First 1ES1959 650 observations with the MAGIC telescope and comparison with Crab Nebula at 40? ZA

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First 1ES1959650 observations with the MAGIC
telescopeand comparison with Crab Nebula at 40?
ZA
Nadia Tonello, Max-Planck-Insitut für Physik,
München

• Introduction
• Data analyzed
• Analysis method
• Preliminary results

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What is 1ES1959650?

• 1998 First ? detection Utah Seven Telescope
  Array
• Weak source
• Confirmed in 2002 by WHIPPLE and HEGRA
• Most interesting aspect orphan flare in June
  2002.
• Candidate source for south neutrino telescopes

Elliptical galaxy Active Galactic Nucleus z
0.047 RA 19h59m59.8s Dec 65?08'54''
Observability from La Palma May-October
35?-54? z.a.
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The MAGIC Telescope

• Canary Island La Palma
• 2200 m asl

• Largest Imaging
• Air Cherenkov
• Telescope
• for ?-ray astronomy
• 17 m ?mirror dish
• 3.5? field of view
• 576 high-QE PMTs
• Design optimized for
• low energy thresholdE? 30 GeV
• fast repositioning tRlt30 sec

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Imaging Air Cherenkov Telescopes
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Standard Analysis
Shower reconstruction and background rejection
based on image shape analysis
raw image
cleaned image
Hillas parameters Length, width, distance, alpha
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MAGIC raw data
Source Days Obs. Time ZA range Azimuth
1ES1959650 September 06, 07 October 07, 10,14,15,16,17 6 h 55 m 4.4 M events min 35? max 47? min -26? max 2?
Crab Nebula September 13, 14, 15, 16,21,22,23 2 h 17 m 1.7 M events min 35? max 46? (selected) min 85? max 94?
Off data September 8, 10, 11, 12, 13, 14, 16, 17 2 h 49 m 2.3 M events min 35? max 46? (selected) min 85? max 94?
Cuts optimized on Crab Nebula and applied to
1ES1959 and Off data
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Preliminary analysis

• Extract pedestals from data
• Image cleaning
• Pedestal RMS levels 4 sigma, 2 sigma (5 rings)
• Absolute number of photons 40 ph, 25 ph
• Image parameters distributions have been compared
  for the 3 data sets.

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Preliminary analysis

• Random Forest
• MC ? noise tuned to september off data sample.
• Hadrons randomly chosen from real on data (25 k
  events).
• Parameters Width, Length, Size, Dist, Conc,
• logLength(logSize), logWidth(logSize), M3Long
• Cut in MHadronness
• chosen from Crab
• Maximum significance had 0.1
• Maximum excess events had 0.5
• Cuts applied to 1ES1959 without any further
  optimization.

Significance
Excess events
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Signal above 2000 ph.
1ES 1959 650 Size gt2000 ph Significance 7.0 ?
Excess events 165
Crab Nebula Size gt2000 ph Significance 26.4 ?
Excess events 529 20
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Time analysis

• Binning in about 2 h data
• No substantial variation of activity

Days Obs time Significance Excess Rate (phot/min)
September 6,7 121 min 3.6 42.8 11.8 0.35 0.09
October 7,10,15 110 min 4.0 49.5 12.3 0.45 0.11
October 16, 17 137 min 5.0 64.0 12.8 0.46 0.09
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X-ray light curve

• Activity not particularly high

5 - 7 Sept
7 -17 Oct
RXTE mission day
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Optical light curve

• Quiescent state

Tuorla Observatory Blazar Monitoring Program
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Crab-1ES1959 comparison

• Same cuts applied to Crab and 1ES1959 for each
  size bin

Size (ph) Significance Excess events
1000ltSlt2000 10.2 ? 296 29
2000ltSlt4000 18 ? 258 14
4000ltSlt8000 17.3 ? 166 10
8000ltSlt16000 4.8 ? 71 15
CRAB
1000ltSlt2000 5.0 ? 364 73
2000ltSlt4000 4.9 ? 87 20
4000ltSlt8000 4.2 ? 42 10
8000ltSlt16000 1.5 ? 29 19
1ES1959
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Crab-1ES1959 comparison

• Excess events/(obs. time size bin width)

Softer spectrum? HEGRA System Results
(2000-2001) 94 h obs. Time. Energy threshold
2TeV Significance 5.4? ? 3.3 0.7 8 Crab flux
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Conclusions

• 1ES1959 has been observed with MAGIC for 7 h.
• Crab and OFF data ( 2h each) have been selected
  to match ZA range 40 deg.
• Data have been analyzed with cuts optimized on
  Crab.
• We have a signal from 1ES1959650 when there was
  no high activity in X-rays
• No variation of state, observations are
  fragmented in time.
• Comparison with Crab in size bins
• 1ES1959 40 to 10 of Crab, compatible with
  HEGRA System flux measurements at high energies.
• Work in progress Energy spectrum.

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Energy distribution of MC ?
1000lt slt 2000 ph 180 GeV
2000lt S lt 4000 ph 300 GeV
4000lts lt8000 ph 500 GeV
8000 ltslt 16000 ph 900 GeV