IceCube and the Development of High-Energy Neutrino Astronomy
Naoko Kurahashi Neilson (Drexel University) for the IceCube Collaboration
TeVPA 2016
Naoko Kurahashi Neilson, Drexel University 1 How it started.... Highest energy particles observed
human-made Charged particles (LHC) nuclei
109eV 1012eV 1015eV 1018eV
GeV TeV PeV EeV
Neutral particles γ ray
Naoko Kurahashi Neilson, Drexel University 2 Naoko Kurahashi Neilson, Drexel University 3 How it started.... Highest energy particles observed
human-made Charged particles (LHC) nuclei
109eV 1012eV 1015eV 1018eV
GeV TeV PeV EeV
Neutral particles γ ray neutrino!
● How are neutral particles created at such high energies? ● Can neutrinos be created the same way γ-rays are? ● What are the most likely sources of these observed neutrinos? Background? Signal? ● Where do they come from? What does that tell us?
Naoko Kurahashi Neilson, Drexel University 4 Neutrino Astronomy – The Dream
Learn how gamma-rays See deeper into are created sources
Learn where cosmic-rays are coming from
Naoko Kurahashi Neilson, Drexel University 5 Neutrino Astronomy – The Reality
Issue 1: cross section Issue 2: backgrounds
Observable universe ~1028cm Galactic disk ~1023cm
Earth radius 6x108cm
Atmosphere thickness 1x106cm
Cross section from Gandhi et al., Phys. Rev. D 58 (1998) 093009
Naoko Kurahashi Neilson, Drexel University 6 NaokoCompleted Kurahashi Neilson, in Dec Drexel 2010!University 7
~250 people for ~40 institutions
Naoko Kurahashi Neilson, Drexel University 8 Topics Not Covered in This Talk (Other Collaboration Talks)
● Flare searches, lightcurve matching, and other time dependent analyses in IceCube – Asen Christov
● IceCube is a multi-physics purpose detector – Dark Matter Morten Medici
– Sterile Neutrinos Carlos Arguelles
– Cosmic Ray Anisotropy Frank McNally
● Future of oscillation physics at the South Pole, PINGU – Jason Koskinen
Naoko Kurahashi Neilson, Drexel University 9 Two Pronged Approach to Neutrino Astrophysics Diffuse Analyses Point Source Analyses Goal: Goal: Resolve each spectral component in energy Resolve sources (clusterings) in space
Requirements: Requirements: - Good energy proxy variable - Good angular resolution - Good purity in data over statistical power - Good statistical power over purity (no events from component that's not fit) (background is spatially uniform) - Accurate estimate of energy proxy error range - Accurate estimate of angular error range - Prior knowledge of characteristics of - Prior knowledge of potential source locations components helpful helpful
Naoko Kurahashi Neilson, Drexel University 10 Diffuse Analysis 1 IceCube's discovery analysis in 2013
Science 342, 1242856 (2013)
μ Veto
Could be an atmospheric muon from a CR shower
νμ
Most likely a neutrino
μ
-2 -8 -2 2 2010-2012 (2 years of data) ● Flux assuming E : ~1.2 x 10 E [/GeV/cm /s/sr] ● Best fit spectral index: -2.2 Naoko Kurahashi Neilson, Drexel University 11 Diffuse Analysis 1 IceCube's discovery analysis in 2013
arXiv:1510.05223
μ Veto
Could be an atmospheric muon from a CR shower
νμ
Most likely a neutrino
μ
-2 -8 -2 2 2010-2014 (4 years of data) ● Flux assuming E : ~1.0 x 10 E [/GeV/cm /s/sr] ● Best fit spectral index: -2.6 Naoko Kurahashi Neilson, Drexel University 12 Diffuse Analysis 2 Updated veto to the discovery analysis
-2.5 -8 2 ● Flux Level:~2.2 (E/100GeV) 10 [/GeV/cm /s/sr] ● Spectral index: -2.5
IceCube Collaboration (2015) Phys. Rev. D. 91 * This was for 2010-2012 data. Update to this analysis in the pipeline
Naoko Kurahashi Neilson, Drexel University 13 Diffuse Analysis 3 A different approach: Only look below the horizon to avoid atmospheric muon background
arXiv:1607.08006
2009-2010 2010-2011 2011-2012 2011-2015
-2.13 -18 2 ● Flux Level:~ 0.9 (E/100TeV) 10 [/GeV/cm /s/sr] ● Spectral index: -2.1
Naoko Kurahashi Neilson, Drexel University 14 Diffuse Analyses Conclusion
● The universe emits high energy neutrinos
● Characterization in progress, but the whole picture is unclear for now 90% confidence interval comparison
Assumptions: - one flux for whole sky - one spectral index - same flux for each flavor
Some tensions imply..... Break in the spectrum? - difference in energy probed imply hardening - but then no Glashow events? - break and cutoff? Spatially different flux?
