GTNGTNThe GLAST Telescope NetworkThe GLAST Telescope Network

Involvement for students and teachers Involvement for students and teachers in the science of the GLAST missionin the science of the GLAST mission

Gordon G. SpearGordon G. Spear

Sonoma State UniversitySonoma State University

March 2003March 2003

GTNGTN What is it? (some motivation)What is it? (some motivation)

– Gamma-rays, AGNs, BlazarsGamma-rays, AGNs, Blazars How does it work?How does it work?

– Observe using telescopes w/CCDs, Observe using telescopes w/CCDs, analyze and submit data, help othersanalyze and submit data, help others

Join us!Join us!– Involvement with exciting science, support Involvement with exciting science, support

the GLAST missionthe GLAST mission

What is the GTN?What is the GTN?

Collaboration among small observatories and Collaboration among small observatories and observersobservers

Surveillance, lead-up, and follow-up Surveillance, lead-up, and follow-up observations of blazars and related objects to observations of blazars and related objects to be observed by GLASTbe observed by GLAST

Archive magnitude measurements and CCD Archive magnitude measurements and CCD imagesimages

Students, teachers, amateur astronomers, Students, teachers, amateur astronomers, professional astronomersprofessional astronomers

Science ObjectivesScience Objectives

Establish base-line optical activity levels Establish base-line optical activity levels for bright, Gamma-loud AGNsfor bright, Gamma-loud AGNs

Provide optical lead-up and follow-up Provide optical lead-up and follow-up observations for GLAST targetsobservations for GLAST targets

Provide optical triggers for observations Provide optical triggers for observations by GLASTby GLAST

What are Gamma-rays?What are Gamma-rays?

Just photons, but with very high Just photons, but with very high energiesenergies

Photons with energies billions of times Photons with energies billions of times greater than visible light photonsgreater than visible light photons

Natural sources of Gamma-raysNatural sources of Gamma-rays Man made sources of Gamma-raysMan made sources of Gamma-rays Gamma-rays from spaceGamma-rays from space

How are Gamma-rays How are Gamma-rays characterized?characterized?

Gamma-rays are characterized by the energy Gamma-rays are characterized by the energy of individual photons.of individual photons.

Energies generally measured in MeV and Energies generally measured in MeV and GeV (millions and billions of eV).GeV (millions and billions of eV).

Infrared photons have energies on the order Infrared photons have energies on the order of eV.of eV.

One erg is about 600 billion eV (600 GeV).One erg is about 600 billion eV (600 GeV). The erg and the mosquito?The erg and the mosquito?

The Objects in the Gamma-Ray SkyThe Objects in the Gamma-Ray Sky

Milky Way glow from cosmic ray Milky Way glow from cosmic ray interactions with dustinteractions with dust

Point sources in the Milky Way are Point sources in the Milky Way are Gamma-ray pulsars (SNRs)Gamma-ray pulsars (SNRs)

Point sources outside the Milky Way are Point sources outside the Milky Way are AGNs (these are the blazars)AGNs (these are the blazars)

Some point sources remain unidentifiedSome point sources remain unidentified

AGNsAGNs

Active Galactic NucleiActive Galactic Nuclei Extragalactic objects that are more Extragalactic objects that are more

luminous than normal galaxiesluminous than normal galaxies The nucleus can be 10 to 100 times The nucleus can be 10 to 100 times

brighter than an entire normal galaxybrighter than an entire normal galaxy The underlying galaxy can appear The underlying galaxy can appear

relatively normal (when it can be seen)relatively normal (when it can be seen) Many different types or sub-classes Many different types or sub-classes

(including Seyfert galaxies, radio (including Seyfert galaxies, radio galaxies, quasars, and blazars)galaxies, quasars, and blazars)

A Typical QuasarA Typical QuasarPKS 1117-248PKS 1117-248

General Characteristics of General Characteristics of AGNsAGNs

ExtragalacticExtragalactic More luminous than normal galaxiesMore luminous than normal galaxies Generally point sources (stellar Generally point sources (stellar

appearance)appearance) Some exhibit jetsSome exhibit jets Bright in X-rays and Gamma-raysBright in X-rays and Gamma-rays All exhibit variability at some level!All exhibit variability at some level!

AGN UnificationAGN Unification

All AGN are manifestations of the same All AGN are manifestations of the same physical phenomenonphysical phenomenon

This phenomenon is the accretion disk This phenomenon is the accretion disk and jets associated with a and jets associated with a supermassive black holesupermassive black hole

The different appearances are simply The different appearances are simply due to the orientation of the jets and due to the orientation of the jets and disk to our line of sightdisk to our line of sight

Artistic Impression of an AGNArtistic Impression of an AGN

Voyage into an AGNVoyage into an AGNA SimulationA Simulation

Starts 100s of Mpc Starts 100s of Mpc away from AGNaway from AGN

Underlying galaxy is a Underlying galaxy is a spiral (20000 stars)spiral (20000 stars)

The AGN engine has The AGN engine has been switched offbeen switched off

Size scale changes by Size scale changes by 10 orders of magnitude10 orders of magnitude

QuickTime™ and aGIF decompressor

are needed to see this picture.

The BlazarsThe Blazars

The blazars appear to be AGN for which the jets are The blazars appear to be AGN for which the jets are pointing directly at us.pointing directly at us.

We are looking directly down the throat of the dragon!We are looking directly down the throat of the dragon! Spectra (SEDs) have bright compton peak in addition Spectra (SEDs) have bright compton peak in addition

to the typical AGN synchrotron peak.to the typical AGN synchrotron peak. These are the only prominent point sources in the These are the only prominent point sources in the

Gamma-ray sky. (Gamma loud)Gamma-ray sky. (Gamma loud) Beams of particles moving at relativistic speeds Beams of particles moving at relativistic speeds

produce intense beams of Gamma-rays.produce intense beams of Gamma-rays. These are the most variable of the AGNs.These are the most variable of the AGNs.

