SDSS J082625.70+612515.10 (V = 11.4; [Fe/H] = −3.1) and SDSS J134144.60+474128.90 (V = 12.4; [Fe/H] = −3.2) were observed with the SDSS 2.5-m telescope as part of the SDSS-MARVELS spectroscopic presurvey, and were identified as extremely metal-poor (EMP; [Fe/H] < −3.0) stars during high-resolution followup with the Hanle Echelle Spectrograph (HESP) on the 2.3-m Himalayan Chandra Telescope. In this paper, the first science results using HESP, we present a detailed analysis of their chemical abundances. Both stars exhibit under-abundances in their neutron-capture elements, while one of them, SDSS J134144.60+474128.90, is clearly enhanced in carbon. Lithium was also detected in this star at a level of about A(Li) = 1.95. The spectra were obtained over a span of 6-24 months, and indicate that both stars could be members of binary systems. We compare the elemental abundances derived for these two stars along with other carbon-enhanced metal-poor (CEMP) and EMP stars, in order to understand the nature of their parent supernovae. We find that CEMP-no stars and EMP dwarfs exhibit very similar trends in their lithium abundances at various metallicities. We also find indications that CEMP-no stars have larger abundances of Cr and Co at a given metallicity, compared to EMP stars.

SCALES is a high-contrast, infrared coronagraphic imager and integral field spectrograph (IFS) to be deployed behind the W.M. Keck Observatory adaptive optics system. A reflective optical design allows diffraction-limited imaging over a large wavelength range (1.0 -5.0 µm). A microlens array-based IFS coupled with a lenslet reformatter ("slenslit") allow spectroscopy at both low (R = 35 -250) and moderate (R = 2000 -6500) spectral resolutions. The large wavelength range, diffraction-limited performance, high contrast coronagraphy and cryogenic operation present a unique optical design challenge. We present the full SCALES optical design, including performance modeling and analysis and manufacturing.

IRIS (Infrared Imaging Spectrograph) is the near-infrared (0.81 µm to 2.4 µm) diffraction-limited imager and integral field spectrograph (IFS) designed for the Thirty Meter Telescope (TMT) and the Narrow-Field Infrared Adaptive Optics System (NFIRAOS). The imager will have a 34 arcsec x 34 arcsec field of view with 4 milliarcsecond (mas) sampling. The IFS consists of a lenslet array and a slicer, enabling four plate scales from 4 mas to 50 mas, with multiple gratings and filters. We will report the progress on the development of the IRIS Data Reduction System (DRS) in the final design phase. The IRIS DRS is developed in Python with the software architecture based on the James Webb Space Telescope science calibration pipeline (stpipe). We are developing a library of algorithms as individual Python classes that can be configured independently and bundled into pipelines. The IRIS DRS will interface with the TMT observatory software and will operate in real-time and as a stand-alone public package for offline reduction. The IRIS DRS also includes a C library for readout processing that is used for both real-time processing and post-processing. Lastly, we will discuss development of the IRIS simulation package that simulates raw spectra and imager readout-data from the Teledyne Hawaii-4RG detectors, which are used to test and develop reduction algorithms.

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A next-generation instrument named, Slicer Combined with Array of Lenslets for Exoplanet Spectroscopy (SCALES), is being planned for the W. M. Keck Observatory. SCALES will have an integral field spectrograph (IFS) and a diffraction-limited imaging channel to discover and spectrally characterize the directly imaged exoplanets. Operating at thermal infrared wavelengths (1-5 µm, and a goal of 0.6-5 µm), the imaging channel of the SCALES is designed to cover a 12 × 12 field of view with low distortions and high throughput. Apart from expanding the mid-infrared science cases and providing a potential upgrade/alternative for the NIRC2, the H2RG detector of the imaging channel can take high-resolution images of the pupil to aid the alignment process. Further, the imaging camera would also assist in small field acquisition for the IFS arm. In this work, we present the optomechanical design of the imager and evaluate its capabilities and performances.