Download presentation
Presentation is loading. Please wait.
Published byLevi Parnham Modified over 9 years ago
1
DPG Tagung, March 2003Nadia Tonello, MPI für Physik (Werner- Heisenberg-Institut), München 1 Observations of 1ES1959+650 with the HEGRA CT1 Cherenkov Telescope (2000, 2001, 2002) Nadia Tonello and Daniel Kranich, Max-Planck-Institut für Physik for the HEGRA Collaboration
2
DPG Tagung, March 2003Nadia Tonello, MPI für Physik (Werner- Heisenberg-Institut), München 2 The Active Galactic Nucleus 1ES1959+650 Discovered in 1993 by comparing X-ray/radio/optical fluxes of objects in the Einstein IPC Slew Survey. First emission detected in 1998 by the Seven Telescope Array in Utah (Nishiyama et al., OG.2.1.21 ). Not seen by EGRET. Studied in 2000-2001 by the HEGRA System of Telescopes: weak signal seen (5.4 8% Crab). Short flare seen by the VERITAS collaboration in spring 2002 (IAU Circ. 7903). Observed with HEGRA CT1 Telescope (2000, 2001, 2002). z 0.047 (= 718·10 6 ly) RA19h59m59.8s (2000) Dec+65d08´54 (2000)
3
DPG Tagung, March 2003Nadia Tonello, MPI für Physik (Werner- Heisenberg-Institut), München 3 Physics Motivation Study the physics processes in AGNs, responsible for the production of high energy gamma rays Measure energy spectrum of gamma rays Study time variability of source emission Multi-wavelength (radio, optical, X-ray) studies Study the absorption by the Extragalactic Background Light Cut-off of energy spectrum comparison with AGNs at different distances Mkn421 (z = 0.031), Mkn501 (z = 0.034)
4
DPG Tagung, March 2003Nadia Tonello, MPI für Physik (Werner- Heisenberg-Institut), München 4 The HEGRA CT1 Telescope ORM, La Palma (Canary Islands) Mirror area10.3 m 2 Camera127 pixels FOV~3°Ø threshold750 GeV (small ZA) sensitivity on CRAB
5
DPG Tagung, March 2003Nadia Tonello, MPI für Physik (Werner- Heisenberg-Institut), München 5 Observation statistics year200020012002 No moon (nom)58 h86 h176 h With moon (reduced hv) hv00 --24 h 8.1 h hv04 --12 h16.1 h hv08 -- 8 h 6.1 h hv12 -- 7 h 2.9 h 2002 data: 180h preliminary analysis Zenith angle range: between 36.4 ° and 54.2 ° Data needed correction for slight mispointing (~0.1º). Correction determined from a 2d-plot, higher probability to have the source.
6
DPG Tagung, March 2003Nadia Tonello, MPI für Physik (Werner- Heisenberg-Institut), München 6 Analysis method gamma/hadron separation using dynamical cuts (determined from real on and off data ): DIST (SIZE, ) WIDTH (SIZE, DIST, ) LENGTH (SIZE, DIST, ) N of events before cuts: 1 661 840 N of events after cuts: 7565 Center of the camera
7
DPG Tagung, March 2003Nadia Tonello, MPI für Physik (Werner- Heisenberg-Institut), München 7 OFF data ON data (2002) signal region Alpha distribution Peaked at 0 deg for point like sources Flat distribution expected for cosmic ray background Estimation of the excesses: Gaussian fit in the signal region. Estimation of the background: fit the ON data with a pol.2nd order between 20 and 80 deg, extended into the signal region.
8
DPG Tagung, March 2003Nadia Tonello, MPI für Physik (Werner- Heisenberg-Institut), München 8 ON data (2002) signal region background fit region Alpha distribution Significance for ALPHA≤13.1º 11.1 Excesses: 664 ± 40 Background: 1672 ± 37
9
DPG Tagung, March 2003Nadia Tonello, MPI für Physik (Werner- Heisenberg-Institut), München 9 2000 and 2001 light curves Source at low state. Signal: not significant. Average estimated flux: ~ 6 % Crab average flux 6% Crab average flux 5% Crab HEGRA CT1
10
DPG Tagung, March 2003Nadia Tonello, MPI für Physik (Werner- Heisenberg-Institut), München 10 TeV and X-ray emission, 2002 HEGRA CT1 En. range 1- 10 TeV All-Sky Mon. En.range: 1.5-12 keV May July
11
DPG Tagung, March 2003Nadia Tonello, MPI für Physik (Werner- Heisenberg-Institut), München 11 TeV and X-ray emission, 2002 HEGRA CT1 En. range 1- 10 TeV All-Sky Mon. En.range: 1.5-12 keV May July
12
DPG Tagung, March 2003Nadia Tonello, MPI für Physik (Werner- Heisenberg-Institut), München 12 Flares of 2002 Maximum activity: CRAB flux (above 1 TeV) reached in May. In July a less strong flare has been seen. combining nom and hv00 data
13
DPG Tagung, March 2003Nadia Tonello, MPI für Physik (Werner- Heisenberg-Institut), München 13 Spectrum preliminary result of all the data taken in 2002 (151 h, max ZA: 45°) Fitted with a power low function = 3.49 ± 0.19 /d.o.f. = 9.1/6
14
DPG Tagung, March 2003Nadia Tonello, MPI für Physik (Werner- Heisenberg-Institut), München 14 Spectrum preliminary result of all the data taken in 2002 (151 h, max ZA: 45°) Fitted with a power low function with a fixed cutoff at E c = 2.4 TeV = 2.54 ± 0.21 /d.o.f. = 7.1/6 Mkn421z = 0.031 2.41 ± 0.10 E c 3.24±0.50 Mkn501z = 0.034 2.03 ± 0.19 E c 6.12 ±1.31 1ES1959z = 0.048 1.5 (fixed) E c 2.4 ± 0.4 HEGRA System results for the source at high state
15
DPG Tagung, March 2003Nadia Tonello, MPI für Physik (Werner- Heisenberg-Institut), München 15 Conclusions CT1 observed 1ES1959+650 in 2000 and 2001 at a low flux level (no significant signal). In 2002 two periods of increased flux have been seen (0.5 -1 times the Crab flux above 1 TeV). The preliminary results of the analysis reveal a spectrum compatible with a power law. Further analysis will be done: optimization for weak source at high zenith angles.
Similar presentations
© 2024 SlidePlayer.com Inc.
All rights reserved.