The HAWC(High Altitude Water

Cherenkov) Observatory

The HAWC CollaborationThe HAWC CollaborationUniversity of Maryland: Jordan Goodman, Andrew Smith,

Greg Sullivan, Jim Braun, David Berley

Los Alamos National Laboratory: Gus Sinnis, Brenda Dingus, John Pretz

University of Wisconsin: Teresa Montaruli, Stefan Westerhoff, Segev Ben Zvi, Juanan Aguilar, Dan Wahl

University of Utah: Dave Kieda, Wayne Springer

Univ. of California, Irvine: Gaurang Yodh’

Michigan State University: Jim Linnemann, Kirsten Tollefson, Dan Edmunds

George Mason University: Robert Ellsworth

Colorado State University: Miguel Mustafa, Dave Warner

University of New Hampshire: James Ryan

Pennsylvania State University: Tyce DeYoung, Patrick Toale, Kathryne Sparks

University of New Mexico: John Matthews, William Miller

Michigan Technical University: Petra Hüntemeyer

NASA/Goddard Space Flight Center: Julie McEnery, Elizabeth Hays, Vlasios Vasileiou

Georgia Institute of Technology: Ignacio Taboada, Andreas Tepe

HAWC Technical Staff: Michael Scheinder, Scott Delay

Instituto Nacional de Astrofísica Óptica y Electrónica (INAOE): Alberto Carramiñana, Eduardo Mendoza, Luis Carrasco, William Wall, Daniel Rosa, Guillermo Tenorio Tagle, Sergey Silich

Universidad Nacional Autónoma de México (UNAM): Instituto de Astronomía: Octavio Valenzuela, V ladimir Avila-Reese, Marco Martos, Maria Magdalena Gonzalez, Sergio Mendoza, Dany Page, William Lee, Hector Hernández, Deborah Dultzin, Erika Benitez Instituto de Física: Arturo Menchaca, Rubén Alfaro, Varlen Grabski, Andres Sandoval, Ernesto Belmont. Arnulfo Matinez-Davalos Instituto de Ciencias Nucleares: Lukas Nellen, Gustavo Medina-Tanco, Juan Carlos D’Olivo Instituto de Geofísica: José Valdés Galicia, Alejandro Lara, Rogelio Caballero

Benemérita Universidad Autónoma de Puebla:Humberto Salazar, Arturo Fernández, Caupatitzio Ramirez, Oscar Martínez, Eduardo Moreno, Lorenzo Diaz, Alfonso Rosado,

Universidad Autónoma de Chiapas: Cesar Álvarez, Eli Santos Rodriguez, Omar Pedraza

Universidad de Guadalajara: Eduardo de la Fuente

Universidad Michoacana de San Nicolás de Hidalgo: Luis Villaseñor, Umberto Cotti, Ibrahim Torres, Juan Carlos Arteaga Velazquez

Centrode Investigacion y de Estudios Avanzados: Arnulfo Zepeda

Universidad de Guanajuato: David Delepine, Gerardo Moreno, Edgar Casimiro Linares, Marco Reyes, Luis Ureña, Mauro Napsuciale, Victor Migenes

USAMexico

The HAWC CollaborationThe HAWC CollaborationUniversity of Maryland: Jordan Goodman, Andrew Smith,

Greg Sullivan, Jim Braun, David Berley

Los Alamos National Laboratory: Gus Sinnis, Brenda Dingus, John Pretz

University of Wisconsin: Teresa Montaruli, Stefan Westerhoff, Dan Wahl

University of Utah: Dave Kieda, Wayne Springer

Univ. of California, Irvine: Gaurang Yodh

Michigan State University: Jim Linnemann, Kirsten Tollefson, Dan Edmunds

George Mason University: Robert Ellsworth

University of New Hampshire: James Ryan

Pennsylvania State University: Tyce DeYoung, Patrick Toale, Kathryne Sparks

University of New Mexico: John Matthews, William Miller

Michigan Technical University: Petra Hüntemeyer

NASA/Goddard Space Flight Center: Julie McEnery, Elizabeth Hays, Vlasios Vasileiou

