A selection of recent results by MAGIC

A. De Angelis – B. De LottoINFN Ud/Ts & Univ. Udine

Trieste, July 08

• Summary• AGN: propagation, variability, MW with AGILE/GLAST • Something on pulsars• The near future

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• MAGIC I slightly better than its design performance– Sensitivity 1.8% Crab @ 5 in

50h, Emin = 20 GeV• Complementarity with AGILE,

MAGIC

• Leader in extragalacticobservations

• ~40 scientific articles on refereed journals (~1/month), with many discoveries: 2 articles published on Science, 1 ~submitted to Nature– The most distant sources

– The first VHE pulsar

E (GeV)

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MAGIC threshold:

50 GeV in normal running conditions

20 GeV with sum trigger

Complementarity with AGILE/GLAST

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Propagation physics

e+

e-

visible/infrared light accumulated by allstars in history of Universe

Absorption:

– Dominant process for the absorption of is

– Only QED, relativity and cosmology in the formula above

• For rays, relevant background component is optical/infrared (EBL)

• EBL minimum density given by cosmology/star formation

eebackgroundmaximal for

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• 23 AGN at VHE discovered by IACTs (including 3c279 at z ~ 0.54)

• Unexpectedly large, given the attenuation expected

• EBL minimum density given by cosmology/star formation

• Is it compatible with the lower limit from galaxy counts?

Marginally for now… (dA, Roncadelli, Mansutti, PRD07; PLB08)

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The most distant:

MAGIC 3C 279 (z=0.54)(MAGIC, Science, Jun 2008)

MAGIC

VLA

MAGIC sky map for

Feb 23, 2006

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Variability: Mkn 421, Mkn501

• Two very well studied sources,

highly variable

– Monitoring from Whipple, Magic…

– TeV-X Correlation• No orphan flares…

– See neutrino detectors

Mkn421

TeV-X-ray-

correlation

Mkn421

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Rapid variability

HESS PKS 2155−304z = 0.116

Peak flux ~15 x Crab~50 x average

Doubling times 67, 116, 173, 178 ±50 s

RBH/c ~ 1...2.104 s

H.E.S.S.arXiV:0706.0797

MAGIC, Mkn 501

Doubling time ~ 2 min

astro-ph/0702008 arXiv:0708.2889

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Violation of the Lorentz Invariance?Light dispersion due to QG effects ?

Mrk 501, MAGIC, astro-ph/0702008

0.15-0.25 TeV

0.25-0.6 TeV

0.6-1.2 TeV

1.2-10 TeV 4 min lag

MAGIC Mkn 501, arXiv:0708.2889

EQG ~ 0.03 MP

EQG > 0.02 MP

However: HESS PKS 2155, arXiv:0706.0797

EQG > 0.04 MP

Whipple 1999, PRL 83(1999)2108

EQG > 0.005 MP

GRB X-ray limits:EQG > 0.001…0.01 MP

… but in most scenariost ~ (E/EQG) , >1 VHE gamma rays even better Mrk 501: EQG > 3.10-9 MP , =2

1st order

V = c [1 +- (E/EQG) – 2 (E/EQG)2 +- …]

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3c454: observation from AGILE, upper

limits from MAGIC

• July 2007: trigger by

AGILE, upper limits

by MAGIC

(AGILE/MAGIC, in preparation)

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PG1553: first simultaneous detection with

AGILE?MAGIC: Elisa Prandini (Padova), Nijil Mankuzhiyil (Udine)

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• 4 hours of observation

(from 16/03 to 13/04)

• Significance (100-600

GeV): 8.0

PG1553 2008: MAGIC (Mankhuzil/Ud +

Prandini/Pd) – Agile (Pian/Ts + ?)

CLEAR SIGNAL!

allows multiwavelength

spectrum

(If AGILE sees a signal, this

would be the first

simultaneous broadband

gamma spectrum of a

blazar)

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And in a few days… (Nature)

• MAGIC discovers pulsed VHE gamma ray emission above 25 GeV from the Crab pulsar

MAGIC reports the detection of the Crab pulsar in very high energy gamma rays. We observed the Crab pulsar from October 2007 until February 2008 for a total of 40 hours. For the analysis 22 hours of data at optimal weather conditions and small zenith angles were selected. The observation took place after installation of a new trigger system which lowered the threshold from 50-60 GeV down to 25 GeV. The analysis reveals a pulse profile that shows a clear signal at a 6.4 sigma confidence level coinciding with an optical signal concurrently recorded by a special photosensor in the camera center. Two peaks in the phaseogram are found, corresponding to the main pulse and the interpulse.

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Summary• High energy photons (often through large distances) are a

probe of fundamental physics under extreme conditions– What better than a crash test to break a theory?

• MAGIC has the lowest threshold, i.e., the deepest horizon– many sources,

=> Transparency of the Universe? New physics?

– often unknown => Together with the others IACTs, a progress comparable with EGRET

– sometimes behaving in an unexpected way=> Rapid variability: new physics?

• Complementarity MAGIC/AGILE for MW observations=> Increment ToOs, MW observations… Guest observers!

• Clear role for Udine/Trieste:– 9 signatures/140; group leader: Barbara De Lotto; data analysis, online

– Physics PI: Massimo Persic

– National responsible: Alessandro De Angelis

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And next…

MAGIC 2September 18/19, 2008

Come to the inauguration!!!

Want to know more? Download DA, Mansutti & Persic, arXiv:0712.0315