brenda dingus, 31 may 2008 - university of canterburyjaa53/presentations/dingus.pdf · brenda...

Multiwavelength Astronomy:Probing Nature’s

Particle Accelerators

Brenda Dingus Los Alamos National Lab

[email protected]

Shedding Some Lighton Potential Neutrino Sources

Brenda Dingus Los Alamos National Lab

[email protected]

Brenda Dingus, 31 May 2008

Nature’s Particle Accelerators

HST Image of M87 (1994)

Black Hole producing relativistic jet of particles

Binary Neutron Star Coalescing

Artist Conception of Short GRBs

Spinning Neutron Star powering a relativistic wind

Massive Star Collapsing into a Black Hole

SuperComputer Calculation

Chandra Image of Crab

HESS TeV+ x-ray

TeV image of Vela Jr. Supernova Remnant


Astrophysical Particle Accelerators

Radio Optical X-ray GeV TeV

E 2 dN/dEor

E dN/dln(E)[ergs/cm2 sec]

[ Photon Energy]

Multiwavelength Spectral Energy Distribution


�Electromagnetic Processes:• Synchrotron Emission

– Probes Magnetic Field, Electron Energy

• Inverse Compton Scattering– Probes Photon Field, Electron Energy

• Bremmstrahlung – Probes Electron Energy, Matter Density

�Hadronic Cascades• p + p −> π+ + πo +… −> e + ν + γ +…• p + γ −> π+ + πo +… −> e + ν + γ +…

E γ ~ E ν ~ 0.1 E p

Gamma-Ray Production


�Electromagnetic Processes:• Synchrotron Emission

– Probes Magnetic Field, Electron Energy

• Inverse Compton Scattering– Probes Photon Field, Electron Energy

• Bremmstrahlung – Probes Electron Energy, Matter Density

�Hadronic Cascades• p + p −> π+ + πo +… −> e + ν + γ +…• p + γ −> π+ + πo +… −> e + ν + γ +…

E γ ~ E ν ~ 0.1 E p

Gamma-Ray Production

Which γ-ray sources are neutrino sources?


Crab Pulsar Wind Nebula

Electron Energies

Synchrotron Self Compton (electrons Inverse Compton scatter on synchrotron emission) spectrum removes the degeneracy to determine B and the electron energies


Active Galactic Nuclei

Suzaku

BeppoSAX

MAGIC,EBL corr.

MAGIC, CAT

M. HayashidaICRC 2007Preliminary

Massive Black Hole Accelerates Jet of Particles to Relativistic Velocities

Urry & PadovaniSimultaneous variability of x-rays and TeV γ-rays supports Synchrotron Self Compton and/or Inverse Compton with external photons


Supernova Remnants

HESS observation of RX J1713-39 shows γ-rays (false color) are spatially correlated with x-rays (contours)

Supernova Remnants are believed to be theaccelerators of Galactic cosmic rays.

Therefore, γ-rays should be produced by cosmic rays interacting with molecular clouds near SNR.


GRBs Observed up to 20 GeVHigh Energy Component Varies Slower than Low Energy Component (Gonzalez, 2003 Nature 424, 749)

The highest energy gamma-ray detected by EGRET from a GRB was ~20 GeV and was over an hour late. (Hurley, 1994 Nature 372, 652)

Evidence of Much More Fluence in aHigher Energy Component (Atkins, 2003, Ap J 583 824)

GRB940217

GRB970417

GRB941017


Galactic Source Characteristics� Angularly Extended

• High Energy Particles can move away from the accelerator before interacting to produce gamma-rays

� Hard Spectrum• Typical Differential photon index of dN/dE ~ E -2.3 (i.e. harder than the observed Galactic cosmic rays of dN/dE ~ E -2.7 )

� Source Classes• Pulsars • Pulsar Wind Nebula• Supernova Remnants• X-ray Binaries• Massive Stellar Winds• Molecular Clouds• Galactic Center• Dark Accelerators (gamma-raysources without counterparts)

HESS Pulsar Wind Nebulae

1o

0.5o0.5o

1o


Extragalactic Source Characteristics� Extreme Rapid Variability

• Few minute variations probe size scales smaller than Schwarzschild radius

� Hard Intrinsic Spectrum� Source Classes

• Blazars (active galactic nuclei with jets pointed at Earth)–FSRQs at GeV energies–BL Lacs at TeV energies

• M87 (nearby non-blazar active galactic nucleus)

• GRBs (up to 20 GeV)• EGRET high latitude unidentified sources

PKS2155-304Aharonian, et al. 2007

� PKS 2155-304• < 2 hr flare with > 50x quiescent flux• Few week moderate state preceded flare

� Most TeV blazars not variable• Observation bias?


