1. Brenda Dingus US Spokesperson Los Alamos National Lab dingus@lanl.gov 8 August 2014 1 July 2014 The TeV Sky with HAWC

2. 2 Gamma -Ray Detectors Wide Field of View, Continuous Operations Fermi AGILE EGRET TeV Sensitivity HAWC ARGO Milagro VERITAS HESS MAGIC HAWC is a wide field of view (~2 sr), continuously operating (>90% duty cycle), TeV observatory.  Unbiased search for transients to initiate multi messenger observations  Highest energy observations with ~100 km 2 hr exposure after 5 years operation on > ½ the sky

3. 3 HAWC Design builds on Milagro Milagro “1 st Generation” Water Cherenkov gamma-ray detector 2650m (8600’) elevation near Los Alamos, NM Covered pond of 4000 m 2 Operated 2000-2008 Detected new Galactic sources, Galactic plane, cosmic ray anisotropy, and put upper limits on prompt emission from gamma-ray bursts HAWC “2 nd Generation” Water Cherenkov gamma-ray detector 4100m (13500’) elevation near Puebla, Mexico 300 water tanks spread over 25000 m 2 Construction 2010-14, Operation 2013-19 15 x Milagro’s sensitivity with 10 x lower energy threshold ©Aurore Simonnet

4. 4 HAWC Design 180 meters 140 meters 300 close packed water tanks (7.3m dia x 4.5 m deep of 200,000 liters) each with 4 upward facing photomultiplier tubes at the bottom

5. 5 HAWC Site Location in Mexico High Altitude Site of 4100 m with temperate climate and existing infrastructure 17 R.L. of atmospheric overburden vs 27 R.L. at sea level Latitude of 19 deg N Pico de Orizaba 5600 m (18,500’) Large Millimeter Telescope (50m dia. dish) HAWC

6. 6 The HAWC Collaboration Los Alamos National Laboratory Univ. of Maryland Michigan State Univ. University of Wisconsin Pennsylvania State Univ. Univ, of Utah Univ. California Irvine George Mason University University of New Hampshire University of New Mexico Michigan Technological University NASA/Goddard Space Flight Center Georgia Institute of Technology University of Alabama Colorado State Univ. Univ. California Santa Cruz Instituto Nacional de Astrofísica Óptica y Electrónica Universidad Nacional Autónoma de México Instituto de Física Instituto de Astronomía Instituto de Geofisica Instituto de Ciencias Nucleares Benemérita Universidad Autónoma de Peubla Universidad Autónoma de Chiapas Universidad Autónoma del Estado de Hidalgo Universidad de Guadalajara Universidad Michoacana de San Nicolás de Hidalgo Centro de Investigacion y de Estudios Avanzados Universidad de Guanajuato Mexico USA ~100 Members

7. 7 11/2010 02/2012 08/2012 05/2013 01/2014 13M USD project funding began Feb 2011 Operations with 111 water Cherenkov detectors began Aug 2013 Currently, 264 water tanks have been built. Construction will be complete by end of 2014

8. 8 PMTs Water Steel Survey Construction Progressing Well

9. 9 HAWC-30 Completed Sept 2012 HAWC 30 Events and Observation of cosmic-ray shadow of Moon with 70 days of data

10. 10 HAWC-95/111 Skymap J. Patrick Harding, Summer Seminar Series

11. 11 HAWC-95/111 Skymap Crab Nebula J. Patrick Harding, Summer Seminar Series

12. 12 HAWC-95/111 Skymap Mrk 501 Blazar J. Patrick Harding, Summer Seminar Series

13. 13 HAWC-95/111 Skymap Mrk 421 Blazar J. Patrick Harding, Summer Seminar Series

14. 14 HAWC Differential Sensitivity Differential Sensitivity per Quarter Decade of Energy http://arxiv.org/abs/1306.5800http://arxiv.org/abs/1306.5800 Astroparticle Physics 2013

15. 15 vs. Declination HAWC Integral Sensitivity vs. High Energy Cut off http://arxiv.org/abs/1306.5800http://arxiv.org/abs/1306.5800 Astroparticle Physics 2013

16. 16 KnownTeV sources are shown, but most of the high latitude sky has not been observed at TeV energies HAWC’s Field Of View Sources from TeVCAT.uchicago.edu

17. 17 Highest Energy Sources For example, MGRO J2019+37 SED peaks >10 TeV. Aliu, et al. 2014, “Spatially resolving MGR0 2019+37 with VERITAS HAWC will likely discover new higher energy peaked sources.

