| Name: Bannanje Ananthamoorthy |
| Affiliation: Manipal Centre for Natural Sciences, Centre of Excellence, Manipal Academy of Higher Education, Manipal, Karnataka, India |
| Conference ID: ASI2026_154 |
| Title: Detection of a UV Star-Forming Knot in the Giant Radio Galaxy NGC 315 |
| Abstract Type: Oral |
| Abstract Category: Galaxies and Cosmology |
| Author(s) and Co-Author(s) with Affiliation: B Ananthamoorthy(Manipal Centre for Natural Sciences, Manipal Academy of Higher Education, Karnataka, Manipal, 576104, India), Debbijoy Bhattacharya(Manipal Centre for Natural Sciences, Manipal Academy of Higher Education, Karnataka, Manipal, 576104, India), Dipanjan Mukherjee(Inter-University Centre for Astronomy and Astrophysics, Post Bag-4, Pune University, Ganeshkhind, Pune 411007, India), P. Sreekumar(Manipal Centre for Natural Sciences, Manipal Academy of Higher Education, Karnataka, Manipal, 576104, India) |
| Abstract: Energy output from Active galactic nuclei (AGNs) plays a crucial role in regulating the star formation properties of the host galaxies, a process known as AGN feedback. Mechanical (jet-driven) feedback can influence the surrounding medium on galactic and even extragalactic scales, often manifesting as cavities in the hot cluster medium that are aligned with radio jets. However, direct observational evidence linking AGN feedback to localized star formation remains limited. We present a study of the ultraviolet (UV) star formation properties of the nearby elliptical galaxy NGC 315, which hosts a prominent large-scale radio jet. Observations with the UltraViolet Imaging Telescope (UVIT) onboard AstroSat reveal a bright UV knot located at a projected distance of $\sim$1.7 kpc from the nucleus. This knot lies along dusty filamentary structures identified in Hubble Space Telescope observations, suggesting a physical association between dust and UV emission. We propose that this UV emission is likely due to ongoing star formation in the galaxy. The star formation rate (SFR), averaged over 100 Myr, is estimated to be 0.23$\pm$0.10 M$_\odot$ yr$^{−1}$, which is significantly higher than the typical SFR observed in elliptical galaxies. We speculate a possible AGN jet-triggered star formation near the nuclear region of the galaxy, where the gas could have been supplied via minor merger, cooled gas falling into the central brightest cluster galaxy, and/or condensing of the gas uplifted by the AGN jet. The results also point to a possible role of the AGN in the formation of dust within the galaxy.
The work has been published in MNRAS as B. Ananthamoorthy et al., 2025, MNRAS, 544, 3394.
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