Cooperate with X-L. Chen , Q. Yuan, X-J. Bi, Z-Q. Shen Approaching the Light Side of Dark Matter? --- issues related to dark matter indirect detection 黄 峰 厦 门 大 学 Cooperate with X-L. Chen , Q. Yuan, X-J. Bi, Z-Q. Shen 2009. 09. 26 @ 恩施

Outline Introduction Dark Matter and its annihilation signals Summary 1, Non-thermal Sunyaev-Zel'dovich (SZ) effect in Cluster and DSphs with two different Dark Matter model considered 2, Constraints on Leptonic DM with associated Inverse Compton Scattering emission (ICS) and Final State Radiation (FSR) in DSphs 3, Synchrotron Emission in Dwarf Galaxies Summary

Introduction Dominant matter component : non-baryonic matter Evidence: Rotation Curves, CMB, BBN, LSS …(gravitational effects) What’s the particle nature? —remain a puzzle

What is Dark Matter? Leptonic DM (TeV) WIMP: Neutralino (10GeV-TeV) Well provided theoretically Phenomenology proposed WIMP: Neutralino (10GeV-TeV) Light DM (MeV) 4

Further Constraints Other dark halos? Multi-wavelength? Colafrancesco, IoP/RAS Meeting 2007

Colafrancesco, IoP/RAS Meeting 2007 Multi-wavelength? 正负电子源 e^+-: SZ effect IC emission Synchrotron emission Colafrancesco, IoP/RAS Meeting 2007 正负电子的在不同 的天体系统的传播

DM annihilates in Nearby Dark Halos Other dark halos? DM annihilates in Nearby Dark Halos Nearby galaxies clusters: cluster as the largest bound containers of DM Dwarf galaxies: dominated by DM both in central regions and outskirts close to be a pure dark halo local group satellites

Clusters v.s. Dwarf galaxies astrophoton.com/dwarf_galaxies.htm Large Scale Hot gas Diffusion irrelevant Small scale Lack of gas Diffusion dominant

SZ effect induced by DM Annihilation in Clusters and DSphs

SZ effect induced by WIMP in Coma Cluster m=40GeV S. Colafrancesco et al. Astro-ph/0507575 Q. Yuan et al. Astro-ph/0902.4294

SZ effect induced by LDM in Coma Cluster <v>(1MeV/m)2~10-30cm3/s (PRL, 2004, 92, 101301) 511keV emission @GC

Other Clusters

number density distribution of electrons in dSphs SZ~ n_e*T_e Uncertainty in the description of equilibrium electrons&positrons distribution

Compare to previous work SZ effect induced by DM self-annihilation Compare to previous work

SZ effect induced by DM self-annihilation With different density profile With Different diffuse model

SZ from DSphs

ICS and FSR associated with Leptonic DM annihilation in DSphs

Motivation Other Constraints Leptonic DM eg: S. Profumo et al., arXiv:0906.0001 Liu et. al., arXiv:0906.3858

ICS and FSR in Nearby Dwarf Halo

Observation Constraints MAGIC：F(E>140GeV) < 1.1d-11 ph /cm^2/s F(E>140GeV) ~ 9.78d-10 ph /cm^2/s @ NFW EGRET：F(E>2GeV) < 3.3d-7 /cm^2/s/sr FERMI: ?

Synchrotron emission from Dwarf galaxies

Radio emission in dSphs: diffuse and weak ~90% of the total flux is from the central region of 2 degree ~50% is within central 50 arcmin region. ~possible enhancement from sub-halo which survived in the outerskirts What’s the implication for observation?

ATA observation (黄峰，陈学雷，沈志强) VLA at 4.885GHz in 1979 very center region (4arcmin ) <2mJy Updated observation required Diffuse ------ large field view weak ------ high sensitivity F.o.V at 1.4GHz: 2.5 degree 42 working antennas Effective bandwidth :103MHz 6hrs on-source time. rms: 0.1mJy/beam @ 1.4GHz Crucial factor: local magnetic field B

More distant dSphs: Leo I Other radio array:Very Large Array at D-configuration The primary beam size of VLA at 1.5GHz at D-configuration is around 30arcmint; 26 working antennas, effective bandwidth of 43 MHz, an rms of 0.02mJy/beam of 6hrs on-source time, the peak-to-rms is tended to be greater than 10. Moreover, the angular distribution of the flux could be resolved (right panel)

Synchrotron radio emission from nearby dIrrs: B_dIrr > B_dSph Stronger radio flux_DM from dIrrs Contaminated by Radio: Cosmic Ray e- accelerated by SNe from massive star Tight and universal FIR-radio correlation in normal galaxies Star formation rate Golbular clusters vs. dwarfs galaxies. No need for dark matter (probably) in globulars because there is enough stellar mass. Dwarfs are more extended and require DM within the tidal radial. -Interesting ‘in between’ population. These could be tidally disrupting dwarfs or globulars. -SDSS only covers 20% of the sky. Does this mean there are 5x more satellites? FIR: UV radiation from young star re-emitted in the surrounding dust

Possible explanation for such a trend is that either the FIR are overestimated in low luminosity galaxies or another kind of non-thermal contribution should be considered. Require to be update

Current Work Larger Samples Good SFR Indicator FIR IR_tot Halpha UV ? Nearby dIrrs with Vmax-Rmax Arxive：0901.4222

Summary Be cautious to interpret experiment data *multi-wavelength consistence *other dark halos Electrons&positrons produced by DM annihilating as an universal source in dark halos with different scales; Clusters and dwarf galaxies are both potential to be good systems for indirect detection of DM Multi-wavelength consistence are needed Lower frequency observations in dwarf galaxies are generally required

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