Astrophysics of the High-Energy Universe10-14 August 2015

Instituto Nacional de Astrofísica Optica y Electrónica (INAOE)Puebla, Mexico

Charles Dermer (Naval Research Laboratory)

Dr. Charles D. DermerNaval Research Lab, Code 7653

Washington, DC 20375‐5352 USA202‐767‐2965

charles.dermer@nrl.navy.mil

Lecture 1. The High-Energy Universe

The most energetic and powerful radiations in nature are made by particles accelerated through Fermi processes in black‐hole jets powered by rotation.

Outline

Fermi 5 year > 1 GeV -ray sky

1. Multi‐wavelength and multi‐messenger astronomy2. Fermi Gamma‐ray Space Telescope3. Diffuse radiation backgrounds

3. Point sources, diffuse sources, and spectral energy distributions4. High‐energy sources, processes, and themes

“The commerce of science is original discovery. That’s our silver and gold.” E.O. Wilson

Multiwavelength Astronomy

thermal vs. nonthermal

rays: particle acceleration or dark matter signatures

log (Hz)

= h/mec2

GeV vs. TeV astronomy

GBM LAT VHE

0. Compton Gamma-Ray Observatory: Pioneering -ray space observatory (1991-2000)

1. Swift Gamma-ray Burst Explorer (NASA 2004 MidEx)2. High Energy Stereoscopic Observatory (HESS)

(Ground-based -ray telescope; Namibia, 2004)3. Very Energetic Radiation Imaging

Telescope Array System (VERITAS) (Arizona; 2007)

4. Major Atmospheric Gamma-rayImaging Cherenkov Telescopes (MAGIC)(Canary Islands; 2004)

5. Fermi Gamma-raySpace Telescope (2008)

6. High Altitude Water Cherenkov (HAWC) (Puebla, Mexico 2015)

7. Cherenkov Telescope Array (CTA South: Chile, 2020;CTA North: Canary Islands)

4

High-Energy Observatories

MAGIC

Compton

Swift

HESSHESS

VERITASHAWC

MAGIC

ssss

Worldwide Radio Networks of Observers

5

TANAMI: Tracking AGN with Austral Milliarcsecond InterferometryMOJAVE: Monitoring of Jets of AGN with VLBA Experiments

Optical Networks: WEBT-- GASP

6

Whole Earth Blazar Telescope

GLAST-AGILE Support Program

Multimessenger Astronomy

Photons

Cosmic rays/ Ultra-High Energy Cosmic Rays

Gravitational waves Neutrinos

8

Fermi Gamma-ray Space Telescope (2008– )

Gamma-ray Burst Monitor (GBM)8 keV – 40 MeV (12+2 detectors)Views entire unocculted sky

NASA/DoE Project Launched June 11, 2008 NRL Fermi Involvement

– Calorimeter– Environmental testing– Interdisciplinary scientist

USA (GSFC/SLAC/NRL)Italy/Japan/Sweden/Germany

Large Area Telescope (LAT)20 MeV → 300 GeV2.4 sr Field of View

9

Launch! June 11, 2008

Launch from Cape Canaveral Air Station 11 June 2008 at 12:05PM EDT

Circular orbit, 565 km altitude (96 min period), 25.6 deg inclination.

10

First light and Observatory Renaming

Gamma ray Large Area Space Telescope (GLAST) becomes Fermi Gamma-ray Space Telescope

4 days of observationunits: 10-8 ph(>100 MeV) cm-2 s-1

Bright sources F-8 ~ 100Limiting 2 wk EGRET sensitivity F-8 ~ 15Limiting Fermi 1 year sensitivity: F-8 ~ 0.5

11

e+ e–

Overview of LAT: How it works

Precision Si-strip Tracker (TKR) Measure the photon direction; gamma ID. pitch = 228 m, 8.8×105

channels, 18 planes

Hodoscopic CsI Calorimeter (CAL) Measure the photon energy; image the shower.

Segmented Anticoincidence Detector (ACD) Reject background of charged cosmic rays; segmentation removes self-veto effects at high energy.

