MAGIC TeV blazars and
Extragalactic Background Light
Daniel Mazin
on behalf of the MAGIC collaboration
Max-Planck-Institut für Physik, Munich
outline
• Active Galactic Nuclei (AGN) and blazars
• Extragalactic Background Light (EBL)
• MAGIC







Markarian 421, z=0.030
Markarian 501, z=0.034
1ES2344+514, z=0.044
Markarian 180, z=0.045
1ES1959+650, z=0.047
1ES1218+304, z=0.182
PG1553+113, z>0.09
redshift
• Conclusions, outlook
MAGIC TeV blazars and Extragalactic Background Light
Daniel Mazin, MPI, Munich
TeV blazars
Kino et al, ApJ, 2002, 564,
97
See talk by Paolo Padovani on
Tuesday
• TeV blazars: non-thermal emission, highly variable
• All but one are HBL (high peaked BL Lacertae)
• Models: leptonic vs. hadronic origin
MAGIC TeV blazars and Extragalactic Background Light
Daniel Mazin, MPI, Munich
EGRET sky
• 273 sources above 100
MeV
MAGIC TeV blazars and Extragalactic Background Light
Daniel Mazin, MPI, Munich
TeV sky
• > 30 sources above 100 GeV, and this is factor
3 larger than before H.E.S.S and MAGIC went
online
MAGIC TeV blazars
and Extragalactic Background Light
Daniel Mazin, MPI, Munich
Where are the sources?
• In the Galactic plane, it starts to be
crowded above 100 GeV. Expectations
fulfilled.
• Extragalactic sources: only 13: 12
blazars and M87 as radio galaxy.
• Expect many more if extrapolate from
EGRET AGNs.
• Possible reasons:


Intrinsic cut-off
Extragalactic absorption
MAGIC TeV blazars and Extragalactic Background Light
Daniel Mazin, MPI, Munich
Attenuation of GeV-TeV
photons
See talk by Luigi
Costamante
EBL
Cherenkov
Telescope
BL-Lac object
Pair
creation:
 HE  EBL  e  e 
Cross section peaks at:
MAGIC TeV blazars and Extragalactic Background Light

