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