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Multi-Messenger Astronomy AY 17 10/19/2011
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Outline What is Multi-messenger astronomy? Photons Cosmic Rays Neutrinos Gravity-Waves Sample-Return
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Outline What is Multi-messenger astronomy? Photons Cosmic Rays Neutrinos Gravity-Waves Sample-Return
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What is Multi-Messenger Astronomy? It’s Astronomy with multiple messengers! – One of the first instances of a clear cut meaning in an astronomical definition Informs you about different conditions in the same object – Photons come from the surface of the Sun – But neutrinos are made from the nuclear reactions in the core
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Outline What is Multi-messenger astronomy? Photons Cosmic Rays Neutrinos Gravity-Waves Sample-Return
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Photons Most widely used messenger particle in Astronomy – Easy to detect (unlike neutrinos) – Can travel long distances (unlike nuclear messenger particles) However…. – Not all frequencies are created equal
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Photons Astronomers are merely fleas on the dog of industry – Cheap Silicon Optical – Radar Radio – Nuclear Testing Gamma rays
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Photons X-Ray Astronomy – Began as a series of Balloon and V-2 Rocket experiments in the 1960s Usually a single astronomical instrument tagging along with various other experiments (atmospheric measurements, NIH experiments, etc.) Initially measured the Sun, and eventually led to the discovery of bright X-ray sources in the Milky Way
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Photons Chandra X-Ray Observatory – 3-10 keV – Launched in 1999 – Plane parallel mirrors
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Photons Galactic and Extragalactic X-Ray Astronomy – 10 keV / k b ~ 10 8 K
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Photons
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Intra-Cluster Gas – Cooled by Thermal Bremsstrahlung Evidence for metal lines in the Intra- cluster gas – How did they get there?
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Photons X-Ray emission within Galaxies? – Supernovae – Accreting Black holes – X-ray binaries NS+NS NS+Blackhole NS+WD etc
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Outline What is Multi-messenger astronomy? Photons Cosmic Rays Neutrinos Gravity-Waves Sample-Return
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Cosmic Rays What are Cosmic Rays – Highly Energetic atomic and subatomic particles – ~90% Protons, 9% He, 1% other (mostly heavy elements)
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Cosmic Rays
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Galactic Cosmic Rays – Originate in supernova remnants – Accelerated by magnetic fields – Localization is hard Deflected by magnetic fields in the galaxy – Can fragment as travel
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Cosmic Rays Extragalactic Cosmic Rays – Some cosmic rays have enough energy to leave the galaxy 1 / m^2 / yr hits the Earth – Little is known about their composition (statisitics problem) – Some evidence they come from AGN – Could also come from colliding galaxies, the early universe, decay of superheavy particles
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Cosmic Rays
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Cosmic Rays and You
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Outline What is Multi-messenger astronomy? Photons Cosmic Rays Neutrinos Gravity-Waves Sample-Return
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Neutrinos 86 Holes 5160 Optical Sensors Sensitive to high energy neutrinos
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Neutrinos Solar Observation – Super-Kamiokande produced a neutrino image of the Sun
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Neutrinos
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Supernova Early Warning System – Neutrinos were detected from SN 1987A before the optical counterpart was discovered – IceCube and other neutrino experiments are poised to detect the neutrinos from the next nearby (galactic) supernova – Icecube will have the ability to pinpoint the neutrino origin accurately
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Neutrinos Avoiding Cosmic Ray Confusion – IceCube also has a cosmic ray detector array on the Antarctic surface Coincidence between cosmic ray detection and “neutrino” detection lowers confusion rates This “junk” is interesting to some people!
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Cosmic Rays with IceCube
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Local Magnetic fields? Stellar magnetic fields? A handful of close pulsars?
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Outline What is Multi-messenger astronomy? Photons Cosmic Rays Neutrinos Gravity-Waves Sample-Return
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Gravity Waves
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Gravitational Waves What the gravity wave sky actually looks like:
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Gravity Waves
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Advanced LIGO Bigger, Better, Stronger – 20x stronger laser – Seismically isolated from 40 Hz down to 10 Hz – Reduced thermal noise – An actual detection likely! – 2015* *Actual finish time may vary
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Outline What is Multi-messenger astronomy? Photons Cosmic Rays Neutrinos Gravity-Waves Sample-Return
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Sample Return
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Collect cometary and interstellar dust particles in aerogel Return the sample to Earth Take millions of photographs of aerogel to identify dust grains – stardust@home 45 interstellar dust grains identified!
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Sample Return
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List of findings: – Organic compounds – Amorphous silicates – Olivine and pyroxene (Solar system matter well mixed with ISM)
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Sample Return Supernova Debris – Fe-60 has a half life of 2.6 Myr (all of it that formed with the Earth is gone)
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Sample Return This points to a core-collapse supernova within a few 10s of parsecs of the Earth exploding several million years ago Contributed to the “Local Bubble” of the ISM – We are in a low density, high temperature, ~150 light year region of the ISM
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