la nascita della astronomia dei raggi cosmici? indicazioni dall' osservatorio p. auger
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La nascita della astronomia dei raggi cosmici? Indicazioni dall' Osservatorio P. Auger. Aurelio F. Grillo Teramo 8/05/08. Nuclear (p, He.... Fe) component. Knee. Ankle. Few/km sq per century. ?. p. Nuclei. p?. for extragalactic protons. On CMBR photons. - PowerPoint PPT PresentationTRANSCRIPT
La nascita della astronomia dei raggi cosmici?Indicazioni dall' Osservatorio P. Auger
Aurelio F. Grillo Teramo 8/05/08
Nuclear (p, He.... Fe) component
Knee
Ankle?
Few/km sqper century
pp?
Nuclei
E ZB Dacc
for extragalactic protons
On CMBR photons
EE
≈m
E
≈6 Mpc Dmax≈50−100 Mpc
The Auger hybrid concept
Almost completely operating, now 1 year full observatory !~
Fluorescence light
Fluorescence Detector FD Surface Detector SD
The Auger hybrid concept
The spectrum: most statistically significant from SD calibrated in energy by “hybrid” events - energy systematic error ~22 %, mostly from systematic of the FD detector (fluorescence yield, atmospheric transparency....)
Surface Detector SD
Fluorescence Detector FD
Ultra High Energy CR spectrum ICRC07
6
E−2.6
Evidence for GZK cutoff? Likely
fit
Cosmic Ray astronomy?
If UHECRs origin is astrophysical, astronomy may be possible above some x 1019 eV if particles are protons(and IG magnetic fields small)
If UHECRs origin is astrophysical, astronomy may be possible above some x 1019 eV if particles are protons(and IG magnetic fields small)
Around ~1020 eV particles can only arrive fromwithin ~ 100 Mpc (in case of GZK)
Cosmic Ray astronomy?
If UHECRs origin is astrophysical, astronomy may be possible above some x 1019 eV if particles are protons(and IG magnetic fields small)
Around ~1020 eV particles can only arrive fromwithin ~ 100 Mpc (in case of GZK)
A statistically significant correlation with sources in theGZK spere would unambiguously prove the reality ofthe cutoff (and give hints on the nature of sources)
Cosmic Ray astronomy?
The “Telescope”
- Angular resolution ~ 1 degree
- Pointing Accuracy ~ 1 degree
- Charged Messengers => deviation in mag. fields
Exposure of the experiment in Galactic coordinates
The (Aug. 2007) astronomy analyses
~9000 km2 sr yr, trigger efficiency ~100%
Search for point sources:the motivation
Small magnetic deflection Only nearby sources if GZK feature ok Nearby Universe anisotropic
1 EeV =1018 eV
Regular Gal. B field
Search for point sources:the motivation
Small magnetic deflection Only nearby sources if GZK feature ok Nearby Universe anisotropic
Indication of GZK from spectrum Bounds on photons/neutrinos Acceleration favoured vs. top-down
1 EeV =1018 eV
Regular Gal. B field
Search for point sources:the method
Need to search correlations of a selected sample of events with astrophysical objects.... how and where?
Large parameter space: -- events -> Energy, angular aperture
Sources -> what sources: type, distance (z)........
Search for point sources:the method
Need to search correlations of a selected sample of events with astrophysical objects.... how and where?
Large parameter space: -- events -> Energy, angular aperture
Sources -> what sources: type, distance (z)........
Method: perform a scan in the parameters space, after having chosen sources of a given type from a catalogue
Chosen Veron-Cetty, Veron Catalogue of AGNs
Search for point sources:the method
Some definitions: p -- exposure-weighted fraction of the sky accessible to observation, covered by windows of radius ψ centred on the selected sources. P -- probability that k or more out of a total of N events from isotropic flux are correlated by chance with the selected objects at the chosen angular scale
this probability needs 'penalization' i.e. Pfin
= P/Nt (from MC)
z<0.018
Search for point sources:the strategy
Performed an exploratory scan. Eth > 4 1019 eV
z < 0.024 Of 15 events with Eth > 5.7 1019 eV,
12 correlated within with AGNs with z<0.019, while 3.2 expected with these parameters
16
3.1o
Search for point sources:the strategy
Performed an exploratory scan. Eth > 4 1019 eV
z < 0.024 Of 15 events with Eth > 5.7 1019 eV,
12 correlated within with AGNs with z<0.018, while 3.2 expected with these parameters
Further search performed with these a priori fixed parameters, ending when the probability to incorrectly reject hisotropy hypotesis < 1%
Search started May 2006, ended May 2007 when 6/8 events found correlating.
In sample May 2006 – Aug 2007 8/13 correlating P= 1.7 10-3
16
3.1o
Search for point sources:the strategy
Rescan whole dataset with improved reconstr. algorithm to fix parameters.
