Markarian 421 with MAGIC telescope
Daniel Mazin for the MAGIC CollaborationMax-Planck-Institut für Physik, München
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
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,393,89
HEGRA, A&A,410,813
+ X-calibration of the instruments
MAGIC data sampleDate comments Preliminary
results (sky plot of number of excess
events):
February 2004
flare, commissioning
phase
April 2004 Strong flare, Overlap with HESS,
commissioning phase
December 2004
Overlap with HESS This talk
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 30 min with HESS
19 Dec 79 min 21
Comparison of MC predictions and data
Good agreement between mc-gamma and excess events
Estimate of energy resolution
SIZE (total number of PEs) simplest energy estimator
improve energy estimation including other image parameters
optimized estimator using Random Forest technique
20% (30%) @ 1 TeV (100 GeV)
Log10(Eest[GeV])
Log10(Eest[GeV])(Eest -Etrue)/Etrue
Sig
ma
[%]
Lo
g10
(Etr
ue[
Ge
V])
Mrk 421: False source plot
For the whole data sample (3.7h): After cuts:
over 700 excess events
Point-like source ( < 0.15 deg )
11.07
38.1
9
11.1011.14 11.04 11.00
38.6
939
.19
37.6
9D
ec (
deg
)
RA (h)
Number of excess events
Alpha plots
For the 4 samples:
Clear signal
detection in all
of them
Energy range for this analysis:
high zenith angle:
250 GeV – 2 TeV
low zenith angle:
100 GeV – 1 TeV
18/12/05, <Zd>=48 18/12/05, <Zd>=12
19/12/05, <Zd>=51 19/12/05, <Zd>=21
Light curve (X-ray)17-20 December 2004
X-rays: no significant variation
Optical data (KVA): quiescent state
18/12 19/12
Dec 04Apr 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!)
Soon to come: Energy spectrum and full light curve for the MAGIC data Combined MAGIC – HESS data analysis
4004 4005 (mjd-49353)
Conclusions / Outlook
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
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
Thank you