18. 18 Cygnus: A Complicated Region MGRO J2031+41:  Collocated extended emission detected by IACTs, Milagro, and ARGO  Spectrum appears to line up with the Fermi cocoon cosmic ray acceleration model can explain the diffuse emission in the cocoon © M. Hui Milagro contours on Fermi counts map

19. 19 HAWC: Extended Sources HAWC will detect Geminga with >50  to measure spectra and map diffusion near source. PAMELA’s positron excess is well fit given Milagro’s flux from Geminga Milagro’s Detection of an extended excess coincident with Geminga ~ 10 parsec Yüksel, Kistler, Stanev PRL 2009

20. 20 HAWC: Active Galactic Nuclei Flares ~50 known TeV AGN IACT observations have <1% duty cycle/AGN & detect no flaring in many HAWC’s will monitor all Northern AGN with 20% duty cycle/day (5 hrs) regardless of sun, moon, or weather HAWC’s 5  sensitivity is (10,1,0.1) Crab in (3 min, 5 hrs, 1/3 yr) Worldwide Dataset of TeV Observations by IACTs of Mrk421 1 month Tluczykont et al. 2010 3 minutes 5 hours

21. 21 TeV  -rays are attenuated by pair production TeV spectra from distant sources probe: Cosmology of Extragalactic Background Light Sources of UHECRs Intergalactic Magnetic Field in Voids Axion Like Particles   a    Hooper & Serpico, PRL 2007) HAWC will survey sky for new TeV AGN, measure multi-TeV spectra and variability, and enable multimessenger observations through prompt notification of flaring activity. HAWC: Distant Sources Essey, Kalashev, Kusenko, Beacom, PRL 2010 TeV spectra extend beyond pair production threshold for many sources (Horns&Meyer 2012)

22. 22 HAWC: Gamma-Ray Bursts Fermi observation of GRB090510, z=0.9 Highest Observed Energy was 33 GeV with 16  -rays >1 GeV Constrained Lorentz Invariance at the Plank Mass scale GRB130427: Fermi detected 94 GeV  -ray HAWC would detect this GRB if it occurred in FOV

23. 23 HAWC: GRB sensitivity Fermi LAT sensitivity assumes 1 gamma-ray > 10 GeV Scaler sensitivity uses sum of single photoelectron rates in individual PMTs to observe shortest and most distant transients Gilmore & Taboada, NIM A 2013 predict HAWC will detect 1.6 GRBs/yr Abeysekara et al., Astroparticle Physics, 2011  GRB130427 z=0.34 z=0.91

24. 24 HAWC has sensitivity to indirect detection of TeV WIMPs in satellite galaxies, the Galactic Center, and galaxy clusters Cosmological simulations predict more satellite galaxies than observed Higher M/L galaxies have been found by Sloan Deep Survey HAWC will observe all M/L galaxies in half the sky, even if L=0 HAWC: Dark Matter Preliminary Solid lines are 5 sigma sensitivity. Dashed lines show sensitivity with the expected Sommerfeld enhancement due to additional resonances. Horizontal line is the cross section for thermal production of WIMPs.

25. 25 Milagro Discovered an Anisotropy of 10 TeV Cosmic Rays (PRL, 2009) Confirmed in Northern Hemisphere by ARGO and now HAWC, and in Southern Hemisphere by Ice Cube Gyroradius of 10TeV proton in 2  G field is 0.005 parsecs=1000 AU No known sources within this distance Heliospheric Effect? Annihilation in protons of nearby Dark Matter? (Harding, astroph/1307.6537) Strangelets (stable quark matter)? (Kotera, Perez-Garcia, Silk astroph/1303.1186v1) HAWC: Cosmic Rays

26. 26 Increase photodetection efficiency for lower energies Winston Cones Large Area Photodetectors Liquid Scintillator Larger Area Array Sensitivity proportional to Area, NOT sqrt(Area) due to background rejection Beyond HAWC: Increase Sensitivity Energy of Secondary Particles in Air Shower at Ground Level (MeV) E dN/dE (arbitrary scale) HAWC Single photoelectron threshold Muons have broad lateral distribution

27. 27 Discovering rare transient events requires full sky coverage GRB finder for Advanced LIGO, which will detect all neutron binary coalescence with z<0.5 AGN flares & GRBs as distant probes of high energy physics (e.g. Lorentz invariance and axions) Galactic Center TeV Source finder for CTA south Beyond HAWC: Southern Site Alto Chorrillo Argentina 4800m

28. 28 Same detector at a higher altitude has increased sensitivity especially at lower energies Factor of 4 increase in sensitivity between ALMA and HAWC altitude Beyond HAWC: Even Lower Energy Sensitivity for one year of observation of an array of 900 tanks with 900 PMTs at different altitudes

29. 29 HAWC is now! Construction complete in 2014 Science operations with 111 tanks began 1 Aug 2013 First results are coming now HAWC detects Crab>10 

30. 30 BACKUP

31. HAWC Performance (a) (d) (c) (b) Milagro HAWC Better Energy Resolution Much Better Background Rejection Much Better Angular Resolution Much Better Low Energy Response

32. 32 Brian Baughman - HAWC Collaboration - ICRC 2013 Rio Gammas Protons Energy deposited away from core 7 24 TeV at =44° 837 Hit PMTs 8 TeV at =10° 838 Hit PMTs 21 TeV at =21° 1131 Hit PMTs 118 TeV at =52° 1116 Hit PMTs

33. 4100m 2600m Higher Altitude means fewer radiation lengths and more particles (~5x) for same primary energy Extensive Air Shower Development