20 out of 27 events correlated
(a posteriori) Pfin(iso)~10-5
Search for point sources:the PAO Sky Map
Equatorial coordinates
South pole
SuperGalactic plane
Galactic plane
Search for point sources:the PAO Sky Map
PAO events
Search for point sources:the PAO Sky Map
AGNs from VC-V catalogue (z<0.018)
PAO events
Search for point sources:the PAO Sky Map
CenAVirgo
AGNs from VC-V catalogue
PAO events
Search for point sources:the PAO Sky Map
CenAVirgo
AGNs from VC-V catalogue
PAO events
Search for point sources:the PAO Sky Map
CenAVirgo
AGNs from VC-V catalogue
If region of Galactic plane excluded, 19 out of 21 events do correlate
PAO events
Search for point sources:the PAO Sky Map
CenAVirgo
AGNs from VC-V catalogue
Leiden – Argentine – Bonn Hydrogen Survey
PAO events
Search for point sources:the PAO Sky Map
Search for point sources:the PAO Sky Map
Both for real events and simulated sets of same size, either isotropic or source
CenA
Search for point sources:the PAO Sky Map
Search for point sources:the PAO Sky Map
AGNs: sources or tracers??
Search for point sources:the PAO Sky Map
AGNs: sources or tracers??
Search for point sources:the PAO Sky Map
AGNs: sources or tracers??No significant correlation (yet) with Abell,REFLEX, NORAS catalogues of clusters of galaxies, nor starburst radio galaxies
Search for point sources:the PAO Sky Map
AGNs: sources or tracers??No significant correlation (yet) with Abell,REFLEX, NORAS catalogues of clusters of galaxies, nor starburst radio galaxies
Search for point sources:the PAO Sky Map
AGNs: sources or tracers??No significant correlation (yet) with Abell,REFLEX, NORAS catalogues of clusters of galaxies, nor starburst radio galaxies
Search for point sources:the PAO Sky Map
CenA
Search for point sources:the PAO Sky Map
The GZK “horizon”
Search for point sources:the PAO Sky Map
The GZK “horizon”
Indication of the need of energy shift?Too early, exclude other selection effects (foreground, bias of method..)
Search for point sources:the PAO Sky Map
Magnetic fields
Extragalactic (irregular)
Search for point sources:the PAO Sky Map
Magnetic fields
Extragalactic (irregular)
B rms L c10−9 G Mpc
Possibly Some open issues:-- Statistic: 27 events E> 5.7 1019 eV. One more year of data will double N.
Birth of (nuclear) Cosmic Ray Astronomy?
Possibly Some open issues:-- Statistic: 27 events E> 5.7 1019 eV. One more year of data will double N.-- Energy: at 5.7 1019 eV GZK Horizon ~ 200 Mp > 75
upward shift of energy calibration consistent with sistematic error can reconcile
Birth of (nuclear) Cosmic Ray Astronomy?
Possibly Some open issues:-- Statistic: 27 events E> 5.7 1019 eV. One more year of data will double N.-- Energy: at 5.7 1019 eV GZK Horizon ~ 200 Mp > 75 but...
upward shift of energy calibration consistent with sistematic error can reconcile-- Type of particles: some hint of heavy nuclei, larger deviation in GMF
Birth of (nuclear) Cosmic Ray Astronomy?
HiRes does not confirm
We are probably at a turning date for Cosmic Ray Astrophysics Sources of Cosmic Rays may have been detected, although their real identity
still unclear The Greisen-Zatsepin-Kuzmin feature has been probably detected
Conclusions?
We are probably at a turning date for Cosmic Ray Astrophysics Sources of Cosmic Rays may have been detected, although their real identity
still unclear The Greisen-Zatsepin-Kuzmin feature has been probably detected
Conclusions?
We are probably at a turning date for Cosmic Ray Astrophysics Sources of Cosmic Rays may have been detected, although their real identity
still unclear The Greisen-Zatsepin-Kuzmin feature has been probably detected
Conclusions?
We are probably at a turning date for Cosmic Ray Astrophysics Sources of Cosmic Rays may have been detected, although their real identity
still unclear The Greisen-Zatsepin-Kuzmin feature has been probably detected
A very interesting future is approaching!!
Conclusions?
Search for point sources:the PAO Sky Map
Magnetic fields
Difficult – impossible if nuclei
Search for point sources:the PAO Sky Map
Magnetic fields
Search for point sources:the PAO Sky Map
Magnetic fields
Search for point sources:the PAO Sky Map
Magnetic fields
Search for point sources:the PAO Sky Map
Magnetic fields
Problem not serious (yet!) also: non correlating events chance correlating events
Preliminary!!
HiRes HiRes energy x 0.83
CenA
Search for point sources:the PAO Sky Map
Preliminary!!
No distinctive feature of correlated AGNs identified. AGNs: sources or tracers?