Recent Searches for Dark Matter with the Fermi-LAT

Recent Searches for Dark Matter with the Fermi-LAT on behalf of the Fermi-LAT Collaboration CETUP* DM Workshop Deadwood, SD 7 July 2016

A One-Slide History of Dark Matter Particle Physics Astrophysics Particle Dark Matter Cosmology 2

Potential Candidates Particle Dark Matter Weakly Interacting Massive Particles Axions Others: asymmetric DM sterile neutrinos etc 3

Detecting Particle Dark Matter 4

Detecting Particle Dark Matter χ SM Indirect Detection χ time SM 4

Detecting Particle Dark Matter χ SM Indirect Detection χ time SM SM SM Direct Detection χ χ 4

Detecting Particle Dark Matter χ SM Indirect Detection χ time SM SM SM SM χ Direct Detection Collider χ χ SM χ 4

Detecting Particle Dark Matter χ SM Indirect Detection SM: χ time SM information about mass, point back to source SM SM SM χ Direct Detection Collider χ χ SM χ 4

Detecting Particle Dark Matter χ SM Indirect Detection SM: χ time SM information about mass, point back to source eventually can get to photons SM SM SM χ Direct Detection Collider χ χ SM χ 4

Detecting Particle Dark Matter χ SM Indirect Detection SM: χ time SM information about mass, point back to source eventually can get to photons SM SM SM χ Direct Detection Collider χ χ Gustafsson et al. PRL 99.041301 SM χ 4

Indirect Searches: γ-rays L. Bergstrom et al., Astropart.Phys.9:137-162,1998 5

Indirect Searches: γ-rays Observed = L. Bergstrom et al., Astropart.Phys.9:137-162,1998 5

Indirect Searches: γ-rays Observed = Particle Properties x Gustafsson et al. PRL 99.041301 x=eγ/mχ L. Bergstrom et al., Astropart.Phys.9:137-162,1998 5

Indirect Searches: γ-rays Observed = Particle Properties x Gustafsson et al. PRL 99.041301 x=eγ/mχ cross section mass photons L. Bergstrom et al., Astropart.Phys.9:137-162,1998 5

Indirect Searches: γ-rays Observed = Particle Properties x Astrophysics Properties Gustafsson et al. PRL 99.041301 density x=eγ/mχ distance cross section mass photons J-Factor: ~ ρ 2 (solid angle, line of sight) L. Bergstrom et al., Astropart.Phys.9:137-162,1998 5

Indirect Searches: γ-rays Observed = Particle Properties x Astrophysics Properties Gustafsson et al. PRL 99.041301 density you are here x=eγ/mχ distance cross section mass photons J-Factor: ~ ρ 2 (solid angle, line of sight) L. Bergstrom et al., Astropart.Phys.9:137-162,1998 5

Fermi Gamma-Ray Space Telescope June 11, 2008 6

Fermi Gamma-Ray Space Telescope June 11, 2008 Large Area Telescope 20% sky at once full sky 3 hours 20 MeV - 1 TeV 6

Fermi Gamma-Ray Space Telescope June 11, 2008 Large Area Telescope 20% sky at once full sky 3 hours 20 MeV - 1 TeV Gamma-ray Burst Monitor full sky continuous 8 kev - 40 MeV 6

Fermi Gamma-Ray Space Telescope 7

Fermi Gamma-Ray Space Telescope Anti-Coincidence Detector charged particle separation 7

Fermi Gamma-Ray Space Telescope Anti-Coincidence Detector charged particle separation Tracker charged particles cause conversion γ e + e - direction 7

Fermi Gamma-Ray Space Telescope Anti-Coincidence Detector charged particle separation Tracker charged particles cause conversion γ e + e - direction Calorimeter Energy measurement 7

Detecting γ-rays Simulated 27 GeV γ-ray event Tracker Calorimeter 8

Detecting γ-rays Simulated 27 GeV γ-ray event Tracker Calorimeter 9

Detecting γ-rays Simulated 27 GeV γ-ray event Tracker Calorimeter 10

Detecting γ-rays Simulated 27 GeV γ-ray event Anti-Coincidence Detector Tracker Calorimeter 11