EHE  EBL  3.6 me c

2 2
Daniel Mazin, MPI, Munich
What is EBL?
Dwek&Krennrich 05, Kneiske et al. 04
2.7K
Red shifted stellar light
Red shifted dust light
MAGIC TeV blazars and Extragalactic Background Light
• Unique imprint of
the history of the
universe
• Test of star
formation and
galaxy evolution
models
• Cosmological
evolution models
have to explain
current EBL
• Opacity source
of
Daniel Mazin, MPI, Munich
MAGIC
• The largest imaging
atmospheric
Cherenkov Telescope
with 17m mirror
diameter
• 3.5° FoV Camera with
576 enhanced QE
PMT’s
Canarian Island La Palma,
2200 m asl
• Trigger threshold: 5060GeV
• Sensitivity: 2.5% Crab
Nebula in 50 hours
• -PSF is about 0.1°
MAGIC
TeV blazars and
Extragalactic Background
• Energy
resolution
30% Light
Daniel Mazin, MPI, Munich
Mkn 421 (z=0.030)
• Dec 2004 – Apr 2005
• 25.6 h, over 7000 excess
events
• Energy threshold: 150 GeV
lightcurv
e
TeV
TeV
X-ray
X-ray
spectru
m
TeV-X-raycorrelation
optica
loptica
ApJ submitted, astro-l
ph/0603478
MAGIC TeV blazars and Extragalactic Background Light
Daniel Mazin, MPI, Munich
Mkn 421 (z=0.030)
log(B)
SSC
constraints
log(B)
SE
D
A
B
C
D
E
log(D)
F
log(D)
• In case of 1-day
variability scale, the
model provides similar
parameters as from the
1994 flare: D=9,
B=0.3G
ApJ submitted, astroMAGIC TeV blazars and Extragalactic Background
Light
ph/0603478
Daniel Mazin, MPI, Munich
Mkn 501 (z=0.034)
• June – July 2005
• 23.1 h, over 85 , over 14000
excess events
• Analysis threshold: 150 GeV
TeV
TeV-X-raycorrelation
TeV-opticalcorrelation
X-ray
optica
l
MAGIC TeV blazars and Extragalactic Background Light
Daniel Mazin, MPI, Munich
Mkn 501 (z=0.034)
• Flare on 9 July 2005
• Doubling time less than 5
min.
• Spectrum shape changes
within minutes
• IC peak detected?
MAGIC TeV blazars and Extragalactic Background Light
Daniel Mazin, MPI, Munich
1ES2344+514 (z=0.044)
•
Whipple: Flare (20-12-95),
F(>350GeV) = 63% Crab, (Catanese, 97)
•
Whipple later upper limits only,
F(>350GeV) < 8% Crab in 96/97 (Schroedter,
05)
•
HEGRA 1997-2002: 4.4 
Fint(>970GeV) = 3.3% Crab (Tluczykont et al.
Clear
8.1 ; F(>350GeV)
= 6%
variability; index: MAGIC.
Aug 05 – Jan
06, Crab,
27.4 nodetection!
2.96±0.12
h:
LightSky
curve
plot:
:
03)
•
MAGIC TeV blazars and Extragalactic Background Light
TeV
X-ray
Daniel Mazin, MPI, Munich
opt.
Mkn 180 (z=0.045)
•
•
Whipple: F(>300GeV)<10.5% C.U.
HEGRA: F(>1.5TeV)<12% C.U.
•
•
•
•
MAGIC: DISCOVERY!
plot
April 2006, 11.1 h
Triggered by optical flare
5.5 , F(>200GeV) =
11%C.U.,
Subm. to ApJL, astro-ph/0606630
index: -3.3 ± 0.7
spectru
m
MAGIC TeV blazars and Extragalactic Background Light
2
sky
plot
SED
Daniel Mazin, MPI, Munich
1ES1959+650 (z=0.047)
• Blazar famous for the
orphan flare in 2002
• MAGIC: Significant signal
in only 6h of effective obs.
ApJ, 639 (2006), 761
• Light curve: flaring or
Spectral index:
quiescent state?
2.72 ± 0.14
• Simultaneous
0.2
multiwavelength data not
enough to distinguish
between hardronic and
leptonic models
• More is in pipeline
MAGIC TeV blazars and Extragalactic Background Light
3.2 ±
TeV
X-ray
opt.
Daniel Mazin, MPI, Munich
1ES1218+304 (z=0.182)
•
•
Whipple: F(>350GeV)<8% C.U.
HEGRA: F(>750GeV)<12% C.U.
2 plot
• MAGIC: DISCOVERY!
• Jan 2005, 8.2 h
• 6.4 , F(>120GeV) = 13%
C.U., index: -3.0 ± 0.4
spectrum
TeV
lightcurve
MAGIC TeV blazars and Extragalactic Background Light
Daniel Mazin, MPI, Munich
1ES1218+304 (z=0.182)
• Is it possible to derive EBL constraints from the 1ES1218 spectrum?
• Assuming 6 different EBL realizations, all reconstructed de-absorbed
spectra do not contradict the rising slope dN/dE  E-,  > 1.5
MAGIC TeV blazars and Extragalactic Background Light
Daniel Mazin, MPI, Munich
PG1553+113 (z>0.09)
• Observed 18.8h in 2005-06
• H.E.S.S.: 4.0 evidence
Alpha plot
(A&A 448L (2006), 43)
• MAGIC: ApJL submitted,
astro-ph/0606161
• 8.8, firm detection.
lightcurve
MAGIC TeV blazars and Extragalactic Background Light
spectru
m
Daniel Mazin, MPI, Munich
PG1553+113 (z>0.09)
• HESS published spectrum
• MAGIC published spectrum
MAGIC
HESS/MAGIC
HESS corr.
• HESS / MAGIC together
• HESS corrected by 7 %
• HESS/MAGIC joint
• Aim: derive constraint on the redshift of the source
• Assumptions: a) intrinsic slope not harder than 1.5
b) intrinsic spectrum has just one
peak
MAGIC TeV blazars and Extragalactic Background Light
Daniel Mazin, MPI, Munich
PG1553+113 (z>0.09)
• Method 1: Preliminary
Loglikelihood
test between result, using the
power law and new method:
broken power
z < 0.42
law
• Method 2:
modified run Published:
test; probability
of the given HESS: z<0.74
distribution of MAGIC: z<0.78
points around
the fitted power
law
MAGIC TeV blazars and Extragalactic Background Light
Daniel Mazin, MPI, Munich
Conclusions / Outlook
• There are 12 blazars above 100 GeV
established
• MAGIC detected 7 of them; 2 of them
discovered by MAGIC, 1 co-discovered with
HESS
• Simple leptonic models usually work but there
are exceptions (e.g. 1ES1959+650)
• De-absorbed spectra are the harder the further
away the sources are. Observational bias or
physics?
• Hard preliminary constraint on the redshift of
PG1553+113 to z<0.42 in case there is one
MAGIC TeV blazars and Extragalactic Background Light
Daniel Mazin, MPI, Munich
peak above 100 GeV. If z>0.42, first
observation