Arrival directions of the highest-energy cosmic rays detected by the - PowerPoint PPT Presentation

Arrival directions of the highest-energy cosmic rays detected by the Pierre Auger Observatory Ugo Giaccari Ugo Giaccari 1 for for the the Pierr Pierre e Auger Auger Collaboration Collaboration 2 2 1 Instituto de Física Instituto de Física – Universidade Federal Rio de Janeir Universidade Federal Rio de Janeiro o – Brazil Brazil now ow at at Centr Centro Brasileir o Brasileiro Pesquisa Física Rio de Janeir o Pesquisa Física Rio de Janeiro o – Brazil Brazil 2 Av. San Martín Norte 304, 5613 . San Martín Norte 304, 5613 Malar Malargüe güe, Ar , Argentina gentina

Outline Pr Previous r evious results on small/intermediate scales anisotr esults on small/intermediate scales anisotropies of the most ener opies of the most energetic CRs getic CRs in ten years of operation, 1/2004 – 3/2014 [ in ten years of operation, 1/2004 – 3/2014 [ApJ ApJ 804, 15, (2015)] 804, 15, (2015)] two lar two largest departur gest departures fr es from isotr om isotropy opy both with post-trial probability ~1.4 both with post-trial pr obability ~1.4 × 10 10 -2 -2 Around Centaurus A Bright AGNs of the Swift-BAT catalog energy thr ener gy threshold E eshold E th th = 58 = 58 EeV EeV E th th = 58 = 58 EeV EeV, , ψ = 18°, for objects within 130 = 18°, for objects within 130 Mpc Mpc for an angular window ψ = 15° for an angular window = 15° and brighter than 10 44 and brighter than 10 44 er erg/s g/s ü Report an update of these two excesses with enlarged dataset ü Search for deviations from isotropy using two extra-galactic populations of gamma-ray sources Star-forming galaxies and AGNs motivated by gamma-ray observations of Fermi -LAT • Weight individual sources in proportion to their fluxes • Same flux-weight analysis for the objects of the Swift -BAT catalog • 2

The Dataset Events detected by the Surface Detector of the Pierre Auger Observatory (*) Events detected by the Surface Detector of the Pierr e Auger Observatory (*) fr from 1 om 1 st st Jan. 2004 to 30 Jan. 2004 to 30 th th April 2017 above 40 April 2017 above 40 EeV EeV, with ~90,000 km , with ~90,000 km 2 2 sr sr yr yr 820 events E > 40 EeV 820 events E > 40 EeV ü zenith angle zenith angle θ ≤ 60°, 60°, 650 (“vertical”) events 650 (“vertical”) events ~30% incr ~30% increase in the ease in the ü zenith angle 60° zenith angle 60° ≤ θ ≤ 80°, 80°, 170 (“inclined”) events 170 (“inclined”) events statistic r statistic respect to espect to pr previous r evious results esults Same quality cuts used in Same qual ity cuts used in ApJ ApJ 804 (2015),1 804 (2015),1 (*) (*) see see F F . Fenu’ . nu’s talk talk Vertical/Inclined exposur ertical/Inclined exposure: 71,070/18,650 km e: 71,070/18,650 km 2 2 yr yr sr sr For each energy threshold 20000 yr] in this analysis energy Geometrical exposure 2 ) [km migration effects taken into account 15000 � ( Correct vertical and inclined � full data set exposures for unfolding factors as 10000 in spectrum studies (*) vertical inclined 5000 E > 40 E > 40 EeV EeV: ~ 5/6% for vert./incl. : ~ 5/6% for vert./incl. E > 80 EeV E > 80 EeV: ~ 8% for : ~ 8% for vert vert, ~20% for incl. , ~20% for incl. 0 -80 -60 -40 -20 0 20 40 60 80 [ ] � ° 3

The Centaurus A region ü Compar Compare e the the cumulative cumulative number number of of observed observed ( (n obs obs ) ) events events with with the the expected expected on on average average fr from om isotr isotropic opic simulations simulations ( (n exp exp ) ) ü Compute Compute the the cumulative cumulative binomial binomial pr probability obability ( ( P ) ) to measur to measure e n obs given given < <n exp exp > > obs E th in [40; 80] in [40; 80] EeV EeV in in steps steps of of 1 1 EeV EeV ü Scan can in in parameters parameters: : th Ψ in [1°; 30°] in in [1°; 30°] in steps steps of of 0.25° 0.25° up up to to 5°, 1° for 5°, 1° for lar larger ger angles angles Largest excess 80 1 preliminary E th = 58 EeV, Ψ = 15° 75 n obs = 19, n exp = 6.0 -1 10 70 P ~ 1.1 × 10 -5 65 (EeV) -2 10 Post-trial probability 60 ~ 1.1 × 10 -3 th -3 10 E 55 (fraction fraction of of isotr isotropic opic simulations simulations that that 50 have a ave a smaller smaller pr probability obability under under the the -4 10 same same scan scan) ) 45 -5 40 10 Region of secondary 0 5 10 15 20 25 30 � minima above ~40 EeV (degree) 4