Reconstructing γ-rays Simulated 27 GeV γ-ray event Fermi-LAT Collaboration, ApJS, 203, 4 (2012) Made publicly available ~24 h 12

Fermi-LAT γ-ray sky 13

Fermi-LAT γ-ray sky π 0 decay Bremsstrahlung Inverse Compton 13

Fermi-LAT γ-ray sky Galactic Plane Diffuse Active Galactic Nuclei Pulsars Point Sources 13

Fermi-LAT γ-ray sky Galactic Plane Diffuse Active Galactic Nuclei +Supernova Remnants + Globular Clusters + Pulsar Wind Nebulae + Starburst Galaxies + Pulsars Point Sources 13

Fermi-LAT γ-ray sky Galactic Plane Diffuse Active Galactic Nuclei +Supernova Remnants + Globular Clusters + Pulsar Wind Nebulae + Starburst Galaxies + Pulsars >3000 sources Point Sources 13

Fermi-LAT γ-ray sky Galactic Plane Diffuse Active Galactic Nuclei +Supernova Remnants + Globular Clusters + Pulsar Wind Nebulae + Starburst Galaxies + Point Sources Pulsars >3000 sources Dark Matter, exotic physics 13

Dark Matter Distribution Search Strategies for WIMPs L. Pieri et al., PRD 83 023518 (2011) 14

Dark Matter Distribution Search Strategies for WIMPs Dwarf Spheroidal Satellite Galaxies Galaxy Clusters Milky Way Halo Galactic Center Spectral Lines Isotropic Background L. Pieri et al., PRD 83 023518 (2011) 14

Galactic Center F. Iocco, Pato, Bertone, Nature Physics 11, 245 248 (2015) 15

Galactic Center Fit to DM profile (NFW) No DM F. Iocco, Pato, Bertone, Nature Physics 11, 245 248 (2015) 15

Galactic Center Why is the Galactic Center so hard to observe? 16

What s Going On in the Galactic Center? 2009 Excess in gamma-ray flux from GC L. Goodenough, arxiv:0910.2998 17

What s Going On in the Galactic Center? 2009 Excess in gamma-ray flux from GC 2009 now Many papers confirming the excess Speculation as to its origin Not exhaustive: L. Goodenough, D. Hooper, arxiv:0910.2998 D. Hooper, L. Goodenough, PLB, arxiv:1010.2752 D. Hooper, T. Linden, PRD, arxiv:1110.0006 K. Abazajian, M. Kaplinghat, PRD, arxiv:1207.6047 D. Hooper, T. Slatyer, PDU, arxiv:1302.6589 C. Gordon, O. Macias, PRD, arxiv:1306.5725 W. Huang, A. Urbano, W. Xue, arxiv:1307.6862 K. Abazajian, N. Canac, S.Horiuchi, M. Kaplinghat, arxiv:1402.4090 T. Daylan, et al., PDU 12 1 (2016), arxiv: 1402.6703 Dark Matter 17

Dividing the Galaxy Constituents of the Model Templates to define different background regions Gamma-ray sources (pulsars, OB stars) Intensity/Index scaled M. Ajello et al., Astrophys. J. 819, 44 (2016) 18

Dividing the Galaxy The 3FGL Catalog The 1FIG Catalog M. Ajello et al., Astrophys. J. 819, 44 (2016) 18

Current GCE and Upgrading to Pass 8 M. Ajello et al., Astrophys. J. 819, 44 (2016) 19

Current GCE and Upgrading to Pass 8 Andrea s talk will discuss the effects of modeling uncertainties 19

Current GCE and Upgrading to Pass 8 Andrea s talk will discuss the effects of modeling uncertainties Current campaigns to identify pulsars in the Galactic Center 19

Spectral Lines Unbinned Maximum Likelihood Fits Background+Signal (red) Background model (grey dashed): Single power law with index Γ bkg allowed to float Energy dependent exposure correction Signal model (blue): E dispersion (Gaussian) n sig fit model independent 20

Spectral Lines Unbinned Maximum Likelihood Fits Gustafsson et al. PRL 99.041301 Background+Signal (red) Background model (grey dashed): Single power law with index Γ bkg allowed to float Energy dependent exposure correction Signal model (blue): E dispersion (Gaussian) n sig fit model independent 20

