SIT 45, a galaxy triplet, was thoroughly examined

Hyper Suprime-Cam (HSC) g-r-i band color image of the isolated triplet SIT 45. Credit: Aihara et al., 2022.

An international team of astronomers has conducted multiwavelength photometric investigations of the SIT 45 galaxy triplet. The study's findings, which were published on arXiv.org on September 26th, reveal crucial information on the physics and behavior of this item. Galaxy triplets are often regarded as fascinating laboratories for studying the formation and development of tiny and massive galaxies. However, because they are uncommon in the nearby universe, identifying new ones and thoroughly analyzing them is critical for astronomers.

SIT 45 (also known as UGC 12589) is an uncommon isolated galaxy triplet comprised of three merging late-type galaxies located 473 million light-years distant. Given that SIT 45 comprises three interacting galaxies, it is likely to have complicated dynamics and the history of star creation. As a result, a group of researchers led by Diana Grajales-Medina of Valencian International University in Spain investigated the evolution of SIT 45 via its dynamic features and configuration, as well as its local surroundings and large-scale structure. They studied data from several surveys, including the Galaxy Evolution Explorer (GALEX) satellite All Sky Survey and the Two Micron All Sky Survey, for this aim (2MASS). According to the paper's authors, "we studied the dynamical parameters and SFH [star formation history] of the isolated merging galaxy triplet SIT 45 in this work." SIT 45 (UGC 12589) is an uncommon isolated triplet of galaxies composed of three interacting late-type galaxies.

As a result, it is an excellent option for studying processes such as the triggering of star formation owing to contact. According to the study, SIT 45 is a highly isolated system in comparison to its large-scale surroundings and is one of the most compact triplets in the SIT (SDSS-based inventory of Isolated Triplets) database. Its tidal force parameter attributable to triplet members has one of the highest values in the SIT collection.

The study discovered that SIT 45 has a continuing star formation history by examining its star formation history, with one of the galaxies, dubbed SIT 45C, displaying starburst activity. In general, the three galaxies show a recent (approximately 200 million years old) spike in star formation, which implies that it was driven by the merger process. According to the results, SIT 45 is highly developed, owing to its harmonic radius and crossing time values that are substantially smaller than those of the other known SIT triplets. It was also discovered that SIT 45 is made up of blue spirals with a high rate of star formation, which might be embedded in a shared dark matter halo. The researchers present the two most likely possibilities for explaining SIT 45's features.

The study's authors stated, "We consider two scenarios for the current configuration of the triplet, one in which one of the members is a tidal galaxy, and another in which this galaxy arrives in the system after the interaction." Both options require additional investigation.

Journal Information: SIT 45: An interacting, compact, and star-forming isolated galaxy triplet, arXiv:2209.12850 [astro-ph.GA] arxiv.org/abs/2209.12850