TIFR Near Infrared Imaging Camera-II on the 3.6 m Devasthal Optical Telescope

Abstract

Tata Institute of Fundamental Research (TIFR) Near Infrared Imaging Camera-II (TIRCAM2) is a closed-cycle Helium cryo-cooled imaging camera equipped with a Raytheon 512[Formula: see text][Formula: see text][Formula: see text]512 pixels InSb Aladdin III Quadrant focal plane array (FPA) having sensitivity to photons in the 1–5[Formula: see text][Formula: see text] wavelength band. In this paper, we present the performance of the camera on the newly installed 3.6[Formula: see text]m Devasthal Optical Telescope (DOT) based on the calibration observations carried out during 2017 May 11–14 and 2017 October 7–31. After the preliminary characterization, the camera has been released to the Indian and Belgian astronomical community for science observations since 2017 May. The camera offers a field-of-view (FoV) of [Formula: see text] on the DOT with a pixel scale of 0.169[Formula: see text]. The seeing at the telescope site in the near-infrared (NIR) bands is typically sub-arcsecond with the best seeing of [Formula: see text] realized in the NIR [Formula: see text]-band on 2017 October 16. The camera is found to be capable of deep observations in the [Formula: see text], [Formula: see text] and [Formula: see text] bands comparable to other 4[Formula: see text]m class telescopes available world-wide. Another highlight of this camera is the observational capability for sources up to Wide-field Infrared Survey Explorer (WISE) W1-band (3.4[Formula: see text][Formula: see text]m) magnitudes of 9.2 in the narrow [Formula: see text]-band ([Formula: see text]; [Formula: see text] 3.59[Formula: see text][Formula: see text]m). Hence, the camera could be a good complementary instrument to observe the bright [Formula: see text]-band sources that are saturated in the Spitzer-Infrared Array Camera (IRAC) ([3.6] [Formula: see text] 7.92 mag) and the WISE W1-band ([3.4] [Formula: see text] 8.1 mag). Sources with strong polycyclic aromatic hydrocarbon (PAH) emission at 3.3[Formula: see text][Formula: see text]m are also detected. Details of the observations and estimated parameters are presented in this paper.