Spectral Lines ROIs 21

Spectral Lines 2013: Tentative Too Narrow More narrow than energy resolution Fermi-LAT analysis with Pass 7 Reprocessed data and 2D PDF fit arxiv: 1305.5597 22

Spectral Lines 2013: All ROIs All σ Wait and see what happens arxiv: 1305.5597 23

133 GeV Feature with Pass 8 Events / ( 5.0 GeV ) Residual( σ) 140 120 100 80 60 40 20 0 2 0-2 P8_CLEAN R3 5.8 yr E γ = 133.0 GeV Γ bkg = 2.47 n sig = 7.3 evts (0.7 σ) n bkg = 700 ± 30 evts 40 60 80 100 120 140 160 180 200 220 Energy (GeV) Pass 8: Full 5.8 years 24

Spectral Lines: Full Eγ range s -1 ) 3 95% CL Limit (cm -27 10-28 10-29 10 NFWc(γ =1.3) R3 Obs Limit P8 (5.8 yr stat+syst) Expected Limit Expected 68% Containment Expected 95% Containment Obs Limit P7REP (3.7 yr, stat-only) <σv> γ γ -30 10-31 10 3 10 4 10 5 10 m χ 10 (MeV) 6 25

Dark Matter Distribution Search Strategies for WIMPs Dwarf Spheroidal Satellite Galaxies arxiv: 1310.0828 arxiv: 1503.02641 arxiv: 1503.02632 Milky Way Halo arxiv: 1205.6474 From the Fermi-LAT Collaboration DES candidates Dwarf Spheroidal Satellite Galaxies arxiv: 1503.02320 arxiv: 1503.06209 External Analyses on DES candidates Galactic Center arxiv:1511.02938 (many external) Galaxy Clusters arxiv: 1511.00014 arxiv: 1308.5654 arxiv: 1002.2239 Spectral Lines arxiv: 1305.5597 arxiv: 1506.00013 Isotropic Background arxiv: 1202.2856 arxiv: 1501.05464 L. Pieri et al., PRD 83 023518 (2011) 26

Dwarf Spheroidal Galaxies J. Bullock, M. Geha, R. Powell 27

Dwarf Spheroidal Galaxies (km/s) Walker, ApJ, 667, L53 J. Bullock, M. Geha, R. Powell 27

Dwarf Spheroidal Galaxies High Dark Matter to Baryonic Matter Ratio (km/s) Walker, ApJ, 667, L53 J. Bullock, M. Geha, R. Powell 27

Dwarf Spheroidal Galaxies less bright than GC Increase in continuum flux (overall excess) High Dark Matter to Baryonic Matter Ratio (km/s) Walker, ApJ, 667, L53 J. Bullock, M. Geha, R. Powell 27

Dwarf Spheroidal Galaxies 27

Dwarf Spheroidal Galaxies Miloslav Druckmüller, National Geographic 27

Dwarf Spheroidal Galaxies Miloslav Druckmüller, National Geographic 50 x50 view of the Milky Way from the LMC Balance between high DM signal and low background 27

Dwarf Spheroidal Galaxies Miloslav Druckmüller, National Geographic 50 x50 view of the Milky Way from the LMC SMC rotation curve Balance between high DM signal and low background Bekki & Stanimirovic, MNRAS (2009) 395 (1) RC, et al.,prd 93.062004 (2016) Di Cintio et al., MINRAS (2013) 437 415 27

Large Magellanic Cloud LMC J-factor: log 10 J 20, Distance: 50 kpc M. Buckley, et al., PRD, 91.102001, (2015) arxiv: 1502.01020 28

Large Magellanic Cloud What we found: The brightest/most energetic Pulsars known Published in Science 11/13/2015 LMC J-factor: log10 J 20, Distance: 50 kpc M. Buckley, et al., PRD, 91.102001, (2015) arxiv: 1502.01020 28

Small Magellanic Cloud SMC J-factor: log 10 J 19.5 Distance: 60 kpc RC, et al., PRD 93.062004 (2016) 29

The Challenge: Astrophysical Backgrounds Effective Background: b eff Study b eff ~actual background insight into correlation i.e.: Σ ~1: completely degenerate Source beff N Isotropic Diffuse 5100 8600 Galactic Diffuse 6400 18000 SMC 140 2000 PS1 81.7 24.8 47 Tuc 0.0043 2150 PS2 0.02 870 Total 25300 31600 R. Caputo UCSC Fermi Symposium 2015 30

