Gamma-rays from Dark Matter Mini-Spikes in Andromeda Galaxy M31. Mattia Fornasa Dipartimento di Fisica G. Galilei I.N.F.N. Padova

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1 Gamma-rays from Dark Matter Mini-Spikes in Andromeda Galaxy M31 Mattia Fornasa Dipartimento di Fisica G. Galilei I.N.F.N. Padova based on astro-ph/ by M. Fornasa, M. Taoso and G.Bertone Journal Club Seminar Giovedì 7 giugno 2007

Galilei I.N.F.N. Padova based on astro-ph/0703757 by M.

2 Introduction Evidences for Dark Matter (DM) WMAP measurement (Ω m =0.25) rotation curves of galaxies the bullet cluster Open Problems DM nature DM interactions Detection techniques signals from colliders direct detection indirect detection of annihilation products such as neutrinos, antiprotons or gamma-rays Chandra photo album: X-ray image of 1E

interactions Detection techniques signals from colliders direct detection indirect

3 Introduction Our work is focused on indirect detection: we are looking for gamma-rays from DM annihilation in high-density regions in the sky (1) search for a signal from the Galactic Center H.E.S.S. reported an excess of gamma-rays no possible interpretation as DM annihilation H.E.S.S. collaboration, astro-ph/06509

for a signal from the Galactic Center H.E.S.

4 Introduction Intermediate Mass Black Holes (IMBHs) located in mini-halos in the Galactic smooth DM profile necessity to consider an extragalactic source (M31) G. Bertone, astro-ph/ High-energy, point-like, unknown gamma-rays sources in a 3 region around Andromeda would be a clear and unquestionable signal for DM annihilations around IMBHs

Bertone, astro-ph/ 0603148 High-energy, point-like, unknown gamma-rays sources in a 3

5 Intermediate Mass Black Holes (IMBHs) mass from 20 M to 6 M no one actually ever detected an Intermediate Mass Black Hole G. Bertone, astro-ph/ Evidences for IMBHs: Ultra Luminous X-ray sources (ULXs) extrapolation of M-σ relation of SMBHs to globular clusters IMBHs would provide massive seeds for the growth of SMBHs Miller, Colbert, astro-ph/

Bertone, astro-ph/ 0603148 Evidences for IMBHs: Ultra Luminous X-ray sources (ULXs)

6 Intermediate Mass Black Holes (IMBHs) G. Bertone, astro-ph/ Koushiappas, Bullock, Dekel, astro-ph/

7 Spike formation at the Galactic center G. Bertone, astro-ph/ ] 3 Galactic halo density profile is supposed to be a Navarro-Frenk-White (NFW): (3) [M /kpc From a power-law density profile, a spike can form with a new slope: r [kpc] (4) (5)

supposed to be a Navarro-Frenk-White (NFW): (3) [M /kpc 9 8 7 6 5 4 3

8 Spike formation at the Galactic center G. Bertone, astro-ph/ Ullio, Zhao, Kamionkowski, astro-ph/01481 From a NFW (γ=-1) the final spike has γ sp =-7/3 (6) (7)

9 Spike formation at the Galactic center Arguments against spikes formation: off-center black hole formation gravitational interaction with stars merger and BH binary effects G. Bertone, astro-ph/ Ullio, Zhao, Kamionkowski, astro-ph/01481 Merritt, Milosavljevic, Verde, Jimenez astro-ph/

10 IMBHs catalogue (Bertone, Zentner, Silk) Focusing on astro-ph/ by G. Bertone, A. Zentner and J. Silk: initial catalogue of IMBHs merging tree selection of unmerged mini-halos no baryonic content and the BH lays in the center G. Bertone, astro-ph/ Bertone, Zentner, Silk, Astro-ph/

Silk: initial catalogue of IMBHs merging tree selection of unmerged

11 IMBHs catalogue for Andromeda How IMBHs are characterized: realization ID Black Hole Mass [M ] IMBH distance from the center of the Galaxy [kpc] r sp [kpc] ρ(r sp ) [M /kpc 3 ] Milky Way Andromeda G. Bertone, astro-ph/ Distance to the center Virial Mass Virial Radius 8.5 kpc M 205 kpc kpc M 180 kpc Andromeda IMBHs are 65.2±14.5 per realization, with an average mass of M and an average distance from M31 center of 32.3 kpc.

Bertone, astro-ph/ 0603148 Distance to the center Virial Mass Virial Radius 8.5 kpc 1.0 12 M 205 kpc 784.0 kpc 6.

