Docstoc

icecube

Document Sample
icecube Powered By Docstoc
					    News from the South Pole:
Recent Results from the IceCube and
   AMANDA Neutrino Telescopes


             Alexander Kappes
               UW-Madison
               PANIC ‘08
        November 2008, Eilat (Israel)
Outline

• High-energy cosmic neutrino sources
• The IceCube and AMANDA neutrino telescopes
• Physics topics (recent results)
   – Moon shadow
   – Steady point-like sources
   – Gamma ray bursts
   – Dark Matter (WIMPs) ➞ Talk by Catherine De Clercq
   – Exotic physics ➞ Talk by John Kelley




Alexander Kappes           PANIC'08, Eilat               2
Cosmic sources of high-energy neutrinos
                                                Supernova remnants
                                                (Cas A)
                         Cosmic ray
                         accelerator


                         Target:                        Gamma-ray bursts
                         •photon field                  (GRB 080319B, Swift)
                         •molecular cloud
                         •interstellar medium

                          p + p(g) → p± + X
                                     9 m + nm
                                        9 e + ne + nm
                          cosmic ray + neutrinos

                          p + p(g) → p0 + X
                          cosmic ray + photons                   ?
Alexander Kappes            PANIC'08, Eilat                             3
Principle of neutrino detection

                          • infrequently, a cosmic neutrino crashes
                            into an atom in the ice and produces a
                            nuclear reaction

                          • muon travels kilometers in the ice


                             muon

                                                     nuclear
                                                     reaction

• blue (Cherenkov) light produced
• optical sensors capture (and map) the light               nm
Alexander Kappes             PANIC'08, Eilat                     4
 The IceCube and AMANDA neutrino telescopes
                             2007-2008:
                             18 Strings
                                                                2006-2007:13 Strings
IceTop
• Air shower detector
                                                                2005-2006: 8 Strings
• 160 ice-tanks in
  surface array
• Threshold ~ 300 TeV                                           2004-2005 : 1 String

                     1450m                                        AMANDA
InIce
• 80 Strings each with                                            (1995-2000)
                                                                  19 Strings
• 60 Optical Modules
• 17 m between Modules                                            677 Modules

• 125 m between Strings
                                                            Currently deployed:
                     2450m
                                                            40 Strings
                                                            80 IceTop tanks
                                                            3 more seasons planned

  Alexander Kappes                        PANIC'08, Eilat                       5
Backgrounds: Atmospheric muons & neutrinos
• Significantly higher sensitivity for up-going n
• High-purity (atmospheric) up-going neutrino sample after cuts
                                                                 Data-MC comparison
               Cosmic neutrinos typically
                have harder spectra (E-2)




         Up-going                     Down-going
         n-induced muons              atm. muons              Backgrounds:
                                                              - Downgoing μ
                                                              - Atmospheric ν

Alexander Kappes                            PANIC'08, Eilat                           6
Pointing accuracy: the Moon shadow in IceCube 40-strings

• Moon shadow observed in                              Preliminary
  first 3 months of IC40 data          true moon               mean from
                                                               fake moons
• Validates pointing capabilities:
  Angular resolution:
   – IceCube 22 < 1.5°
   – IceCube 80 < 1°


                                       difference




Alexander Kappes                     PANIC'08, Eilat                        7
2000-2006 AMANDA point source search


                                                 Max Significance
                                                    =54 , =11.4h
                                                        o

                                                          3.38




                             Significance

• Unbinned likelihood method using energy information
• Final 7 year AMANDA (3.8 yr livetime) analysis
• 95% of RA-randomized skymaps have maximum significance > 3.38 σ
  → Not significant

Alexander Kappes               PANIC'08, Eilat                       8
2000-2006 AMANDA point source search

          3yr max significance:                        Max Significance
              3.73  1.5                                  =54 , =11.4h
                                                              o