Correlations between SMC and DM PS1, Isotropic and SMC float 10σ nominal value Correlation Factor (ρ) calculated using covariance matrices R. Caputo UCSC Fermi Symposium 2015 31

750 GeV excess??? Natural place in gamma-rays The Model Assumptions Couples to DM pseudo-scalar Investigate couples to γ only m χ >375 GeV couples also to g m χ <375 GeV 32

750 GeV excess??? Natural place in gamma-rays The Model Assumptions Couples to DM pseudo-scalar Investigate couples to γ only m χ >375 GeV couples also to g m χ <375 GeV Air Cherenkov Telescopes 32

And now for something completely different 33

Axion Like Particles (ALPs) A solution to a different problem Quantum chromodynamics (QCD) Axions! 10-5 to 10-3 ev Couple to photons in an external magnetic field strong field = more coupling Axion-Like Particles (ALPs) < this one not restricted to those masses but still light Strong magnetic fields in galaxy clusters M. Ajello et. al, Phys. Rev. Lett. 116, 161101 (2016) arxiv:1603.06978v1 http://depts.washington.edu/admx/index.shtml 34

Perseus Cluster Interact with SM via photon-alp oscillations test mass/photon coupling ind. parameters DM candidate! coupling to gamma-rays in astrophysical B fields light ALPs m a μev stolen from M. Mayer 35

Central Galaxy of the Perseus cluster: NGC 1275 M. Ajello et. al, Phys. Rev. Lett. 116, 161101 (2016) arxiv:1603.06978v1 36

Current Axion Limits M. Ajello et. al, Phys. Rev. Lett. 116, 161101 (2016) arxiv:1603.06978v1 37

MeV Dark Matter: Axions Axions produced in supernovae (arxiv:1410.3747) core collapse supernova (SN1987A) 38

MeV Dark Matter: Axions Axions produced in supernovae (arxiv:1410.3747) core collapse supernova (SN1987A) Limited by PSF @<100 MeV 38

Axions in Pulsating Radio Stars (Pulsars) Rapidly rotating Neutron Stars 1967: Jocelyn Bell - LGM signal Rotational axis!= magnetic axis Rotational periods: ms to s Magnetic field strength: ~10 11-12 (up to 10 14 G - 0.2 G Earth) 39

Axions in Pulsars Away from galactic plane Close Measured B-Field Predicted Spectral Energy Distribution for gamma rays from axion decays for J0108 1431 B. Berenji, et al., Phys. Rev. D 93, 045019 (2016) arxiv:1602.00091 40

Pulsar Target! Known Source(s) Our Pulsar Eγ: 60-200 MeV No excess, set a limit: 7.9 10 2 ev 41

Fin Fermi-LAT is an excellent probe into of Dark Matter Indirect detection is the only detection technique that searches for DM in astrophysical targets The LAT is the only instrument sensitive to DM annihilation at the thermal relic cross section The LAT has a suite of DM targets: Galactic Center, Galaxy Clusters, dwarf galaxies, the sun, etc Complementary searches between DD and Collider are necessary to understand the nature of a potential discovery Not finding DM in the obvious places Continue searching because we really need to figure this whole thing out 42

Discussion! 43

Summary of Fermi-LAT Dark Matter Searches h vi [cm 3 s 1 ] 10 22 10 23 10 24 10 25 MW Halo: Ackermann+ (2013) MW Center: Gomez-Vargas+ (2013) dsphs: Ackermann+ (2015) Unid. Sat.: Bertoni+ (2015) Virgo: Ackermann+ (2015) Isotropic: Ajello+ (2015) X-Correl.: Cuoco+ (2015) APS: Gomez-Vargas+ (2013) 10 26 10 27 b b Thermal Relic Cross Section (Steigman+ 2012) Daylan+ (2014) Calore+ (2014) Gordon & Macias (2013) Abazajian+ (2014) 10 1 10 2 10 3 10 4 m [GeV] E. Charles et al, arxiv:1605.02016 44

Future WIMP Dark Matter Searches E. Charles et al, arxiv:1605.02016 45