apsaprilpresentationppt
- 1. A S T U D Y O F S P A T I A L L Y - C O I N C I D E N T I C E C U B E N E U T R I N O S A N D F E R M I G A M M A - R A Y S O U R C E S H A N N A H S E Y M O U R - B A R N A R D C O L L E G E 1
- 2. • Multi-messenger Astronomy Search for Cosmic-Ray Sources • IceCube Neutrino Observatory and Fermi Gamma-Ray Observatory • Neutrino Events and Fermi Blazars • Implications of Data 2
- 3. N E U T R I N O / M U L T I - M E S S E N G E R A S T R O N O M Y • Neutrinos mostly interact via weak force • Cross-section is very low • Cosmic rays-mainly charged particles and nuclei • Can be scattered by B-fields • Don’t “point back” to source • Cosmic rays thought to be produced by astrophysical nuclear processes • Charged pion decay • Same processes produce neutrinos and gamma rays 3
- 4. N E U T R I N O A S T R O N O M Y - P O T E N T I A L S O U R C E S • TeV-PeV neutrinos most likely produced in extreme astrophysical environments • Proton interaction with gas • Starburst Galaxies • Blazars and other AGN • FSRQs more likely to be neutrino-bright • Optically thick accretion disk/strong external radiation field • Expect ~1e-6 neutrinos detected by IceCube for Mrk 501 flare* • ~30% probability of detecting neutrinos from flare, few per year* • Could detect a few neutrinos from flares (i.e., 3C 279)* 4 *A. M. Atoyan and C. D. Dermer. Neutral Beams from Blazar Jets. , 586:79–96, March 2003.
- 5. I C E C U B E N E U T R I N O O B S E R V A T O R Y • >2km of ice near South Pole • 86 strings of 60 PMTs and electronics • Charged-current interaction • Cherenkov Radiation • Detects muon events as tracks, other events as showers (in case of charged- current interaction) • Much better angular resolution for muons • Compare ~1º to ~20º • Select for events going through Earth 5
- 6. E A R L I E S T L I G H T L A T E S T L I G H T B I G B I R D * * 2 P E V 7 1 T E V 6 **(Icecube.wisc.edu, 2016)
- 7. I C E C U B E S K Y M A P 7 W H E R E A R E T H E P O I N T S O U R C E S ? ***Phys. Rev. Lett. 115, 081102 (2015)
- 8. F E R M I S P A C E T E L E S C O P E • Sensitive to energies up to 1 TeV • LAT sees 20% of sky • Covers entire sky in 3hrs • Gamma ray -> e-e+ pair • Si measures path to determine direction • Calorimeter measures energy 8
- 9. S K Y , M O D E L , R E S I D U A L S M A P S F O R E A C H N E U T R I N O E V E N T • Fermi analysis of a 7ºx7º region around 15 IceCube track events • 1-300 GeV • Search for Fermi sources with ~1º radius of neutrino • 2 events with one source, 1 event with two • 1 FSRQ and 3 BL LAC • Analysis using Fermi Science Tools, P7REP_SOURCE_V16 • Light Curves • 14 one-day bins (one week before neutrino event, one week after) 9
- 10. Neutrino Event 11 Count Model Residual 1 0 7 º X 7 º P H / S / C M ^2 P H O T O N + / - W E E K
- 11. Neutrino Event 12 Count Model Residual 1
- 12. Neutrino Event 17 Count Model Residual 1
- 13. I N T E R P R E T A T I O N • Probability of spatial coincidence • Constant declination, random right ascension • IceCube positions dependent on declination • Compare to FSRQ, BL LAC Positions for 3FGL • Repeat 10000x 1
- 14. F U T U R E D I R E C T I O N S • VERITAS analysis of point sources • Higher energy gamma rays • Better understanding of AGN and cosmic rays? 1
- 15. M A R C O S S A N T A N D E R J O H N P A R S O N S M I K E S H A E V I T Z R E S H M I M U K H E R J E E T H E N A T I O N A L S C I E N C E F O U N D A T I O N T H E N E V I S L A B O R A T O R I E S R E U Acknowledgements 1 5