Italian astronomers inspect the Markarian 509 galaxy with ALMA

Using the Atacama Large Millimeter / submillimeter Array (ALMA), Italian astronomers studied an active galaxy known as Markarian 509. The results of the study, presented in an article published on July 14 on arXiv .org, provide important information on the distribution and kinematics of the galaxy’s cold molecular gas.

At a distance of some 466 million light years, Markarian 509 (or Mrk 509 for short) is a Seyfert 1.5 galaxy harboring an active galactic nucleus (AGN). Observations show that Mrk 509 is a medium-sized, bulge-like galaxy with a disk of ionized gas and a ring of stars where star formation currently continues at a rate of about five solar masses per year.

Mrk 509 is a complex system with minor fusion in progress and showing evidence of multiphase gaseous winds – from hot ionized gaseous wind to highly ionized ultrafast flows (UFOs). In order to find more evidence of molecular winds, a team of astronomers led by Maria Vitttoria Zanchettin from the University of Trieste in Italy, analyzed data from ALMA as part of the IBISCO survey, focusing on the carbon monoxide (CO) emission line. from Mrk 509.

“We presented an analysis of the CO line (2-1) and the 1.2 mm continuum of Mrk 509, a Seyfert 1.5 galaxy taken from the IBISCO sample of local AGN selected by hard x-rays,” wrote the researchers in the article.

The study found that Mrk 509 has a reservoir of molecular gas with a level of 1.7 billion solar masses, located in a disc of about 17,000 light years tilted 44 degrees and with a mass of about 20 billion solar masses. Inside this disk, a molecular fraction of gas has been estimated to be around 5%, which is typical of local star galaxies with similar star mass.

Upon further studying the disc, astronomers have found that it is unstable across the ring of stars and stable against fragmentation at the nucleus level. In addition, the kinematics of gases in the nuclear region of Mrk 509 within a radius of about 2300 light years, suggests the presence of a deformed nuclear disk.

“The presence of a molecular disc with ongoing star formation in a star ring and the signatures of a minor merger are consistent with the scenario where galaxy mergers produce destabilization of the gas, fueling the both star formation and AGN activity, ”the article’s authors explained.

The research also found significant disturbances in molecular gas kinematics at two different locations in the disc. In these two regions, the molecular gas exhibits deviations from the rotation of the disk, which have been interpreted as molecular winds and given the designations: wind A and wind B.

Astronomers noted that wind A has a speed of around 250 km / s and is located at a distance of around 980 light years from AGN, in the same region where an ionized gas wind was detected. With respect to the B wind, it has been identified at a distance of about 4,600 light years from AGN, and a short projected distance from the tidal tail. However, its speed at a level of 200 km / s indicates that this wind is not related to the tidal tail.

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