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HAWC Science. Survey of 2 p sr up to 100 TeV energies Probe knee in cosmic ray spectrum Identify sources of Galactic cosmic rays Extended Sources The Galactic Plane and Molecular Clouds Supernova Remnants and Pulsar Wind Nebula Galaxy Clusters Transient Sources - PowerPoint PPT Presentation
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HAWC Science Survey of 2 sr up to 100 TeV energies
• Probe knee in cosmic ray spectrum• Identify sources of Galactic cosmic rays
Extended Sources• The Galactic Plane and Molecular Clouds• Supernova Remnants and Pulsar Wind Nebula• Galaxy Clusters
Transient Sources• Active Galactic Nuclei (AGN)• Gamma Ray Bursts (GRBs)• Solar Energetic Particles
Fundamental Physics Measurements• Tests of Lorentz Invariance at High Energies• Indirect Detection of Dark Matter
Increase Scientific Return of Other Projects• Identifies new and flaring TeV sources for VERITAS and IceCube• Extends GLAST and VERITAS spectra to higher energies
From Milagro to HAWC
High Altitude Water Cherenkov (HAWC)• Increase Altitude to 4300 m from 2650 m
• Increase Area to 22000 m2 from 4000 m2
• Reuse Milagro PMTs and electronics
• HAWC ~15x Sensitivity of Milagro• HAWC: Detect Crab in ~ 1 day• Milagro: Detects Crab in ~1/2 yr
e
150 meters
4 meters
e
HAWC Design:Single layer of 900 PMTs (4 m depth vs Milagro’s 2 layers at 1.5 and 6 m) optically separated by curtains or in individual tanks
4300m
2600m
Difference between 2600m (Milagro) and 4300m (HAWC):~ 6x number of particles
HAWC’s median trigger energy ~1 TeV vs Milagro’s ~4 TeV
Higher Altitude is Closer to Shower Max.
Gamma/Hadron Separation
Gam
mas
Prot
ons
30 GeV 70 GeV 230 GeV
20 GeV 70 GeV 270 GeVSize of HAWC
Size of Milagro deep layer Energy Distribution at ground level
Larger Area implies better angular resolution + better cosmic ray background rejection
Lateral Distribution
• Protons have BROAD lateral distribution of muons
• Gammas have NARROW lateral distribution of electrons
HAWC sensitivity calculation
Milagro MC is used to calculate HAWC sensitivity increase of 15x• Milagro Crab flux is within 10% of ACT flux• Milagro Cosmic Ray flux is within 30-50% of balloon flux and is
used to correct the HAWC background calculation
B.O.T.E.C. (back of the envelope calculation) is similar• Energy Threshold 3x lower than Milagro (Approx. B gives
6x more particles, but density of PMTs is less)– Sensitivity increase depends on spectrum, but is ~3x
• Area for Triggering is 5x larger than Milagro– Sensitivity increase is ~2x
• Angular resolution improves because of increased lever arm, better core location, …
– Sensitivity increase is 1.5-2x• Gamma/hadron rejection improves due to increased probability
of detecting muon away from the core– Sensitivity increase is >1.5x
~10~6
~15
HAWC Sensitivity calculation
Milagro MC is used to calculate the HAWC sensitivity increase of 15x• Milagro Crab flux is within 10% of ACT flux• Milagro Cosmic Ray flux is within 30-50% of balloon flux and is
used to correct the HAWC background calculation
Milagro MC of gamma/hadron separation parameter for gamma rays, cosmic rays, and data
Gamma-Ray Sensitivity to Crab-like Source
GeV
VERITAS, HESS, MAGIC, Whipple sensitivity in 50 hours, (~0.2 sr/year)
GLAST sensitivity in 1 year (4 sr)
HAWC, Milagro, sensitivity in 1 year (2 sr)
~ 6 TeV
Survey Sensitivity
Angular Resolution
Comparison of -ray sensitivity between the IACT and HAWC 2 year sky surveys as a function of source angular diameter. The HESS detected Galactic sources are shown.
Extended Source Sensitivity
HAWC Extended Source Sensitivity
Flaring Blazars detectable by HAWC at 5 Crab in 10 minutes
HAWC & Transients
Orphan Flare
Full Moon
X-ray binary periods unobstructed by Moon or Sun
GRBs out to z~0.3 (0.7) for 10-6 (10-5) ergs/cm2
Plus Solar EnergeticParticles and …
TeV
10 keV
Ecutoff= 700 260 170 GeV
HAWC and GLAST Transient Sensitivity
GLAST and HAWC sensitivity for a source of spectrumdN/dE=KE-2
above 10 GeV
z=0 no E cutoffz=0.1 Eexp~700GeVz=0.3 Eexp~260GeVz=0.5 Eexp~170GeV10
-12
10-1
010
-810
-6
AGN flares1-15 x Crab
GRB <1 MeVFlux
Site Location is Sierra Negra, Mexico• 4100 m above sea level• Easy Access
• 2 hr drive from Puebla • 4 hr drive from Mexico City
• Existing Infrastructure• Few km from the US/Mexico
Large Millimeter Telescope• Power, Internet, Roads• Sierra Negra Scientific
Consortium of ~7 projects • Excellent Mexican Collaborators• ~15 Faculty at 7 institutions
have submitted proposal to CONACYT for HAWC
• Experience in HEP, Auger, and astrophysics (including TeV)
LANL Design of Pond
Excavate ~102,000 m3 reusing ~78,000 m3 with ~24,000 m3
excess
Top of Pond at 4098 m a.s.l.Topographic Survey of Site
Steel Building with Structural Supports in the Water
LANL Engineering Study of Pond Cover
Floating Cover with Access Ports for Installation and Repairs
Individual Plastic Tanks of ~4m height and ~4m diameter in
30 x 30 array
HAWC Proposal and Budget
Joint Proposal to NSF and DoE High Energy Physics
Additional Collaborators – University of New Mexico, University of Utah and International Partners
Construction Budget
Milagro Construction Budget was $3.4M ($2.7M from NSF and $0.7M from DoE HEP)
Site Preparation & Water Acquisition $0.6M
Pond or Tanks $3.2M
PMT Refurbishment & Calibration System $0.4M
Cabling, Electronics, Computers $0.8M
Contingency 20% $1.0M
Total ~$6 M
Conclusion
• Milagro has demonstrated the power of the water Cherenkov technique
• Detection of Crab Nebula and Mrk 421, known TeV sources• Discovery of new TeV sources• 1st detection of TeV diffuse emission from the Galactic plane
• Future: HAWC • Building on expertise with Milagro• Design improvements in Size, Altitude, Curtains . . . • 15x Milagro sensitivity
• Milagro /HAWC complementary to other particle astrophysics observatories
TeV -rays: A New Window on the Sky
0.1 GeV
Milagro 10 TeV gamma-rayTeV gamma ray
Milagro HESS
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