Galaxy NGC 4696 hosts a complex globular cluster system, observations find

Utilizing the Magellan Telescopes in Chile, astronomers have carried out photometric observations of a large elliptical galaxy referred to as NGC 4696. The observations reveal that the galaxy has a fancy globular cluster system. The discovering was detailed in a paper published June 12 on the pre-print server arXiv.

NGC 4696 is an elliptical galaxy at a distance of about 145 million gentle years. It’s the brightest galaxy of the Centaurus Cluster of galaxies, has an obvious dimension of 4.5 by 3.2 arcminutes, and a heliocentric velocity of roughly 2,958 km/s.

Earlier observations of NGC 4696 have detected a filamentary structure crossing its central area and increasing in the direction of a close-by galaxy designated NGC 4696B. This means that NGC 4696 could have undergone a merger up to now or that the fabric was acquired by ram-pressure stripping of NGC 4696B.

Examine of globular clusters (GCs) in and round NGC 4696 has the potential to supply extra hints about its historical past, specifically its meeting and evolution. That’s the reason a crew of astronomers led by Sara Federle of the Andrés Bello Nationwide College in Chile has investigated NGC 4696, focusing primarily on its globular cluster system (GCS).

“We offered the evaluation of the GCS of the enormous elliptical NGC 4696. The measurements are primarily based on deep Magellan 6.5m/MegaCam (g′, r′, i′) photometry,” the researchers wrote within the paper.

To start with, Federle’s crew chosen a pattern of three,973 globular cluster candidates within the area of NGC 4696. Afterward, by making use of a two colour choice, they recognized a total of three,818 GC candidates.

By analyzing the pattern of recognized GC candidates, the astronomers discovered that the GCS of NGC 4696 is disturbed, which suggests a fancy evolution with different neighboring members of the Centaurus Cluster.

It turned out that the GCS of NGC 4696 has a bimodal colour distribution with the blue peak at 0.763 magazine and the pink peak at 1.012 magazine. The blue and pink populations are divided at roughly 0.905 magazine.

Moreover, the research discovered that the colour distribution within the GCS doesn’t present the presence of a major blue tilt—when blue peaks change into redder for growing cluster’s luminosities. Nonetheless, it reveals a development with the radius, the place at small galactocentric distances, a unimodal distribution is preferable to a bimodal one, which factors to the presence of an intermediate GC inhabitants.

The research additionally discovered that the GCS’ metallicity distribution additionally showcases a bimodal development and that the radial density profiles present completely different slopes for the blue and pink populations. As well as, it seems that the azimuthal distributions for the total, pink and blue populations of GC candidates are nicely fitted by an asymmetrical sinusoidal distribution, suggesting that interactions between NGC 4696 and its two close by galaxies could have performed a job in shaping its GCS.

“All these outcomes level towards a fancy GCS, strongly influenced by the interplay historical past of NGC 4696 with the opposite galaxies of the Centaurus cluster,” the authors of the paper concluded.

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