Galactic Plane Paper Update

Curtis Lansdell

Milagro Collaboration Meeting

December 18, 2006

Curtis LansdellDecember 18, 2006 Milagro Collaboration Meeting

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

Curtis LansdellDecember 18, 2006 Milagro Collaboration Meeting

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, …

Curtis LansdellDecember 18, 2006 Milagro Collaboration Meeting

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

epochslice

epochslice dayswgtdayW ))(/()(

)(/)(" " WexcessMapCrab

dEddNegionCrab Map RxRegion Flu /""""

Curtis LansdellDecember 18, 2006 Milagro Collaboration Meeting

Significance Plot

Which one?

Curtis LansdellDecember 18, 2006 Milagro Collaboration Meeting

Profile Plots ICygnus Hot Spot

Cygnus Region

Optimized Model

Longitude Profile

Latitude ProfileInner Galaxy (IG)

Outer Galaxy (OG)Latitude Profile

flux calculated at 12 TeV and -2.62 spectrum

Curtis LansdellDecember 18, 2006 Milagro Collaboration Meeting

Profile Plots II

Latitude Profile

Latitude Profile

Latitude ProfileInner Galaxy, “below” Cygnus Region

Inner Galaxy, Cygnus Region

Inner Galaxy, “above” Cygnus Region

Curtis LansdellDecember 18, 2006 Milagro Collaboration Meeting

>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°]

Curtis LansdellDecember 18, 2006 Milagro Collaboration Meeting

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°

Curtis LansdellDecember 18, 2006 Milagro Collaboration Meeting

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

Curtis LansdellDecember 18, 2006 Milagro Collaboration Meeting

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)

Curtis LansdellDecember 18, 2006 Milagro Collaboration Meeting

l=40.6

Low declination object ( ~ 6°) Possibly a flaring source (see Gary’s talk tomorrow)

Curtis LansdellDecember 18, 2006 Milagro Collaboration Meeting

Flux and Position Tables IObject significance

(std deviations)

flux

(/TeV/cm2/s/sr)

GALPROP

(/TeV/cm2/s/sr)

position box

|b|<5

IG 7.3 (1.46±0.20)x10-12 6.79x10-13 30<l<120, |b|<5

IG below Cygnus 4.8 (2.19±0.46)x10-12 1.06x10-12 30<l<65, |b|<5

IG in Cygnus 8.5 (2.29±0.27)x10-12 5.94x10-13 65<l<85, |b|<5

IG above Cygnus 1.2 (2.39±1.99)x10-13 3.47x10-13 85<l<120, |b|<5

OG 1.4 (2.82±1.95)x10-13 2.02x10-13 120<l<216, |b|<5

Object significance

(std deviations)

flux

(/TeV/cm2/s/sr)

GALPROP

(/TeV/cm2/s/sr)

position box

|b|<2

IG 9.1 (2.99±0.33)x10-12 9.64x10-13 30<l<120, |b|<2

IG below Cygnus 6.6 (4.87±0.74)x10-12 1.61x10-12 30<l<65, |b|<2

IG in Cygnus 10.0 (4.20±0.42)x10-12 7.99x10-13 65<l<85, |b|<2

IG above Cygnus 1.3 (4.08±3.13)x10-13 4.17x10-13 85<l<120, |b|<2

OG 0.8 (2.50±3.14)x10-13 2.32x10-13 120<l<216, |b|<2

Working on getting upper limits for galactic plane OG and IG above Cygnus region…

flux calculated at 12 TeV and -2.62 spectrum

Curtis LansdellDecember 18, 2006 Milagro Collaboration Meeting

Flux and Position Tables II

Object flux (>12 TeV)

(/cm2/s/sr)

PRL flux (>12 TeV)

(/cm2/s/sr)

position box

IG (PRL) (0.89±0.14)x10-11 (1.02±0.21±0.32)x10-11 40<l<100, |b|<5

OG (PRL) (2.58±1.30)x10-12 < 5.57x10-12 140<l<200, |b|<5

Object 1significance

(std deviations)

flux

(/TeV/cm2/s)

GALPROP

(/TeV/cm2/s)

width

(deg)

position

(l, b)

Crab 14.2 (4.68±0.44)x10-14 3.86x10-16 0.64±0.05 -175.4±0.1,-5.7±0.1

l=40.6 6.9 (3.95±0.80)x10-14 5.31x10-15 0.61±0.11 40.6±0.1, -1.0±0.1

MGRO J2019+37 10.9 (2.42±0.33)x10-14 2.09x10-15 1.00±0.17 74.9±0.1, 0.4±0.2

2l=76.3 5.2 (7.65±2.17)x10-15 7.28x10-16 0.35±0.11 76.3±0.1, -2.0±0.1

2l=77.5 5.0 (9.36±2.18)x10-15 4.01x10-16 0.64±0.21 77.5±0.3, -4.0±0.2

l=80 5.8 (1.67±0.33)x10-14 2.29x10-15 2.26±0.53 80.1±0.5, 1.0±0.5

l=105.9 5.2 (6.25±3.56)x10-15 8.41x10-16 0.36±0.15 105.9±0.1, 3.0±0.1

“l=“ region fluxes taken from box centered at the fit position1 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

Curtis LansdellDecember 18, 2006 Milagro Collaboration Meeting

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! …