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1. The upgraded camera for the prototype Schwarzschild-Couder Telescope of the Cherenkov Telescope Array

   https://doi.org/10.1117/12.2530431  

   Paoletti, Riccardo ( September 2019 , The upgraded camera for the prototype Schwarzschild-Couder Telescope of the Cherenkov Telescope Array)

   The Schwarzschild-Couder Telescope (SCT) is a mid-size telescope proposed for the Cherenkov Telescope Array. In order to substantially improve the eld of view and image resolution compared to i traditional Davies-Cotton telescopes, innovative solutions are foreseen in the design, like the use of Silicon Photomultipliers (SiPM) as light sensors and waveform digitizers for recording the fast light signals from atmospheric showers. A project is now underway to upgrade the camera by increasing its pixel count to 11; 328 pixels and field of view of 8:0. The camera electronics has been completely redesigned by using new waveform digitizer and trigger ASICs with the final goal of lowering the gamma-ray energy threshold and therefore provide an excellent instrument tailored for extended sources investigations and multi-messenger astronomy. 

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2. The Role of the Large Millimeter Telescope in Black Hole Science with the Next-Generation Event Horizon Telescope

   https://doi.org/10.3390/galaxies11010002  

   Bustamante, Sandra ; Blackburn, Lindy ; Narayanan, Gopal ; Schloerb, F. Peter ; Hughes, David ( February 2023 , Galaxies)

   The landmark black hole images recently taken by the Event Horizon Telescope (EHT) have allowed the detailed study of the immediate surroundings of supermassive black holes (SMBHs) via direct imaging. These tantalizing early results motivate an expansion of the array, its instrumental capabilities, and dedicated long-term observations to resolve and track faint dynamical features in the black hole jet and accretion flow. The next-generation Event Horizon Telescope (ngEHT) is a project that plans to double the number of telescopes in the VLBI array and extend observations to dual-frequency 230 + 345 GHz, improving total and snapshot coverage, as well as observational agility. The Large Millimeter Telescope (LMT) is the largest sub-mm single dish telescope in the world at 50 m in diameter, and both its sensitivity and central location within the EHT array make it a key anchor station for the other telescopes. In this work, we detail current and planned future upgrades to the LMT that will directly impact its Very Large Baseline Interferometry (VLBI) performance for the EHT and ngEHT. These include the commissioning of a simultaneous 230 + 345 GHz dual-frequency, dual-polarization heterodyne receiver, improved real-time surface measurement and setting, and improvements to thermal stability, which should enable expanded daytime operation. We test and characterize the performance of an improved LMT joining future ngEHT observations through simulated observations of Sgr A* and M 87. 

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3. Camera design and performance of the prototype Schwarzschild-Couder Telescope for the Cherenkov Telescope Array

   C. Adams, G. Ambrosi ( January 2019 , ICRC 2019)
4. Prototype Schwarzschild-Couder Telescope for the Cherenkov Telescope Array: Commissioning Status of the Optical System

   C. Adams, G. Ambrosi ( January 2019 , ICRC 2019)
5. Conditions for detecting lensed Population III galaxies in blind surveys with the James Webb Space Telescope , the Roman Space Telescope , and Euclid

   https://doi.org/10.1093/mnras/stac488  

   Vikaeus, Anton ; Zackrisson, Erik ; Schaerer, Daniel ; Visbal, Eli ; Fransson, Emma ; Malhotra, Sangeeta ; Rhoads, James ; Sahlén, Martin ( February 2022 , Monthly Notices of the Royal Astronomical Society)

   Dark matter haloes that reach the H i-cooling mass without prior star formation or external metal pollution represent potential sites for the formation of small – extremely faint – Population III galaxies at high redshifts. Gravitational lensing may in rare cases boost their fluxes to detectable levels, but to find even a small number of such objects in randomly selected regions of the sky requires very large areas to be surveyed. Because of this, a small, wide-field telescope can in principle offer better detection prospects than a large telescope with a smaller field of view. Here, we derive the minimum comoving number density required to allow gravitational lensing to lift such objects at redshift z = 5−16 above the detection thresholds of blind surveys carried out with the James Webb space telescope (JWST), the Roman space telescope (RST) and Euclid. We find that the prospects for photometric detections of Pop III galaxies are promising, and that they are better for RST than for JWST and Euclid. However, the Pop III galaxies favoured by current simulations have number densities too low to allow spectroscopic detections based on the strength of the He ii1640 emission line in any of the considered surveys unless very high star formation efficiencies (ϵ ≳ 0.1) are evoked. We argue that targeting individual cluster lenses instead of the wide-field surveys considered in this paper results in better spectroscopic detection prospects, while for photometric detection, the wide-field surveys perform considerably better.

    

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