Astronomy & Space

Blazar 3C 279 Reveals Extreme Behavior During Global Telescope Campaign

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During a comprehensive April 2017 observing campaign, the blazar 3C 279 exhibited complex multiwavelength variability including increased radio flux in its innermost core, the ejection of a superluminal knot, record-breaking UV-optical flares in late March, and subsequent gamma-ray activity that declined by mid-April. X-ray emissions remained low and no very high energy emission was detected during this period. Modeling suggests the observed broadband spectrum and variability can be explained by turbulent plasma cells compressed by a stationary conical shock within the jet, though alternative mechanisms like magnetic reconnection cannot be ruled out.


This extensive multiwavelength dataset provides critical insights into the physical processes driving jet formation and emission in blazars, helping astronomers understand how supermassive black holes accelerate matter to near light-speed. The publicly available data will serve as an important reference for future studies of relativistic jets and extreme astrophysical phenomena.


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arXiv:2606.25868v1 Announce Type: new
Abstract: The archetypal blazar 3C 279 hosts a prominent relativistic jet and exhibits strong broadband variability across the electromagnetic spectrum. In April 2017, the Event Horizon Telescope (EHT) observed 3C 279, alongside one of the most extensive quasi-simultaneous multiwavelength (MWL) campaigns ever conducted. With the aim of investigating the physical processes governing 3C 279, we analyzed individual observations and multiband light curves, and constructed a new quasi-simultaneous MWL spectrum. We also performed phenomenological modeling using the turbulent extreme multi-zone (TEMZ) model to constrain the fundamental physical properties of the source. The EHT observations reveal a clear flux increase in the innermost core between April 5 and 11, 2017. Over a broader timescale, radio measurements at longer wavelengths show concurrent enhancements in core flux and polarization around mid-April, coinciding with the ejection of a superluminal knot. Record UV-optical flares with strong polarization variability occurred in late March, followed by gamma-ray activity that declined before the end of the EHT observing period. During this interval, the source remained in a low X-ray state and showed no detectable VHE emission. The TEMZ modeling suggests that the broadband spectrum and variability of 3C 279 can be explained within a jet scenario in which turbulent plasma cells are compressed by a stationary conical shock. However, alternative interpretations, such as magnetic reconnection or a moving shock-in-jet event, remain plausible. This coordinated MWL campaign advances our understanding of the origin of jet and gamma-ray emission in 3C 279, while also providing a comprehensive publicly available dataset that will serve as a valuable reference for future studies.

Source: Broadband multiwavelength properties of the archetypal blazar 3C 279 during the 2017 Event Horizon Telescope campaign