Detection of transient sources with the ANTARES telescope. Manuela Vecchi CPPM

Transcription

1 Detection of transient sources with the ANTARES telescope Manuela Vecchi CPPM

2 Multimessenger Astronomy CRs astronomy feasible at energies higher than 1019 ev extragalactic origin UHECRs horizon limited to Mpc due to interaction with CMBR (GZK effect) Multi-messenger astronomy is likely to open new insights into the physics of the most violent events, combining results from CRs, -rays and traditional astronomy, neutrinos and gravitational waves. M.Vecchi LPHE - 01/07/2011 2

3 Neutrino Astronomy Advantages: HE s are expected together with UHECRs, e.g. p n UHECRs + 's Neutral particles propagation not affected by B point-back to the source Only weakly interacting particles: observation over cosmological distances identify production sites inner layers of astrophysical objects understand production mechanisms Always of hadronic origin Flavor mixing at the source ( e : μ : ) = (1:2:0) at Earth ( e : μ : ) = (1:1:1) Only weakly interacting particles + Low fluxes expected from the sources Large detection volume (~km 3 ) required M.Vecchi LPHE - 01/07/2011 3

4 Detection principle Neutrinos can interact in the medium surrounding the telescope. They can be detected using the visible Cherenkov radiation produced as the highenergy charged lepton passes through the transparent medium. 3D PMT array Cherenkov light from μ 42 Sea bed μ μ interaction A deep underwater/ice detector is required to reduce the number of atmospheric s. M.Vecchi LPHE - 01/07/2011 4

5 Sky Coverage M.Vecchi LPHE - 01/07/2011 5

6 The ANTARES detector ANTARES has an area of about 0.1 km 2 and it can be considered as a first generation HE cosmic neutrino detector. Data taking has started in 2006 with the deployment of the first line. Detector complete since May M.Vecchi LPHE - 01/07/2011 6

7 Particle Background Atmospheric muons ~10 per second Atmospheric neutrinos few per day Cosmic neutrinos few per year (maybe) Looking for up-going events M.Vecchi LPHE - 01/07/2011 7

8 Environmental Background J. Aguilar et al., Astropart. Phys. 33, (2010) M.Vecchi LPHE - 01/07/2011 8

9 Point-like source search M.Vecchi LPHE - 01/07/2011 9

10 Point-like source search Optimization in order to have the best discovery power ANTARES Preliminary Galactic Latitude Visibility Fraction Galactic Longitude GX 339 as the most likely candidate source: 2 events within 1. The probability to observe this or a larger excess due to a fluctuation of the bkd is 7% M.Vecchi LPHE - 01/07/

11 Point-like source search ANTARES: Best limits for the Southern sky! preliminary result: no significant signal found limits reported for few candidate neutrino sources * interesting gamma/x-ray sources for which models predict neutrinos * galactic center: no events within resolution M.Vecchi LPHE - 01/07/

12 HE Neutrinos from Transient Sources Gamma Ray Bursts (GRBs): Protons acceleration in relativistic jets (Fireball model) Meszaros & Rees, Waxman CRs Acceleration Core Collapse SuperNovae(CCSN): SN-GRB connection (chocked jet, midly relativistic) Razzaque & al, Ando & Beacom Stellar enveloppe opaque to EM radiation, unique prompt signal. M.Vecchi LPHE - 01/07/

13 Microquasars Galactic sources! M.Vecchi LPHE - 01/07/

14 Search for emission from -ray flaring blazars More than 50% of sources are found to be variable Use this time information directly in the analysis: * reduce effectively the background * improve the discovery potential over a time integrated search. Search for signal from blazars AGN candidate sources for UHECR (p- or p-p strong correlation between -ray and neutrino fluxes) M.Vecchi LPHE - 01/07/

15 Search for transient sources with the ANTARES telescope Triggered search method Time dependent search method Rolling search method M.Vecchi LPHE - 01/07/

16 Triggered search method Triggered search method: dedicated low level trigger after a gammaray satellite alert (GCN) Analysis in progress M.Vecchi LPHE - 01/07/

17 Triggered search method (2) Detection principle: Whenever a GRB alert is received, a dedicated data taking strategy is performed: all raw data covering a 2 min window are saved to disk. Advantages: almost background-free due to the transient nature of the source. Cumulative number of alerts flaring activity of SGR But Time window is constrained by models. Limited by the satellite field of view. Dependent on external sources most of GRB alerts by the Swift satellite black: GRB alerts received red: the ones Antares tri ggered on GRB alerts also from the Fermi satellite Time (date) M.Vecchi LPHE - 01/07/

18 Search for transient sources with the ANTARES telescope Triggered search method Time dependent search method Rolling search method M.Vecchi LPHE - 01/07/

19 Time dependent search (FERMI AGN) 3C454.3 FERMI LAT Light Curve Search for emission in the state periods of the AGN light curve. The assumed time distribution extracted from the gamma-ray light curve. ANTARES Dataset : 4 months 2008 Sensitivity improved by about a factor 2 with respect to a standard time-integrated point source search. Preliminary M.Vecchi LPHE - 01/07/

20 Candidate list (FERMI AGN) List of bright variable Fermi blazars selected for this analysis Abdo et al., arxiv: F300: flux gamma above 300MeV (*10 8 photons/cm 2 /s) 2 NXS : amplitude of the variability in the LC ( 'normalized excess variance' ) M.Vecchi LPHE - 01/07/