arXiv:1607.08006
Naoko Kurahashi Neilson, Drexel University 15 Point Source Analysis 1 Search for cluster: all-sky and around known sources
BL Lac PWN PKS 0537-441 Geminga PKS 2155-304 Crab Nebula PKS 0235+164 MGRO J2019+37 1ES 0229+200 HESS J1356-645 W Comae PSR B1259-63 Mrk 421 HESS J1303-631 Mrk 501 MSH 15-52 All-sky search H 1426+428 HESS J1023-575 3C66A HESS J1616-508 1ES 2344+514 HESS J1632-478 1ES 1959+650 Vela X S5 0716+71 HESS J1837-0 PKS 2005-489 SFR PKS 0426-380 Cyg OB2 PKS 0548-322 SNR H 2356-309 IC443 1ES 1101-232 Cas A 1ES 0347-121 TYCHO FSRQ Cen A PKS 1454-354 M87 PKS 1622-297 3C 123.0 QSO 1730-130 Cyg A PKS 1406-076 NGC 1275 QSO 2022-077 M82 3C279 RCW 86 3C 273 RX J0852.0-4622 PKS 1502+106 RX J1713.7-3946 PKS 0528+134 W28 3C 454.3 Seyfert 4C 38.41 ESO 139-G12 PKS 0454-234 XB/mqso PKS 0727-11 SS433 Time-integrated unbinned search of hot spots in 7 years of data GC HESS J0632+057 Sgr A* Cyg X-1 (4-year version Astrophys.J. 796:109,2014) NI Cyg X-3 MGRO J1908+06 LSI 30 HESS J1507-622 Cir X-1 HESS J1503-582 GX 339-4 HESS J1741-302 S 5039 HESS J1834-087 cluster HESS J1614-51
Naoko Kurahashi Neilson, Drexel University 16 Point Source Analysis 2 Stack the sources
Stacking of 127 nearby bright starburst galaxies • Within z < 0.03 Stacking of 862 Fermi 2LAC Blazars • FFIR(60 micron) > 4 Jy Quasi-diffuse search (~10% of the • F (1.4 GHz) > 20 mJy sky at our angular resolution) radio
Waxman, TeVPA ‘13
2010-2013 data IceCube Collab., arXiv:1410.1749 (2014) Astrophys.J. 796:10 (,2014) Naoko Kurahashi Neilson, Drexel University 17 Point Source Analyses conclusion
● No TeV sources in neutrinos (yet)
● Statistically insignificant overfluctuations come and go, but will any stick?
