1. Robert Benjamin (UW-W) and the GLIMPSE team with special thanks to
GLIMPSE results on the Mid IR Stellar and Diffuse Emission in the Galactic Plane
Robert Benjamin (UW-W) and the GLIMPSE team with special thanks to
SSC and the IRAC team
Spitzer Science Center 2005 Conference IR Diagnostics of Galaxy Evolution (Nov 14-16,2005)

2. GLIMPSE (Galactic Legacy Infrared Mid-Plane Survey Extraordinaire)
• PI: Ed Churchwell (UW-Madison)
• Galactic Spitzer Legacy Program
• Over 320,000 Spitzer /IRAC frames
• bandsurveymicrons
• GalacticLatitudeb| < 1 degree
• GalacticLongitudel-65degrees
• Totalsurveytimehours
• Angular Resolution: <2 arcseconds
(Almost) no extinction!
Benjamin et al (2003)
PASP, 115, 953

3. Data Products GLIMPSE Point Source Catalog (> 99.5% reliable)
GLIMPSE Point Source Archive (~5s)
Mosaicked Images in 4 bands
“Web Infrared Tool Shed” Mid-IR models of circumstellar dust and PDRs
GLIMPSE Point Source Catalog and Archive
l msel mbr msens Catalog Archive
3.55 mm million million 4.49 mm million million 5.66 mm million million 7.84 mm million million TOTAL million million
Note: ~85% of sources expected to be between K2 giants (d<7 kpc) and M5 giants (d<124 kpc).

4. Mean Free Path in Galactic ISM
Indebetouw et al. 2005, ApJ 619, 931 • Extinction in mid IR is nearly flat across IRAC bands!
A[3.6] /AK=0.56±0.06
A[4.5] /AK=0.56±0.08
A[5.8] /AK=0.43±0.10
A[8.0] /AK=0.43±0.10
X-ray opacity (Benjamin 2004), UV/Optical (Clayton, Cardelli, Mathis 1989), IR (Li & Draine 2001)
Assuming nH=1 cm-3

5. Objects Uncovered by GLIMPSE
RCW 79
329 PAH Bubbles Churchwell et al (2005), in prep
Supernova Remnant Survey Reach et al (2005), astro-ph/
IR Dark Cloud Survey Devine et al (2005), in prep
New Planetary Nebulae Cohen et al (2005), ApJ, 627, 446
24 New Mid IR Stellar Bowshocks Benjamin et al (2005), in prep
Large (R>9000 AU) Circumstellar Disk Candidate Walker et al (2005), in prep
92 New Open Stellar Clusters Mercer et al (2005), ApJ in press
New Galactic Globular Cluster Kobulnicky et al (2005) AJ 129, 239 G K
IRAS (near RCW49)
GLIMPSE-C01

6. Galaxy Cluster?
• Edge-on spiral, face-on spiral, eight other candidates seen at l=317o b=-0.5o • “Transparency” of Galactic ISM at midplane relevant to search for “Zone of Avoidance” galaxies and using light profiles of external edge-on systems.

7. Galaxy Cluster?
Associated with Great Attractor? (10 kpc=30”)

8. 10 deg to Galactic Center
• Extinction still affects star counts for some small areas with dense CO clouds. • 25 % more stars to the left of Galactic Center (l=10-30) than to the right (l= )

9. Blue right of G.C. (l= )
Red left of G.C. (l=10-65)
• Galaxy approx. axisymmetric outside l=30o, but some enhancements, e.g. l=307o • Fit by N=No(l/lo)K1(l/l0) where lo=24±4o [4.5 band] (17-30o)

10. ? Fits of data to n=no(S/So)-a yield aavg=1.83-1.95
Blue right of G.C. (l= )
Red left of G.C. (l=10-65)
Fits of data to n=no(S/So)-a yield aavg=

11. Galactic Longitude More sources: Faint and small l
Sun
G.C.
34o
Molecular cloud/W41/W42 at l=23-25
Fewer sources: Bright and large l
Galactic Longitude

12. Galactic structure parameters (Benjamin et al 2005 ApJL 630, 149)
BAR
Rbar=4.4±0.5 kpc
fbar=44 ±10o
M[4.5]=-2.15 ±0.2 mag (early K giants)
DISK
N=No(l/lo)K1(l/l0)
lo=24±4o (17-30o)
Rdisk=3.5 ±0.5 kpc
SPIRAL ARMS
Clear enhancement at
l= (Centaurus) No enhancement at
l= 49 (Sagittarius)

13. Galactic Longitude Asymmetry
l=-16o (344o)
Credit: Robert Hurt (SSC/JPL/NASA)
Galactic Longitude Asymmetry

14. GLIMPSE: A Legacy for Galactic AND Extragalactic Research
GLIMPSE is uncovering a plethora of objects (clusters, star formation regions, PAH rings, planetary nebulae, SNR, mid IR stellar bowshocks, protostellar jets, other galaxies, etc.) that will provide detailed understanding of emission mechanisms for distant sources.
Mid IR star counts can now be used for the study of Galactic stellar structure to yield the scale-length of the stellar disk, the angle and size of the bar, and the locations of stellar spiral arms.* The bar seems to be enhanced in early K giants (lucky for us).
Coming up soon:
GLIMPSE II (the inner 20 degrees)
Refined Galactic modelling results (including amplitudes of bar/disk/arms).
Diffuse emission variation vs. location in Galaxy
* [The length and] angle of the bar are also new”, said astronomer Michael Merrifield, “It’s a very different angle from the degrees of previous analyses. In some sense, the new method is really pretty elegant but it’s at odds with previous estimates using different methods. Clearly, at least one of them is definitely wrong. ” [discoverychannel.com, Sept 9, 2005]
• Data is available to you now for FREE from SSC website.
THANK YOU, SPITZER LEGACY PROGRAM!
SSC website: data.spitzer.caltech.edu/popular/glimpse GLIMPSE website: (includes this talk)