Discovery of an Active Galactic Nucleus (AGN) in the Sombrero Galaxy
A recent analysis of images captured by the Hubble Space Telescope (HST) has unveiled an intriguing find within the Sombrero Galaxy. Conducted by Elio Quiroga Rodriguez from the Mid Atlantic University in Spain, this discovery sheds light on a previously unnoticed galaxy that harbors an active galactic nucleus (AGN). The findings were detailed in a research paper released on August 11 via the arXiv pre-print server.
Active Galactic Nuclei: A Brief Overview
Active Galactic Nuclei, or AGNs, denote compact regions positioned at a galaxy’s center, radiating more luminosity than its surrounding galactic light. These AGNs are characterized by their high energy output, attributed to either the presence of a black hole or significant star formation activities within the core of the galaxy.
AGNs are traditionally classified into two primary groups based on the features of their emission lines. Type 1 AGNs exhibit broad and narrow emission lines, whereas Type 2 AGNs display narrow emission lines. Interestingly, some AGNs have been observed transitioning between different spectral types, giving rise to the term “changing-look” (CL) AGNs.
The Sombrero Galaxy: Messier 104
Situated at approximately 31 million light years between the Virgo and Corvus constellations, the Sombrero Galaxy (Messier 104 or NGC 4594) is an unbarred spiral galaxy. Boasting a substantial mass of around 800 billion solar masses, it ranks among the most massive entities within the Virgo galaxy cluster. Furthermore, the Sombrero Galaxy is home to an intricate system of globular clusters.
Elio Quiroga Rodriguez delved into HST images of the Sombrero Galaxy, specifically focusing on a particular entity within its halo. Previously labeled as a candidate for a globular cluster, this object may be a barred spiral galaxy categorized as SBc, housing an AGN at its core.
Rodriguez observed the object at coordinates 12:40:07.829-11:36:47.38 (in j2000), measuring approximately four arcseconds in diameter while studying HST images accessible through the HST Legacy website. Leveraging VO tools, he identified the object as an SBc galaxy with an AGN of the Seyfert type.
Characteristics of the Iris Galaxy
The object, cataloged as PSO J190.0326-11.6132 in the Pan-STARRS1 data archive, was subjected to detailed examination using the Aladin Sky Atlas RGB. Rodriguez’s analysis unveiled a galaxy featuring a prominent central arm, nucleus, and potentially two spiral arms adorned with young, hot stars and dust. He proposes that this newfound galaxy should be christened, the “Iris Galaxy.”
The Iris Galaxy possesses a radial velocity of 1,359 km/s. If gravitationally tied to the Sombrero Galaxy, it might be its satellite, sporting an angular size of roughly 1,000 light years. Nonetheless, if the Iris Galaxy isn’t linked to the Sombrero Galaxy, its distance could be around 65 million light years, accompanied by an angular size of approximately 71,000.
Emission Luminosity and AGN Classification
Based on a distance assumption of 65 million light years, the X-ray emission luminosity of the Iris Galaxy is estimated at 18 tredecillion erg/s. This high luminosity suggests the presence of an active galactic nucleus. Further observations are necessary to ascertain whether the AGN is Type 1 or Type 2.
In conclusion, the meticulous analysis of HST images has led to the discovery of the Iris Galaxy, a previously unnoticed barred spiral galaxy with an active galactic nucleus at its core within the Sombrero Galaxy’s halo. This finding underscores the dynamic and diverse nature of galaxies within our universe.
Read the original article on PHYS.
Read more: The Sense of Smell in Dogs is Highly Skilled at Detecting 8 Different Diseases.