Gamma-Ray Detectors� Space-Based� Imaging Atmospheric Cherenkov Telescopes� Extensive Air Shower Detectors


Space Based Gamma-Ray Telescopes�Compton Observatory 1991-2000

• BATSE, OSSE, Comptel at ~< MeV• EGRET 30 MeV – 30 GeV

�GLAST 5 June 2008 !!!• ~50 x EGRET’s sensitivity• 1 day of GLAST = 9 yrs of EGRET

γ

e+ e– calorimeter (energy measurement)

particle tracking detectors

conversion foil

anticoincidenceshield

Pair-Conversion Telescope

EGRET

GLAST


TeV Observational Techniques

Atmospheric Cherenkov Telescope Extensive Air Shower DetectorGround Based Gamma-Ray Astronomy

HESS,MAGIC,VERITAS Milagro, Tibet AS, ARGO


Gamma-Ray Detectors ~ Current CapabilitiesExtensive Air Shower(EAS) Observatories

Imaging Atmospheric Cherenkov Telescopes (IACTs)

Space-BasedGLAST

10-12 (Milagro lifetime)10-13 (50 hours)10-12(1 year)Sensitivity (ergs/cm2sec)85%(55o) 2.7 sr~10%0.5o

>>99%1 m2

1 GeV

95%10%Duty Cycle(45o) 1.8 sr (2o) 0.003 srAperture~50%~15%Energy Resolution0.7o0.05oAngular Resolution>95%>99%Background Rejection104 m2104 m2Area20 TeV1 TeVOptimal γ-ray Energy

HESSMAGICVERITAS

MilagroTibet ASγARGO

EGRETAGILEGLAST


The 100 MeV Catalog of EGRET

GLAST will detect 1000s of sources as well as new classes of sources


Jim HintonICRC 2007

TeV Catalog


Abdo, et al. ApJ Lett 2007

Milagro Observation of Galactic Sources

• 5 of the 7 Milagro TeV Excesses have GeV counterparts.• Only 13 GeV counterparts in this region - excluding Crab.• Probability of the chance coincidence is 3x10-6

LS I + 61 303

HESS J0632+057

IC443

H H


Abdo, et al. ApJ Lett 2007

Milagro Observation of Galactic Sources

• 5 of the 7 Milagro TeV Excesses have GeV counterparts.• Only 13 GeV counterparts in this region - excluding Crab.• Probability of the chance coincidence is 3x10-6

LS I + 61 303

HESS J0632+057

IC443

H H

AMANDA’s 3 Lowest Chance ProbabilitySource Excesses

Brenda Dingus, 31 May 2008Multiwavelength Milky Way

0.1 GeV

Milagro 10 TeV gamma-rayTeV gamma ray

Milagro HESS


Galactic Diffuse γ-rays� Gamma-rays probe Cosmic Rays Fluxes and Spectra outside the Earth’s environment� Different spatial and spectral characteristics of electrons and protons

GALPROP Conventional (solid) and Optimized (dashed) Models

65o < l < 85o

|b| < 2o

30o < l < 65o

|b| < 2o

MilagroObs.

Inverse Compton ScatteringCMBDustStarlight

Pion DecayExtragalactic BackgroundBrems.


Galactic Diffuse Emission (Spatial Distribution)

Cygnus Region65o<longitude<85o

Inner Galaxy30o<longitude<65o

GALPROP Modelπo decay Inverse Compton Total

GALPROP Modelπo decay Inverse Compton Total

• Different Latitude Distribution for Different Regions of the Galaxy• Milagro Measures Width of Galaxy at TeV energies• Pionic Component Width determined by Matter Density• Inverse Compton Component Width determined by diffusion of electrons

γ/TeV

/cm2/s

r/sec

@ 15

TeV

γ/TeV

/cm2/s

r/sec

@ 15

TeV


Extensive Air Shower Detectors Survey the TeV Sky

Tibet AS γ ARGO

Milagro


CrabNebulaMrk 421

Cygnus Region

Milagro Performed Deepest Survey of TeV Gamma-Ray Sky

Detected Crab Nebula and Mrk421 (known TeV sources)7 New TeV Galactic source candidates (Abdo, et al. ApJ Lett 2007)

