of commitment, but there is an incredible pay-off from this as you are in an environment where every week, it seems, we are learning exciting new things about the Universe.

Are there any social or political implications for your research?

The quest to understand the Universe has been a popular theme in human thought and society for a very long time.

Dr. Alexander J. Blustin
UCL Department of Space & Climate Physics
Mullard Space Science Laboratory
Holmbury St. Mary, Dorking, Surrey, UK

A Closer Look...

Below are image(s) sent in by Alex Blustin which correspond with the featured paper, or current research.

Figure 1:

Figure 1:
Artist’s impression of the ‘central engine’ of a Gamma-Ray Burst, where veils of hot plasma conceal the black hole formed at the core of a massive collapsing star, with jets of matter shot out at speeds close to the speed of light along the rotation axis of the black hole.
Image courtesy NASA/SkyWorks Digital.

ESI Special Topics, October 2006
Citing URL - http://www.esi-topics.com/fbp/2006/october06-AlexBlustin.html