Electronics System Hardware trigger, software filters

Systems work together to identify and measure the flux of cosmic gamma rays with energy 20 MeV - >300 GeV

Calorimeter

Tracker

ACD

12

Operations and observing modes

Almost all observations in survey mode - the LAT observes the entire sky every two orbits (~3 hours), each point on the sky receives ~30 mins exposure during this time.

– 39 deg rocking angle to Sept 2, 50 deg after September 3, 2009. Very high ontime! , Autonomous Repointing

– In response to bright GBM-detected GRBs, LAT-triggered GRBs Dedicated Pointings

– Crab flares, bright blazars, -ray novae

LAT sensitivity on 4 different timescales: 100 s, 1 orbit (96 mins), 1 day and 1 year

Optical transients– Meteors, Comets– Supernovae

Hammer-Aitoff Projection of the Full Sky

13

Gamma-ray transients– Blazars– Gamma Ray Bursts

All-sky/Large field-of-view coverage provided by Fermi and HAWC

Large Field-of-View vs. Pointing (Narrow-Field) InstrumentsSources of Background

14

The Fermi LAT (3 month) Sky

Fermi >1 GeV 5 Year Sky Map

Fermi: >10 GeV Skymap

Calibration and AnalysisCatalogsGalactic SourcesDiffuse and Molecular Clouds (and Other Galaxies) Sources in the Solar SystemBlazars and other AGNsGamma Ray BurstsDark Matter and New Physics

HAWC, successor of Milagro, is a large‐field‐of‐view TeV telescope.

Fermi ‐ray sky

• >100 MeV, 36 months• Galactic ‐ray glow: 

accelerated particles meet target gas  and photons

• ~80% of the emission is diffuse

• Transient  and flaring sources

• Normal and ms pulsars• Blazars• GRBs• Other ‐ray galaxies• Unidentified sources

18

Sample of Early Discoveries from Fermi

W44

Crab Nebula

GRB090902All sources Blazars

Populations

3C279

Energy Units

Microphysical quantities related to electron mass and energy

2cmE e

F Spectra: Point Sources

Photon flux:

Energy flux (density):

Flux density F in Jansky1 Jy = 10-23 erg cm-2 s-1 Hz-1

Energy Flux:

F in Jansky-Hertz or erg cm-2 s-1

Notation:

Blazar 3C 454.3

dAdtddN

)(

)(

z = 0.858

Ned Wright’s cosmology calculator z = 0.859 dL =1.7e28 cm 13.7 Gyr *c = 1.3e28 cm

SUN

Solar constant: 1400 Watt/m2

1.4x106 erg/s‐cm2

Earth‐Sun distance: (1 AU): 1.5x1013 cm

Solar luminosity: 4x1033 erg/s

Solar mass: 2x1033 gm

Macrophysical quantities related to Sun

Optical Energy Fluxes

25th magnitude star has energy flux 10-15 erg cm-2 s-1

Instrumental Sensitivities

10-20

10-18

10-16

10-14

10-12

10-10

10-8

10-6

6 9 12 15 18 21 24 27 30

F S

ensi

tivity

(erg

cm

-2 s

-1)

log [(Hz)]

BATSE/GBM

EGRET

GLAST LAT

VLAChandra

HESS/VERITAS

Optical; 25th mag.

Optical; 30th mag.

Swift BAT

sensitivity for nominal observing times

human eye

JWST

Spitzer MIPS

IRAC

ASM

PCA

RXTE HEXTE ACT/GRB

Fermi

Sensitivities of High Energy Instruments

10-13

10-12

10-11

10-10

10-9

10-8

0.001 1 1000 106

Sen

sitiv

ity (e

rg c

m-2

s-1

)

E(MeV)keV GeV TeV

EGRET

(1 year)

GLAST Whipple

VERITAS/ HESS

OSSECOMPTEL

INTEGRAL/ IBIS

ACT(concept)

MAGIC

(106s)

Crab Total

(106s)

Fermi

INTEGRAL SPI

100 MeV ×10-6 ph(>100 MeV)/cm2-s = 1.6×10-10 erg/cm2-s

2 spectrum

Point Sources and Diffuse Emission

Photon intensity: ph/(cm2-s-energy-sr)

