Multiwavelength Observations of the Extreme X-Ray-selected BL Lacertae Object PG 1553+11 (1ES 1553+113)

Osterman, M. A.; Campbell, A. I.; Marshall, Kevin; McFarland, John; Aller, H. D.; Aller, M. F.; Fried, Robert; Kurtanidze, O. M.; Nikolashvili, M. G.; Tornikoski, M.; Valtaoja, E.

doi:10.1086/505565

Cited by 20 publications

(26 citation statements)

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“…It is classified as a BL Lac object based on its featureless spectrum (Miller & Green 1983) and significant optical variability (Miller et al 1988). The object has been well studied from radio to VHE γ-ray (>100 GeV), including several simultaneous multi-wavelength observation campaigns (see Osterman et al 2006;Mankuzhiyil et al 2009). …”

Section: Introductionmentioning

confidence: 99%

Polarization and photometric observations of the gamma-ray blazar PG 1553+113

Andruchow

Combi

Muñoz‐Arjonilla

et al. 2011

A&A

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We present the results of an observational photo-polarimetry campaign of the blazar PG 1553+113 at optical wavelengths. The blazar was recently detected at very high energies (>100 GeV) by the HESS and MAGIC γ-ray Cherenkov telescopes. Our high-temporal resolution data show significant variations in the linear polarization percentage and position angle at inter-night time-scales, while at shorter (intra-night) time-scales both parameters varied less significantly, if at all. Changes in the polarization angle seem to be common in γ-ray emitting blazars. Simultaneous differential photometry (through the B and R bands) shows no significant variability in the total optical flux. We provide B and R magnitudes, along with a finding chart, for a set of field stars suitable for differential photometry.

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Section: Introductionmentioning

confidence: 99%

Polarization and photometric observations of the gamma-ray blazar PG 1553+113

Andruchow

Combi

Muñoz‐Arjonilla

et al. 2011

A&A

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“…portion of the SED of PG 1553+113 is well-studied, including several simultaneous multi-wavelength observation campaigns (see, e.g., Osterman et al 2006). However, the only data in the high-energy hump are from HESS and MAGIC.…”

Section: Introductionmentioning

confidence: 99%

HESS observations and VLT spectroscopy of PG 1553+113

Aharonian

Akhperjanian

Almeida

et al. 2007

A&A

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Aims. The properties of the very high energy (VHE; E > 100 GeV) γ-ray emission from the high-frequency peaked BL Lac PG 1553+113 are investigated. An attempt is made to measure the currently unknown redshift of this object. Results. A VHE signal, ∼10 standard deviations, is detected by HESS during the 2 years of observations (24.8 h live time). The integral flux above 300 GeV is (4.6 ± 0.6 stat ± 0.9 syst ) × 10 −12 cm −2 s −1 , corresponding to ∼3.4% of the flux from the Crab Nebula above the same threshold. The time-averaged energy spectrum is measured from 225 GeV to ∼1.3 TeV, and is characterized by a very soft power law (photon index of Γ = 4.5 ± 0.3 stat ± 0.1 syst ). No evidence for any flux or spectral variations is found on any sampled time scale within the VHE data. The redshift of PG 1553+113 could not be determined. Indeed, even though the measured SINFONI spectrum is the most sensitive ever reported for this object at near infrared wavelengths, and the sensitivity is comparable to the best spectroscopy at other wavelengths, no absorption or emission lines were found in the H+K spectrum presented here.

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“…When putting the observed optical flare in perspective with the multiwavelength observations back in 2003 [Ost06b] however, more complex scenarios that can explain isolated optical and X-ray flares might have to be conceived. Interestingly, the only significant (3.75σ ) deviation of an individual VHE data point during our observations was recorded on MJD 53797 with F = (1.86 ± 0.40) × 10 −10 cm −2 s −1 , few days prior to the onset of the optical flare.…”