The Synchrotron ProcessThe Synchrotron ProcessProbably produces the synchrotron peakProbably produces the synchrotron peak

Inverse Compton ScatteringInverse Compton ScatteringProbably produces the compton peakProbably produces the compton peak

AGN Variability?AGN Variability?

All AGNs appear to be variable at some All AGNs appear to be variable at some levellevel

The emission lines vary in strengthThe emission lines vary in strength The continuum levels vary in brightnessThe continuum levels vary in brightness Variability has been documented over Variability has been documented over

decades, years, months, weeks, days, decades, years, months, weeks, days, and even hoursand even hours

Characteristics of AGN VariabilityCharacteristics of AGN Variability

Periodicity has NOT been convincingly Periodicity has NOT been convincingly demonstrated!demonstrated!

Slow, longterm irregular changesSlow, longterm irregular changes Outbursts (flares) and declinesOutbursts (flares) and declines General increase in variability for shorter General increase in variability for shorter

wavelengths (higher energy photons)wavelengths (higher energy photons) General increase in variability for longer time General increase in variability for longer time

scalesscales Apparent increase in variability with luminosityApparent increase in variability with luminosity Apparent increase in variability with redshiftApparent increase in variability with redshift

AGN Variability DataAGN Variability Data

Available observationsAvailable observations– Longterm (few per year)Longterm (few per year)

– Intraday (few per week)Intraday (few per week)

– Microvariability (many per Microvariability (many per hour)hour)

Lightcurve classificationLightcurve classification– OutburstsOutbursts

– DeclinesDeclines

– Outbursts and declinesOutbursts and declines

The blazarsThe blazars– Most variable of the Most variable of the

AGNsAGNs– Amplitudes to 4 Amplitudes to 4

magnitudes or moremagnitudes or more– Can exhibit detectable Can exhibit detectable

variations from night-to-variations from night-to-night and within a nightnight and within a night

A Blazar with a Long History of Observation

B2 1308+326outbursts

B2 1215+303declines

B2 1215+303outbursts and

declines

PG 0804+762non-blazar AGN

Intraday Variability

Mrk 5010.1 mag miniflare

BL Lac0.4 mag in 30 minutes

The GTNThe GTN

What is it?What is it?

How does it work?How does it work?

Small telescopes with CCDsSmall telescopes with CCDs– Schools, students,amateurs, professionalsSchools, students,amateurs, professionals

AAVSO partnershipAAVSO partnership Robotic telescope systems are idealRobotic telescope systems are ideal Target objectsTarget objects

– One or more objects observable any time of yearOne or more objects observable any time of year

Observing techniquesObserving techniques Reduction techniquesReduction techniques

Some Examples of GTN DataSome Examples of GTN Data

3C66A3C66A

V-filter, stack of 4 2-minute exposuresV-filter, stack of 4 2-minute exposures

3C66A - SSUO & AAVSO3C66A - SSUO & AAVSO

Sonoma State University ObservatorySonoma State University Observatory

The SSU Robotic Telescope SystemThe SSU Robotic Telescope System

Paramount-ME w/Celestron-14 and Apogee AP-47Paramount-ME w/Celestron-14 and Apogee AP-47– 0.4 meter telescope, point to better than 10 arcseconds, 0.4 meter telescope, point to better than 10 arcseconds,

track to better than 2 arcsec, CCD with better than 90% QEtrack to better than 2 arcsec, CCD with better than 90% QE– Capable of reliable photometry to 18th magnitudeCapable of reliable photometry to 18th magnitude

Currently being tested at SSUOCurrently being tested at SSUO Will be installed at dark site and begin science Will be installed at dark site and begin science

observations in 2003observations in 2003 Observe GTN blazar fields every clear night Observe GTN blazar fields every clear night

beginning 2003 and continuing through the GLAST beginning 2003 and continuing through the GLAST missionmission

Testing the SSU Robotic TelescopeTesting the SSU Robotic Telescope

Likely dark site installation

How can you participate and How can you participate and contribute?contribute?

Obtain CCD observations of GTN blazarsObtain CCD observations of GTN blazars Provide telescope time or telescope access Provide telescope time or telescope access

for GTN participantsfor GTN participants Reduce and analyze CCD data obtained by Reduce and analyze CCD data obtained by

other GTN participantsother GTN participants Participate in intense microvariability Participate in intense microvariability

campaignscampaigns Mentor GTN participants in observing Mentor GTN participants in observing

procedures, data reduction, basic astronomyprocedures, data reduction, basic astronomy

What is in it for you?What is in it for you?

Participation in a significant research program Participation in a significant research program supporting a major space observatorysupporting a major space observatory

Opportunities for collaboration with other GTN Opportunities for collaboration with other GTN participants and GLAST scientistsparticipants and GLAST scientists

Access to the data in the GTN archiveAccess to the data in the GTN archive Announcements of outbursts and other activity Announcements of outbursts and other activity

reported for blazars and other AGNsreported for blazars and other AGNs GTN Newsletter (including news about GLAST)GTN Newsletter (including news about GLAST) Tutorials and curriculum materialsTutorials and curriculum materials

The GTNThe GTN

Join with us!Join with us!

Exciting science.Exciting science. Student projects.Student projects. Contribute to the GLAST mission.Contribute to the GLAST mission. Involvement with a major space observatory.Involvement with a major space observatory.

http://glast.sonoma.edu/gtnhttp://glast.sonoma.edu/gtn