Searches for dark matter subhaloes with wide field Cherenkov telescope surveys J-F. Glicenstein, P.Brun, E.Moulin (IRFU-Saclay) J.Diemand (ITP-Zurich) Phys Rev D,83, 015003 (2011) Image courtesy of Via Lactea Project: http://www.itp.uzh.ch/~diemand/vl/

Searches for DM subhaloes with Cherenkov telescopes surveys Outline HESS flux sensitivity map (Galactic plane) Search for clumps in HESS galactic plane survey CTA flux sensitivity map (Galactic plane) predictions for clumps in CTA galactic plane survey conclusion ICRC 2011 Searches for DM subhaloes with Cherenkov telescopes surveys

Indirect dark matter search strategy WIMP annihilation flux into rays observed in solid angle : fAP: dark halo model particle model Astrophysical factor: dN/dE given by a particle model neutralinos DW: assumes point source search 3

Signal boosts astrophysics: particle physics: unresolved sub-clumps Sommerfeld effect: effective low velocity dispersions resonances at: Internal Brehmstrahlung annihilation to W+W-,ff (c heavy higgsino-like) relative velocity b FSR IB

The H.E.S.S. survey of the Galactic plane F.A. Aharonian et al (HESS) , ApJ. 636, 777 (2006) ICRC 2011 Searches for DM subhaloes with Cherenkov telescopes surveys

Galactic plane sensitivity map in each bin (b,l) of the map, get Ng (g candidates)/ Nhadr outside sources, Ng is dominated by fake gammas background B estimated by the « template method » Ng compared to B  90% C.L. upper limit on signal S90 F90 obtained from S90 by Assumes dN/dE from ccbb (not sensitive to this assumption) Mc = 500 GeV (from Berge et al 2007) _

Galactic plane flux sensitivity map (HESS) from HESS galactic survey (2004-2007) |b| ≤3o, -30o ≤l≤ 60o map divided into 0.02o x 0.02o bin smoothed to a 0.1o x 0.1o resolution (HESS) F.Aharonian et al (HESS)+Bertone,PRD 78 (2008), 072008 ICRC 2011 Searches for DM subhaloes with Cherenkov telescopes surveys

Searches for DM subhaloes with Cherenkov telescopes surveys Dark matter clumps HESS sensitivity clumps from ViaLacteaII (Diemand, Kuhlen, Madau, 2008) ~104 resolved halos in MW (M>105Msol) 103 random realizations (rotate the observer position @8.5 kpc) 168±44 clumps inside HESS galactic survey ICRC 2011 Searches for DM subhaloes with Cherenkov telescopes surveys

Searches for DM subhaloes with Cherenkov telescopes surveys HESS clump limits use the HESS Galactic plane sensitivity map find <sv> so that 2.3 subhalos are seen on average 90% C.L. limits comparable to Sgr dwarf, Galactic Center (point source) ICRC 2011 Searches for DM subhaloes with Cherenkov telescopes surveys

Expectations for Galactic plane survey Funk,Hinton,Hermann,Digel, arXiV0901.1885 HESS map of the Gal.plane, total exp ~500 hours simulated CTA map, flat exposure ~ 5 hours/field assumes x 2 improvement in hadron rejection x 2 gain in angular resolution x 10 gain in effective area  overall increase in sensitivity of ~ 9 expect ~ 300 sources in -30 deg≤ l ≤ 30 deg ICRC 2011 Searches for DM subhaloes with Cherenkov telescopes surveys

Galactic plane sensitivity (CTA) ~400 hours total 10 hours each bin assume Emin = 50 GeV 500 GeV WIMP annihilating to bb x10 gain in effective area, x2 gain in hadron rejection reaches 10-13 cm-2 s-1 sensitivity, except on new sources ICRC 2011 Searches for DM subhaloes with Cherenkov telescopes surveys

CTA clump limits (Galactic plane) 90% C.L. limits improved by an order of mag/ HESS interesting <sv>s not reached ICRC 2011 Searches for DM subhaloes with Cherenkov telescopes surveys

CTA clump limits (1/4 sky) 1/4 survey in ~6 years assume 5 10-13 cm-2s-1 sensitivity (5 hour/bin) number of subhalos: 3907±324 thermal WIMPs region reachable ICRC 2011 Searches for DM subhaloes with Cherenkov telescopes surveys

Searches for DM subhaloes with Cherenkov telescopes surveys Conclusions 168 DM clumps (estimated from Via Lactea II) expected in field of view of the HESS galactic plane survey Visibility of clumps depends on <sv>  90% CL limits on <sv> equivalent to HESS galactic center limits. Limits improved with CTA, however <sv> typical of thermally produced WIMPs not accessible. Contraints at the level of <sv> ~ 10-26 cm3/s can be obtained by a 6-year survey of ¼ of the sky with CTA. ICRC 2011 Searches for DM subhaloes with Cherenkov telescopes surveys

Searches for DM subhaloes with Cherenkov telescopes surveys Back-up slides ICRC 2011 Searches for DM subhaloes with Cherenkov telescopes surveys

Dark matter annihilation around IMBH 200 MC realisations NIMBH inside galactic survey HESS sensitivity « scenario B » of Bertone, Zentner, Silk 2005 collapse of a primordial cloud of gas ~105 Msol into ~4 104 Msol Intermediate Mass Black Hole 101±22 IMBH in MW (4.3±2.3 in Hess galactic survey) very luminous (due to the DM spike around BH) ICRC 2011 Searches for DM subhaloes with Cherenkov telescopes surveys

HESS IMBH limits (scenario B) for each mDM, decrease <s v> until NIMBH < 2.3 F.Aharonian et al (HESS)+Bertone,PRD 78 (2008), 072008 ICRC 2011 Searches for DM subhaloes with Cherenkov telescopes surveys