Intensity: (cm2-s-sr)-1

Energy intensity: energy/(cm2-s-sr)

Blackbody intensity: erg/(cm2-s-Hz-sr)

Point-source detection significance in a diffuse background:

Signal counts:

Background counts:

dddtdAdN

)()(

dddtdA

d

)(

dddtdA

d

)(

1)/exp(/2)(

23

kThch

bb

BS

)()( EEAdEtfS

)()( EEAdEtB (now use Bayesian techniques)

GLAST flaring rate: Dermer & Dingus 2004

Diffuse Radiations

Fermi High-Energy Subjects and Sources

Calibration and AnalysisEnergy/Effective Area; FoV; ImagingLLE/Transient/Source/Diffuse Classes

CatalogsBSL/LBAS/1FGL/1LAC/2FGL/2LAC/3FGL/3LAC 1st PSR/2nd PSR/GRB/SNR/1FHL/FAVA

Galactic SourcesPulsars

normal (radio‐loud and radio quiet), msPulsar Wind Nebulae/Crab/flaresGlobular ClustersSNRsHigh‐mass X‐ray/gamma‐ray binariesNovae

Diffuse, Molecular Clouds, and Other GalaxiesDiffuse Galactic EmissionGalactic Center/Fermi BubblesLMC, SMC, M31Starburst GalaxiesCosmic‐ray ions/electrons/positronsExtragalactic Background LightDiffuse Isotropic gamma‐ray background/EGB

Sources in the Solar SystemEarth/CRsSun/ Quiescent and Solar FlaresMoonJupiter/Zodiacal LightTGFs

Blazars and other AGNsBlazars/ FSRQs and BL LacsRadio GalaxiesRLNLSy1

Gamma Ray BurstsLong SoftShort HardSGRs

Dark Matter and New PhysicsDM lines and featuresAxionsLorentz Invariance ViolationPrimordial Black Hole AnnihilationMagnetogenesis

205      132            1500        700          1900        1017      2100        1450    

45 114              7/28       62/6

High-Energy Astrophysical Processes

Particle Interactions and RadiationLeptonicHadronicPhotonsMagnetic FieldsCascades

Acceleration PhysicsFermi ProcessesElectric Field AccelerationMagnetic Reconnection

Relativistic Flows

Black Hole PhysicsAccretionBlandford‐Znajek ProcessJet formation

Dark Matter Decay and Annihilation 

ep (ion)

e + e →  e´ + e´ Thermalizatione + e →  e´ + e´ +  Electron‐electron bremsstrahlunge + e →  e´ + e´ + e+ + e‐ Electron‐electron pair production

e + p →  e´ + p’ Thermalizatione + p →  e´ + p’ +  Electron(‐proton) bremsstrahlung CRe + p →  e´ + p’ + e+ + e‐ Electron‐proton pair production

e + →  e´ + ’ Compton scattering CR, Jetse + →  e´ + ’ +  ″ Double Compton scatteringe + →  e´ + e+ + e‐ Triplet pair productione + B →  e´ + B  + ’  Synchrotron emission CR, Jets

p + p →  p´ + p´ Thermalization (including elastic nuclear scattering)p + p →  p´ + p´ +  Proton bremsstrahlungp + p →  p´ + p´ +  Secondary nuclear production CR, p + →  p´ + e+ + e‐ Bethe‐Heitler pair production UHECRsp + →  p´ +  Photopion production UHECRs, p + B →  p´ + B  + ’  Proton synchrotron emission Jets

+ → ´ + ’ Photon‐photon scattering + → e+ + e‐ pair production Jets + B → e+ + e‐ + B  Magnetic pair production Pulsars

(some) High-Energy Radiation Processes

High-Energy Astronomy Themes

Cosmic Ray and Ultra‐High Energy Cosmic Ray Origin

The Search for Dark Matter

Extreme Stars and the Endpoints of Stellar Evolution

Structure and Content of the Galaxy in  rays

Nonthermal Particle Acceleration in Nature

The Black‐Hole Universe

Radiation and Field Content of the Universe