12 Annihilation Flux (8) G. Bertone, astro-ph/ To compute the differential energy spectrum a particular model of physics beyond the SM is needed: (9) ()

13 Differential energy spectrum FPS (Fornengo-Pieri-Scopel) MSSM is assumed and the DM candidate is the lightest neutralino focused on hadronization of b quarks fit from simulated data, using standard package as PYTHIA (x=e/m χ ) () G. Bertone, astro-ph/ a=-1.5 b=0.37 c= d=18.01 e= for m χ =1 TeV

quarks fit from simulated data, using standard package as PYTHIA (x=e/m χ ) ()

14 Thresold effect (11) (12) G. Bertone, astro-ph/ m χ = 50 GeV m χ = 150 GeV m χ = 300 GeV m χ = 500 GeV Φ (E thr =4 GeV) cm -2 s cm -2 s cm -2 s cm -2 s -1 ACTs GLAST E thr 0 GeV 4 GeV (see later) m χ 1 TeV 150 GeV

GeV m χ = 500 GeV Φ (E thr =4 GeV) 5.26-11 cm -2 s -1 7.

15 Detection of IMBHs with ACTs m χ =1 TeV and σv=3-26 cm 3 s -1 E th =0 GeV typical ACT angular resolution is 0.1 typical ACT effective area is 3 4 m 2 exposure time is 0 hours

16 Detection of IMBHs with ACTs (13) Origin of background: EGRET: (14) Hadronic and electronic: (15) (16)

17 Detection of IMBHs with ACTs ACT sensitivity for a 5σ detection results cm -2 s -1, higher than the brightest bins of the previous sky map.

18 Detection of IMBHs with ACTs Number of IMBHs over ACT sensitivity is 5.2 ± 3.1 for m χ =1 TeV

19 Detection of IMBHs with GLAST m χ =150 GeV and the energy threshold is MeV GLAST angular resolution is expected to be 3 (from MeV to 500 MeV), 0.5 (from 500 MeV to 4 GeV) and 0.15 (above 4 GeV) a selection is made and only high-energy photons (above 4 GeV) are considered extragalactic background hadronic and electronic backgrounds are absent the effective area times the exposition time is roughly 8 9 cm 2 s the resulting sensitivity for a 2 months period is cm -2 s -1

15 (above 4 GeV) a selection is made and only high-energy photons (above 4 GeV) are considered extragalactic background

20 Detection of IMBHs with GLAST Number of IMBHs over GLAST sensitivity is 17.1 ± 5.8 for m χ =150 GeV

21 Detection of IMBHs with GLAST

22 Conclusions fluxes from DM annihilations in mini-halos around IMBHs that populate the Andromeda Galaxy have been computed detection with an ACT is very challenging, due to the hadron background the scenario with GLAST is more promising, even if the best angular resolution is achieved only after a strict selection (very high-energy photons) the picture is that of isolated, point-like, bright sources in a region 3 wide around the Andromeda center

23 Differential energy spectrum FPS (Fornengo-Pieri-Scopel) MSSM is assumed and the DM candidate is a neutralino focused only on the main channel (hadronization of b quarks) fit from simulated data, using standard package as PYTHIA (x=e/m χ ) differential spectrum for τ leptons hadronization is presented too (see later) (17) (a, b, c, d, e)=(-1.5, 0.37, , 18.01, ) (a, b, c, d, e)=(-1.31, 6.94, -4.93, -0.51, -4.53) Kretzer Fragmentation Functions DM candidate is again a neutralino FF is the probability to have an hadron h with xq 2 from a parton p with Q 2

24 Differential energy spectrum focused on the photon production from a π 0 resulting from quarks b (i.e. p=b, h=π 0 ) (18) a flat spectrum for photons from pions is assumed (19) BBEG (Bergstrom-Bringmann-Eriksson-Gustafsson) differential spectrum is calculated for a DM candidate from Universal Extra-Dimension, what is called B (1) contribution of primary photons from charged leptons is no longer neglected (B (1) B (1) γl + l - ) (20)

25 Differential energy spectrum Flux from Andromeda FPS Kretzer FFs BBEG cm -2 s cm -2 s cm -2 s -1 From now on, only the FPS parametrization will be used

26 Exclusion Plot Solid line: all realizations with at least one detectable IMBH Dashed line: 20 realizations over 200 with at least one detectable IMBH v [cm s -1 ] % m [GeV]

Search for supersymmetric Dark Matter with GLAST!!

Search for supersymmetric Dark Matter with GLAST!! Aldo Morselli INFN, Sezione di Roma 2 & Università di Roma Tor Vergata ICCRC2003 The 28th International Cosmic Ray Conference Tsukuba, Japan, July 31-