Brenda DingusUS SpokespersonLos Alamos National Labdingus@lanl.gov

8 August 2014

1 July 2014

The TeV Sky with HAWC

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Gamma-Ray Detectors

Wide Field of View, Continuous Operations

FermiAGILEEGRET

TeV Sensitivity

HAWCARGO

Milagro

VERITASHESS

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 km2 hr exposure

after 5 years operation on > ½ the sky

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HAWC Design builds on Milagro

Milagro “1st Generation” Water Cherenkov gamma-ray detector• 2650m (8600’) elevation near Los

Alamos, NM• Covered pond of 4000 m2 • Operated 2000-2008• Detected new Galactic sources, Galactic

plane, cosmic ray anisotropy, and put upper limits on prompt emission from gamma-ray bursts

HAWC “2nd Generation” Water Cherenkov gamma-ray detector• 4100m (13500’) elevation near Puebla,

Mexico• 300 water tanks spread over 25000 m2

• Construction 2010-14, Operation 2013-19

• 15 x Milagro’s sensitivity with 10 x lower energy threshold

©Aurore Simonnet

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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

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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

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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

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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

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PMTs

Water

Steel

Survey

Construction Progressing

Well

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HAWC-30 Completed Sept 2012

HAWC 30 Events andObservation of cosmic-ray shadow of Moon with 70 days of data

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HAWC-95/111 Skymap

J. Patrick Harding, Summer Seminar Series

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HAWC-95/111 SkymapCrab Nebula

J. Patrick Harding, Summer Seminar Series

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HAWC-95/111 SkymapMrk 501 Blazar

J. Patrick Harding, Summer Seminar Series

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HAWC-95/111 SkymapMrk 421 Blazar

J. Patrick Harding, Summer Seminar Series

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HAWC Differential SensitivityDifferential Sensitivity per Quarter Decade of Energy

http://arxiv.org/abs/1306.5800 Astroparticle Physics 2013

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vs. Declination

HAWC Integral Sensitivity

vs. High Energy Cut off

http://arxiv.org/abs/1306.5800 Astroparticle Physics 2013

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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

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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.

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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

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HAWC: Extended Sources

HAWC will detect Geminga with >50s 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

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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 s 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

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• TeV g-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 Particlesg a g (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)

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HAWC: Gamma-Ray Bursts

Fermi observation of GRB090510, z=0.9• Highest Observed Energy

was 33 GeV with 16 g-rays >1 GeV

• Constrained Lorentz Invariance at the Plank Mass scale

GRB130427: Fermi detected 94 GeV g-ray

HAWC would detect this GRB if it occurred in FOV

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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

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• 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.

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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 2mG 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

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• 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 d

N/d

E (

arb

itra

ry s

cale

)

HAWC Single photoelectron threshold

Muons have broad lateral distribution

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• 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 ChorrilloArgentina4800m

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• 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

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HAWC is now!

• Construction complete in 2014• Science operations with 111 tanks

began 1 Aug 2013 • First results are coming now

HAWC detects Crab>10s

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BACKUP

HAWC Performance

(a)

(d)

(c)

(b)

Milagro

Milagro

Milagro

Milagro

HAWC

HAWC

HAWC

HAWC

Better Energy

Resolution

Much Better Background

Rejection

Much Better Angular

Resolution

Much Better Low Energy Response

32Brian Baughman - HAWC

Collaboration - ICRC 2013 Rio

Gammas

Protons

Energy deposited away from core

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24 TeV at ϴ=44°837 Hit PMTs

8 TeV at ϴ=10°838 Hit PMTs

21 TeV at ϴ=21°1131 Hit PMTs

118 TeV at ϴ=52°1116 Hit PMTs

4100m

2600m

• Higher Altitude means fewer radiation lengths and more particles (~5x) for same primary energy

Extensive Air Shower Development