Cross-Correlation with bright AGNs (Swift-BAT) ü Count Count the the cumulative cumulative number number of of pairs pairs btw btw CRs CRs and and objects objects dir directions ections ( (n obs obs ) ) ü Excess xcess pr probability obability pr provides ovides by by the the fraction fraction of of isotr isotropic opic simulations simulations ( (f min min ) ) with with equal equal or or gr greater eater number number of of pairs pairs E th in [40; 80] in [40; 80] EeV EeV in in steps steps of of 1 1 EeV EeV ü Scan can in in parameters parameters: : th Ψ in [1°; 30°] in in [1°; 30°] in steps steps of of 0.25° 0.25° up up to to 5°, 1° for 5°, 1° for lar larger ger angles angles Largest excess (E/ ψ ) scan for D max = 130 Mpc, L min = 10 44 erg/s E th = 62 EeV, Ψ = 16° 80 1 preliminary n obs = 57, n exp = 26.4 75 -1 10 f min = 1 × 10 -7 70 -2 10 65 (EeV) Post-trial probability -3 10 60 ~ 6.5 × 10 -4 th -4 10 E 55 -5 10 after fter accounting accounting for for 50 the scan the scan in (E, in (E, ϑ , , Dmax Dmax, , Lmin Lmin) -6 10 45 -7 40 10 0 5 10 15 20 25 30 � 5 (degree)

Gamma-ray Sources Active Galactic Nuclei - Selected fr Selected from 2FHL Catalog ( om 2FHL Catalog ( Fermi Fermi -LA -LAT, 360 sour , 360 sources): ces): Φ (> 50 (> 50 GeV GeV) ---> pr ) ---> proxy for UHECR flux oxy for UHECR flux - Selection of the 17 objects within 250 - Selection of the 17 objects within 250 Mpc Mpc - Majority - Majority blazars blazars of BL-Lac type and radio-galaxies of FR-I type of BL-Lac type and radio-galaxies of FR-I type Star-forming or Starburst Galaxies Use of Use of Fermi- Fermi- LA LAT sear search list for star ch list for star - formation objects (Ackermann+ 2012) formation objects (Ackermann+ 2012) - 63 objects within 250 63 objects within 250 Mpc Mpc, only 4 detected in gamma rays: , only 4 detected in gamma rays: corr correlated elated Φ (> 1.4 GHz) ---> pr (> 1.4 GHz) ---> proxy for UHECR flux oxy for UHECR flux - Selection of brightest objects (flux completeness) with - Selection of brightest objects (flux completeness) with Φ (> 1.4 GHz) > 0.3 (> 1.4 GHz) > 0.3 Jy Jy - 23 objects, size similar to the gamma-ray AGN sample 23 objects, size similar to the gamma-ray AGN sample Assumption UHECRs flux proportional to non thermal photon flux 6

Maximum likelihood technique Build probability maps of CRs arrival directions - Weight objects by their r eight objects by their relative flux in the corr elative flux in the corresponding esponding Smearing Angle Ψ electromagnetic wavelength electr omagnetic wavelength first free parameter - Fisher-V Fisher -Von on Mises Mises (~2D Gaussian) smearing (~2D Gaussian) smearing centered on astr center ed on astrophysical objects ophysical objects - Isotr Isotropic fraction (dif opic fraction (diffuse flux) fuse flux) - Account for directional exposur Account for dir ectional exposure e Anisotropic Fraction f ani = 1 - f iso second free parameter and normalize to the total number of events and normalize to the total number of events Test statistic (TS) likelihood ratio Wilk’ Wilk’s Theor Theorem em: : TS TS distributed distributed accor ccording ding a a Χ 2 2 with with two two degr degrees ees of of fr freedon eedon TS = 2 log [ L( Ψ ,f TS = 2 log [ L( ,f ani ani ) / L( ) / L(f ani ani = 0) ] = 0) ] (good good agr agreement eement with with isotr isotropic opic simulations simulations) ) Scan in energy threshold [20; 80] EeV in steps of 1 EeV lowering minimum energy to 20EeV Maximum deviation from 5514 events, same quality cuts of 5514 events, same quality cuts of ApJ ApJ 2015 2015 Isotropy found at ~40 EeV 4396 (“vertical”) events 4396 (“vertical”) events for one model 1118 (“inclined”) events 1118 (“inclined”) events 7

Test Statistic vs. Energy Homogeneous distribution of sour Homogeneous distribution of sources ces EPOS-LHC, γ = 1 EPOS-LHC, = 1 Mass Mass composition composition model model following following log og 10 10 (R cut cut /V) = 18.68 /V) = 18.68 JCAP 04 (2017) 38 for accounting JCAP 04 (2017) 38 for accounting f H (%) = 0, (%) = 0, f He He (%) = 67.3 , (%) = 67.3 , f N (%) = 28.1 (%) = 28.1 CRs pr CRs propagation opagation f Si Si (%) = 4.6, (%) = 4.6, f Fe Fe (%) = 0 (%) = 0 attenuation: negligible impact on nearby objects (starburst) more impact on distant objects (AGNs) Other scenarios also tested Starburst Galaxies TS = 24.9, E TS = 24.9, E th th = 39 = 39 EeV EeV γ -ray detected AGNs TS = 15.2, E TS = 15.2, E th th = 60 = 60 EeV EeV Swift -BAT AGNs TS = 19.9, E TS = 19.9, E th th = 60 = 60 EeV EeV 8