The Neil Gehrels Swift Observatory

Description of the Swift Guest Investigator Program - Cycle 2

This information parallels the information available through NASA Headquarters in the Swift front page of the ROSES-2005 Announcement, "C.12 Swift Guest Investigator - Cycle 2" section, part 1.

Scope of Program

1. Overview

The Swift Guest Investigator program element solicits proposals for basic research relevant to the Swift gamma-ray burst mission. The primary goal of this mission is to determine the origin of gamma-ray bursts (GRBs) and use these bursts to probe the early universe. This solicitation is for Cycle 2 of the Swift Guest Investigator (GI) Program, which begins 16 months after launch and will last 12 months.

The Swift GI Program is open only to scientists at U.S. institutions; similar GI programs may be considered in the United Kingdom and Italy if desired in those countries and if funding is available. Consistent with Explorer Program policy, there will be no proprietary data rights to observations conducted on Swift. All science data will be made freely available online.

The GI program is intended to provide the following benefits to participating scientists:

2. The Swift mission

Swift is a Medium Class Explorer (MIDEX) mission under development at the NASA Goddard Space Flight Center (GSFC). The lead domestic partners include Pennsylvania State University and the spacecraft contractor, Spectrum Astro. There is significant international participation by groups in the United Kingdom and Italy. The Swift mission was launched on November 20, 2004 from Cape Canaveral Air Force Station, Florida. Swift was launched into a low Earth orbit with an inclination of 22 degrees and an altitude of 600 km. The baseline mission duration is two years, with possible extension beyond this initial period depending upon the continued scientific productivity of the mission. The orbital lifetime of the satellite is estimated to be approximately 8 years. The Swift spacecraft carries three science instruments: a wide-field gamma-ray Burst Alert Telescope (BAT) and two sensitive, coaligned narrow-field instruments - the X-ray Telescope (XRT) and UV Optical Telescope (UVOT). The spacecraft can be autonomously repositioned to direct the XRT and UVOT toward events detected by the BAT. The BAT is a wide-field gamma-ray imager that will detect GRB's and rapidly send positions of arc minute accuracy to the spacecraft and to the ground. The BAT operates in the 15-150 keV range and has a 1.4 steradian (half-coded) field of view. It will have a GRB detection sensitivity that is ~2-5 times (depending on the burst position in the field-of-view) better than the Burst and Transient Source Experiment (BATSE) that flew on the Compton Gamma-Ray Observatory (CGRO). In addition to detecting GRBs, the BAT will perform a survey of the hard x-ray sky to a sensitivity of ~ 1 mCrab (2 x 10-11 erg cm-2 s-1). It will also scan most of the sky each 90-minute orbit and serve as a sensitive monitor for high energy transients. Positions and spectra of transients detected by BAT will be telemetered to the ground and distributed immediately to the community.

In response to GRB alerts from the BAT, the spacecraft will reorient on a time scale of ~ 1 minute to point the XRT and UVOT instruments at a GRB or other transient. These instruments will perform multiwavelength measurements of the bright early afterglow (and also later-time afterglow) emission to provide sub-arc second positions, precise photometry and fine spectroscopy. The XRT is a Wolter 1 grazing incidence telescope which operates in the 0.2-10 keV band and has a field-of-view of 24 arc minutes with an angular resolution of 18 arcseconds and positional determination accuracy of 5 arcseconds. The detector is a cooled CCD, providing spectroscopy with a resolution E/δE ~ 10 at 1 keV and an effective area of 110 cm2. An onboard thermoelectric cooler (TEC) designed to maintain the CCD temperature at a level of ~ -100o C failed to activate during the instrument turn-on. Operation of the CCD at a suboptimal temperature is expected to result in a gradual degradation of the XRT spectral resolution and line sensitivity over the life of the mission. Prospective proposers whose investigations are dependent upon the spectral performance of the XRT are encouraged to consult the Swift Web site for information on the status of the instrument. The UVOT is a Ritchey-Chrétien folded-optics telescope operating in the 170 - 650 nm band. It has a field-of-view of 17 arcminutes, with an angular resolution of 0.9 arcseconds and positional determination accuracy of 0.3 arcseconds. UVOT will provide a sensitivity of 24th magnitude for a 1000 second integration and has 6 filters for color photometry and 2 grisms for fine spectroscopy (E/δE ~ 300) of sources brighter than 17th magnitude. The narrow-field instruments will produce and optical finding chart and X-ray spectra of the afterglow within minutes of the burst. This information will be distributed immediately over the Internet. Data from continued observations of the afterglow will be made available on a public Web site. Data from serendipitous sources in the fields-of-view of both instruments will routinely be sent to the ground for analysis.

