Long-term optical monitoring of TeV emitting blazars

Nilsson, K.; Lindfors, E.; Takalo, L. O.; Reinthal, R.; Berdyugin, A.; Sillanpää, A.; Ciprini, S.; Halkola, A.; Heinämäki, P.; Hovatta, T.; Kadenius, V.; Nurmi, P.; Ostorero, L.; Pasanen, M.; Rekola, R.; Saarinen, J.; Sainio, J.; Tuominen, T.; Villforth, C.; Vornanen, Tommi; Zaprudin, B.

doi:10.1051/0004-6361/201833621

Cited by 119 publications

(99 citation statements)

References 132 publications

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“…10 peak ( ) . The low state is characterized by a much more constrained peak frequency, n log Hz 10 peak ( ) , of 14.49 -+ 0.54 0.17 from the model, with boundaries from the IR and optical data-consistent with the results of Nilsson et al (2018), based on the Roma-BZCAT Multifrequency Catalog up to 2012. Thus, if only this low state were considered, this source would be classified as an IBL.…”

Section: Extreme Shift Of the Synchrotron Peak Frequencysupporting

confidence: 71%

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A Decade of Multiwavelength Observations of the TeV Blazar 1ES 1215+303: Extreme Shift of the Synchrotron Peak Frequency and Long-term Optical–Gamma-Ray Flux Increase

Valverde

Horan

Bernard

et al. 2020

ApJ

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Blazars are known for their variability on a wide range of timescales at all wavelengths. Most studies of TeV gamma-ray blazars focus on short timescales, especially during flares. With a decade of observations from the Fermi-LAT and VERITAS, we present an extensive study of the long-term multiwavelength radio-to-gamma-ray flux-density variability, with the addition of a couple of short-time radio-structure and optical polarization observations of the blazar 1ES 1215+303 (z=0.130), with a focus on its gamma-ray emission from 100MeV to 30TeV. Multiple strong GeV gamma-ray flares, a long-term increase in the gamma-ray and optical flux baseline, and a linear correlation between these two bands are observed over the ten-year period. Typical HBL behaviors are identified in the radio morphology and broadband spectrum of the source. Three stationary features in the innermost jet are resolved by Very Long Baseline Array at 43.1, 22.2, and 15.3 GHz. We employ a two-component synchrotron self-Compton model to describe different flux states of the source, including the epoch during which an extreme shift in energy of the synchrotron peak frequency from infrared to soft X-rays is observed.

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Section: Extreme Shift Of the Synchrotron Peak Frequencysupporting

confidence: 71%

“…Source 1ES1215+303 was monitored in the R-band at the Tuorla Observatory over the past 15 yr as part of the Tuorla blazar monitoring program (Takalo et al 2008;Nilsson et al 2018). We show the long-term R-band flux density in Figure 1.…”

Section: Optical Datamentioning

confidence: 99%

A Decade of Multiwavelength Observations of the TeV Blazar 1ES 1215+303: Extreme Shift of the Synchrotron Peak Frequency and Long-term Optical–Gamma-Ray Flux Increase

Valverde

Horan

Bernard

et al. 2020

ApJ

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“…The present work shows, in particular, data from the 1.03 m telescope at Tuorla Observatory, Finland, and the 35-cm telescope at the KVA observatory on La Palma, Canary Islands, Spain. The data are analyzed with a semi-automatic pipeline using standard procedures (Nilsson et al 2018) The Boston University (BU) group uses the 1.83-m Perkins Telescope at Lowell Observatory (Flagstaff, AZ) to carry out optical observations of a sample of γ-ray blazars, including S5 0716+714. The telescope is equipped with the PRISM camera operating in photometric (UBVRI) and polarimetric modes.…”

Section: Optical Observations and Polarimetry Datamentioning

confidence: 99%

Multi-wavelength characterization of the blazar S5 0716+714 during an unprecedented outburst phase

