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We present recent developments on Cornell’s 2nd generation z (redshift) and Early Universe Spectrometer (ZEUS-2). ZEUS-2 is a long-slit echelle-grating spectrometer, originally implemented to deliver R∼1000 spectroscopy in the 350-, and 450-micron telluric windows using NIST Transition-Edge Sensed (TES) bolometer arrays. We have expanded its capabilities to also cover the 200-micron window, and present first-light data for the new array from our 2019 observing campaign on the Atacama Pathfinder EXperiment (APEX) telescope. We also discuss the various enhancements we have implemented to improve observing efficiency and noise performance, including identifying and mitigating vibrations in hardware and improving the stability and robustness of the control software for the detector temperature. Furthermore, we have implemented several software routines to interface with the telescope control systems. These improvements, demonstrated during our recent observing campaign in Nov-Dec 2021, resulted in enhanced reliability and ease of operation, as well as increased sensitivity. A data-driven software pipeline, leveraging data from all 300 detectors on the array to remove common-mode noise, was implemented, and noise performance was further improved by robustly detecting unstable detectors and disabling them during observations. 

An often unglamorous, yet critical, part of most millimeter/submillimeter astronomical instruments is cryogenic temperature monitoring and control. Depending on the operating wavelength of the instrument and detector technology, this could be stable temperatures in the Kelvin range for millimeter heterodyne systems to 100 mK temperatures at sub-micro-Kelvin stability as for many submillimeter bolometer systems. Here we describe a project of the HARDWARE.astronomy initiative to build a low-cost open-source temperature monitoring and control system. The HARDWARE.astronomy Housekeeping Box, or H.aHk Box (pronounced “hack box”) is developed primarily by undergraduates and employs existing open-source devices (e.g Arduino, Raspberry Pi) to reduce costs while also limiting the complexity of the development. The H.aHk Box features a chassis with a control computer and ten expansion slots that can be filled with a variety of expansion cards. These cards include initially an AC 4-wire temperature monitor and PID control cards. Future work will develop 2-wire temperature monitors, stepper motor controller, and high-power supply. The base-system will also be able to interface with other house-keeping systems over USB, serial port and ethernet. The first deployment of the H.aHk Box will be for the ZEUS-2 submillimeter grating spectrometer. All designs, firmware, software and parts list will be published online allowing for other projects to adopt the system and create custom expansion cards as needed. Here we describe the design (including mechanical, electrical, firmware, and software components) and initial performance of the H.aHk Box system with initial AC/DC 4-wire and PID cards. 

We report CO(5 → 4) and CO(6 → 5) line observations in the dusty starbursting galaxy CRLE (z= 5.667) and the main-sequence (MS) galaxy HZ10 (z= 5.654) with the Northern Extended Millimeter Array. CRLE is the most luminousz> 5 starburst in the COSMOS field and HZ10 is the most gas-rich “normal” galaxy currently known atz> 5. We find line luminosities for CO(5 → 4) and CO(6 → 5) of (4.9 ± 0.5) and (3.8 ± 0.4) × 10¹⁰K km s⁻¹pc²for CRLE and upper limits of < 0.76 and < 0.60 × 10¹⁰K km s⁻¹pc²for HZ10, respectively. The CO excitation of CRLE appears comparable to otherz> 5 dusty star-forming galaxies. For HZ10, these line luminosity limits provide the first significant constraints of this kind for an MS galaxy atz> 5. We find the upper limit of$L_{5\to 4}^{\prime }/L_{2\to 1}^{\prime }$in HZ10 could be similar to the average value for MS galaxies aroundz≈ 1.5, suggesting that MS galaxies with comparable gas excitation may already have existed one billion years after the Big Bang. For CRLE we determine the most likely values for the H₂density, kinetic temperature, and dust temperature based on excitation modeling of the CO line ladder. We also derive a total gas mass of (7.1 ± 1.3) × 10¹⁰M_⊙. Our findings provide some of the currently most detailed constraints on the gas excitation that sets the conditions for star formation in a galaxy protocluster environment atz> 5.

 

We present a detailed overview of the science goals and predictions for the Prime-Cam direct-detection camera–spectrometer being constructed by the CCAT-prime collaboration for dedicated use on the Fred Young Submillimeter Telescope (FYST). The FYST is a wide-field, 6 m aperture submillimeter telescope being built (first light in late 2023) by an international consortium of institutions led by Cornell University and sited at more than 5600 m on Cerro Chajnantor in northern Chile. Prime-Cam is one of two instruments planned for FYST and will provide unprecedented spectroscopic and broadband measurement capabilities to address important astrophysical questions ranging from Big Bang cosmology through reionization and the formation of the first galaxies to star formation within our own Milky Way. Prime-Cam on the FYST will have a mapping speed that is over 10 times greater than existing and near-term facilities for high-redshift science and broadband polarimetric imaging at frequencies above 300 GHz. We describe details of the science program enabled by this system and our preliminary survey strategies.

 

We report the serendipitous discovery of a dusty, starbursting galaxy at z=5.667 (called CRLE hereafter), in close physical association to the "normal" Main Sequence galaxy HZ10 at z=5.654. CRLE was identified by detection of [CII], [NII] and CO(2-1) line emission, making it the highest redshift, most luminous starburst in the COSMOS field. This massive, dusty galaxy appears to be forming stars at a rate of at least 1500$\,M_\odot$ yr$^{-1}$ in a compact region only ~3 kpc in diameter. The dynamical and dust emission properties of CRLE suggest an ongoing merger driving the starburst, in a potentially intermediate stage relative to other known dusty galaxies at the same epoch. The ratio of [CII] to [NII] may suggest that an important contribution to the [CII] emission comes from a diffuse ionized gas component, which could be more extended than the dense, starbursting gas. CRLE appears to be located in a significant galaxy overdensity at the same redshift, potentially associated with a large scale cosmic structure recently identified in a Lyman Alpha Emitter survey. This overdensity suggests that CRLE and HZ10 reside in a protocluster environment, offering the tantalizing opportunity to study the effect of a massive starburst on protocluster star formation. Our findings support the interpretation that a significant fraction of the earliest galaxy formation may occur from the inside-out, within the central regions of the most massive halos, while rapidly evolving into the massive galaxy clusters observed in the local Universe.