                                                                  3.38




                                  Significance
                                                     5yr max significance:
                                                         3.74  2.8
• Unbinned likelihood method using energy information
• Final 7 year AMANDA (3.8 yr livetime) analysis
• 95% of RA-randomized skymaps have maximum significance > 3.38 σ
  → Not significant

Alexander Kappes                   PANIC'08, Eilat                           9
Search for point sources with IceCube 22-strings




                                                                     preliminary




•    Unbinned likelihood method using energy information
•    Hottest spot found at r.a. 153º , dec. 11º
•    pre-trial p-value: 7×10-7 (4.8 sigma)
•    Accounting for all trials, p-value for analysis is 1.34% (2.2 sigma).
•    At this significance level, consistent with fluctuation of background.
    Alexander Kappes                    PANIC'08, Eilat                            10
Current neutrino flux limits / sensitivities




                                                              AMANDA 3.8 years




                                                              IceCube 22
                                                 IceCube 80




Alexander Kappes               PANIC'08, Eilat                             11
Analysis of “naked eye” GRB 080319B

 March 19, 06:12:49 UTC (duration ~70 s)
 Position: RA = 217.9º, Dec = +36.3º
 Brightest (optical) GRB ever observed:
  z = 0.94 (DA = 1.6 Gpc, light travel time 7.5 Gyr)


 Expect ~0.1 events in IceCube 9-strings              Pi-of-the-Sky (optical)
  (Fireball model, G = 300)




Alexander Kappes                    PANIC'08, Eilat                        12
Analysis of “naked eye” GRB 080319B

 March 19, 06:12:49 UTC (duration ~70 s)
 Position: RA = 217.9º, Dec = +36.3º
 Brightest (optical) GRB ever observed:
  z = 0.94 (DA = 1.6 Gpc, light travel time 7.5 Gyr)


 Expect ~0.1 events in IceCube 9-strings              Pi-of-the-Sky (optical)
  (Fireball model, G = 300)
 Unbinned likelihood method
  yields 0 signal events

 Expect O(1) event
  in IceCube 80
  from similar burst!



Alexander Kappes                    PANIC'08, Eilat                        13
Gamma-ray bursts with IceCube 22-strings

• Currently analyzing data from                         preliminary
  41 bursts (Swift, AGILE + others)

• Individual modeling of bursts
  according to GRB fireball model



                                                    Discovery potential for average WB bursts
• Expected events:
  – average Waxman-Bahcall ~0.7
  – individual GRB spectra ~0.5

• Outlook:
  IceCube 80 will be able to see                           ~30% chance
  WB GRB flux within few years

Alexander Kappes                      PANIC'08, Eilat                                       14
Conclusions and Outlook
• IceCube halfway completed (40 strings), completion planned for 2011

• Verification of pointing accuracy via observation of Moon shadow

• Search for point-like sources over the whole sky
   – Final AMANDA 7 year (3.8 years livetime) analysis
   – IceCube 22-string analysis
   ➞ no significant access above background observed

• Search for neutrinos from gamma-ray bursts
   – Individual analysis of “naked eye” GRB 080319B
     ➞ no signal events found
   – Analysis results for 41 bursts with IceCube 22-strings coming soon

• With the nearing completion of the first km3-scale detector, IceCube,
  neutrino astronomy enters into a new era
                                                    Exciting times lie ahead !
Alexander Kappes                  PANIC'08, Eilat                                15
  The IceCube collaboration

  The IceCube collaboration                                          • Uppsala University
                                                                     • Stockholm University
                        University of Oxford

