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Galactic Plane Paper Update

Galactic Plane Paper Update. Curtis Lansdell Milagro Collaboration Meeting December 18, 2006. Outline. Paper outline Calculating the flux Plots for the paper Longitude & latitude profiles, significance Plots of the position fits Flux and position tables Point-like, diffuse

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Galactic Plane Paper Update

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  1. Galactic Plane Paper Update Curtis Lansdell Milagro Collaboration Meeting December 18, 2006

  2. Outline • Paper outline • Calculating the flux • Plots for the paper • Longitude & latitude profiles, significance • Plots of the position fits • Flux and position tables • Point-like, diffuse • Summary and To-do List

  3. Paper Outline • Keep it simple! • Title suggestion: Milagro TeV Gamma-Ray Survey of the Galactic Plane • Introduction • why is this paper interesting? • Analysis • reference A4 weighted analysis from ApJ paper • talk about steps to get a flux map in the weighted analysis • mention energy response as a function of declination (i.e., why did we choose 12 TeV?) • Plots and numbers • significance map for the galactic plane (or entire sky?) • longitude and latitude profiles (with GALPROP model - conventional, EGRET-optimized?) • 4 latitude profiles: inner galaxy left of Cygnus region, inner galaxy right of Cygnus region, Cygnus region, and outer galaxy • table of >4.5 sigma “point-like” blobs on the plane (include Crab): position, significance, flux • table of diffuse regions: source l,b box, significance, flux, GALPROP flux • inner & outer galaxy, Cygnus region (with or without hotspot and/or other blobs?), regions of inner galaxy not including Cygnus region • Discussion • flux compared to GALPROP is high in some regions - possible reasons • GALPROP bumps compared to Milagro - line up? • SNRs and PWNs in blobs • Conclusion • scanned the plane for new sources at >4.5 sigma level, GALPROP under-predicts, …

  4. Flux Calculation for Weighted Analysis • Simulate expected gammas per day as a function of declination with user-defined input flux and spectrum • Use exposure time for each data epoch and pre-defined weights to get expected weighted events as a function of declination • Scale the real data excess by expected weights to get data map in Crab flux units • Sum up regions of interest, normalize with thrown flux, spectrum, and median energy of analysis, average with respect to angular size

  5. Significance Plot • Which one?

  6. Profile Plots I flux calculated at 12 TeV and -2.62 spectrum Longitude Profile Cygnus Hot Spot Optimized Model Cygnus Region Latitude Profile Inner Galaxy (IG) Latitude Profile Outer Galaxy (OG)

  7. Profile Plots II Latitude Profile Inner Galaxy, “below” Cygnus Region Latitude Profile Inner Galaxy, Cygnus Region Latitude Profile Inner Galaxy, “above” Cygnus Region

  8. >4.5 regions • 6 regions, all within inner galaxy • Expect 0.3 spots >4.5 in l[30°,120°], b[-5°, 5°] • Expect 0.6 spots >4.5 in l[30°,216°], b[-5°, 5°]

  9. Crab and MGRO J2019+37 • Fit performed on unsmoothed map and overlayed on smoothed excess map • Green circles are 0.5 contours • Purple dots are initial guesses on position (or known position in the case of the Crab (l, b) = (-175.4°, -5.8°)) • Weighted events point source resolution ~0.64°

  10. l=76.3 and l=77.5 • Limited search box to 2°x2° centered at purple dot to avoid poor fits due to nearby sources • For ~0.6° resolution, a bin of ~2° seems reasonable

  11. l=80 and l=105.9 • HEGRA spot is at (l, b) = (80.2°, 1.1°) • More parameters in the fit (e.g., elliptical) does not give a better fit (e.g., for l=105.9, 2/ndf = 3617/3594 and position is the same)

  12. l=40.6 • Low declination object (~ 6°) • Possibly a flaring source (see Gary’s talk tomorrow)

  13. Flux and Position Tables I flux calculated at 12 TeV and -2.62 spectrum Working on getting upper limits for galactic plane OG and IG above Cygnus region…

  14. Flux and Position Tables II “l=“ region fluxes taken from box centered at the fit position 1 Gaussian-smoothed significance, not corrected for declination (or assuming a spectrum) 2 2°x2° box used instead of 3°x3° so that fit doesn’t go crazy due to nearby hot spots

  15. Summary and To-Do List • 6 spots >4.5 in Galactic plane from l[30°,216°], b[-5°,5°] • All 6 spots within the Inner Galaxy • Total flux from the 6 spots is(6 spots, 12 TeV) = (1.04±0.10)x10-13 /TeV/cm2/s • Total flux from the IG is(IG,12 TeV) = (4.00±0.55)x10-13 /TeV/cm2/s • The 6 spots make up ~25% of the flux from the Inner Galaxy • Get upper limits on low significance diffuse regions (OG, IG above Cygnus region) • List SNRs, PWNs within these 6 spots • Bumps in GALPROP match excess bumps? • i.e., do any of our “source” regions match with regions of higher diffuse emission? • Finish the draft! • …

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