Ahnen¹,

Ansoldi²,

Antonelli³

et al. 2018

A&A

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Context. The BL Lac object S5 0716+714, a highly variable blazar, underwent an impressive outburst in January 2015 (Phase A), followed by minor activity in February (Phase B). The MAGIC observations were triggered by the optical flux observed in Phase A, corresponding to the brightest ever reported state of the source in the R-band. Aims.The comprehensive dataset collected is investigated in order to shed light on the mechanism of the broadband emission. Methods. Multi-wavelength light curves have been studied together with the broadband spectral energy distributions (SEDs). The sample includes data from Effelsberg, OVRO, Metsähovi, VLBI, CARMA, IRAM, SMA, Swift-UVOT, KVA, Tuorla, Steward, RINGO3, KANATA, AZT-8+ST7, Perkins, LX-200, Swift-XRT, NuSTAR, Fermi-LAT and MAGIC. Results. The flaring state of Phase A was detected in all the energy bands, providing for the first time a multi-wavelength sample of simultaneous data from the radio band to the very-high-energy (VHE, E > 100 GeV). In the constructed SED, the Swift-XRT+NuSTAR data constrain the transition between the synchrotron and inverse Compton components very accurately, while the second peak is constrained from 0.1 GeV to 600 GeV by Fermi+MAGIC data. The broadband SED cannot be described with a one-zone synchrotron self-Compton model as it severely underestimates the optical flux in order to reproduce the X-ray to γ-ray data. Instead we use a two-zone model. The electric vector position angle (EVPA) shows an unprecedented fast rotation. An estimation of the redshift of the source by combined high-energy (HE, 0.1 GeV < E < 100 GeV) and VHE data provides a value of z = 0.31 ± 0.02stats ± 0.05sys, confirming the literature value. Conclusions. The data show the VHE emission originating in the entrance and exit of a superluminal knot in and out of a recollimation shock in the inner jet. A shock–shock interaction in the jet seems responsible for the observed flares and EVPA swing. This scenario is also consistent with the SED modeling.

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“…These observations were performed in the R-band (Cousins) by the 35 cm telescope attached to the Kungliga Vetenskapsakademien Academy (KVA) system. The data were analysed using the differential photometry method described by Nilsson et al (2018). In order to perform differential photometry, the comparison stars were selected in the same field of view (reported in Figure 3).…”

Section: Kva Data Analysismentioning

confidence: 99%

Testing emission models on the extreme blazar 2WHSP J073326.7+515354 detected at very high energies with the MAGIC telescopes

Acciari¹,

Ansoldi²,

Antonelli³

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Extreme high-energy-peaked BL Lac objects (EHBLs) are an emerging class of blazars. Their typical two-hump-structured spectral energy distribution (SED) peaks at higher energies with respect to conventional blazars. Multiwavelength (MWL) observations constrain their synchrotron peak in the medium to hard X-ray band. Their gamma-ray SED peaks above the GeV band, and in some objects it extends up to several TeV. Up to now, only a few EHBLs have been detected in the TeV gamma-ray range. In this paper, we report the detection of the EHBL 2WHSP J073326.7+515354, observed and detected during 2018 in TeV gamma rays with the MAGIC telescopes. The broad-band SED is studied within an MWL context, including an analysis of the Fermi-LAT data over 10 yr of observation and with simultaneous Swift-XRT, Swift-UVOT, and KVA data. Our analysis results in a set of spectral parameters that confirms the classification of the source as an EHBL. In order to investigate the physical nature of this extreme emission, different theoretical frameworks were tested to model the broad-band SED. The hard TeV spectrum of 2WHSP J073326.7+515354 sets the SED far from the energy equipartition regime in the standard one-zone leptonic scenario of blazar emission. Conversely, more complex models of the jet, represented by either a two-zone spine-layer model or a hadronic emission model, better represent the broad-band SED.

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Long-term optical monitoring of TeV emitting blazars

Cited by 119 publications

References 132 publications

A Decade of Multiwavelength Observations of the TeV Blazar 1ES 1215+303: Extreme Shift of the Synchrotron Peak Frequency and Long-term Optical–Gamma-Ray Flux Increase

A Decade of Multiwavelength Observations of the TeV Blazar 1ES 1215+303: Extreme Shift of the Synchrotron Peak Frequency and Long-term Optical–Gamma-Ray Flux Increase

Multi-wavelength characterization of the blazar S5 0716+714 during an unprecedented outburst phase

Testing emission models on the extreme blazar 2WHSP J073326.7+515354 detected at very high energies with the MAGIC telescopes

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