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Multi-frequency VLBA study of the blazar S5 0716+714 during the active state in 2004: I. Inner jet kinematics
E. A. Rastorgueva, K. Wiik, T. Savolainen +4
We observed the blazar \object{0716+714} with the VLBA during its active state in 2003-2004. In this paper we discuss multi-frequency analysis of the inner jet (first 1 mas) kinema…
MAGIC Observations of PG 1553+113 during a Multiwavelength Campaign in July 2006
MAGIC Collaboration, Albert
The active galactic nucleus PG 1553+113 was observed by the MAGIC telescope in July 2006 during a multiwavelength campaign, in which telescopes in the optical, X-ray, and very high…
The June 2008 flare of Markarian 421 from optical to TeV energies
The Agile Collaboration, Webt Collaboration, Magic Collaboration +2
We present optical, X-ray, high energy ( GeV) and very high energy ( GeV; VHE) observations of the high-frequency peaked blazar Mrk 421 taken betwee…
Improving the performance of the single-dish Cherenkov telescope MAGIC through the use of signal timing
MAGIC Collaboration
The Cherenkov light flashes produced by Extensive Air Showers are very short in time. A high bandwidth and fast digitizing readout, therefore, can minimize the influence of the bac…
MAGIC upper limits to the VHE gamma-ray flux of 3C454.3 in high emission state
H. Anderhub, S. Vercellone, I. Donnarumma +2
We report upper limits to the very high energy flux (E>100 GeV) of the flat spectrum radio quasar 3C454.3 (z=0.859) derived by the Cherenkov telescope MAGIC during the high states…
The WEBT Campaign on the Intermediate BL Lac Object 3C66A in 2007-2008
M. Boettcher, K. Fultz
Prompted by a high optical state in September 2007, the Whole Earth Blazar Telescope (WEBT) consortium organized an intensive optical, near-IR (JHK) and radio observing campaign on…
A new activity phase of the blazar 3C 454.3. Multifrequency observations by the WEBT and XMM-Newton in 2007-2008
C. M. Raiteri, M. Villata, V. M. Larionov +2
We present and analyse the WEBT multifrequency observations of 3C 454.3 in the 2007-2008 observing season, including XMM-Newton observations and near-IR spectroscopic monitoring, a…
Discovery of a very high energy gamma-ray signal from the 3C 66A/B region
MAGIC Collaboration, E. Aliu
The MAGIC telescope observed the region around the distant blazar 3C 66A for 54.2 h in 2007 August-December. The observations resulted in the discovery of a gamma-ray source at ene…
A massive binary black-hole system in OJ287 and a test of general relativity
M. J. Valtonen, H. J. Lehto, K. Nilsson +23
Tests of Einstein's general theory of relativity have mostly been carried out in weak gravitational fields where the space-time curvature effects are first-order deviations from Ne…
Observation of Pulsed Gamma-rays Above 25 GeV from the Crab Pulsar with MAGIC
The MAGIC Collaboration, E. Aliu
One fundamental question about pulsars concerns the mechanism of their pulsed electromagnetic emission. Measuring the high-end region of a pulsar's spectrum would shed light on thi…
Very-High-Energy Gamma Rays from a Distant Quasar: How Transparent Is the Universe?
MAGIC Collaboration, J. Albert
The atmospheric Cherenkov gamma-ray telescope MAGIC, designed for a low-energy threshold, has detected very-high-energy gamma rays from a giant flare of the distant Quasi-Stellar R…
Detection of the host galaxy of S5 0716+714
K. Nilsson, T. Pursimo, A. Sillanpää +2
We have acquired a deep i-band image of the BL Lacertae object S5 0716+714 while the target was in an low optical state. Due to the faintness of the nucleus, we were able to detect…
Periodic very high energy gamma-ray emission from LS I +61 303 observed with the MAGIC telescope
MAGIC Collaboration, J. Albert
The MAGIC collaboration has recently reported the discovery of gamma-ray emission from the binary system LS I +61 303 in the TeV energy region. Here we present new observational re…
Very High Energy Gamma-Ray Observations of a Strong Flaring Activity in M87 in 2008 February
MAGIC Collaboration, J. Albert
M87 is the only known non blazar radio galaxy to emit very high energy (VHE) gamma-rays. During a monitoring program of M87, a rapid flare in VHE gamma-rays was detected by the MAG…
The high activity of 3C 454.3 in autumn 2007. Monitoring by the WEBT during the AGILE detection
C. M. Raiteri, M. Villata, W. P. Chen +5
The quasar-type blazar 3C 454.3 underwent a phase of high activity in summer and autumn 2007, which was intensively monitored in the radio-to-optical bands by the Whole Earth Blaza…
Clustering environment of BL Lac object RGB 1745+398
H. Lietzen, K. Nilsson, L. O. Takalo +4
The BL Lac object RGB 1745+398 lies in an environment that makes it possible to study the cluster around it more deeply than the environments of other BL Lac objects. The cluster c…
Multifrequency monitoring of the blazar 0716+714 during the GASP-WEBT-AGILE campaign of 2007
M. Villata, C. M. Raiteri, V. M. Larionov +5
Since the CGRO operation in 1991-2000, one of the primary unresolved questions about the blazar gamma-ray emission has been its possible correlation with the low-energy (in particu…
MAGIC observations of the unidentified TeV gamma-ray source TeV J2032+4130
J. Albert
We observed the first known very high energy (VHE) gamma-ray emitting unidentified source, TeV J2032+4130, for 94 hours with the MAGIC telescope. The source was detected with a sig…
Simultaneous multiwavelength observations of the blazar 1ES1959+650 at a low TeV flux
G. Tagliaferri, L. Foschini, G. Ghisellini +7
We present the results from a multiwavelength campaign on the TeV blazar 1ES 1959+650, performed in May, 2006. Data from the optical, UV, soft- and hard-X-ray and very high energy…
Radio-to-UV monitoring of AO 0235+164 by the WEBT and Swift during the 2006--2007 outburst
C. M. Raiteri, M. Villata, V. M. Larionov +2
The blazar AO 0235+164 was claimed to show a quasi-periodic behaviour in the radio and optical bands. Moreover, an extra emission component contributing to the UV and soft X-ray fl…
Multi-wavelength (radio, X-ray and gamma-ray) observations of the gamma-ray binary LS I +61 303
MAGIC Collaboration, J. Albert
We present the results of the first multiwavelength observing campaign on the high-mass X-ray binary LS I +61 303 comprising observations at the TeV regime with the MAGIC telescope…
Upper limit for gamma-ray emission above 140 GeV from the dwarf spheroidal galaxy Draco
MAGIC Collaboration, J. Albert
The nearby dwarf spheroidal galaxy Draco with its high mass to light ratio is one of the most auspicious targets for indirect dark matter searches. Annihilation of hypothetical DM…
Color Variability of the Blazar AO 0235+16
V. A. Hagen-Thorn, V. M. Larionov, C. M. Raiteri +5
Multicolor (UBVRIJHK) observations of the blazar AO 0235+16 are analyzed. The light curves were compiled at the Turin Observatory from literature data and the results of observatio…
Host galaxy subtraction of TeV candidate BL Lacertae objects
K. Nilsson, M. Pasanen, L. O. Takalo +4
We have derived R-band host galaxy fluxes of 20 TeV candidate BL Lacertae objects as a function of aperture radius and FWHM. The results are given as correction tables, that list t…