Proposal for a workshop on "Implications of Swift's Discoveries About Gamma-Ray Bursts"

1. Workshop dates and duration:

o The organizers are currently available for the entire duration of the 2007 ACP summer program. o Preferred length of the workshop is two weeks

o Preferred dates are 4-15 June, 11-22 June, or 18-29 June; acceptable dates are 3 June - 17 August; impossible dates are 20 August - 7 September because of conflict with international conference on GRBs sponsored by Los Alamos National Laboratory that will be held in September or early October.

o Adjacency to, or better yet, overlap with supernova workshop being proposed by Josh Frieman would be valuable.

2. Principal organizers:

o Neil Gehrels Code 661 NASA Goddard Space Flight Center Greenbelt, MD 20771 U.S.A.

Tel: 301-286-6546 Email: [email protected]..gov

o Don Lamb Department of Astronomy and University of Chicago 5640 South Ellis Avenue Chicago, IL 60637

Tel: 773-350-3838 (cell) Email: [email protected] U.S.A.

o Luigi Piro Istituto Astrofisica Spaziale Fisica Cosmica, Sez. Roma, INAF Via Fosso del Cavaliere 100 I-00133 Roma Italy

Tel: +39-06-4993-4007 Email:[email protected]

3. Partial list of possible participants*:

Tom Abel Lorenzo Amati Jean-Luc Atteia David Band Scott Barthelmy Chris Belczynski Edo Berger Josh Bloom David Burrows Hsiao-Wen Chen Guido Chincarini Enrico Costa Stefan Covino Brenda Dingus Ed Fenimore Claudio Firmani Derek Fox Dale Frail Filippo Frontera Chris Fryer Andy Fruchter Giancarlo Ghirlanda Gabrielle Ghisillini Jonathan Granot Carlo Graziani Dafne Guetta Kevin Hurley Jens Hjorth Nobuyuki Kawai Chryssa Kouveliotou Shri Kulkarni Pawan Kumar Davide Lazzati Edison Liang Avi Loeb Keith Mason Andrew MacFadyen Sandro Mereghetti Peter Meszaros Ehud Nakar John Nousek Paul O'Brien Julian Osborne Alin Painatescu David Palmer Brian Penprase Rosalba Perna Tsvi Piran J. Xavier Prochaska Enrico Ramirez-Ruiz Dan Reichart James Rhoads George Ricker Peter Roming Elena Rossi Takanori Sakamoto Alicia Soderberg Ginacarlo Tagliaferri Nial Tanvir Marco Tavani Dan Vanden Berk Roland Vanderspek Tom Vestrand Alan Wells Ralph Wijers Stan Woosley Ryo Yamazaki Daisuke Yonetoku Astumasa Yoshida Sarah Yost Bing Zhang

*Given the continued rapid pace of discoveries in the GRB field and the consequent interest in the field, restricting the number of participants to what is typical of Aspen Center for workshops will be a challenge.

4. Description and justification:

In the year and a half since its launch, Swift has accurately localized more than 150 gamma-ray bursts (GRBs). Already Swift has added to our understanding of the GRB/supernova connection; played a key role in largely solve the mystery of short GRBs; explored the transition between the prompt emission and the afterglow emission of GRBs; discovered unexpected new behaviors of the X-ray afterglow of GRBs, including dramatic flaring activity; provided rapid, accurate localizations of GRBs, enabling high-resolution optical spectra to be taken of GRB afterglows that are yielding unique information about the abundances of heavy elements in the circumburst environment, the host galaxies of the bursts, and galaxies along the line of sight from the bursts to us; and discovered the first GRBs at z > 5, which are powerful probes of the very high redshift universe.

In the coming year, Swift will accurately localize another 100 or so GRBs. These bursts will no doubt yield many new surprises. Furthermore, by the time of the proposed workshop, Swift will have accurately localized more than 250 GRBs -- more than all previous GRBs missions combined. This sample of GRBs will make possible important new statistical studies of the bursts.

As is always the case, the new discoveries and the new insights that Swift has made possible have answered many questions about GRBs and raised many more. The purpose of the workshop will be to (1) assess our understanding of GRBs in the light of the discoveries that Swift has made, (2) understand the implications of these discoveries for the of GRBs and for their use as tools to probe the universe, including the properties of the very high redshift universe and the nature of dark energy, and (3) identify the most important questions for future study. Topics that the workshop will address include the following:

o The GRB/supernova connection;

o The nature of short GRBs and their redshift distribution;

o Implications of X-ray observations for the nature of GRBs and their afterglows; o The nature of GRB jets, as implied by Swift XRT observations of GRB afterglows;

o Evidence of long-lived central engines in short and long GRBs and the implications for the nature of the central engines

o Implications of the abundances of heavy elements in the circumburst environment, the host galaxies of GRBs, and DLAs along the line of sight from the bursts to us, as inferred from high resolution optical spectra of GRB afterglows;

o GRBs as probes of the missing baryon mass in the local (z < 1) universe and of the very high redshift (z > 5) universe; and o The use of short GRBs as "standard sirens" and long GRBs as "standard candles" to constrain the properties of dark energy.

5. Contact person: o Don Lamb (University of Chicago) Tel: 773-350-3838 (cell) Email: [email protected]

6. Organizer responsible for working to ensure diversity: o Don Lamb (University of Chicago) Tel: 773-350-3838 (cell) Email: [email protected]

7. Each of the organizers has read and approved this proposal.