Further information on the Swift mission may be found at the Swift Web site.

3. Types of Proposals

The Swift science team core science program is organized by Key Projects that cover both GRB and non-GRB topics. These projects represent investigations directed toward addressing the science goals discussed in the original Swift MIDEX proposal. Each Key Project has a small number of Swift science team members assigned to it. This Cycle 2 Swift GI program (during years 2 and 3) solicits proposals in the following areas:

In Cycle 2, GIs may propose to initiate their own new GRB projects, avoiding duplication of existing efforts while supplementing the Swift science return with their unique facilities and capabilities. Proposers should address how their activities will complement the Swift science team core science program. The extent to which the proposed research will enhance the science return from Swift and the demands placed upon mission resources by an investigation will be considered in the proposal evaluation process (see Section 2.2 below).

It is anticipated that correlative observations will substantially augment the science return from Swift. The Swift instruments will make breakthrough measurements of GRB afterglows starting immediately following the burst. However, it will not be possible to follow up all GRB's on all time scales since viewing constraints and scheduling conflicts will preclude some Swift observations. Also, the onboard capability, although significant, does not cover all of the scientifically valuable measurements that need to made. Candidate correlative observations that will add significantly to the Swift science include radio imaging and photometry, infrared spectroscopy (for high z bursts redshifted out of the bandpass of the UVOT), deep optical imaging and spectroscopy (relative to the UVOT 24th magnitude limit) of the afterglow and possible host galaxy, deep X-ray imaging and spectroscopy, and rapid optical observations with time scales shorter than the 1-minute Swift response time.

Finally, theoretical studies related to the observations conducted with Swift hold the potential to significantly enhance the scientific impact of the mission. Accordingly, GI proposals for theoretical investigations are solicited during Cycle 2 with the requirement that they specifically address how the anticipated results will advance the mission GRB science objectives.

It is anticipated that the Swift GI program may be expanded in the future to include areas of research in non-GRB science and possibly allow GI-specified pointings. Note that proposals for non-GRB research are not solicited under Cycle 2. Depending upon the experience gained during Cycle 1, the above restrictions may be relaxed and prospective investigators will be notified. In any event, investigators seeking support for such research during Cycle 2 may submit their proposals to the Astrophysics Data Analysis Program (ADP) discussed in Appendix C.2 of this NRA.

Swift observations of gamma ray bursts and their follow-up observations immediately flow to the community through the Swift Quick Look Facility and later the HEASARC. The current Announcement covers investigations using Swift data for the 12 months beginning approximately March 2006. Note that 100% of the observing time is immediately available to the scientific community; i.e., there is no guaranteed time for the instrument teams, and there is no proprietary period for any observations. Swift investigations to be funded through this announcement will be selected by a competitive peer review process directed by the cognizant discipline scientist in the Science Mission Directorate, NASA Headquarters.

All proposals submitted in response to this Announcement must be for scientific investigations of gamma ray bursts related to Swift data. Proposals for pointed Swift observations, or for investigations of non-GRB science using Swift data will not be accepted in Cycle 2.

For more details about the science payload and operations plan, please see the Swift Technical Handbook. For further information on proposal preparation and submission, please see our Information for proposers regarding proposal submission page.

4. Funding

Accepted Cycle 2 Swift investigations will be funded as resources permit, with budgets allocated through a peer review process. Since no targets will be awarded as part of Swift Cycle 2, both scientific justification and budget information are expected and required as part of Swift Cycle 2 proposals.

Return to Swift GI Information Page