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GLIMPSEGalactic Legacy Infrared Mid-Plane Survey Extraordinaire
Spitzer Legacy Science Programs |
![]() to Spitzer home page |
NASA's Spitzer Telescope Brings 360-Degree View of Galaxy to Our Fingertips
The 360-Degree Image can be found here
GLIMPSE project summary page
Deep GLIMPSE: Exploring the Far Side of the Galaxy
GLIMPSE360: Completing the Spitzer Galactic Plane Survey
See the Zoomable GLIMPSE/MIPSGAL Image Here
Bubbles Within Bubbles
Credit: NASA/JPL-Caltech/University of Wisconsin
NASA/Spitzer Press Release:
Spitzer Sees Milky Way's Blooming Countryside (June 5, 2013)
Finding Bubbles in the Milky Way
Credit: NASA/JPL-Caltech/R. Simpson (Oxford University)
NASA/Spitzer Press Release:
Citizen Scientists Reveal a Bubbly Milky Way (March 7, 2012)
GLIMPSE360 Press Release
A Shocking Outflow
Beastly Stars and a Bubble
Awash in Green and Red
Credit: NASA/JPL-Caltech/2MASS/B. Whitney (SSI/University of Wisconsin)
NASA/Spitzer Press Release:
Into the Wild: Spitzer Space Telescope Surveys the Milky Way's Outback (July 28, 2010)
The Evolution of Star Formation around the M17 Nebula
Credit: NASA/JPL-Caltech/M. Povich (Penn State Univ)
NASA/Spitzer Press Release:
Spitzer Spies a 'Flying Dragon' Smoldering with Secret Star Birth (July 07, 2010)
The GLIMPSE survey spans 130 degrees in longitude (65 degrees on either side
of the center of the Galaxy), and 2-4 degrees in latitude. Since we are
located about half-way out of a very flattened spiral Galaxy, this survey
actually encompasses a large fraction of the volume of the Galaxy, as our
team logo cartoon illustrates:
The GLIMPSE survey was performed using the Spitzer Space Telescope. The
telescope was pointed to 111,000 different positions on the sky and
snapshots were taken in four different infrared wavelengths (3.6, 4.5, 5.8,
and 8 um; about 10 times longer wavelength than visible light), creating a
total of 444,000 images. The MIPSGAL survey followed up with another
approximately 400,000 images at 24 and 70 um.
The second image shows GLIMPSE+MIPSGAL 24 um in blue-green-red also. Note here
the 24 um is shown in red and the 8 um in green with the shorter GLIMPSE
wavelengths in blue.
Note that the images shown here, even at poster-size, are still scaled-down
from the original. To see them at full resolution, these images are best
viewed in the zoomable web browser developed by James Harold and Evaldas
Vidugiri at the Space Science Institute.
There you can see interesting features at size scales ranging from solar
system size (less than 1 light year) to Galactic scales (100,000 light years in
diameter). The viewer was made possible through an education supplement by
NASA's Science Mission Directorate. The viewer will ultimately be made
available in both Spanish and English for display in science centers and
libraries.
These are just some of the results produced by our team. Because this is a
legacy project, the data products (Catalogs and images) are publicly
available. Other groups have produced numerous scientific papers
(757 as of August 4, 2015) using the GLIMPSE data.
to UW-Madison Astronomy department
to
this page is: http://www.astro.wisc.edu/glimpse/index.html
webmaster: meade (at) astro.wisc.edu
GLIMPSE,GLIMPSEII,GLIMPSE3D areal coverage
GLIMPSEI, GLIMPSEII, GLIMPSE3D, GLIMPSE360 Enhanced Data Products
(password required)
The GLIMPSE and MIPSGAL Surveys
GLIMPSE (Galactic Legacy Infrared Midplane Extraordinaire) is a survey of
the inner Milky Way Galaxy in which we reside. You can see the Milky Way
plane on dark nights as a (milky) band across the sky, as the picture below
shows:
The Milky Way viewed from the Kofa Mountains in Arizona (credit Richard Payne)
Why Infrared?
