Abstract Details

Name: Mousumi Das
Affiliation: Indian Institute of Astrophysics
Conference ID: ASI2021_276
Title : Star formation in Low Stellar Density Environments in Galaxies
Authors and Co-Authors : Das, M. (IIA); Yadav, J. (IIA); Patra, N. (RRI); Dwarakanath, K.S. (RRI); McGaugh, S.S. (CWRU); Schombert, J.S. (University of Oregon); Rahna, P.T. (SHAO); Murthy, J. (IIA)
Abstract Type : Poster
Abstract Category : Extragalactic Astronomy
Abstract : Star formation generally occurs in the inner disks of galaxies where the stellar disk surface density is high and there is copious amounts of dense molecular hydrogen gas. However, young star forming regions have been discovered in low density environments where there is HI gas but only a diffuse stellar disk. The star formation processes in these metal poor, low stellar density regions is not well understood. I will present two examples of such star formation, extended UV (XUV) disks and low surface brightness (LSB) galaxies. XUV galaxies are spirals that show filamentary/diffuse star formation in the outer parts of their optical disks. These regions have low stellar surface densities, low metal content and are adverse environments for star formation. Previous studies by GALEX found that surpringly 30% of nearby spiral galaxies have XUV disks. It maybe driven by galaxy interactions, gas infall, or accretion from the IGM. We present a study of three XUV galaxies using the UVIT. We compare the properties of the star forming complexes inside and outside the optical radius. Our observations suggest that they formed due to local disk instabilities and that their distribution is well correlated with the HI gas distribution, and the HI holes. We then present a UVIT study of the LSB galaxy UGC9024, which appears to show the highest star formation rate compared to other low redshifts LSB galaxies. We discuss the SFCs and compare it with our GMRT HI observations of this galaxy. We discuss the SFCs and compare it with our GMRT HI observations of this galaxy.