Georgia Institute of Technology: Ignacio Taboada, Andreas Tepe

HAWC Technical Staff: Michael Scheinder, Scott Delay

Instituto Nacional de Astrofísica Óptica y Electrónica (INAOE): Alberto Carramiñana, Eduardo Mendoza, Luis Carrasco, William Wall, Daniel Rosa, Guillermo Tenorio Tagle, Sergey Silich

Universidad Nacional Autónoma de México (UNAM): Instituto de Astronomía: Octavio Valenzuela, V ladimir Avila-Reese, Marco Martos, Maria Magdalena Gonzalez, Sergio Mendoza, Dany Page, William Lee, Hector Hernández, Deborah Dultzin, Erika Benitez Instituto de Física: Arturo Menchaca, Rubén Alfaro, Varlen Grabski, Andres Sandoval, Ernesto Belmont. Arnulfo Matinez-Davalos Instituto de Ciencias Nucleares: Lukas Nellen, Gustavo Medina-Tanco, Juan Carlos D’Olivo Instituto de Geofísica: José Valdés Galicia, Alejandro Lara, Rogelio Caballero

Benemérita Universidad Autónoma de Puebla:Humberto Salazar, Arturo Fernández, Caupatitzio Ramirez, Oscar Martínez, Eduardo Moreno, Lorenzo Diaz, Alfonso Rosado,

Universidad Autónoma de Chiapas: Cesar Álvarez, Eli Santos Rodriguez, Omar Pedraza

Universidad de Guadalajara: Eduardo de la Fuente

Universidad Michoacana de San Nicolás de Hidalgo: Luis Villaseñor, Umberto Cotti, Ibrahim Torres, Juan Carlos Arteaga Velazquez

Centrode Investigacion y de Estudios Avanzados: Arnulfo Zepeda

Universidad de Guanajuato: David Delepine, Gerardo Moreno, Edgar Casimiro Linares, Marco Reyes, Luis Ureña, Mauro Napsuciale, Victor Migenes

USA Mexico

HAWC Collaboration April 2010

HAWC Science ObjectivesHAWC Science Objectives

• Discover the origin of cosmic rays by measuring gamma-ray spectra to 100 TeV

– Hadronic sources have unbroken spectra beyond 30-100 TeV– Galactic diffuse gamma rays probe the distant cosmic ray flux

• Understand particle acceleration in astrophysical jets with wide field of view, high duty factor observations.

– Trigger Multi-Messenger/Multi-Wavelength Observations of Flaring Active Galactic Nuclei (including TeV orphan flares)

– Detect Short and Long Gamma-Ray Bursts

• Explore new physics via HAWC’s unbiased survey of ½ the sky.

– Increase understanding of TeV sources to search for new physics.

– Study the local TeV cosmic rays and their anisotropy.

HAWC ScienceHAWC Science

• Gamma Astronomy with wide FoV and high duty cycle:– Understand particle acceleration in AGN and GRB jets through the

discovery of short and long GRBs at > 100 GeV energies and

• MWL Target of Opportunity programs on flares;– Understand the sources of Galactic CRs through the observation of galactic

sources including extended ones (SNRs in molecular clouds, superbubbles)

• Studies on EBL and diffuse gamma emissions.

• Hadronic Astronomy:– find evidence of proton acceleration in Galactic CR sources (eg

understanding Milagro regions with larger statistics)

• Exotic phenomena– photon oscillations in axion-like particles through EBL studies;

– Lorentz invariance;

– Slow Monopoles and Q-balls.

Comparison of Gamma-Ray Comparison of Gamma-Ray Detectors Detectors

Large Aperture/High Duty CycleMilagro, Tibet, ARGO, HAWC

Moderate Area

Excellent Background Rejection

Large Duty Cycle/Large Aperture

Unbiased Sky Survey

Extended sources

Transients (GRB’s) > 100 GeV

High Energies up to 100 TeV

Low Energy ThresholdEGRET/Fermi

Space-based (Small Area)

“Background Free”

Large Duty Cycle/Large Aperture

Sky Survey (< 10 GeV)

