| Author(s) and Co-Author(s) with Affiliation: Chayan Mondal(S. N. Bose National Centre for Basic Sciences, Kolkata-700106, India), Kanak Saha(Inter-University Centre for Astronomy and Astrophysics, Pune - 411007, India), Rogier A. Windhorst(School of Earth & Space Exploration, Arizona State University, Tempe, AZ 85287-1404, USA), Chian Chou Chen(Academia Sinica Institute of Astronomy and Astrophysics, Taipei 106319, Taiwan), Rolf A. Jansen(School of Earth & Space Exploration, Arizona State University, Tempe, AZ 85287-1404, USA), Anshuman Borgohain(Inter-University Centre for Astronomy and Astrophysics, Pune - 411007, India), Brent M. Smith(School of Earth & Space Exploration, Arizona State University, Tempe, AZ 85287-1404, USA), Naveen Reddy(Department of Physics and Astronomy, University of California, Riverside, CA 92521, USA), Souradeep Bhattacharya(Centre for Astrophysics Research, University of Hertfordshire, Hatfield AL10 9AB, UK), Shyam N. Tandon(Inter-University Centre for Astronomy and Astrophysics, Pune - 411007, India), Keiichi Umetsu(Academia Sinica Institute of Astronomy and Astrophysics, Taipei 106319, Taiwan), Marc Rafelski(Space Telescope Science Institute, Baltimore, MD 21218, USA), Harry I. Teplitz(IPAC, California Institute of Technology, Pasadena, CA 91125, USA) |
| Abstract: The importance of multi-band Deep Field observations to study distant galaxies has become evident during the last few decades. Among various wavelengths, rest-frame far-ultraviolet emission is particularly sensitive to both young stellar populations and interstellar dust in galaxies. We use deep UV imaging from the Ultra-Violet Imaging Telescope (UVIT) onboard AstroSat, combined with observations in optical and infrared bands, to disentangle the dust extinction and the nature of the attenuation law in star-forming galaxies at redshifts of ~ 0.40-0.75 in the AstroSat UV Deep Field (AUDF) north. We further utilize mid-infrared imaging from the James Webb Space Telescope (JWST) of a sample of UV-selected galaxies in the AUDF south field to probe the 7.7 and 11.3 μm emission strength of the Polycyclic Aromatic Hydrocarbon (PAH) dust molecules under varying galaxy properties within the same redshift window. We find that the PAH emission strength increases with stellar mass and rest-frame FUV luminosity, identifying massive, UV-bright galaxies as strong PAH emitters. In addition, we observe an anti-correlation between the strength of PAH emission and the O32 line ratio, suggesting PAH destruction in harder radiation fields. Overall, our study presents key insights into interstellar dust of galaxies in a relatively unexplored redshift range that bridges the cosmic noon and the present-day universe. I will also discuss the unique scope of the AUDF survey in discovering Lyman Continuum (LyC) leaking galaxies at redshift ~ 1 - 3, along with our recent finding of a z=2.9803 He II1640 emitting potentially LyC leaking galaxy (GNHeII~J1236+6215) showing a promising signature of PopIII-like star formation. |
