Presentation is loading. Please wait.

Presentation is loading. Please wait.

Recent Results from the HiRes Experiment Chad Finley UW Madison for the HiRes Collaboration TeV Particle Astrophysics II Madison WI 2006 August 28.

Published byWalter Webb Modified over 8 years ago

Similar presentations

Presentation on theme: "Recent Results from the HiRes Experiment Chad Finley UW Madison for the HiRes Collaboration TeV Particle Astrophysics II Madison WI 2006 August 28."— Presentation transcript:

1 Recent Results from the HiRes Experiment Chad Finley UW Madison for the HiRes Collaboration TeV Particle Astrophysics II Madison WI 2006 August 28

2 Chad Finley UW MadisonTeV II 2006 Aug. 28 2 HiRes Air-Fluorescence Detector HiRes consists of two sites 12 km apart in the Utah desert (US Army Dugway Proving Ground) Rings of mirrors at each site observe night sky A cosmic ray induces a shower in the atmosphere which can be observed in UV fluorescent light by both sites. Operation on clear, moonless nights with good atmospheric conditions, so small duty cycle about 10%

3 Chad Finley UW MadisonTeV II 2006 Aug. 28 3 Distribution of opening angles between true and reconstructed arrival directions for MC events. HiRes Air-Fluourescence Detector Stereo observations provide the sharpest angular resolution for searching for small-scale anisotropy –In simulations, 68% of events above 10 EeV are reconstructed within 0.6° of their true arrival direction Monocular observations currently provide the largest exposure for measuring the energy spectrum –HiRes-I was built first and obtained almost three-years more data than HiRes-II

4 I. BL Lac Correlations II. Energy Spectrum and GZK Effect

5 Chad Finley UW MadisonTeV II 2006 Aug. 28 5 BL Lacertae Objects Blazars are established sources of TeV  -rays Candidates for accelerating cosmic rays to EeV energies Somewhat controversial recent history regarding correlations of UHECR with BL Lac objects: Tinyakov and Tkachev, JETP 74 (2001) 445. Tinyakov and Tkachev, Astropart. Phys. 18 (2002) 165. Gorbunov et al., ApJ 577 (2002) L93. Evans, Ferrer, and Sarkar, Phys.Rev. D67 (2003) 103005. Torres et al., Astrophys.J. 595 (2003) L13. Gorbunov et al., JETP Lett. 80 (2004) 145. Stern and Poutanen, ApJ 623 (2005) L33. Jet of active galaxy M87 (Hubble) BL Lacertae Object - special type of blazar, active galaxy with jet axis aligned with our line of sight.

6 Chad Finley UW MadisonTeV II 2006 Aug. 28 6 BL Lac Correlations: Previous Claims Previous correlations were found using AGASA and Yakutsk data. We test each claim with HiRes data: Tinyakov & Tkachev, JETP 74 (2001) 445. Tinyakov and Tkachev, Astropart. Phys. 18 (2002) 165. Gorbunov et al., ApJ 577 (2002) L93. No previous claims are confirmed.

7 Chad Finley UW MadisonTeV II 2006 Aug. 28 7 BL Lac Correlations: New Claim Most recent claim by Gorbunov is based on published HiRes data. It uses a 10 EeV threshold, so it is a new claim. Gorbunov et al., JETP Lett. 80 (2004) 145. Need to test with new data

8 Chad Finley UW MadisonTeV II 2006 Aug. 28 8 BL Lac Objects BL Lacs Equatorial Coords.

9 Chad Finley UW MadisonTeV II 2006 Aug. 28 9 BL Lac Objects and HiRes Events BL Lacs HiRes events (E>10 EeV) Equatorial Coords.

10 Chad Finley UW MadisonTeV II 2006 Aug. 28 10 The 0.8º angular bin size was optimized by Gorbunov et al. It is preferable to perform an unbinned maximum likelihood analysis, using the individual errors of each event. The test hypothesis is that the cosmic rays arrive from two distributions, a source distribution and an isotropic background distribution. The likelihood is maximized for the best estimate for n s, that is, the number of events from the source locations, assuming the remaining N-n s events are background. We find: Estimated number of source events:n s = 8.0 (~ excess of events correlating with BL Lacs) Fraction F of isotropic MC sets with stronger signal: F = 2×10 -4 BL Lac Correlations: New Claim