AGN Physics

Transients (GRBs) < 300 GeV

High SensitivityHESS, MAGIC, VERITAS

Large Effective Area

Excellent Background Rejection

Low Duty Cycle/Small Aperture

High Resolution Energy Spectra up to ~20 TeV

Studies of known sources

Surveys of limited regions of sky

HAWC Collaboration April 2010

Milagro and HAWCMilagro and HAWC• Milagro was a first generation wide-field gamma-ray telescope:

– Proposed in 1990

– Operations began in 2001/04

– Developed /h separation

• Discovered:• more than a dozen TeV sources

• diffuse TeV emission from the Galactic plane

• a surprising directional excess of cosmic rays

• Showed that most bright galactic GeV sources extend to the TeV

• Best instrument for hard spectrum and extended sources

• HAWC is the next logical step– It will be 15x more sensitive than Milagro

– It can be running in 3 yrs (with Fermi)

IntroIntro

HAWC Science ReviewsHAWC Science Reviews

• PASAG - October 2009 – HAWC is a moderate-priced initiative that will

carry out excellent astrophysics using a novel technique; there is also the possibility of surprising results of relevance for particle physics.

• NSF Review Panel December 2007: – “There is a strong case for HAWC as a wide

field of view survey instrument at the TeV scale.” They concluded the project is well understood and technically ready with a strong collaboration.

Abdo et al. ApJL (accepted)arXiv:0904.1018

15 TeV associations out

of 35 likely galactic sources

in our field of view

Milagro Results

GeV Pulsars Produce TeV PWNGeV Pulsars Produce TeV PWN

GeV Emission is pulsed & due to rotation axis misaligned with Magnetic Dipole of ~1012 G

TeV Emission is produced by particles further accelerated in the shock interacting

with the ambient medium.

IMPLICATIONS• TeV PWN are prevalent with GeV pulsars

• GeV emission has broad beam

Geminga (J0634.0+1745)Geminga (J0634.0+1745)

• Brightest GeV source of 34 searched is Geminga

• Old (300 kyr) PWN and nearby (250 pc)

• ~10 parsec extent is similar to HESS observations of more distant PWN

10 parsecs

68% PSFMilagro

HAWC Milagro sees Geminga at 30% of the Crab at ~20 TeVwhile IACTs have a limit of ~1% of the Crab at >200 GeV

Geminga with HAWCGeminga with HAWC

• Brightest GeV source of 34 searched is Geminga

• Old (300 kyr) PWN and nearby (250 pc)

• ~10 parsec extent is similar to HESS observations of more distant PWN

10 parsecs

Milagro sees Geminga at 30% of the Crab at ~20 TeVwhile IACTs have a limit of ~1% of the Crab at >200 GeV

HAWC

68% PSFMilagro

Milagro Spectrum of the CrabMilagro Spectrum of the Crab

HESS Crab data/fit

Energy reach from ~3TeV to >100 TeVPeak sensitivity for E-2 source at ~100 TeV

Milagro68%

HAWC

Milagro Results

Milagro Spectrum of the Crab w/HAWCMilagro Spectrum of the Crab w/HAWC

Energy reach from ~3TeV to >100 TeVPeak sensitivity for E-2 source at ~100 TeV

Milagro68%

HAWC

HEGRA Crab data/fit

In Milagro J2019+37 is 700 mCrabThe flux in γ/s >200 GeV is 95mCrab

HESS Crab fit:(Io =3.76x10-7,Γ=2.39,Ec=14.1 TeV)

MGRO J2019+37/ 0FGL J2020.8+3649MGRO J2019+37/ 0FGL J2020.8+3649

Milagro68%

HAWC

Milagro Results

This source is almost as bright as the Crab at Milagro’s energy

In Milagro J2019+37 is 700 mCrabThe flux in γ/s >200 GeV is 95mCrab

HESS Crab fit:(Io =3.76x10-7,Γ=2.39,Ec=14.1 TeV)

MGRO J2019+37/ 0FGL J2020.8+3649MGRO J2019+37/ 0FGL J2020.8+3649

Milagro68%

HAWC

MGRO J1908+06MGRO J1908+06

Ecut 14 40 (1σ56 (2σ

Milagro68%

HAWC

Milagro Results

A Milagro discovered source now seen by HESS and VERITASUsing HESS spectrum of -2.1 as input, Milagro requires a cut-off at <40(56) TeV(N.B. Milagro measures a larger flux, possibly because we are integrating over a larger area than HESS)

