ASTRONIRCAM - infrared camera-spectrograph for Sternberg institute 2.5 METER TELESCOPE

TL;DR

ASTRONIRCAM is a cryogenic infrared spectrograph and imager for the 2.5-meter telescope, enabling detailed spectral and photometric observations in the 1-2.5 micron range with high sensitivity and resolution.

Contribution

This paper presents the design, capabilities, and performance characteristics of ASTRONIRCAM, a new infrared instrument for the Caucasian observatory's 2.5-meter telescope.

Findings

Achieves limiting magnitudes of J=20 and K=19 with 15-minute exposures.

Provides spectral resolution up to R=1200 for extended and point sources.

Demonstrates 40-50% transmission efficiency in the wide-band mode.

Abstract

ASTRONIRCAM is a cryogenic-cooled slit spectrograph for the spectral range 1-2.5 mkm installed at the Nasmyth focus of the 2.5-meter telescope of the Caucasian observatory of Sternberg Astronomical Institute of Lomonosov Moscow State University. The instrument is equipped with the HAWAII-2RG 2048x2048 HgCdTe array. Grisms are used as dispersive elements. In the photometric mode ASTRONIRCAM allows for extended astronomical object imaging in the field of view of 4.6x4.6 arc minutes with the 0.269 arcsec/pixel scale in standard photometric bands J, H, K and Ks as well as in narrow-band filters CH_4, [Fe II], H_2 v=1-0 S(1), Br_gamma and CO. In the spectroscopic mode, ASTRONIRCAM takes spectra of extended or point-like sources with spectral resolution R=lambda/Delta lambda <= 1200. The general design, optical system, detector electronics and readout, amplification and digitization scheme are considered. The conversion factor GAIN measurement results are described as well as its dependence on the accumulated signal (non-linearity). The full transmission of the atmosphere-to-detector train ranges from 40 to 50\% in the wide-band photometry mode. The ASTRONIRCAM sensitivity at the 2.5-m telescope is characterized by the limiting J=20, K=19 star magnitudes measured with the 10% precision and 15 minutes integration at the 1 arcsec atmospheric seeing conditions. The references to first results published on the base of ASTRONIRCAM observations are given.