11 Chad Finley UW MadisonTeV II 2006 Aug. 28 11 BL Lac Correlations: New Claim Charged primaries with energies ~ 10 EeV are expected to be deflected many degrees by the galactic magnetic field. Correlations on the scale of the HiRes angular resolution (0.6º) imply that primary must be neutral (at least over most of its path through GMF). But neutron decay length and photon mean free path are very short (~ few Mpc) at this energy, whereas BL Lacs are ~ 100 - 1000 Mpc distant Attenuation Length Torres & Anchordoqui, 2004

12 Chad Finley UW MadisonTeV II 2006 Aug. 28 12 BL Lac Correlations: Current Study The Gorbunov et al. correlation was based on limited information (arrival directions only, for just the data set above 10 EeV) Use the published sample of data up until 2004 January to decide a priori what will be tested before arrival directions of new data are analyzed Consider: –Energy dependence –Source sample

13 Chad Finley UW MadisonTeV II 2006 Aug. 28 13 BL Lac Correlations: Energy Dependence If we perform the analysis on all the events below 10 EeV, there is correlation: n s = 22 with ln R = 3.10. The fraction of isotropic MC sets with stronger signal is F = 6×10 -3. For the total HiRes data set: –n s = 31 –F = 2×10 -4

14 Chad Finley UW MadisonTeV II 2006 Aug. 28 14 BL Lac Correlations: Source Sample Confirmed BL Lacs in the Veron Catalog are classified as “BL” or “HP” for high polarization. So far, only “BL” have been considered. We perform the same analysis on the 47 “HP” BL Lacs, using the same m<18 cut as was used for “BL” –use HiRes events above 10 EeV –Result: n s = 3.0, with F = 6×10 -3. For the combined set of BL Lacs (i.e. “BL” + “HP”) with m<18, and HiRes events above 10 EeV, we find: n s = 10.5, with F = 10 -5. The m 18, and no correlation is found.

15 Chad Finley UW MadisonTeV II 2006 Aug. 28 15 Six BL Lacs are confirmed sources of TeV  -rays. Five are in the northern hemisphere and well observed by HiRes. We perform the maximum likelihood analysis on each source individually using all HiRes events: For the TeV blazars taken as a set, the ML analysis yields: –All energies: n s = 5.6 with F = 10 -3 TeV BL Lac Correlations

16 Chad Finley UW MadisonTeV II 2006 Aug. 28 16 Six results which we wish to test with independent data (all objects with m<18): Note: –These are not independent results: the samples overlap. –Analysis has been a posteriori, so F values are not true probabilities. –Must be tested with independent data –Data taking through March 2006 has yielded an independent data set ~ 70% of the current sample size: Analysis is ongoing R.U. Abbasi et al., Astrophys.J. 636 (2006) 680 [astro-ph/0507120] BL Lac Correlations: Summary of Results Fraction of MC sets with greater ln(R) value than data

17 I. BL Lac Correlations II. Energy Spectrum and GZK Effect

18 Chad Finley UW MadisonTeV II 2006 Aug. 28 18 HiRes-I and HiRes-II Data Sets Current analysis of HiRes-I –May 1997 - June 2005 Current analysis of HiRes-II –Dec. 1999 - Aug. 2004 HiRes-I has more exposure than HiRes-II Include only pure monocular statistics for HiRes-I when doing fits

19 Chad Finley UW MadisonTeV II 2006 Aug. 28 19 HiRes-I and HiRes-II Data Sets Current analysis of HiRes-I –May 1997 - June 2005 Current analysis of HiRes-II –Dec. 1999 - Aug. 2004 HiRes-I has more exposure than HiRes-II Include only pure monocular statistics for HiRes-I when doing fits

20 Chad Finley UW MadisonTeV II 2006 Aug. 28 20 Broken Power Law Fits Fit Spectra to broken power law: –Allow break point to float No break point: –Bad fit:  2 =154 / 39

21 Chad Finley UW MadisonTeV II 2006 Aug. 28 21 Broken Power Law Fits Fit Spectra to broken power law: –Allow break point to float No break point: –Bad fit:  2 =154 / 39 DOF One break point: –Better fit:  2 =67.0 / 37 DOF –Find Ankle at 4 EeV

22 Chad Finley UW MadisonTeV II 2006 Aug. 28 22 Broken Power Law Fits Fit Spectra to broken power law: –Allow break point to float No break point: –Bad fit:  2 =154 / 39 DOF One break point: –Better fit:  2 =67.0 / 37 DOF –Find Ankle at 4 EeV Two break points: –Good fit:  2 =40.0 / 35 DOF –Reduce  2 by 27 –HE break at 60 EeV