Milagro 3Milagro 3σσ source detected at 20 source detected at 20σσ HAWC (3months) HAWC (3months)HAWC Simulation

HAWC Simulation

Milagro 3Milagro 3σσ source detected at 20 source detected at 20σσ HAWC (3months) HAWC (3months)

HAWC Simulation

Milagro 3Milagro 3σσ source detected at 20 source detected at 20σσ HAWC (3months) HAWC (3months)

Diffuse TeV ExcessDiffuse TeV Excess• Whether or not there is a GeV excess, Milagro sees a TeV excess.

• This excess could be due to unresolved sources or hadronic cosmic rays hitting matter near their source.

• If the TeV excess has a flat spectrum, it is likely hadronic in origin and may not be detectable at GeV energies.

– With help from ACTs and Fermi we will do a source subtraction

– This will allow us to measure the spectrum and morphology of the excess

• This study could point to regionsof the galaxy with a higher concentration of cosmic raysthan near earth - pointing to sites of acceleration.

Abdo et. al ApJ 2008

Milagro Results

Active Galactic Nuclei Flares Active Galactic Nuclei Flares

• HAWC makes daily observations without weather, moon, or solar constraints. • HAWC’s 5 σ sensitivity for Mrk 421 is (10,1,0.1) Crab in (3 min, 5 hrs, 1/3 yr)

• HAWC will notify multiwavelength observers in real time of flaring AGN• Study correlations with x-rays, etc to determine emission mechanisms

• Discovery potential for orphan TeV flares producing neutrinos and UHECR

1 month

Milagro’s 9σ Mrk421

X-ray flux

Mila

gro

flux

Quadratic or Linear? Synchrotron Self

Compton or External Compton?

Crab Flux

Distinguishing New Physics from AstrophysicsDistinguishing New Physics from Astrophysics

• Violation of Lorentz Invariance OR Energy Dependent Particle Acceleration– HAWC will detect multiple flaring extragalactic sources (AGN and

GRBs) to resolve redshift vs source mechanisms

• Cosmological Star Formation OR Spectral Cut-offs in the source– HAWC will trigger multiwavelength observations of flaring AGN to

obtain best measured and modeled TeV spectra

• Continuum Gamma-Ray Emission from Dark Matter Annihilation OR Astrophysical Source– HAWC will search for time variability which would imply an

astrophysical source

Cosmic Ray ObservationsCosmic Ray Observations

• Milagro data show an unexpected anisotropy (PRL 101, 221101, 2008)

• No weighting or cutting.

• Map dominated by charged cosmic rays.

• 10o smoothing, looking for intermediate sized features.

• Two regions of excess 15.0σ and 12.7σ. Fractional excess of 6x10-4 (4x10-4) for region A(B).

HeliotailGeminga

Significance (σ’s)

Milagro Results

21http://people.roma2.infn.it/~aldo/RICAP09_trasp_Web/Vernetto_ARGO_RICAP09ar.pdf

Milagro Results

HAWC Collaboration April 2010

Cosmic Ray AnisotropyCosmic Ray Anisotropy

• Data are not consistent with:– Mostly gamma-rays –> data looks hadronic

– with cosmic ray spectrum –> flatter, with ~10 TeV cutoff

• HAWC with better energy resolution and gamma-hadron rejection can:– Measure the spectrum with much higher precision

– Measure the gamma-ray fraction

• Understanding this is important for Dark Matter Searches

Milagro Results

HAWC Collaboration April 2010

Geminga as a Local Cosmic Ray SourceGeminga as a Local Cosmic Ray Source

• “If the observed cosmic ray excess does indeed arise from the Geminga SN explosion, the long–sought “smoking gun” connecting cosmic rays with supernovae would finally be at hand. - Salvati and Sacco (AA 09)

• The confirmed presence of a nearby, ancient source of high-energy electrons and positrons immediately suggests an explanation for the positron excess.

-Yüksel, Kistler, Stanev

arXiv:0810.2784

PAMELA’s positron excess

Fit well given Milagro’s flux from Geminga