GLIMPSE

GLIMPSE - the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire - will be a fully sampled, confusion limited, 4-band near- to mid-infrared survey of the inner two-thirds of the Galactic disk with a spatial resolution of ~2". The Infrared Array Camera (IRAC) will be used to image 240 square degrees at wavelengths centered on 3.6, 4.5, 5.8, and 8.0 microns in the Galactic longitude range 10 deg to 70 deg on both sides of the Galactic center and in Galactic latitude +/- 1 deg. About 780 million resolution elements will be required to cover this area at each wavelength.

The area covered by GLIMPSE contains most of the star formation activity in the Galaxy and ~70% of the molecular gas in the Galaxy. The inner cutoff at |l| = 10 deg permits adequate sampling of both ends of the purported ~3 kpc central bar and possibly some of the nuclear bulge stellar population. We expect to determine the asymmetry of the bar (brighter at l>0 deg) with high accuracy. The outer cutoff at |l| = 70 deg includes all of the 5 kpc molecular ring, the Sagittarius spiral arm tangent, and the Norma spiral arm tangent. The Galactic center region is not included because of its extreme background brightness and high confusion limits.

The GLIMPSE Survey will provide a comprehensive view of the stellar dust content in the inner Galaxy. The broad scope of this unbiased survey will provide a global understanding that studies of narrowly-defined, selected regions cannot. GLIMPSE will enable a wide range of stellar and interstellar science. The GLIMPSE team will focus on two important scientific questions:
(1) What is the structure of the inner Galaxy, including the disk, molecular ring, number and location of spiral arms, and central bar as traced by the spatial distribution of stars and IR- bright star formation regions?
(2) What are the statistics and physics of star formation as a function of mass, stage of evolution, and location in the Milky Way?

The team will provide the following products: a near-instantaneous GLIMPSE Bright Source Catalog (GBSC; ~20 sigma), a GLIMPSE Point Source Catalog (GPSC; ~5 sigma), and a Mosaiced Image Atlas of the entire surveyed area at all four IRAC bands, all of which will be made available via the IPAC data archive. In addition, a set of web modeling tools will be provided that will permit users to analyze and interpret SIRTF and other IR data. The IPAC data archive can cross-reference the GLIMPSE catalogs with other databases in its archive such as 2MASS and MSX. Preliminary versions of the GBSC will be released every two months during data acquisition. We expect to catalog >100 million sources detected with S/N >= 5.