# Presentation: 115246

## GLAST Large Area Telescope Multiwavelength Planning

**D. J. Thompson (NASA/GSFC), R. A. Cameron, S. W. Digel (SLAC), K. S. Wood (NRL)**
**On behalf of the GLAST LAT Collaboration **

| Science Objective | GLAST Provides | MultiwavelengthRequirements | MultiwavelengthPlanning Activities |
| --- | --- | --- | --- |
| Differential measurement (vs Z) of extragalactic background light to   Z ~5.5 | Measurement of blazar spectra in band where cutoffs are expected from      + ebl → e+ + e-  | Broadband contemporaneous/ simultaneous spectral measurements (radio, optical, X-ray, TeV) of blazar spectra, particularly around the synchrotron peak 

Redshift and afterglow measurements for GRB | 
Cooperate with and expand existing multiwavelength blazar and GRB campaigns (e.g. WEBT, ENIGMA, GTN, Swift) to have the broadest possible coverage during the mission  |
| Resolve origin of particle acceleration and emission mechanisms in systems with relativistic jets, supermassive black holes | All-sky monitoring coverage of blazar flares and Gamma Ray Bursts (GRB) | 
Radio and optical surveys of flat-spectrum radio sources to extend blazar catalogs, including redshift measurements | 
Participate with and encourage programs to expand blazar catalogs and measure redshifts for flat-spectrum radio sources  |
| Reliable model of Milky Way diffuse emission required for accurate source localization and to facilitate search for dark matter | Mapping of cosmic ray interactions with all forms of interstellar matter  | Extend CO surveys to high galactic latitude;
survey special directions (eg. spiral arms, galactic center) with optically thin tracer (e.g.  C18O) | Promote needed CO and other tracer observations; work with observers to reduce data and incorporate into a model of the diffuse gamma-ray emission  |
| Search out and understand new classes of gamma-ray sources | Large number of source detections; Relatively uniform sky coverage; Good positions, energy spectra, time histories | Counterpart searches at all other wavelengths; 
Population studies;
Correlated variability;
Multiwavelength modeling;
Contemporary, complete astronomical catalogs  | Identify facilities and plan proposal strategies for obtaining observing time needed to identify gamma-ray sources at other wavelengths; Cooperate with existing and planned monitoring surveys;
Prepare for use of the many available astronomical catalogs |
| Understand particle acceleration and emission mechanisms in extreme environments of rotating neutron stars | Spectra and light curves resulting from primary interactions of the most energetic particles  | Contemporaneous radio and X-ray pulsar timing observations  | Select pulsar candidates for radio timing; work with radio astronomers to monitor timing of selected pulsars; plan proposals for X-ray pulsar observations   |

**Planning Approach**

**The GLAST LAT Multiwavelength Coordination Group (GLAMCOG) has recently been formed to prioritize science-driven needs and develop an implementation plan for cooperative multiwavelength observations before and during the GLAST mission. This work will be coordinated with the GLAST Burst Monitor and GLAST Project science teams. **
**Some of the known multiwavelength needs are described in this poster, along with the steps being taken to meet those needs.  This work is preliminary and does not represent the full range of multiwavelength activities that will be investigated. **

**SUMMARY OF SOME MULTIWAVELENGTH NEEDS AND PLANNING**

**SUMMARY**
**The GLAST Large Area Telescope science will be optimized by coordinated multiwavelength observations and analysis.**
**GLAST welcomes cooperative efforts from observers at all wavelengths. See ****http://glast.gsfc.nasa.gov/science/multi/**
**To be added to the Gamma-Ray Multiwavelength Information mailing list, please contact Dave Thompson (**_[djt@egret.gsfc.nasa.gov](mailto:djt@egret.gsfc.nasa.gov)_**). **
**The GLAST Guest Investigator program will have opportunities for developmental and correlative observations. See ****http://glast.gsfc.nasa.gov/ssc/proposals/**