Gamma-ray emission from the Perseus cluster of
galaxies observed with MAGIC
Gamma-ray emission from the Perseus cluster of
galaxies observed with MAGIC
P. Colin*, D. Eisenacher, D. Hildebrand, S. Lombardi, E. Lindorfs, D. Paneque, S. Partini, F. Prada, J. Sitarek, F. Zandanel for the MAGIC
collaboration, and T. Dauser, M. Kadler, F. Krauss, J. Kataoka, C. Pfrommer, A. Pinzke, Y. Takahashi, S. Wilbert, J. Wilms
*Max-Planck-Institut für Physik
The Perseus cluster of galaxies (Abel 426)
• Brightest galaxy cluster in X-ray • Typical cool-core Cluster • Dominant central galaxy: NGC 1275• CR - ICM interactions expected
• Brightest galaxy cluster in X-ray • Typical cool-core Cluster • Dominant central galaxy: NGC 1275• CR - ICM interactions expected
Chandra – X-ray (0.5- 7keV) Blackbird Obs. - Optical
NGC 1275
5’ (~100 kpc)Fabian et al. 2011
3C 84 (VLBA – 15GHz)Distance: ~73 Mpc (z=0.018)
5
pc
MAGIC Telescopes in 2009-2011
85 m
At Observatorio del Roque de los Muchachos (La Palma), Altitude = 2200 m
3.5°ø 3.5°ø
17m ø
17m ø
Sensitivity: 0.8% crab in 50hEnergy threshold: ~50 GeV
576 Pixels 1039 Pixels
Map of the Perseus cluster with MAGIC
NGC 1275
IC 310
Energy >150 GeV
85h of Stereo observation from 2009 to 2011 NGC 1275 spectrum(2010-2011)
• Two point-like sources detected:- NGC 1275: the central galaxy- IC 310: a head-tail radio galaxy ??
• First “cluster” of TeV galaxies !
• Two point-like sources detected:- NGC 1275: the central galaxy- IC 310: a head-tail radio galaxy ??
• First “cluster” of TeV galaxies !
Sig
nif
ican
ce
[σ]
IC 310 spectrum(2009-2010)
Spectral index = -2.0
Spectral index = -4.1
Aleksić et al. ApJ. 723 (2010) L207
Aleksić et al. A&A 539 (2012) L2
Aleksić et al. A&A 541 (2012) A99
NGC 1275 (3C 84): a complex object
Hubble Space Telescope image
Unclear classification:- Seyfert 1.5 in Veron&Veron (2006)- FR I radio galaxy ?- Strong variability: BL Lac suggested in 1978- Counter-jet visible: Jet orientation = 30°- 55°
Supermassive Black Hole
sub-pc
15 m
as /
5
pc
60” (~20 kpc)
http://images.nrao.edu/263
Detection of NGC 1275 with MAGIC
Source discoveryin 2010-2011 data
Recent re-analysis of 2009-2010 data
PRELIMINARY
Flux >100 GeV
Aleksić et al. A&A 539 (2012) L2
Flux >100 GeV
NGC 1275 spectrum in 2009-2010
Compatible with 2010-2011 spectrum:f0 = 3.1±1.0 and α = -4.1±0.7
NGC 1275: 39h from Oct. 2009 to Feb. 2010
NGC 1275 MWL light curves
C1
C2C3
VLBA (MOJAVE) 15GHz
~1 pc
S. Partini
2009 2010 2011
NGC 1275 SED
Broad-band emission model:- Fast variability: need contemporaneous data !- Compact emission region: inner-jet ?- Synchrotron peak not well defined - Need HST image to resolve the inner-jet optical emission ?
Abdo at al. (2009) ApJ 699 31
Archival SED Fermi-LAT
MAGIC
Spectral break or cut-off at ~50 GeV Spectral break or cut-off at ~50 GeV SSC model like BL Lac objects ? SSC model like BL Lac objects ?
MAGIC (2010-2011)
IC 310: Head-tail radiogalaxy or Blazar ?
