Our solar system resides about 2/3 the way out from the center of a large flattened spiral galaxy. From this vantage point, we view the Galaxy as a narrow strip that extends across the sky. This strip appears as the “Milky Way” on a dark moonless night away from city lights.
When we first proposed to survey the inner 10-65 degrees of the Galactic plane with the Spitzer Space Telescope, we never dreamed it would be so successful and would grow into several GLIMPSE surveys spanning the entire 360 degrees of the Galactic plane. The Spitzer Space Telescope is an infrared observatory with a leap in sensitivity and spatial resolution that allows us to see stars and star forming regions to the edge of the Galaxy for the first time.
The acronym for GLIMPSE has meaning in that we originally went for the shortest exposures possible to allow for the largest mapping area in a reasonable time on the telescope, that is, to “glimpse” the Galactic plane. We use the Infrared Array Camera (IRAC) with a wavelength range of 3.6 – 8 microns. (currently 3.6 – 4.5 microns in the “warm mission” phase of the observatory).
Our most recently awarded survey will return toward the center of the Galaxy and map above and below our original survey with deeper exposures in order to map the far outer Galaxy as it warps up and below the midplane. This survey is aptly named “Deep GLIMPSE”.
The various GLIMPSE surveys (GLIMPSE, GLIMPSE II, GLIMPSE3D, GLIMPSE360, and Deep GLIMPSE) have to date mapped an area of 960 square degrees, producing beautiful panoramic images of the Galactic plane, and catalogs of over 160 million sources. Our team has worked diligently, especially researchers Marilyn Meade and Brian Babler, to produce high quality images and catalogs. These data products are publicly available at the Spitzer Science Center and IRSA. The Principle Investigators of the various GLIMPSE projects are Edward Churchwell, Bob Benjamin, and Barbara Whitney.
Our team has also processed the Spitzer IRAC data (catalogs and images) for the Large and Small Magellanic Clouds. See this page for descriptions of those projects.
GLIMPSE360
GLIMPSE360 will map the remaining 187 degrees of the Galactic Plane that have not been observed with the Spitzer Space Telescope. The survey will cover longitude l=65-265 degrees excluding l ~102-109 and l~76-82. The latitude range will be 3.1 degrees, wider than the previous GLIMPSE surveys (2 degrees) because the disk flares more in the Outer Galaxy. The latitude center will follow the Galactic warp.
Three visits on each sky position with 0.6&12s HDR frames will provide a high dynamic range of sensitivity that exceeds both GLIMPSE and the planned WISE mission surveys at both ends. This will allow us to determine the edge of the Galactic stellar disk, study low and high mass star formation in the nearby Perseus arm as well as in the Far Outer Galaxy, and study evolved stars throughout the Galaxy.
The combination of GLIMPSE360 and the previous GLIMPSE (abs(l)<65 deg.) and smaller surveys will provide us with a lasting global dataset, encompassing most of the stars and star formation in our Galaxy. This database will allow us to determine the star-formation rate in the Galaxy, how the stellar disk scale heights and lengths vary across the Galaxy, and how the dust extinction law varies with location in the disk. In addition, we will catalog stars, star clusters, PAH bubbles, supernova remnants, infrared dark clouds, outflows from massive protostars, planetary nebulae, external galaxies in the Zone of Avoidance, and many other types of objects. Following the tradition of the previous GLIMPSE Legacy programs, we will deliver enhanced data products for the survey-source lists and cleaned mosaics-to the community.