| Name: | Chandan Watts |
| Affiliation: | Indian Institute of Astrophysics, Bengaluru |
| Conference ID: | ASI2025_71 |
| Title: | A Tale of NGC 3785: The formation of an ultra-diffuse galaxy at the end of the longest tidal tail |
| Authors: | Chandan Watts 1,2, Sudhanshu Barway 1, Omkar Bait 3, Yogesh Wadadekar 4 |
| Authors Affiliation: | 1 Chandan Watts, Sudhanshu Barway Affiliation (Indian Institute of Astrophysics, Bengaluru-560034, India)
2 Chandan Watts Affiliation (Pondicherry University, R.V. Nagar, Kalapet, 605014, Puducherry, India)
3 Omkar Bait Affiliation (SKA Observatory, Jodrell Bank, Lower Withington, Macclesfield, SK11 9FT, UK)
4 Yogesh Wadadekar Affiliation (National Centre for Radio Astrophysics, Pune-411007, India) |
| Mode of Presentation: | Oral |
| Abstract Category: | Galaxies and Cosmology |
| Abstract: | We present the discovery of an extended and faint tail associated with the galaxy NGC 3785 in an isolated environment. When galaxies interact, they produce tidal features based on the nature of the interaction and the fraction of gas involved. During this process, gas and stars are extracted in the form of tidal tails and streams (Watts et al. 2024). Studies indicate that these tidal tails are blue, and most of the gas accumulates near the tip of the long tails, which results in the formation of tidal dwarf galaxies during gas-rich mergers (Duc et al. 2004).
In this work, we studied the nearby galaxy NGC 3785, which possesses lenticular (S0) morphology, and we observed a long extended tail associated with it. This tail is visible in the Dark Energy Camera Legacy Survey (DECaLS ), Sloan Digital Sky Survey (SDSS), and Panoramic Survey Telescope and Rapid Response System (Pan-STARRS) images. However, it is most clearly seen in the DECaLS observations due to their higher sensitivity. We created a detection map using the optical g-band and used the boundaries of this map to measure the length of the tail through the cubic spline fitting method. The projected length of the tail is ~390 kpc, making it the most extended tail observed in an isolated environment so far. This study also provides observational evidence supporting the formation of ultra-diffuse galaxies (UDGs) at the end of the tail. We proposed two possible scenarios for the formation of the tail and one of the scenarios indicates that this tail resulted from the interaction of the NGC 3785 with a gas-rich galaxy, which leads to the formation of a UDG at the terminus of the tail. |