Radio - WENSS
Neronov et al (2010)
NRAO image, VLA
Kadler et al. (2012)
IC 3101.4 GHz
NGC 1265Head-tail radio galaxy:- Jets bent due to intra-cluster motion - NGC 1265 is a typical example
IC 310 originally classified "head-tail" but no evidence of jet bendingBlazar-like radio morphology of inner jetNo counter-jet: θ ≤ 38°
IC 310 originally classified "head-tail" but no evidence of jet bendingBlazar-like radio morphology of inner jetNo counter-jet: θ ≤ 38°
IC 310 light curve
Daily Light curve
High state
Variability:Published results:- Hints of week and month scale variability- Year scale confirmed in Aug 2010- Jan 2011 data
New analysis:(Poster of Eisenacher et al)- Day scale variability established (>5σ)
Compact emission region
Confirm Blazar-like behavior
IC 310 spectrum
Very hard spectrum: Intrinsic spectral index ≤ 2 No variation of the spectral index !
Γint = 1.85 ± 0.11stat ± 0.2syst
Γint = 1.81 ± 0.13stat ± 0.2syst
EBL model: Dominguez et al. 2011
Origin of IC 310 emission ?
• Very extreme BL Lac object - Need very low accretion rate- Powerful enough for the kpc structure ???
• Misaligned extreme BL Lac - Mrk 501 or H 1426+428 with ~10° angle ?
• M87 type models ?- Multi-zones jet- Black Hole magnetosphere- Hadronic models
• Very extreme BL Lac object - Need very low accretion rate- Powerful enough for the kpc structure ???
• Misaligned extreme BL Lac - Mrk 501 or H 1426+428 with ~10° angle ?
• M87 type models ?- Multi-zones jet- Black Hole magnetosphere- Hadronic models
Fermi galaxy divideDermer, arXiv:1202.2814
Archival IC 310 SED
IC 310 ?
(2009-2010)(2009-2010)
Gamma-ray from Hadron Cosmic Rays
Perseus radio mini-halo
14
Cosmological Simulation:- High energy gamma-ray emission- Spectral index: α= ~2.2
Synchrotron Radiation from
cosmic electrons
Synchrotron Radiation from
cosmic electrons
Hadronic model
• Theoretical predictions: - CR acceleration in cluster formation (merging) shocks- CR injection by the AGNs and galaxies of the cluster- CR accumulation in the cluster (lifetime ≈ Hubble time)
• Observation: Radio Halo (mini-Halo) from High energy electrons- Re-acceleration of existing electrons by MHD turbulences ?- Secondary electrons from CR/ICM interactions (Hadronic model)
Magnetic
field
γ + γICM
Typical cool core cluster: ~16 μG(from Faraday RM studies)
Constraints from MAGIC observation
IC 310
No gamma-ray signal above 630 GeVfrom the central region (r < 0.15°)
where ~60% of CR signal is expected
MAGICUpper limits
Minimal Flux of the hadronic model
Energy >630 GeV
Flux ULs reach optimistic CR model(50% acceleration efficiency in formation shocks)
Sig
nif
ican
ce [
σ]
CR / Thermal pressure ratio
≤ 1-2 %
CR models
from cosmologic
al simulations
CR models
from cosmologic
al simulations Hadroni
c model of radio
mini-halo
Hadronic model of radio
mini-halo
Central B-field > 4-9 μG
Aleksić et al. A&A 541 (2012) A99
Summary
• MAGIC searches for new classes of VHE emitter• Deep observation of Perseus cluster (85h) • Discovery of 2 peculiar AGNs• Double the TeV radio galaxies known (2 → 4)• Blazar-like emissions (but unusual - misaligned ?)• Need MWL campaign to probe emission models • No signal from CR-ICM interactions• First constraints on CR physics in cluster• Interesting B-constraint in Hadronic model of radio (mini-)Halo, perspective to probe this model with more observation or with CTA.
• MAGIC searches for new classes of VHE emitter• Deep observation of Perseus cluster (85h) • Discovery of 2 peculiar AGNs• Double the TeV radio galaxies known (2 → 4)• Blazar-like emissions (but unusual - misaligned ?)• Need MWL campaign to probe emission models • No signal from CR-ICM interactions• First constraints on CR physics in cluster• Interesting B-constraint in Hadronic model of radio (mini-)Halo, perspective to probe this model with more observation or with CTA.