21 Time dependent search: Results =0.56 p-value = 10%. Fermi gamma-ray light curve for the blazar 3C279. The high state period is emphasized in blue. Red histogram: number of coincident events. M.Vecchi LPHE - 01/07/

22 Time dependent search in IceCube IceCube 40 IceCube 40 : 7 AGN + 1 source non identifiée 1 événement coïncidant avec PKS : p-value = 29% arxiv: M.Vecchi LPHE - 01/07/

23 Search for neutrinos from microquasars S. Galatà, PhD thesis in CPPM M.Vecchi LPHE - 01/07/

24 Search for neutrinos from microquasars M.Vecchi LPHE - 01/07/

25 GRB analysis: 2007 data 90% CL Upper limits on nu fluxes from 37 GRBs 148 GRB candidate alerts received during operation of Line 1-5 detector (exposure 1882 s): 72 above the horizon 23 rejected by run selection 16 false trigger 37 GRBs in the analysis More than 1300 alerts from GCN have been recorded (Jan 2011) M.Vecchi LPHE - 01/07/

26 IceCube-40 GRB analysis IceCube E 2 GeVcm -2 s -1 sr GRBs in the Nothern hemisphere No neutrino candidate found in coincidence with an alert. Most optimistic predictions have been excluded. Phys.Rev.Lett.106:141101,2011 M.Vecchi LPHE - 01/07/

27 Search for transient sources with the ANTARES telescope Triggered search method Time dependent search method Rolling search method M.Vecchi LPHE - 01/07/

28 Optical follow-up of events The detection of the optical counterpart even of a single neutrino candidate is significant enough to claim a discovery M.Ageron et al. arxiv: M.Vecchi LPHE - 01/07/

29 The Telescopes Network M.Vecchi LPHE - 01/07/

30 Refined Position Reco On-line : Simplified geometry ~ 0.5 at HE Reco Off-line : More accurate geometry description ~ 0.2 at HE (soon online!!) TAToO HE cuts TAToO HE cuts Ang Resolution ~ 0.2 Extend the telescope network to small FOV objects, like ZADKO,SWIFT, M.Vecchi LPHE - 01/07/

31 Observation Strategy Optical signal we re looking for alert T0 T0+1 T0+7 T0+9 T0+15 Prompt ROTSE (T exp =20/60s) TAROT (T exp =180s) Follow-up observations ZADKO (T exp =180s) - only follow up T0+27 T0+45 M.Vecchi LPHE - 01/07/

32 State of the art System operational since neutrino alerts sent to telescopes 10 not followed: Pbm telescopes 29 with optical images 5 with only one night (not prompt) 24 alerts with exploitable images M.Vecchi LPHE - 01/07/

33 Image Analysis (for dummies) Image from TAToO Follow-Up Reference Image (No signal) Residual Image To keep To reject Reject bad subtracted residuals Keep good SNR/FWHM residuals Detected more than 1 day Cross-check with asteroids and known stars catalogues Study the light curve (Magnitude/Flux VS time) Currently using ROTSE pipeline. Development of a second pipeline in progress. M.Vecchi LPHE - 01/07/

34 Search for GRB optical afterglows 2010 prompt observations (T images -T neutrino <24h) Alert Number of images Exposure Observation time since trigger ANT100123A 17 images 20 s 15h20mn15s ANT100302A 30 images 20 s 24h20mn8s ANT100725A 28 images 20 s 0h01mn15s ANT100922A 30 images 20 s 1h08mn06s ANT101211A 8 images 60 s 12h03mn30s In progress M.Vecchi LPHE - 01/07/

35 Conclusions ANTARES is complete since 2008: detector is working well within design specifications; Results on the search for neutrinos from transient sources: Triggered search in ANTARES (analysis in progress): Dedicated data-taking configuration in addition to standard daq is performed in coincidence with alert sent by GCN. On average ~ 1-2alert/day is received. Time-dependent search in ANTARES: Point like source search with candidate list, searching for FERMI flaring sources: One neutrino candidate with =0.56 o (post trial probability=10%). PRELIMINARY! Search for neutrinos from microquasars in progress. Results by the end of the year. Search for neutrinos from GRB in coincidencse with satellite alerts on 2007 data. Upper limits have been set wrt to WB flux. Rolling search in ANTARES (analysis in progress): Optical follow-up is well established and automatically working well since 2009: 39 alerts have been sent to optical telescopes. Analysis of optical images is in progress. M.Vecchi LPHE - 01/07/

36 What s next? Towards the realization of a km 3 scale detector in the Mediterranean sea M.Vecchi LPHE - 01/07/

37 Km 3 -scale detector DESIGN GOALS: Volume = 5 km 3 Core process: μ +N μ+x at μ energies > 100 GeV Data taking period > 10 year Optimized for energy range 1 TeV 1 PeV Kinematics KM3NeT M.Vecchi LPHE - 01/07/

38 Sensitivity to point sources (E -2 spectrum) IceCube KM3NeT The red lines indicate the MRF exclusion limit (full line) and the MDF for 5 detection at 50% probability (dashed line). IceCube MRF sensitivities for one year in black. IceCube MDF for 5 detection at 50% probability is also indicated (shaded band) M.Vecchi LPHE - 01/07/

39 M.Vecchi LPHE - 01/07/ Thank you for your attention!