                                                                  Universität Mainz
                                                                 • Humboldt Univ., Berlin
                          University Utrecht                     • DESY, Zeuthen
                                                                 • Universität Dortmund
                                                                 • Universität Wuppertal
                                                                 • MPI Heidelberg
• Univ Alabama, Tuscaloosa                                       • RWTH Aachen                      Chiba
• Univ Alaska, Anchorage                                                                            University
• UC Berkeley
• UC Irvine                                     • Universite Libre de Bruxelles
• Clark-Atlanta University                      • Vrije Universiteit Brussel
• U Delaware / Bartol Research Inst             • Université de Mons-Hainaut
• Georgia Tech                                  • Universiteit Gent
• University of Kansas                          • EPFL, Lausanne
• Lawrence Berkeley National Lab
• University of Maryland
• The Ohio State University                                            Univ. of Canterbury, Christchurch
• Pennsylvania State University
• University of Wisconsin-Madison
• University of Wisconsin-RiverFalls                   32 Institutions, ~250 members
• Southern University, Baton Rouge

    Alexander Kappes                           PANIC'08, Eilat                                             16
                   Backup




Alexander Kappes    PANIC'08, Eilat   17
Effective muon neutrino area




Alexander Kappes           PANIC'08, Eilat   18
Separation of atmospheric and cosmic neutrinos




             • Atmospheric neutrinos irreducible background
               (~60,000 per year in IceCube with 80 strings)
             • Cosmic neutrinos typically have harder spectra (E-2)
               (detected events peak at higher energies)
Alexander Kappes                       PANIC'08, Eilat                19
                      A Priori Source List for IC22
                                            Obj. Name      ra(deg) dec(deg) p-value (pre-trial)
                                -------------   -------     ------    --------
                                MGRO_J2019+37 (304.830    , 36.830) :    0.251
                                MGRO_J1908+06 (287.270    , 6.280) :     -----
                                      Cyg_OB2 (308.083    , 41.510) :    -----
                                       SS_433 (287.957    , 4.983) :     0.317
                                      Cyg_X-1 (299.591    , 35.202) :    -----
                                 LS_I_+61_303 ( 40.132    , 61.229) :    -----
                                 GRS_1915+105 (288.798    , 10.946) :    -----
                                XTE_J1118+480 (169.545    , 48.037) :    0.082
Lowest p-value (0.07)            GRO_J0422+32 ( 65.428    , 32.907) :    -----
is for 1ES 1959+650.                  Geminga ( 98.476    , 17.770) :    -----
                                  Crab_Nebula ( 83.633    , 22.014) :    -----
                                        Cas_A (350.850    , 58.815) :    -----
Not significant after trial           Mrk_421 (166.114    , 38.209) :    -----
                                      Mrk_501 (253.468    , 39.760) :    -----
factor of 28 sources in list.    1ES_1959+650 (299.999    , 65.149) :    0.071
                                 1ES_2344+514 (356.770    , 51.705) :    -----
                                   H_1426+428 (217.136    , 42.672) :    -----
                                 1ES_0229+200 ( 38.202    , 20.287) :    -----
                                       BL_Lac (330.680    , 42.278) :    0.368
                                   S5_0716+71 (110.473    , 71.343) :    0.309
                                        3C66A ( 35.665    , 43.035) :    0.313
                                     3C_454.3 (343.491    , 16.148) :    -----
                                     4C_38.41 (248.815    , 38.135) :    -----
                                 PKS_0528+134 ( 82.735    , 13.532) :    -----
                                       3C_273 (187.278    , 2.052) :     0.369
                                          M87 (187.706    , 12.391) :    -----
                                     NGC_1275 ( 49.951    , 41.512) :    0.213
                                        Cyg_A (299.868    , 40.734) :    -----

                         (only excesses reported, otherwise given as “---”)
           All Flavor GRB Limits from AMANDA II

Limits from triggered searches
assume ~700 bursts per year
~420 GBs investigated                                       Cascade
                                    only                    searches
AMANDA starts to exclude           rolling                 (trig + roll)
flux models!
Cascade search in IceCube
much more competitive
(factor 70 in instrumented vol.)
Eff. volume (cascades) grows                   Muon
faster than eff. area (muon)!                searches
                                             (only trig)

				
DOCUMENT INFO
Shared By:
Categories:
Tags:
Stats:
views:14
posted:9/18/2012
language:English
pages:21