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Gamma-ray Large Area Space Telescope. Arecibo Synergy with GLAST (and other gamma-ray telescopes) Frontiers of Astronomy with the World’s Largest Radio Telescope 12 September 2007 Dave Thompson GLAST Large Area Telescope Multiwavelength Coordinator [email protected]

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Arecibo Synergy with GLAST (and other gamma-ray telescopes)

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Arecibo synergy with glast and other gamma ray telescopes

Gamma-ray Large Area Space Telescope

Arecibo Synergy with GLAST (and other gamma-ray telescopes)

Frontiers of Astronomy with the World’s Largest Radio Telescope

12 September 2007

Dave Thompson

GLAST Large Area Telescope Multiwavelength Coordinator

[email protected]

for the GLAST Mission Team

see http://glast.gsfc.nasa.gov and links therein


Known gamma ray sources are multiwavelength

GLAST LAT AGILE

TeV

Known Gamma-ray Sources Are Multiwavelength

Gamma-ray sources are nonthermal, typically produced by interactions of high-energy particles.

Known classes of gamma-ray sources are multiwavelength objects, seen across much of the spectrum.

INTEGRAL GLAST GBM Swift


Arecibo synergy with glast and other gamma ray telescopes

Gamma-ray Facilities: More Numerous, More Capable

Swift

GLAST

INTEGRAL

ARGO-YBJ

H.E.S.S.

CANGAROO

Milagro

MAGIC

VERITAS


Arecibo synergy with glast and other gamma ray telescopes

GLAST: Gamma-ray Large Area Space Telescope

Two GLAST instruments:

Large Area Telescope

LAT: 20 MeV – >300 GeV (LAT was originally called GLAST by itself)

LAT field of view ~2.5 sr

GLAST Burst Monitor

GBM: 10 keV – 25 MeV

GBM field of view ~9 sr

Launch: This Winter

Lifetime: 5 years minimum, 10 years goal


Arecibo synergy with glast and other gamma ray telescopes

What Do Gamma-ray Measurements Offer?

  • Huge energy range – 9+ orders of magnitude

  • All-sky coverage, from both ground and space (GLAST will see the entire sky every three hours)

  • Excellent sensitivity compared to previous instruments (GLAST LAT is about 30 times more sensitive than EGRET on the Compton Gamma Ray Observatory)

  • Good source locations – 1 arcmin in many cases

  • High time resolution for individual photons

  • Imaging for some extended sources


Arecibo synergy with glast and other gamma ray telescopes

Some Other Needs for Astrophysics

  • Distance – redshift, Dispersion Measure, proper motion, column density

  • Composition – spectroscopy

  • Precise source locations and imaging

  • Velocities

  • Polarization

  • Magnetic fields

  • Theories to connect the observations to physical models


Arecibo synergy with glast and other gamma ray telescopes

  • What gamma-ray science topics offer the best opportunities for cooperation with the Arecibo telescope?

  • Some possibilities:

    • Gamma-ray bursts (talk tomorrow)

    • Diffuse Galactic emission

    • Blazars

    • Radio galaxies

    • Microquasars

    • Pulsars (already discussed by Alice Harding)

  • Special thanks to Chris Salter for advice!

So far, gamma-ray telescopes have only seen the brightest objects – the “tip of the iceberg.” The fainter sources are where Arecibo will be critical.


Arecibo synergy with glast and other gamma ray telescopes

Diffuse Emission

How do the GALFACTS and GALPROP/gamma-ray studies compare in interpreting the Galactic magnetic field/particle distributions?

What do these results imply about particle confinement and propagation?

Can we use this information to search for local sources of cosmic rays?

  • Diffuse gamma-ray emission comes from particle interactions with matter and photon fields. Due to the limited angular resolution of gamma-ray detectors, it also represents a significant background.

  • The model we use (shown above) uses GALPROP, a cosmic-ray propagation code that incorporates information about gas, radiation, and magnetic fields.

  • The Arecibo GALFACTS program is strongly complementary to the gamma-ray diffuse study.


Arecibo synergy with glast and other gamma ray telescopes

Blazars

  • Blazars are a major gamma-ray source class.

  • There is some evidence of correlation between gamma-ray flares and emergence of new radio components of the jet, seen in VLBI.

  • Several VLBI programs are monitoring blazars for GLAST (MOJAVE, VIPS, Boston, Australian).

  • GLAST is expected to see more than 1000 blazars. Most will not be bright radio sources.

  • Higher sensitivity VLBI measurements will be needed.

What do the combined radio/gamma-ray observations tell us about particle acceleration and interaction – processes, location?

What can this information reveal about jet formation and collimation?


Arecibo synergy with glast and other gamma ray telescopes

Radio Galaxies

Left: TeV and radio images of M87, one of a handful of radio galaxies seen in gamma rays.

Right: TeV variability of M87.

Is the gamma-ray variability related to changes in the jet? In the core?

What about fainter radio galaxies?


Arecibo synergy with glast and other gamma ray telescopes

Microquasars – Binary Systems

LSI 5039 – compact object in orbit around an O star.

Gamma-ray emission varies during the 4 day orbit.

VLBI suggests that the emission comes from a jet.

LSI +61 303 – compact object in orbit around a Be star.

Gamma-ray emission varies during the 26 day orbit.

VLBI suggests that the emission comes from a pulsar wind.

What sort of compact object?

How are the particles accelerated?

Are there different types of such high-mass binary systems?


Arecibo synergy with glast and other gamma ray telescopes

The Unknown

Over half the sources in the third EGRET catalog remain unidentified.

GLAST will detect many more sources.

Identifying and understanding such sources will be a multiwavelength challenge.

What other types of objects produce high-energy gamma rays and radio?

Are there radio-quiet gamma-ray sources (e.g. beamed)?


Arecibo synergy with glast and other gamma ray telescopes

Summary

The nonthermal nature of high-energy gamma-ray emission almost assures that gamma-ray sources will be radio sources.

The new generation of gamma-ray telescopes is already expanding the number and types of sources, and this process will accelerate with GLAST.

Radio, especially the great sensitivity of Arecibo, will be a critical partner with gamma-ray astrophysics.


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