3671: Multi-wavelength Astronomy
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DEPARTMENT OF PHYSICS AND ASTRONOMY
3671: Multi-wavelength Astronomy3671: Multi-wavelength Astronomy
Dr. Matthew BurleighDr. Matthew Burleigh
www.star.le.ac.uk/~mbuwww.star.le.ac.uk/~mbu
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Dr. Matt Burleigh
Gamma Ray Xray EUV UV Optical IR Micro-wave Radio
100MeV 100keV 0.1keV 1000A 5000A 1micron 1cm 100m
The Electro-magnetic Spectrum
http://imagine.gsfc.nasa.gov/docs/science/know_l1/emspectrum.html
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Dr. Matt Burleigh
Multi-wavelength AstronomyMulti-wavelength AstronomyWavebandWaveband WavelengthWavelength
/Energy/EnergyTemperatureTemperature What can be What can be
studiedstudied
Gamma raysGamma rays 100keV-100MeV100keV-100MeV >10>1088KK accretion disks, gamma-accretion disks, gamma-ray burstsray bursts
X-raysX-rays <1-100keV<1-100keV 101066-10-1088KK Hot gas in clusters of Hot gas in clusters of galaxies, stellar coronae, galaxies, stellar coronae, accretion disks, accretion disks,
Ultra-violetUltra-violet 900-3000A900-3000A 101044-10-1066KK Hot stars, white dwarfs, Hot stars, white dwarfs, instellar gasinstellar gas
OpticalOptical 3000-10,000A3000-10,000A 101033-10-1044KK Sun-like stars. Sun-like stars.
Infra-redInfra-red 1-100 micron1-100 micron 10-1010-1033KK Dust, planets, brown Dust, planets, brown dwarfsdwarfs
MicrowaveMicrowave 1cm1cm <10K<10K Background radiation of Background radiation of the Universe (remnant of the Universe (remnant of Big Bang)Big Bang)
RadioRadio >1m>1m <10K<10K Radiation from electrons Radiation from electrons moving in a magnetic moving in a magnetic field: pulsarsfield: pulsars
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Dr. Matt Burleigh
Wavelength scalesWavelength scales
• Rather annoyingly, astronomers use a variety of Rather annoyingly, astronomers use a variety of wavelength scales depending on the waveband wavelength scales depending on the waveband involved (see diagram on last slide) involved (see diagram on last slide) – Radio astronomers use m and cmRadio astronomers use m and cm– Infra-red astronomers use micronsInfra-red astronomers use microns– Optical and UV astronomers use Angstroms or nano-Optical and UV astronomers use Angstroms or nano-
metersmeters– X-ray and gamma ray observers switch to an energy X-ray and gamma ray observers switch to an energy
scale, i.e. in electron-Voltsscale, i.e. in electron-Volts
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Dr. Matt Burleigh
Conversion factorsConversion factors
• E = hE = h= hc/= hc/in Joulesin Joules• 1eV = 1.6x101eV = 1.6x10-19-19JJ• Wavelength Wavelength in Angstroms -> Energy in keVin Angstroms -> Energy in keV
– keV = 12.4/keV = 12.4/• 1Angstrom = 101Angstrom = 10-10-10mm• 1 nm = 101 nm = 10-9-9mm• 11m (micron) = 10m (micron) = 10-6-6m = 10,000Am = 10,000A
– Point at which optical becomes infra-red!Point at which optical becomes infra-red!
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Dr. Matt Burleigh
What is multi-wavelength astronomy?What is multi-wavelength astronomy?
