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WISE J224607.6–052634.9 (W2246–0526) is a hot dust-obscured galaxy atz = 4.601, and the most luminous obscured quasar known to date. W2246–0526 harbors a heavily obscured supermassive black hole that is most likely accreting above the Eddington limit. We present observations with the Atacama Large Millimeter/submillimeter Array (ALMA) in seven bands, including band 10, of the brightest far-infrared (FIR) fine-structure emission lines of this galaxy: [OI]_63 μm, [OIII]_88 μm, [NII]_122 μm, [OI]_145 μm, [CII]_158 μm, [NII]_205 μm, [CI]_370 μm, and [CI]_609 μm. A comparison of the data to a large grid of CLOUDYradiative transfer models reveals that a high hydrogen density (n_H ∼ 3 × 10³cm⁻³) and extinction (A_V ∼ 300 mag), together with extreme ionization (log(U) = − 0.5) and a high X-ray to UV ratio (α_ox ≥ −0.8) are required to reproduce the observed nuclear line ratios. The values ofα_oxandUare among the largest found in the literature and imply the existence of an X-ray-dominated region (XDR). In fact, this component explains the a priori very surprising non-detection of the [OIII]_88 μmemission line, which is actually suppressed, instead of boosted, in XDR environments. Interestingly, the best-fitted model implies higher X-ray emission and lower CO content than what is detected observationally, suggesting the presence of a molecular gas component that should be further obscuring the X-ray emission over larger spatial scales than the central region that is being modeled. These results highlight the need for multiline infrared observations to characterize the multiphase gas in high redshift quasars and, in particular, W2246–0526 serves as an extreme benchmark for comparisons of interstellar medium conditions with other quasar populations at cosmic noon and beyond. 

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. 

Abstract 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. 

The Fred Young Submillimeter Telescope (FYST), which is the telescope of the CCAT-prime project, will be located at 5600 m near the summit of Cerro Chajnantor in northern Chile, and will host the modular instrument called Prime-Cam. Two of the instrument modules in Prime-Cam will be a spectrometer with a resolving power of R ∼ 100 and populated with a detector array of several thousand KIDs (Kinetic Inductance Detectors). The main science goal of this spectrometer module, called EoR-Spec, is to probe the Epoch of Reionization (EoR) in the early universe using the Line Intensity Mapping (LIM) technique with the redshifted [CII] fine-structure line. This presentation provides an overview of the optical, mechanical, and spectral design of EoR-Spec, as well as of the detector array that will be used. The optical design consists of four silicon lenses that have anti-reflection metamaterial layers. A scanning Fabry-Perot Interferometer (FPI) will be located at the pupil and provides the spectral resolution over the full spectral coverage of 210 GHz to 420 GHz in two orders, resulting in a redshift coverage of the [CII] line from z = 3.5 to z = 8. The detector array consists of three subarrays of KIDs, two of which are tuned for the frequency range between 210 GHz and 315 GHz, and one that is tuned for the 315 GHz to 420 GHz range. The angular resolution will be between about 30'' to 50''. This presentation also addresses the spectral and spatial scanning strategy of EoR-Spec on FYST. EoR-Spec is expected to be installed into Prime-Cam about 1 year after first light of FYST.