| Authors : | Samyaday Choudhury1,2, Prasanta K Nayak3, Dhanush SR4, Snehalata Sahu5, Richard de Grijs6,7, Annapurni Subramaniam4 |
| Authors Affiliation: | 1. Samyaday Choudhury -School of Arts and Sciences, Ahmedabad University, Ahmedabad 380009, Gujarat, India
2. Samyaday Choudhury -International Centre for Space and Cosmology, Ahmedabad University, Ahmedabad 380009, Gujarat, India
3. Prasanta K Nayak -Institute of Astrophysics, Pontificia Universidad Católica de Chile, Av. Vicuña MacKenna 4860, 7820436, Santiago, Chile
4. Dhanush SR, Annapurni Subramaniam -Indian Institute of Astrophysics, Koramangala II Block, Bengaluru 560034, Karnataka, India
5. Snehalata Sahu - University of Warwick, Coventry CV4 7AL, UK
6. Richard de Grijs - School of Mathematical and Physical Sciences, Macquarie University, Balaclava Road, Sydney, NSW 2109, Australia
7. Richard de Grijs - International Space Science Institute-Beijing (ISSI-BJ), 1 Nanertiao, Zhongguancun, Hai Dian District, Beijing 100190, China |
| Abstract : | The Magellanic Bridge, a trail of stars and gas connecting the Large and Small Magellanic Cloud (LMC and SMC), is believed to have formed during a gravitational tussle between them about 100-300 million years ago. However, the origin, structure and formation of the Bridge are still poorly understood. We have carried out observations of four fields in the Bridge using the UVIT/AstroSat (~3° across the sky) to understand the above aspects. These fields host seven UV bright star clusters for which we estimated ages, extinction and distances. We combined UVIT data with Gaia DR3 and employed statistical methods to remove Galactic contaminations and identify probable cluster members. The cluster parameters were estimated using a technique that performs an automated fitting of Padova isochrones to the complete cluster sequence using a grid of parameters (age, distance and extinction) with a range of values, and assuming constant metallicity (Z=0.004). Five out of the seven clusters are parametrized for the first time. We note that two out of the seven clusters are possibly a chance superposition of a few bright stars, and hence not clusters. The estimated ages of the clusters (~ a few 10 Myr) are indicative of an in-situ star formation in this region near the south-east part of the SMC, which is possibly originating from the tidal interactions between the LMC and SMC. The estimated distances are indicative of variation along the line of sight depth, however, the errors are significantly high to place constraints on the same. We have also carried out spectral energy distribution analysis to estimate T_eff and logg of the FUV bright stars in these clusters by combining UVIT data with multi-wavelength data from sky surveys like GALEX, Gaia, VISTA and 2MASS. We discuss the results in the context of massive stars observed in other galaxies. |
