SearcharxivSearch

arXiv subjects

R. McGeehan

Publications and source records attributed to R. McGeehan.

2 recordsLinked to original sources

Data reduction pipeline for the SuMAC millimeter-wave spectrometer at the LMT

We present the data reduction and analysis pipeline for the SuperSpec-MUSCAT Collaboration (SuMAC) along with several key science data products. In Summer 2025, SuperSpec on-chip spectrometers operating from $190-300$ GHz at $R\sim200$ were deployed in the MUSCAT cryostat at the Large Millimeter Telescope, obtaining several days of on-sky data. Analysis of these data has been used to characterize noise performance and study spectra of various astrophysical sources, establishing the viability of deploying SuperSpec detectors in future instruments. These proceedings discuss the modular data reduction pipeline which uses timestreams of the kinetic inductance detectors (KIDs) and auxiliary instrument data to generate a variety of data products. We present an on-sky calibration method for converting the KID fractional frequency shift to on-sky brightness temperature. The mapmaking module generates 3D data cubes of extended sources, while the spectrum module produces a millimeter-wave spectrum of an object. The observations all incorporate measurements of the atmosphere to model and correct for absorption. We also discuss data processing choices including detector weighting, despiking, and notch filtering. Finally, we present preliminary data products including detection of carbon monoxide in NGC 253 and spectral maps of the central region of the Orion KL nebula.

astro-ph.IM

Full-Array Noise Performance of Deployment-Grade SuperSpec mm-wave On-Chip Spectrometers

SuperSpec is an on-chip filter-bank spectrometer designed for wideband moderate-resolution spectroscopy at millimeter wavelengths, employing TiN kinetic inductance detectors. SuperSpec technology will enable large-format spectroscopic integral field units suitable for high-redshift line intensity mapping and multi-object spectrographs. In previous results we have demonstrated noise performance in individual detectors suitable for photon noise limited ground-based observations at excellent mm-wave sites. In these proceedings we present the noise performance of a full $R\sim 275$ spectrometer measured using deployment-ready RF hardware and software. We report typical noise equivalent powers through the full device of $\sim 3 \times 10^{-16} \ \mathrm{W}/\sqrt{\mathrm{Hz}}$ at expected sky loadings, which are photon noise dominated. Based on these results, we plan to deploy a six-spectrometer demonstration instrument to the Large Millimeter Telescope in early 2020.

astro-ph.IM