23 Chad Finley UW MadisonTeV II 2006 Aug. 28 23 Statistical Significance Significance of observed events beyond break point compared with expected: –Expect 44.9 events –Observe 14 –P(14 ; 44.9) = 7x10 -8 5  is 3x10 -7 6  is 1x10 -9

24 Chad Finley UW MadisonTeV II 2006 Aug. 28 24 Statistical Significance Significance of observed events beyond break point compared with expected: –Expect 44.9 events –Observe 14 –P(14 ; 44.9) = 7x10 -8 5  is 3x10 -7 6  is 1x10 -9

25 Chad Finley UW MadisonTeV II 2006 Aug. 28 25 Is it the GZK Cutoff? Compare integral spectrum to spectrum without cutoff

26 Chad Finley UW MadisonTeV II 2006 Aug. 28 26 Is it the GZK Cutoff? Compare integral spectrum to spectrum without cutoff

27 Chad Finley UW MadisonTeV II 2006 Aug. 28 27 Is it the GZK Cutoff? Compare integral spectrum to spectrum without cutoff E ½ is energy when measured integral is half expectation: –HiRes finds log 10 E ½ =19.73±0.07 –Berezinsky et al. prediction for GZK log 10 E ½ = 19.72

28 Chad Finley UW MadisonTeV II 2006 Aug. 28 28 Expectation of GZK Fit spectrum to a model: –Uniform source density for extragalactic sources –Energy losses

29 Chad Finley UW MadisonTeV II 2006 Aug. 28 29 Expectation of GZK Fit spectrum –Uniform source density for extragalactic sources –Energy losses –Use composition Protons – Extragalactic Iron – Galactic

30 Chad Finley UW MadisonTeV II 2006 Aug. 28 30 Expectation of GZK Fit spectrum –Uniform source density for extragalactic sources –Energy losses –Use composition Protons – Extragalactic Iron – Galactic

31 Chad Finley UW MadisonTeV II 2006 Aug. 28 31 Expectation of GZK Fit spectrum –Uniform source density for extragalactic sources –Energy losses –Use composition Protons – Extragalactic Iron – Galactic Find good fit –Ankle from pair production losses –Indeterminate 2 nd Knee

32 Chad Finley UW MadisonTeV II 2006 Aug. 28 32 Conclusions HiRes monocular data consistent with GZK suppression –Significance of HE suppression beyond 2nd break point: ~ 5  –Energy of break agrees with GZK predictions The data is well fit by a uniform source density model. Recently observed correlations between HiRes and BL Lacs must be tested with independent data: –Data taking through March 2006 has yielded an independent data set ~ 70% of the current sample size –Analysis is ongoing; independent test of BL Lac correlations will be performed

33 Chad Finley UW MadisonTeV II 2006 Aug. 28 33

Download ppt "Recent Results from the HiRes Experiment Chad Finley UW Madison for the HiRes Collaboration TeV Particle Astrophysics II Madison WI 2006 August 28."

Similar presentations

Anisotropy in Cosmic Ray Arrival Directions Using IceCube and IceTop Frank McNally ISCRA.

Anisotropy in Cosmic Ray Arrival Directions Using IceCube and IceTop Frank McNally ISCRA.
JNM Dec. 2001 Annecy, France The High Resolution Fly’s Eye John Matthews University of Utah Department of Physics and High Energy Astrophysics Institute.

JNM Dec Annecy, France The High Resolution Fly’s Eye John Matthews University of Utah Department of Physics and High Energy Astrophysics Institute.
Stereo Spectrum of UHECR Showers at the HiRes Detector  The Measurement Technique  Event Reconstruction  Monte Carlo Simulation  Aperture Determination.

Stereo Spectrum of UHECR Showers at the HiRes Detector  The Measurement Technique  Event Reconstruction  Monte Carlo Simulation  Aperture Determination.
TeV Particle Astrophysics 2010 Results from the HiRes Experiment Gordon Thomson University of Utah.

TeV Particle Astrophysics 2010 Results from the HiRes Experiment Gordon Thomson University of Utah.
Status of Top-Down Models for the Origin of Ultra-High Energy Cosmic Rays I. Observation of ultra-high energy cosmic rays before the Pierre Auger Observatory.

Status of Top-Down Models for the Origin of Ultra-High Energy Cosmic Rays I. Observation of ultra-high energy cosmic rays before the Pierre Auger Observatory.
High Energy Neutrinos from Astrophysical Sources Dmitry Semikoz UCLA, Los Angeles & INR, Moscow.

