There are many astrophysical questions which require highly sensitive, high spatial resolution observations of thousands of astrophysical objects in a relatively short time. Large aperture telescopes equipped with very powerful instruments, which have multiplexing ability, are being built worldwide to address these fundamental science questions. The astronomical community in India is also actively participating in this endeavor. India is planning to build a large aperture (8-10 meter) telescope (NLOT), and is also part of the international Thirty-Meter Telescope (TMT) project, which is expected to be operational in the decade of 2030-40. The IR group at TIFR has initiated the concept design and development of a Multi-Object Infrared Spectrograph (MOIS) with configurable slits operating in the near-IR wavelengths (0.9 – 2.5 μm) that can be deployed on such a large aperture telescope. We have completed the concept design and testing and are currently building a prototype that can be deployed on the 3.6 m Devasthal Optical Telescope.
MOIS is a configurable slit spectrograph (R=2500) and wide field imager (~ 9.6 arcmin across) operating at the near-IR wavelengths (0.9 – 2.5 micron) with 5 configurable slits, and is being designed as a facility instrument for DOT. The wide-field imaging capability of MOIS and the ability to do near-simultaneous imaging and multi-object spectroscopy of astrophysical objects spread over a large field of view makes it an ideal workhorse instrument for DOT. We have completed a preliminary optical design of the spectrograph, including the design of the main opto-mechanical assemblies, along with preliminary tolerance and stray-light analysis and various trade studies. The most challenging component of MOIS, the Configurable Slit Unit (CSU), has been successfully demonstrated in the lab, with a 3-slit prototype built and validated at cryogenic temperatures. Additionally, we have developed observation and raw data simulators to simulate and test various instrument modes and data to better understand different aspects of observations and data handling. I will describe the salient features of MOIS and the current status of its development, and briefly highlight some of the science cases that can be optimally addressed by MOIS.
Prof. Manoj Puravankara is currently a faculty member at the Dept. of Astronomy & Astrophysics, Tata Institute of Fundamental Research, Mumbai. Before joining TIFR, he worked as a Research Associate at the University of Rochester, Rochester, NY, USA, and was a postdoctoral fellow at the Academia Sinica Institute for Astronomy & Astrophysics, Taipei, Taiwan, and at the Inter-University Center for Astronomy & Astrophysics, Pune, India. He obtained his Ph. D. in 2005 from the Indian Institute of Astrophysics, Bangalore, India. His primary research interests are in the area of star and planet formation and currently working on young stellar objects and protoplanetary disks and developing instruments to study them.