Section: Light Curvementioning

confidence: 99%

“…Based on its spectral characteristics [Mil83,Fal90], its optical variability (∆m = 1.8, [Mil88]) and the broadband spectral energy distribution up to X-rays (detections by BeppoSAX [Don05] and XMM Newton [Per05]) the object was classified as a high-frequency peaked BL Lac [Gio95] or more recently as an "intermediate BL Lac" [Lau99,Nie06] with the synchrotron peak in the SED at ν sy peak = 3 · 10 16 Hz. Recent multiwavelength observations claim an XBL nature even more extreme than that of Mkn 501 [Ost06b].…”

Section: Introductionmentioning

confidence: 99%

Measurement of Very High Energy Gamma‐Ray Emission from Four Blazars Using the MAGIC Telescope and a Comparative Blazar Study

Wagner¹

2007

PUBL ASTRON SOC PAC

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SummaryThe thesis reports on the measurement of very high energy (VHE) gamma-rays from four Active Galactic Nuclei (AGN) with the Major Atmospheric Gamma-ray Imaging Cherenkov telescope (MAGIC). When taking into account -ray absorption by the extragalactic background light (EBL), a hint for an inverse Compton peak is found with the peak energy moving from (0.3 ± 0.1) TeV to (1.4 ± 0.7) TeV with increasing flux level. This evidence is strengthened by the observation of a moving structure also in the measured spectra, which are free of uncertainties of the EBL model used.Unprecedented rapid flux variability with doubling times of ≤ 5 minutes was found during some of the observation nights. These fast flares are used to infer significant limits on the size of the acceleration region of R · δ −1 ≤ 10 12 cm for homogeneous one-zone SelfSynchrotron Compton models. Significant spectral hardening of ∆α = 0.4 within less than 20 minutes could be observed. The well-defined fast flares were also used to infer a lower limit on the quantum gravity energy scale of 1.5 × 10 17 GeV.For the BL Lac object 1ES 2344+514 for the first time a differential energy spectrum during a state of low -ray activity is inferred, which between 140 GeV and 5 TeV can be vii described by a power law of the form dF dE = (1.18 ± 0.13) × 10The study of the 24-day VHE -ray light curve of 1ES 2344+514 yields a low flux level of 0.04 ≤ F E>350 GeV ≤ 0.11 times the Crab nebula flux. In combination with the all-time (1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)) light curve a low emission level of about ≈4% of the Crab nebula flux is found.Within the thesis, predictions for the detectability of BL Lac candidate objects in VHE -rays with the MAGIC telescope are presented. These predictions led to the discovery of two new objects in this energy domain, PG 1553+113 and BL Lacertae. PG 1553+113 was detected at a high significance level of 8.8σ . The softest gamma ray spectrum observed so far in VHE -rays was found for this source. It can be described by a pure power law between 95 GeV and 500 GeV:The spectrum is used to infer an upper limit of z < 0.78 on the yet undetermined redshift of PG 1553+113 by imposing a maximum hardness of the intrinsic spectrum. While the light curve does not show apparent short-term variability, simultaneously recorded optical data feature a substantial flare, which leaves room for interpretation of the non-existing correlations.BL Lacertae, the prototype of the BL Lac objects, was detected at a significance level of 5.6σ . This object is the first low-frequency peaked BL Lac object seen in VHE -rays. A preliminary spectrum hints at a steep slope of ≈ −3.7 between 100 GeV and 1 TeV.For the first time a synoptic study of all high-frequency peaked BL Lac-type objects detected as VHE gamma-ray emitters is performed. The intrinsic properties of the observed emission are compared and correlated among each other and with the individual estimated black hole masses. Key findings are (1) that all currently known VHE -r...

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Multiwavelength Observations of the Extreme X-Ray-selected BL Lacertae Object PG 1553+11 (1ES 1553+113)

Cited by 20 publications

References 24 publications

Polarization and photometric observations of the gamma-ray blazar PG 1553+113

Polarization and photometric observations of the gamma-ray blazar PG 1553+113

HESS observations and VLT spectroscopy of PG 1553+113

Measurement of Very High Energy Gamma‐Ray Emission from Four Blazars Using the MAGIC Telescope and a Comparative Blazar Study

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