High Energy Neutrinos from Astrophysical Sources Dmitry Semikoz UCLA, Los Angeles & INR, Moscow.
Results from the Telescope Array experiment H. Tokuno Tokyo Tech The Telescope Array Collaboration 1.

Results from the Telescope Array experiment H. Tokuno Tokyo Tech The Telescope Array Collaboration 1.
GZK Horizons and the Recent Pierre Auger Result on the Anisotropy of Highest-energy Cosmic Ray Sources Chia-Chun Lu Institute of Physics, National Chiao-Tung.

GZK Horizons and the Recent Pierre Auger Result on the Anisotropy of Highest-energy Cosmic Ray Sources Chia-Chun Lu Institute of Physics, National Chiao-Tung.
Nuclei As Ultra High Energy Cosmic Rays Oleg Kalashev* UCLA, INR RAS GZK 40: The 3rd International Workshop on THE HIGHEST ENERGY COSMIC RAYS AND THEIR.

Nuclei As Ultra High Energy Cosmic Rays Oleg Kalashev* UCLA, INR RAS GZK 40: The 3rd International Workshop on THE HIGHEST ENERGY COSMIC RAYS AND THEIR.
Recent Results for Small-Scale Anisotropy with HiRes Stereo Data Chad Finley Columbia University HiRes Collaboration Rencontres de Moriond 17 March 2005.

Recent Results for Small-Scale Anisotropy with HiRes Stereo Data Chad Finley Columbia University HiRes Collaboration Rencontres de Moriond 17 March 2005.
An update on the High Energy End of the Cosmic Ray spectra M. Ave.

An update on the High Energy End of the Cosmic Ray spectra M. Ave.
Magnetic Field Workshop November 2007 Constraints on Astrophysical Magnetic Fields from UHE Cosmic Rays Roger Clay, University of Adelaide based on work.

Magnetic Field Workshop November 2007 Constraints on Astrophysical Magnetic Fields from UHE Cosmic Rays Roger Clay, University of Adelaide based on work.
The Pierre Auger Observatory Nicolás G. Busca Fermilab-University of Chicago FNAL User’s Meeting, May 2006.

The Pierre Auger Observatory Nicolás G. Busca Fermilab-University of Chicago FNAL User’s Meeting, May 2006.
AGASA update M. Teshima ICRR, U of CfCP mini workshop Oct 4 2002.

AGASA update M. Teshima ICRR, U of CfCP mini workshop Oct
Searching for Small-Scale Anisotropies in the Arrival Directions of Ultra-High Energy Cosmic Rays with the Information Dimension Eli Visbal (Carnegie Mellon.

Searching for Small-Scale Anisotropies in the Arrival Directions of Ultra-High Energy Cosmic Rays with the Information Dimension Eli Visbal (Carnegie Mellon.
March 2005E. Armengaud - Moriond Search methods for UHECR anisotropies within the Pierre Auger Observatory Eric Armengaud (APC/IAP - Paris) for the Auger.

March 2005E. Armengaud - Moriond Search methods for UHECR anisotropies within the Pierre Auger Observatory Eric Armengaud (APC/IAP - Paris) for the Auger.
A Search for Point Sources of High Energy Neutrinos with AMANDA-B10 Scott Young, for the AMANDA collaboration UC-Irvine PhD Thesis:

A Search for Point Sources of High Energy Neutrinos with AMANDA-B10 Scott Young, for the AMANDA collaboration UC-Irvine PhD Thesis:
07/05/2003 Valencia1 The Ultra-High Energy Cosmic Rays Introduction Data Acceleration and propagation Numerical Simulations (Results) Conclusions Isola.

07/05/2003 Valencia1 The Ultra-High Energy Cosmic Rays Introduction Data Acceleration and propagation Numerical Simulations (Results) Conclusions Isola.
TAUP 2005: Zaragoza Observations of Ultra-high Energy Cosmic Rays Alan Watson University of Leeds Spokesperson for Pierre Auger Observatory

TAUP 2005: Zaragoza Observations of Ultra-high Energy Cosmic Rays Alan Watson University of Leeds Spokesperson for Pierre Auger Observatory
Recent Results from the HiRes Experiment Andreas Zech ( Rutgers University & LPNHE, Université de Paris ) for the High Resolution Fly’s Eye Collaboration.

Recent Results from the HiRes Experiment Andreas Zech ( Rutgers University & LPNHE, Université de Paris ) for the High Resolution Fly’s Eye Collaboration.

Similar presentations

Ads by Google