dark matter & astroparticle physics - veritasgibbs/veritas_opsreview...dark matter &...

Dark Matter & Astroparticle Physics

J. S. Perkins, VERITAS Review, 2009

Thursday, December 10, 2009

DM Searches @ VHE• Objective: indirect detection of DM

• Strategy: observe objects with low astrophysical background and high DM content

• Local large galaxies: M31, M32, M33...

• DM halo expected like MW but MW core not detected

• Globular clusters: M15, M5 ...

• High Density (500x MW), Pulsars, DM Dominated

• Galaxy clusters: Coma, Perseus ...

• 1000’s of galaxies, 85% DM, many g-ray production chains, far away

• Dwarf galaxies: Draco, Ursa Minor, Willman I ...

• DM Dominated, no astrophysical processes

Coma cluster (D. Carter et al. and the Coma HST ACS Treasury Team)


Dwarf Galaxy Survey• Few billion stars

• 10x less than normal galaxy

• Close, ~14 orbiting the MW

• No warm gas, cosmic-ray production or dust

• No astrophysical backgrounds

• Extremely DM dominated

• Only at the core

• Assumes: self-annihilation of MSSM-type neutralino or Kaluza-Klein particle

• Dwarf galaxies are ideal: best chance for DM detection


Target Dates Hours Usable SignificanceM15 9/2006 10 0 n/a

M5 2/2009 - 3/2009 15.6 12 no signal (prelim)

M33 11/2007 - 2/2008 15.8 11.8 0.412

M31/M32 10/2008 - 1/2009 13.2 12 0.6 (prelim)

Coma Cluster 3/2008 - 4/2008 20.6 18.6 <1.5% Crab (99% c.l.)

Draco dSph 4/2007 - 5/2007 23.7 18.4 -1.51

Ursa Minor dSph 2/2007, 5/2007 26.2 18.9 -1.77

Willman I dSph 12/2007 - 2/2008 15.4 13.7 -0.08

Boötes 1 dSph 3/2009 - 4/2009 13 11.6 0.7 (prelim)

TOTAL: 153.5 117 ~15% of Budget

2 Years of DM Searches

Future Plan: Continue survey of dwarf galaxies

Note: H.E.S.S spends < 20hr/year on DM


Neutralino Limits

<σv> Limit:

Astrophysical Factor

Particle Physics

dSph Rγ(95%c.l.)counts/min

flux(95% c.l.)

cm-2s-1J

Draco 0.0079 1.05×10-12 4 (2-9)

Ursa Minor 0.0029 0.29×10-12 7 (4-20)

Willman I 0.045 2.23×10-12 22


Astroparticle Physics• Primarily symbiotic observations

• Relic particle/defect decay signals

• Primordial black hole evaporation

• Gamma-ray interactions with the EBL

• IG magnetic influence on cascade development

• Lorentz invariance violation

• Cosmic ray studies - spectrum and composition


Lorentz InvarianceEnergy Dependent Speed of Light


Previous MeasurementsH

.E.S

.S. P

KS

2155

-304

Fla

re

τpeak ~20 s>800 GeV

200 - 800 GeV

Compatible with zero, most constraining limit.

|ξ| < 23 or |ζ| < 7.3 x 1019


VERITAS MeasurementsMrk421 flare caught by the

10m, then observed by VERITAS

~10x the Crab Nebula’s Flux


Bonus Slides


Auger HotspotsFall 2007, triggered using DDT

Pair A: Centered on PC2207+0122 (200 minutes) Pair B: Centered Between

NGC 1358 and NGC 1346 (608 minutes)


Auger Hotspots

• Very weak

• Outside our FoV

• Very extended

• Time variable

No Detections. Why?


IceCube Hotspot• All-sky neutrino map reveals

‘hotspot’ (T. Montaruli, private comm.)

• 7.7 excess events (4.8σ/2.2σ pre/post trials)

• IceCube/VERITAS collaboration

• DDT on VERITAS

• 2.5h in April 2009 (moon)

• No signal, consistent with bkgrnd

γ-ray flux limit (E > 1TeV) < 4 % of the CrabThursday, December 10, 2009

Direct Cherenkov


SGARFace

• Hardware addition to 10m

• Searches for large bursts of gamma rays (>100 MeV) over many short timescales

• Primordial black holes

• Pulsars

• Very short GRBs?

• PBH evaporation limits published

• Preliminary search with VERITAS yielded one event in 1693 total events


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