• Several candidates are angularly extended few deg. diameter• 5 of 7 are consistent with 14 GeV sources in Milagro f.o.v. 1

is Geminga -- the brightest GeV source in Milagro f.o.v.• 3 confirmed by Tibet AS, 1 confirmed by HESS


Future of EAS DetectorsMilagro Turned Off April 2008

• 4 years of operation of full detector• See this month’s CERN Courier for

general highlightsARGO producing 1st results

• ~2 x sensitivity of Milagro

High Altitude Water Cherenkov (HAWC) Observatory is next generation version of Milagro• > 10 x sensitivity of Milagro

–HAWC: Detect Crab in ~ 1 day (5σ)–Milagro: Detects Crab in 3 months

• < $10M including new site

HAWC Detector Design• 900 water tanks(5 meter diameter and 4.3 meter deep

• One 8” PMT/tank

• Tank array covers area of 150m x 150m with 78% coverage

DAQ trailer

Road

HAWC Tank Array in GEANT 4


Tanks vs Pond� Less expensive� Build incrementally� Expandable &

upgradeable

GEANT4 SimulationMuon (thinned 1/50) produces up to 100s of pes depending on impact parameter

100 MeV γ−ray (thinned 1/200) produces 1pe/60 MeV independent of impact parameter


HAWC Site Location is Sierra Negra, Mexico• 4100 m above sea level• Easy Access• 2 hr drive from Puebla • 4 hr drive from Mexico City

• Existing Infrastructure• Few km from the US/Mexico Large Millimeter Telescope

• Power, Internet, Roads• Sierra Negra Scientific Consortium of ~7 projects

• Excellent Mexican Collaborators• ~15 Faculty at 7 institutions have submitted proposal to CONACYT for HAWC

• Experience in HEP, Auger, and astrophysics (including TeV)


HAWC CollaborationUSA:Los Alamos National Laboratory Brenda Dingus, Gus Sinnis, Petra Huntemeyer, John PretzUniversity of Maryland Jordan Goodman, Andrew Smith, Vlasios Vasileiou, Greg SullivanUniversity of Utah Dave KiedaUniversity of New Mexico John MatthewsMichigan State University Jim LinnemannPennsylvania State University Ty DeYoungNASA/Goddard Space Flight Center Julie McEneryUniversity of New Hampshire James RyanUniversity of California, Irvine Gaurang YodhMexico:Instituto Nacional de Astrofísica Óptica y Electrónica (INAOE)Alberto Carramiñana, Eduardo MendozaUniversidad Nacional Autónoma de México (UNAM)Instituto de Astronomía: Magdalena González, Dany Page, William Lee, Hector Hernández, Deborah Dultzin, Erika BenitezInstituto de Física: Arturo Menchaca, Rubén Alfaro, Andres Sandoval, Ernesto Belmont Instituto de Ciencias Nucleares: Lukas Nellen, G. Medina-TancoInstituto de Geofísica: José Valdés Galicia, Alejandro LaraBenemérita Universidad Autónoma de PueblaHumberto Salazar, Oscar Martínez, Cesar Álvarez, Arturo FernándezUniversidad Michoacana de San Nicolás de Hidalgo Luis VillaseñorCINVESTAV Arnulfo ZepedaUniversidad de GuanajuatoDavid Delepine, Gerardo Moreno, Marco Reyes, Luis Ureña, Victor Migenes


HAWC Sensitivity

e µ γ

(a) Larger Effective Area at Lowest Energies

(b) Better Angular Resolution

(c) Improved Background Rejection

=> 10-15 x improvement in flux sensitivity

=> (10-15)2 = 100-200 x faster to observe same flux

(a)

(b)

(c)

100 GeV 1 TeV 10TeV 100 TeV


Hadro

n Effic

iency

Ang.

Res.

(deg)

Ef

f. Area

(m2 )


100 GeV 1 TeV 10TeV 100 TeV 10-3

105

0.3o


E F(> E

) (Te V

/c m2 s)

Sensitivity to Crab-like (dN/dE=E-2.6) Point Source

GeV

� HESS/VERITAS, MAGIC, Whipple, CTA sensitivity in 50 hours, (~0.2 sr/year)� GLAST sensitivity in 1 year (4π sr)� HAWC sensitivity in 1(5) years shown as solid (dashed) line (2π sr)� HAWC exposure>10 TeV in 5 years is 5x1015 cm2sec = 1 km2 x 140 hrs


HAWC’s Field of View

= 2.6 π sr= 1.8 π sr


HAWC Science Objectives

�Constrain the origin of cosmic rays via HAWC’s observations of γ-rays up to 100 TeV from discrete sources and the Galactic plane.�Probe particle acceleration in extreme magnetic and gravitational fields via HAWC’s observations of transient TeV sources, such as gamma ray bursts and supermassive black holes.�Explore new TeV physics via HAWC’s unbiased sky survey with a detection threshold of ~30 mCrab in two years.