● MeV neutrinos still lead in number of sources (0 vs 2) The Sun Supernova 1987A
kamiokande
super-kamiokande
*No direction, just timing
Naoko Kurahashi Neilson, Drexel University 18 Putting diffuse and point source together
Astrophysical Diffuse Flux
All-sky source flux limit arXiv:1502.03104
Naoko Kurahashi Neilson, Drexel University 19 Limits in terms of % of diffuse flux
Upper limit in notes diffuse flux Blazars ~ 17% 862 from Fermi 2nd AGN cat. Spectral index = -2.5 Nearby Starburst Galaxies ~ 8% 127 nearby Spectral index = -2 Galactic Young SNR ~ 5% 30 with no PWN or MC Sources Spectral index = -2 Young PWN ~ 3% 10 with no MC Spectral index = -2 Galactic Plane ~14% Fermi Diffuse γ Spatial template Spectral index = -2.5 to -2.7 GRBs ~1% 506 bursts observed Spectral index = -2 to -2.7 Astrophys.J. 796:10 (,2014), ApJ, 805, L5 (2015)
Naoko Kurahashi Neilson, Drexel University 20 Is it time to consider....
– New (more correct? more exotic?) models of emission?
– New sources? Optical or x-ray counterparts?
– “Dark” sources? Does this require new methods?
Naoko Kurahashi Neilson, Drexel University 21 Multi-Messenger Astronomy with Non-EM partners
Ultra-high Energy Cosmic Rays Gravity Waves
JCAP 1601 (2016) 01, 037 Correlation study with highest energy LIGO gravity signal and neutrino events from Auger and TA events within +/-500s No correlation beyond 3.3σ
Naoko Kurahashi Neilson, Drexel University 22 How can we increase our chances of discovering sources sooner?
Factor of 10 doesn't seem like much until you realize how old you are in 10 years vs 100 years!
Naoko Kurahashi Neilson, Drexel University 23 IceCube's Realtime Efforts
Naoko Kurahashi Neilson, Drexel University 24 Example: HESE-160427A , on April 27 2016
Naoko Kurahashi Neilson, Drexel University 25 Historical Perspective: Gamma-ray Astronomy Diffuse signal → first source → catalog! 1970's
NOW Fermi 5-year data
SAS-2
Diffuse celestial radiation GSFC nasa.gov
COS-B Discreet sources 1980's
GSFC nasa.gov Naoko Kurahashi Neilson, Drexel University 26 Historical Perspective: X-ray Astronomy Diffuse signal → first source → catalog (Sun detected in x-rays 1940's)
Diffuse emission and Scorpius X-1 1960's
APOD 8/19/2000 ROSAT
“The Cosmic Century” M. S. Longair
Naoko Kurahashi Neilson,xte.mit.edu Drexel University 27 IceCube Gen2 – The next generation facility for neutrino physics and astronomy at the South Pole
arXiv:1412.5106 Naoko Kurahashi Neilson, Drexel University 28 Getting there sooner
Naoko Kurahashi Neilson, Drexel University 29 Conclusions
● High-energy Neutrino Astronomy is becoming a reality ● IceCube has had great success so far ● We keep learning lessons, and have plans to get us to discovery sooner
For more on the field, what it all means, and a vision for the future, stay tuned for Tom Gaisser's talk later!
Naoko Kurahashi Neilson, Drexel University 30 Backups
Naoko Kurahashi Neilson, Drexel University 31 More IceCube Jargon
40-strings (IC-40), 376 days livetime, ~50% complete 59-strings (IC-59), 348 days livetime, ~50% complete 79-strings (IC-79), 333 days livetime, almost complete 86-strings (IC-86), 329 days livetime, complete
Naoko Kurahashi Neilson, Drexel University 32 A pitch for optical/x-ray/gamma-ray to followups on IceCube observations
● IceCube is updating fast alert systems (GCN/ATEL) to be sent when a “significant” neutrino is seen
● The (current) best case is ~0.5 degree error circle → not great for follow-up observations It's a lot to ask other telescopes to observe for a long time in a large area, for most likely, nothing
● But lets not forget, the upshot is huge here! Your telescopes can discover the first non-photon source in the sky!
Naoko Kurahashi Neilson, Drexel University 33 Topologies of different event types
Charge Current Electron/Tau Neutrinos Charge Current Muon Neutrinos All Neutral Current Neutrinos
Through-going Track Starting Track Naoko Kurahashi Neilson, Drexel University Shower 34 Naoko Kurahashi Neilson, Drexel University 35