30th Annual Report 2017-18

36 UVIT Finding of Multiple Stellar Populations in NGC 1851 UVIT Imaging of Ram-Pressure Stripping in Action: Star Formation in the Stripped Gas of the GASPJellyfishGalaxy JO201 inAbell 85 Jellyfish galaxies observed in galaxy clusters are subjected to strong ram-pressure effects that strip the gas from the galaxy. The UVIT observation of a jellyfish galaxyJO201, the "UV- brightest cluster galaxy" inAbell 85, has provided high spatial resolution images revealing knots and streams of star formation in the ultraviolet. K. George, et al., including Shyam Tandon , 2018 have found star forming knots both in the stripped gas and in the galaxy disk, and measured star formation rates in the individual knots. Figure 6: NUV (measured with UVIT)-V Colour Plot for HB Stars of NGC 1851 shows presence of multiple populations with different ages in the range 10 to 13.5 billion years. (Taken from: A. Subramaniam, et al., including ShyamTandon 2017). Figure 7: UVIT/NUV image of the GASP jellyifish galaxy JO201 in Abell 85 showing star formation in stripped gas (Taken from K. George, et al 2018).