| Name: | Geethika Santhosh |
| Affiliation: | NSS College, Pandalam |
| Conference ID : | ASI2024_373 |
| Title : | Obscured star formation in the post-merger system NGC 7252 |
| Authors : | Geethika Santhosh1, Rakhi R1, Koshy George2, Smitha Subramanian3, Indulekha Kavila4 |
| Authors Affiliation: | 1 Department of Physics, NSS College, Pandalam, Kerala 689501, India
2 Faculty of Physics, Ludwig-Maximilians-Universität, Scheinerstr. 1, 81679, Munich, Germany
3 Indian Institute of Astrophysics, Bangalore 560034, India
4 School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala 686560, India |
| Mode of Presentation: | Oral |
| Abstract Category : | Galaxies and Cosmology |
| Abstract : | Mergers play a significant role in the formation and evolution of galaxies in the Universe. Small, actively star-forming systems called Tidal Dwarf Galaxies (TDGs) can form during a merger event. NGC 7252 is an advanced merger of two disc galaxies, has already attained a high degree of relaxation, resulting in a single coalesced nucleus (a post-merger remnant). Two tidal tails emanate from the merger remnant, and the tails host star-forming knots, including TDGs. The UV continuum is a direct tracer of recent star formation in galaxies but it is highly sensitive to dust. Dust-obscured star formation activity in the NGC 7252 system is studied using high-resolution FUV and NUV data from the Ultra Violet Imaging Telescope (UVIT) onboard AstroSat. The internal extinction due to dust is estimated from the slope β of the UV continuum, and the star formation rate (SFR) is calculated from the extinction-corrected FUV luminosities. Six star-forming regions are identified in the NGC 7252 system, including the remnant. It is found that the fraction of UV flux obscured in the UVIT bands ranges from fobs ≈ 0.73 - 0.97. The location of the merger remnant and TDGs with respect to the Kennicutt-Schmidt (KS) relation was examined and it is found that while the TDGs in the system fall along with normal/irregular type galaxies, the remnant lies in the starburst regime. The estimated SFR of the remnant is almost 1 dex above the prediction made from the observed total gas surface density using the KS relation. It is approximately ten times the SFR of normal spirals; the SFR of the TDGs is similar to the estimates for nearby independent dwarf galaxies. |
