Investigating the blazar TXS 0506+056 through sharp multi-wavelength eyes during 2017-2019

Abstract

The blazar TXS 0506+056 got into the spotlight of the astrophysical community in September 2017, when a high-energy neutrino detected by IceCube (IceCube-170922A) was associated at the 3 $\sigma$ level to a $\gamma$-ray flare from this source. This multi-messenger photon-neutrino association remains, as per today, the most significant one ever observed. TXS 0506+056 was a poorly studied object before the IceCube-170922A event. To better characterize its broad-band emission, we organized a multi-wavelength campaign lasting 16 months (November 2017 to February 2019), covering the radio-band (Metsähovi, OVRO), the optical/UV (ASAS-SN, KVA, REM, Swift/UVOT), the X-rays (Swift/XRT, NuSTAR), the high-energy $\gamma$ rays (Fermi/LAT) and the very-high-energy (VHE) $\gamma$ rays (MAGIC). In $\gamma$ rays, the behaviour of the source was significantly different from the 2017 one: MAGIC observations show the presence of flaring activity during December 2018, while the source only shows an excess at the 4$\sigma$ level during the rest of the campaign (74 hours of accumulated exposure); Fermi/LAT observations show several short (days-to-week timescale) flares, different from the long-term brightening of 2017. No significant flares are detected at lower energies. The radio light curve shows an increasing flux trend, not seen in other wavelengths. We model the multi-wavelength spectral energy distributions in a lepto-hadronic scenario, in which the hadronic emission emerges as Bethe-Heitler and pion-decay cascade in the X-rays and VHE $\gamma$ rays. According to the model presented here, the December 2018 $\gamma$-ray flare was connected to a neutrino emission that was too brief and not bright enough to be detected by current neutrino instruments.

arXiv comment18 pages, 6 figures; V2 to match published version, typo fixed

References in corpus (57)

• Measuring Reddening with SDSS Stellar Spectra and Recalibrating SFD
• The Large Area Telescope on the Fermi Gamma-ray Space Telescope Mission
• On the Absorption of X-rays in the Interstellar Medium
• The Leiden/Argentine/Bonn (LAB) Survey of Galactic HI: Final data release of the combined LDS and IAR surveys with improved stray-radiation corrections
• The Swift X-ray Telescope
• The Nuclear Spectroscopic Telescope Array (NuSTAR) Mission
• The Swift Ultra-Violet/Optical Telescope
• Methods and results of an automatic analysis of a complete sample of Swift-XRT observations of GRBs
• Fermi Large Area Telescope Fourth Source Catalog
• On characterising the variability properties of X-ray light curves from active galaxies
• The All-Sky Automated Survey for Supernovae (ASAS-SN) Light Curve Server v1.0
• Multi-messenger observations of a flaring blazar coincident with high-energy neutrino IceCube-170922A
• Neutrino emission from the direction of the blazar TXS 0506+056 prior to the IceCube-170922A alert
• The Spectral Energy Distribution of Fermi bright blazars
• The extragalactic optical-infrared background radiations, their time evolution and the cosmic photon-photon opacity
• Limits and Confidence Intervals in the Presence of Nuisance Parameters
• ANTARES: the first undersea neutrino telescope
• Blazars in the Fermi Era: The OVRO 40-m Telescope Monitoring Program
• The major upgrade of the MAGIC telescopes, Part II: A performance study using observations of the Crab Nebula
• Structured jets in TeV BL Lac objects and radiogalaxies
• First Year Performance of The IceCube Neutrino Telescope
• Time-integrated Neutrino Source Searches with 10 years of IceCube Data
• Monte-Carlo simulations of photohadronic processes in astrophysics
• A Multimessenger Picture of the Flaring Blazar TXS 0506+056: implications for High-Energy Neutrino Emission and Cosmic Ray Acceleration
• Energy spectra of gamma-rays, electrons and neutrinos produced at interactions of relativistic protons with low energy radiation
• The contribution of Fermi-2LAC blazars to the diffuse TeV-PeV neutrino flux
• A hadronic origin for ultra-high-frequency-peaked BL Lac objects
• The blazar TXS 0506+056 associated with a high-energy neutrino: insights into extragalactic jets and cosmic ray acceleration
• TeV BL Lac objects at the dawn of the Fermi era
• Modelling the coincident observation of a high-energy neutrino and a bright blazar flare
• Lepto-hadronic single-zone models for the electromagnetic and neutrino emission of TXS 0506+056
• Dissecting the region around IceCube-170922A: the blazar TXS 0506+056 as the first cosmic neutrino source
• Blazar Flares as an Origin of High-Energy Cosmic Neutrinos?
• Multi-Epoch VLBA Observations of EGRET-Detected Quasars and BL Lac Objects: Connection between Superluminal Ejections and Gamma-Ray Flares in Blazars
• TXS 0506+056, the first cosmic neutrino source, is not a BL Lac
• The redshift of the BL Lac object TXS 0506+056
• Radiation Mechanisms and Physical Properties of GeV-TeV BL Lac Objects
• Leptohadronic blazar models applied to the 2014-15 flare of TXS 0506+056
• Long-term optical monitoring of TeV emitting Blazars
• Cascading Constraints from Neutrino Emitting Blazars: The case of TXS 0506+056
• An adaptive-binning method for generating constant-uncertainty/constant-significance light curves with Fermi-LAT data
• Search for steady point-like sources in the astrophysical muon neutrino flux with 8 years of IceCube data
• Multi-Epoch Modeling of TXS 0506+056 and Implications for Long-Term High-Energy Neutrino Emission
• The connection between gamma-ray emission and millimeter flares in Fermi/LAT blazars
• A two-zone model for blazar emission: implications for TXS 0506+056 and the neutrino event IceCube-170922A
• Association of IceCube neutrinos with radio sources observed at Owens Valley and Metsähovi Radio Observatories
• Lepto-hadronic $\gamma$-ray and neutrino emission from the jet of TXS 0506+056
• Multiwavelength Cross-Correlations and Flaring Activity in Bright Blazars
• A Neutral Beam Model for High-Energy Neutrino Emission from the Blazar TXS 0506+056
• Active Galactic Nuclei and the Origin of IceCube's Diffuse Neutrino Flux
• Broadband characterisation of the very intense TeV flares of the blazar 1ES 1959+650 in 2016
• VERITAS observations of the BL Lac object TXS 0506+056
• Apparent superluminal core expansion and limb brightening in the candidate neutrino blazar TXS 0506+056
• First broadband characterization and redshift determination of the VHE blazar MAGIC J2001+439
• Implications of a proton blazar inspired model on correlated observations of neutrinos with gamma-ray flaring blazars
• ANTARES search for point-sources of neutrinos using astrophysical catalogs: a likelihood stacking analysis
• Medium-band observation of the neutrino emitting blazar, TXS 0506+056

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• VERITAS and multiwavelength observations of the Blazar B3 2247+381 in response to an IceCube neutrino alert
• Proton Synchrotron, an explanation for possible extended VHE gamma-ray activity of TXS 0506+056 in 2017
• A Very-High-Energy Gamma-Ray View of the Transient Sky
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