HESS J1616-5080.2 Crab @ 1 TeV α=-2.3Highest energy ~20 TeV

HAWC’s High Energy Reach


HESS J1616-5080.2 Crab @ 1 TeV α=-2.3Highest energy ~20 TeVSimulated HAWC data for 1 year with no cutoff



HESS J1616-5080.2 Crab @ 1 TeV α=-2.3Highest energy ~20 TeVSimulated HAWC data for 1 year with 40 TeV exponential cutoff



HAWC’s Transient Reach

Orphan Flare

• Some TeV flares are correlated with x-ray flares and some are orphan TeV flares -- excellent candidates for neutrino sources.

• HAWC would detect such a flare in <15 minutes and promptly notify multiwavelength observers.


Expect the Unexpected with Unbiased SurveysFor example, Milagro Observes Anisotropy in 10 TeV Cosmic Rays� 10 deg size scale with a fractional excess of 7e-4 above the cosmic ray

background (15 σ)� Excess is not gamma rays, but charged cosmic rays (7 σ)� Explanations are difficult because the gyroradius of a 10 TeV proton in

a 1 µG field is 0.01 parsecs=2000 AU� Maybe Geminga SNR??? Salvati & Sacco astroph0802.2181

Heliotail

Geminga

GalacticPlane


Summary• Multiwavelength Spectra probe Nature’s Particle Accelerators• Gamma rays provide > 6 orders of magnitude of energy in the multiwavelength spectrum

• The physics of these accelerators is constrained by gamma-ray observations, but more information is needed

• Increased Sensitivity of New Gamma-Ray Observatories guarantees New Discoveries

• Neutrino Detections would revolutionize our understanding


Thank youto Neutrino 2008

organizers.Good on ya!


Cosmic Ray Anisotropy1o RA bins (unsmoothed) for 10o<Dec.<20o

Large Scale Feature at ~180 deg observed by many detectors.Smaller Scale Features require larger numbers of events.


Milagro & Tibet AS γ Observations

K. Munakata, M. Amenomori, et al AIP Conf Vol 932, 283

Mrk421Crab

Cygnus region

Abdo, A. et al astroph0801.3827

Milagro Observation using Background Calculation over 2 hour (30o in RA) intervals

Tibet AS Observation after subtracting model of large scale anisotropy

K. Munakata, M. Amenomori, et al AIP Conf Vol 932, 283


Galactic Sources are Extended

Sextended ≈ Spointσ sourceσ detector

σEAS ~0.5o σIACT ~0.1o

HAWC’s large fov of 2 sr:Entire source & background are simultaneously observableBackground is well measured


Milagro Observation in Galactic Coordinates

Crab Nebula

30°

210°

90° 65°

Cygnus Region


• Gammas have NARROW lateral distribution of electrons

• Protons have BROAD lateral distribution of muons

Lateral Distribution of Extensive Air Showers


Gamma/Hadron Separation

Gamm

asProton

s

30 GeV 70 GeV 230 GeV

20 GeV 70 GeV 270 GeVSize of HAWC

Size of Milagro deep layer Energy Distribution at ground level

Rejection factor ~ e-<µ>


Background Rejection in MilagroProton MC Proton MC

Data Dataγ MC γ MC

Hadronic showers contain penetrating component: µ’s & hadrons

– Cosmic-ray showers lead to clumpier bottom layer hit distributions– Gamma-ray showers give smooth hit distributions


Milagro Background Rejection (Cont’d)

( )mxPE

nFitfOut+fTop=A ∗4

mxPE: maximum # PEs in bottom layer PMTfTop: fraction of hit PMTs in Top layerfOut: fraction of hit PMTs in OutriggersnFit: # PMTs used in the angle reconstruction

S/B increases with increasing A4 so analysis weights events by S/B as determined by the A4value of the event

Background Rejection Parameter

brenda dingus, 31 may 2008 - university of canterburyjaa53/presentations/dingus.pdf · brenda...

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