• Astronomers used to think of themselves as Astronomers used to think of themselves as either ‘optical’, ‘radio’, ‘IR’ or ‘Xray’either ‘optical’, ‘radio’, ‘IR’ or ‘Xray’
• But modern astrophysics requires studying an But modern astrophysics requires studying an object across the whole EM spectrum object across the whole EM spectrum
• Different physical processes can be studied at Different physical processes can be studied at different wavelengths different wavelengths
• Xray, gamma ray and radio astronomers need Xray, gamma ray and radio astronomers need to identify their sources with optical to identify their sources with optical counterpartscounterparts
http://imagine.gsfc.nasa.gov/docs/science/know_l1/multiwavelength.html
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Dr. Matt Burleigh
The Milky Way: OpticalThe Milky Way: Optical
Stars, Dust lanes
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Dr. Matt Burleigh
The Milky Way: IRThe Milky Way: IR
See through dust
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Dr. Matt Burleigh
The Milky Way: XrayThe Milky Way: Xray
Hot gas
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Dr. Matt Burleigh
Andromeda (M31): OpticalAndromeda (M31): Optical
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Dr. Matt Burleigh
Andromeda (M31): IRAndromeda (M31): IR
Star forming regions in spiral arms
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Dr. Matt Burleigh
Andromeda (M31): UVAndromeda (M31): UV
Young, hot stars in spiral arms
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Dr. Matt Burleigh
Andromeda (M31): XrayAndromeda (M31): Xray
Xray binaries, supernova remnants, hot gas
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Dr. Matt Burleigh
Orion in the optical and xrays Orion in the optical and xrays
Optical Xrays
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Dr. Matt Burleigh
Multi-wavelength study of Xray sourcesMulti-wavelength study of Xray sources
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Dr. Matt Burleigh
Binary stars: Sirius A & BBinary stars: Sirius A & B
Chandra: XraysOptical photograph
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Dr. Matt Burleigh
Binary white dwarfs revealed in the Binary white dwarfs revealed in the ultra-violetultra-violet
Optical UV: white dwarf companion (star Ab)
HST
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Dr. Matt Burleigh
Brown dwarfs & extra-solar planets in Brown dwarfs & extra-solar planets in the infra-redthe infra-red
Gl 229:
Red dwarf + brown dwarf companion
HST IR image
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Dr. Matt Burleigh
Brown dwarfs & extra-solar planets in Brown dwarfs & extra-solar planets in the infra-redthe infra-red
J band (IR) image from Gemini North of a nearby white dwarf
Estimate a 10Mjup planet would have a magnitude of J~20.5
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Dr. Matt Burleigh
Effect of atmosphereEffect of atmosphereBandBand Stopped byStopped by Observe Observe
fromfromExampleExample
Gamma raysGamma rays Ionisation, Ionisation, compton compton scatteringscattering
Balloon, Balloon, spacespace
XraysXrays Ionisation OIonisation O22, , NN22
SpaceSpace
UVUV OO22, N, N2, 2, OO3 3
disassociationdisassociationSpaceSpace
OpticalOptical Clear!Clear! GroundGround
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Dr. Matt Burleigh
Effect of atmosphereEffect of atmosphereBandBand Stopped byStopped by Observe Observe
fromfromExampleExample
Infra-red Infra-red <10microns<10microns
COCO22, H, H22O O but clear but clear bandsbands
mountainmountain
Infra-red >20 Infra-red >20 micronsmicrons
Molecular Molecular absorptionabsorption
Space, Space, aircraftaircraft
Sub mmSub mm Molecular Molecular absorptionabsorption
MountainMountain
RadioRadio Clear!Clear! GroundGround
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Dr. Matt Burleigh
Types of observationTypes of observation• Photometry – the brightness of an object in a certain waveband
• Time-resolved photometry -
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Dr. Matt Burleigh
Types of observationTypes of observation
