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Markarian 421 with
MAGIC telescope
Daniel Mazin for the MAGIC Collaboration
Max-Planck-Institut für Physik, München
[email protected]
Outline
 The MAGIC telescope
 AGN Markarian 421
 Data sample
 Analysis status
 Conclusion / outlook
The MAGIC Telescope
 The largest imaging
atmospheric Cherenkov
Telescope with 236 m2 mirror
surface
 3.5° FoV Camera with 576
high-QE PMT’s
 Design optimized for:

Low energy threshold

E = 30 GeV
Fast repositioning
tp < 30 sec
Canarian Island La Palma,
2200 m asl
AGN Markarian 421
 Right Ascension 11:04:27 (h:m:s)
Declination: +38:12:32 (deg:m:s)
 BL Lac object, z=0.030 (370 MLy)
 Mass: 1.9 •108 M
 First detected extragalactic TeV
-ray source (Punch et al, 1992)
 Many known flares, active in 2004
 Well described by SSC models
(e.g. Konopelko et al, ApJ,597:851)
 Still many correlations not
understood
Aimo Sillanpaa, NOT
Advantages of simultaneous
observations






HEGRA,
A&A,393,89
One experiment: one decade in energy
Two experiments: two decades
Multiwavelength campaigns
Correlation studies
Change hardness during flares (Krennrich et al, ICRC 2003)
Light curves, look for fast flares
HEGRA, A&A,410,813
 + X-calibration of the instruments
MAGIC data sample
Date
comments
February
2004
flare,
commissioning phase
April 2004
Strong flare,
December
2004
Overlap with HESS,
commissioning phase
Overlap with HESS
This talk
Preliminary results
(sky plot of number of
excess events):
MAGIC data sample (December 04)
 Triggered by RXTE and VERITAS (Dec 14)
 After a few hours: MAGIC and HESS agreed
to make simultaneous observations
 Due to bad weather only 2 days of MAGIC
data: 18 and 19 December
Date
Obs.time
Mean zenith
angle (deg)
comments
18 Dec
55 min
48
30 min with HESS
18 Dec
59 min
12.5
19 Dec
30 min
51
19 Dec
79 min
21
30 min with HESS
Comparison of MC predictions
and data
Good agreement between mc-gamma and excess events
Log10(Etrue[GeV])
Estimate of energy resolution
 SIZE (total number of
Sigma[%]
Log10(Eest[GeV])
(Eest -Etrue)/Etrue
Log10(Eest[GeV])
PEs) simplest energy
estimator
 improve energy
estimation including
other image parameters
 optimized estimator
using Random Forest
technique
 20% (30%)
@ 1 TeV (100 GeV)
Number of excess events
 For the whole data
sample (3.7h):
 After cuts:
over 700 excess
events
 Point-like source
( < 0.15 deg )
37.69
38.19
Dec (deg)
38.69 39.19
Mrk 421: False source plot
11.14
11.10
11.07
11.04
11.00
RA (h)
Alpha plots
18/12/05, <Zd>=48
18/12/05, <Zd>=12
 For the 4
samples:
Clear signal
detection in all
of them
19/12/05, <Zd>=51
19/12/05, <Zd>=21
 Energy range
for this
analysis:
high zenith angle:
250 GeV – 2 TeV
low zenith angle:
100 GeV – 1 TeV
Light curve (X-ray)
17-20 December 2004
18/12
19/12
 X-rays: no
significant
variation
 Optical data
(KVA):
quiescent
state
Apr 04
Dec 04
Light curve (GeV, MAGIC)
 Low zenith angle points
only, 20 min bins
 No strong variations
visible
 Looks like we just missed
the peak of the flare
(weather!)
4004
4005 (mjd-49353)
 Soon to come:
 Energy spectrum and full light curve for the MAGIC data
 Combined MAGIC – HESS data analysis
Conclusions / Outlook
 MAGIC clearly detected a flare of Markarian 421 in
December 2004
 Due to bad weather: too late for the peak of the flare
 3.7 hours of data: enough statistics to produce light
curves and energy spectra  work in progress
 Coordinated ground based Cherenkov telescopes
observations going on
 Almost full time coverage possible (CANGAROO,
HESS, VERITAS, MAGIC)
 Up to 3 decades in energy due to energy threshold and
different zenith angle conditions
Thank you