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Astronomers have conducted very long baseline Interferometry (VLBI) observations of an active galaxy known as Markarian 110. As a result, they detected a relativistic jet in this galaxy. The in a research paper published June 4 on the arXiv pre-print server.

Active galactic nuclei (AGNs) are small regions at the center of an active galaxy dominated by the light emitted by dust and gas. Narrow-line Seyfert 1 (NLS1) galaxies are a class of AGNs exhibiting excessive behavior at all wavelengths. They show peculiar characteristics like narrow Balmer lines, strong ionized iron emission lines, and extreme properties in the X-rays.

Markarian 110 (or Mrk 110 for short) is a radio-quiet AGN and an NLS1 at a redshift of 0.035. The galaxy has an apparent magnitude of 15.4 mag and showcases a highly irregular morphology, which suggests a recent interaction or a merging event in this system. It also has a variable core confined to an extremely compact region.

The properties of Mrk 110 make it an exceptional laboratory for studying weak radio emission mechanisms in AGN, which could help answer fundamental questions about jet formation conditions. That is why a team of astronomers led by Ailing Wang of the Chinese Academy of Sciences decided to perform VLBI observations (at 1.6, 4.7, 4.9, and 7.6 GHz) of Mrk 110, between 2015 and 2024, using the Very Long Baseline Array (VLBA) and the European VLBI Network (EVN).

"In this Letter, we present new Very Long Baseline Interferometry observations of Mrk 110, designed to probe its radio structure with high resolution and sensitivity," the researchers wrote in the paper.

The observations reveal intermittent jet activity in Mrk 110: between 2015 and 2016 as well as between 2022 and 2024. The astronomers explain that the 2015–2016 data clearly show evidence of an earlier jet ejection episode with significant positional shift in the northwest direction.

The jet evolution reveals a dramatic change after 2022 and analysis of 7.6-GHz observations between August 2023 and February 2024 yields a proper motion of 0.6 mas/year.

The relativistic jet activity in Mrk 110 appears to have a superluminal velocity. It represents one of the highest velocity outflows detected in a radio-quiet AGN. The observations show that the jet decelerates at about 10–20 light years from the galaxy's core.

The astronomers noted that this deceleration accompanies dramatic spectral evolution from the steep spectral index to inverted.

"The observed spectral progression in Mrk 110 quantitatively matches the theoretical models of evolving self-absorbed synchrotron emission in nascent jets, with the inverted spectrum precisely corresponding to the canonical value for optically thick synchrotron emission from a homogeneous source," the researchers explained.

Trying to find the physical mechanism behind the jet activity in Mrk 110, the authors of the paper assume that it involves a combination of key factors like high accretion rate, high black hole spin, as well as episodic magnetic flux accumulation and dissipation cycles.

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