• Spectroscopy -
http://imagine.gsfc.nasa.gov/docs/science/how_l1/analysis.html
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Dr. Matt Burleigh
Course OutlineCourse Outline• Overview: Today
– The electro-magnetic spectrum– What is multi-wavelength astronomy?– Observing at different wavelengths
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Dr. Matt Burleigh
Course OutlineCourse Outline
• Basic physical processes: Tomorrow– Attenuation of radiation by matter
• (important to IR, UV and X-ray)– BB radiation
• (how to decide which waveband to observe in)
• Emission processes
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Dr. Matt Burleigh
Optical astronomy Optical astronomy • TelescopesTelescopes
– Modern telescope designModern telescope design– Diffraction limit, resolutionDiffraction limit, resolution– SeeingSeeing– Adaptive opticsAdaptive optics
• DetectorsDetectors– CCDsCCDs
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Dr. Matt Burleigh
Optical astronomy Optical astronomy • TechniquesTechniques
– Spectroscopy: grating equation, resolutionSpectroscopy: grating equation, resolution
– Imaging: magnitude system, filters, colourImaging: magnitude system, filters, colour
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Dr. Matt Burleigh
Infra-red Astronomy Infra-red Astronomy
• Infra-redInfra-red– Absorption by and emission from dustAbsorption by and emission from dust– Interstellar reddeningInterstellar reddening– Detectors, telescopes and satellite Detectors, telescopes and satellite
missionsmissions
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Dr. Matt Burleigh
Ultraviolet Astronomy Ultraviolet Astronomy
• UltravioletUltraviolet– Satellite MissionsSatellite Missions– Interstellar absorptionInterstellar absorption– Curve of growthCurve of growth
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Dr. Matt Burleigh
Radio Astronomy Radio Astronomy
• Radio astronomyRadio astronomy– Differences between optical and radioDifferences between optical and radio– The radio telescopeThe radio telescope– InterferometersInterferometers– Examples: Pulsars, radio galaxies, neutral HExamples: Pulsars, radio galaxies, neutral H
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Dr. Matt Burleigh
The High-Energy Universe The High-Energy Universe
• X-ray astronomyX-ray astronomy– HistoryHistory– X-ray detectorsX-ray detectors– Absorption processesAbsorption processes– X-ray emitting objectsX-ray emitting objects– Accretion onto compact objectsAccretion onto compact objects– Black holes and the Eddington luminosityBlack holes and the Eddington luminosity
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Dr. Matt Burleigh
Complimentary coursesComplimentary courses
• 4326 Interaction radiation/matter – Wynn4326 Interaction radiation/matter – Wynn• 3611.2 Galaxies – O’Brien3611.2 Galaxies – O’Brien• 3611.1 Active Galaxies – Stewart3611.1 Active Galaxies – Stewart• 3631.2 Interstellar Medium - Jameson3631.2 Interstellar Medium - Jameson• 3631.1 Binary stars – Wynn3631.1 Binary stars – Wynn• 3677 Life in the Universe – 3677 Life in the Universe –
Raine/Sims/BurleighRaine/Sims/Burleigh• 4424 High Energy Astrophysics – 4424 High Energy Astrophysics –
Ward/WatsonWard/Watson
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Dr. Matt Burleigh
Lecture timetableLecture timetable
• Thursdays 10.30am LRBThursdays 10.30am LRB• Fridays 1.30pm LRBFridays 1.30pm LRB
3rd Yr Support course TBD
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Dr. Matt Burleigh
BooksBooks
• Modern AstrophysicsModern Astrophysics – Carroll & Ostlie – Carroll & Ostlie• High Energy AstrophysicsHigh Energy Astrophysics – Longair – Longair
(Cambridge University Press) ISBN 0-521-38873-6(Cambridge University Press) ISBN 0-521-38873-6• Active Galactic NucleiActive Galactic Nuclei – Robson – Robson
(Wiley)(Wiley) ISBN 0-471-96050-0ISBN 0-471-96050-0• Active Galactic NucleiActive Galactic Nuclei – Peterson – Peterson
(Cambridge University Press) ISBN 0-521-47911-8(Cambridge University Press) ISBN 0-521-47911-8• Observational AstronomyObservational Astronomy - Kitchin - Kitchin