At visible wavelengths, we can only see about 5% of the way through the
Galaxy on average, due to the opaqueness of the dust particles distributed
throughout the Galaxy. In the infrared, not only are these dust particles
less opaque, but the heated dust radiates infrared radiation, announcing its
presence to our cameras. These surveys have 100 times the sensitivity and
over 10 times the resolution of previous infrared surveys, allowing us to
see stars and dusty objects throughout most of the Galaxy for the first
time.
The Survey Images: GLIMPSE and MIPSGAL
The GLIMPSE and MIPSGAL images were stitched together into a large mosaic
that spans about 180 x 2.75 feet at full resolution (390,000 x 6000 pixels)!
A full-size banner of this image was unveiled on June 3 at the American
Astronomical Society meeting in St. Louis. The images below show the survey
area split up into five panels stacked on top of each other for easier
viewing. The Galactic center is at the center of the image.
These can be
downloaded for poster-size printing (48"x36"). The
first image displays the GLIMPSE wavelengths (3.6 - 8 um) in the familiar
blue-green-red that our eyes see, with the shortest wavelengths displayed in blue
and the longest in red.
What do the Colors Mean?
The different colors in the images highlight different physical processes.
The GLIMPSE 8 um wavelength
shows emission from Polycyclic Aromatic Hydrocarbons (PAHs), which
are small molecules excited by strong ultraviolet radiation from massive hot
stars. These molecules exist in the surface layers of dense molecular
clouds. So this PAH emission is a signpost of recent high-mass star
formation, which requires molecular clouds to form in. In the GLIMPSE
survey, these high-mass star formation regions are lit up like fireworks,
announcing their existence. Other physical processes highlighted in the
different colors are ionized and shocked gas at 4.5 um. This shows up in
green in the GLIMPSE color display. The ionized gas also arises
in high-mass star formation regions, and the shocked emission arises in
Supernovae remnants and also in very young massive stars in their earliest
stages of star formation. These can be seen in zoomed in regions of web
browser, as these are much smaller features than the large-scale PAH
emission. All of the wavelengths show thermal emission, which arises mostly
in dust of various temperatures (30-1600 K). The cooler the dust, the
longer the wavelength it radiates at. Usually these observations need to be
combined with radiation transfer models (e.g., Whitney et al. 2003a,
b,
2004b) which calculate the flux at different wavelengths from dust at a
range of temperatures, as you would see in a forming star surrounded by a
disk or envelope of gas and dust. The MIPSGAL image highlights the youngest
forming stars in red.
Scientific Results from the GLIMPSE survey
We have cataloged over 72 million stars in the GLIMPSE survey (over 100 million including the GLIMPSE3D survey).
For more information about how to obtain the GLIMPSE source lists and images from the Spitzer Science Center
or the Infrared Science Archive (IRSA), click
here).
These have been used to
identify the structure of the central bar in our Galaxy (Benjamin et al.
2005) and the spiral arm structure (Benjamin et al., in preparation), since
we can see further through the Galaxy than ever before. We have also
cataloged over 20,000 "red" sources, consisting of about 75% newly forming
stars and 25% evolved stars (Robitaille et al. 2008); 591 PAH
bubbles formed by the stellar winds of massive stars (Churchwell et al.
2006, 2007); over 500 variable stars (Robitaille et al. 2007b); over 300
outflows from newly forming massive stars (Cyganowski et al. 2008); and 59
new star clusters (Mercer et al. 2005). We have studied in detail several
individual star forming regions (Whitney et al. 2004a,
Shepherd et al. 2007,
Watson et al. 2008, Povich et al. 2007, 2008); discovered a globular cluster
(Kobulnicky et al. 2005) and a new planetary nebula (
Cohen et al. 2005); and
determined a new infrared dust extinction law for the Galaxy (Indebetouw et
al. 2005). One of the main goals of this project is to determine the Star
Formation Rate of the Galaxy by actually counting the number of newly
forming stars, viewed in unprecedented detail and sensitivity. We have
developed modeling tools to aid in this monumental task, which include a
large grid of 200,000 Spectral Energy Distributions of forming stars
(Robitaille et al. 2006, 2007a, Whitney et al. 2003a,
b,
2004b); see
www.astro.wisc.edu/protostars). These are being used to analyze individual
star forming regions and to produce a Galaxy-wide model of star formation to
compare to our red-source catalog.
to NASA home page
to SSC home page
to IRAC home page
University of Wisconsin-Madison home page
updated August 04, 2015