The Large Millimeter Telescope (LMT) Alfonso Serrano is a bi-national (Mexico and USA) telescope facility constructed on the summit of Sierra Negra, at an altitude of 4600m, in the Mexican state of Puebla. The LMT is a 50-m diameter single-dish telescope, with an active surface control-system to correct gravitational and thermal deformations of the primary reflector, designed and optimized to conduct scientific observations using heterodyne and continuum receivers, as well as VLBI observations, at frequencies between ~70 and 350 GHz. We describe the current status and technical performance of the recently commissioned LMT 50-m, the instrumentation development program, and future engineering upgrades that will optimize the optical efficiency of the telescope and increase its scientific productivity.
The TolTEC camera is a next generation three-band imaging polarimeter for the Large Millimeter Telescope. With 7514 lumped element kinetic inductance detectors across three simultaneously observing passbands at 1.1 mm, 1.4 mm, and 2.0 mm, TolTEC has diffraction-limited beams with FWHM of 5, 7, and 11 arcsec, respectively. Herein, we cover a brief overview of the instrument along with the first quantitative measures of TolTEC’s performance at the LMT. We also provide initial reductions of commissioning targets - demonstrating TolTEC's ability to detect both faint and extended structures over a wide dynamic range of flux and angular scales.
The far-infrared imager and polarimeter (FIP) for the Origins Space Telescope (Origins) is a basic far-infrared imager and polarimeter. The camera will deliver continuum images and polarization measurements at 50 and 250 μm. Currently available detector technologies provide sufficient sensitivity for background limited observations from space, at least on a single pixel basis. FIP incorporates large next-generation superconducting detector arrays and our technology development plan will push the pixel numbers for the arrays to the required size of 8000. Two superconducting detector technologies are currently candidates for the instrument: transition edge sensors or microwave kinetic inductance devices. Using these detectors and taking advantage of the cryogenic telescope that is provided by Origins, FIP will achieve mapping speeds of up to eight orders of magnitude faster than what has been achieved by existing observatories. The science drivers for FIP include observations of solar system objects, dust properties, and magnetic field studies of the nearby interstellar medium, and large scale galaxy surveys to better constrain the star formation history of the universe to address one of the main themes of Origins: “How does the Universe work?” In addition to the science, the FIP instrument plays a critical functional role in aligning the mirrors during on orbit observatory commissioning.
KEYWORDS: Space telescopes, Telescopes, James Webb Space Telescope, Mirrors, Optical instrument design, Astronomy, Space operations, Cryogenics, Aerospace engineering, Cryocoolers
The Origins Space Telescope will trace the history of our origins from the time dust and heavy elements permanently altered the cosmic landscape to present-day life. How did galaxies evolve from the earliest galactic systems to those found in the universe today? How do habitable planets form? How common are life-bearing worlds? We describe how Origins was designed to answer these alluring questions. We discuss the key decisions taken by the Origins mission concept study team, the rationale for those choices, and how they led through an exploratory design process to the Origins baseline mission concept. To understand the concept solution space, we studied two distinct mission concepts and descoped the second concept, aiming to maximize science per dollar and hit a self-imposed cost target. We report on the study approach and describe the concept evolution. The resulting baseline design includes a 5.9-m diameter telescope cryocooled to 4.5 K and equipped with three scientific instruments. The chosen architecture is similar to that of the Spitzer Space Telescope and requires very few deployments after launch. The cryo-thermal system design leverages James Webb Space Telescope technology and experience.
The Origins Survey Spectrometer (OSS) is a multi-purpose far-IR spectrograph for Origins. Operating at the photon background limit, OSS covers the 25- to 588-μm wavelength range instantaneously at a resolving power (R) of 300 using six logarithmically spaced grating modules. Each module couples at least 30 and up to 100 spatial beams simultaneously, enabling true [three-dimensional (3D)] spectral mapping. In addition, OSS provides two high-resolution modes. The first inserts a long-path Fourier-transform spectrometer (FTS) into a portion of the incoming light in advance of the grating backends, enabling R up to 43 , 000 × [ λ / 112 μm ] , while preserving the grating-based sensitivity for line detection. The second incorporates a scanning etalon in series with the FTS to provide R up to 300,000 for the 100-to 200-μm range.
The Origins Space Telescope (Origins) concept is designed to investigate the creation and dispersal of elements essential to life, the formation of planetary systems, and the transport of water to habitable worlds and the atmospheres of exoplanets around nearby K- and M-dwarfs to identify potentially habitable—and even inhabited—worlds. These science priorities are aligned with NASA’s three major astrophysics science goals: How does the Universe work? How did we get here? and Are we alone? We briefly describe the science case that arose from the astronomical community and the science traceability matrix for Origins. The science traceability matrix prescribes the design of Origins and demonstrates that it will address the key science questions motivated by the science case.
The Origins Space Telescope will trace the history of our origins from the time dust and heavy elements permanently altered the cosmic landscape to present-day life. How did galaxies evolve from the earliest galactic systems to those found in the Universe today? How do habitable planets form? How common are life-bearing worlds? To answer these alluring questions, Origins will operate at mid- and far-infrared (IR) wavelengths and offer powerful spectroscopic instruments and sensitivity three orders of magnitude better than that of the Herschel Space Observatory, the largest telescope flown in space to date. We describe the baseline concept for Origins recommended to the 2020 US Decadal Survey in Astronomy and Astrophysics. The baseline design includes a 5.9-m diameter telescope cryocooled to 4.5 K and equipped with three scientific instruments. A mid-infrared instrument (Mid-Infrared Spectrometer and Camera Transit spectrometer) will measure the spectra of transiting exoplanets in the 2.8 to 20 μm wavelength range and offer unprecedented spectrophotometric precision, enabling definitive exoplanet biosignature detections. The far-IR imager polarimeter will be able to survey thousands of square degrees with broadband imaging at 50 and 250 μm. The Origins Survey Spectrometer will cover wavelengths from 25 to 588 μm, making wide-area and deep spectroscopic surveys with spectral resolving power R ∼ 300, and pointed observations at R ∼ 40,000 and 300,000 with selectable instrument modes. Origins was designed to minimize complexity. The architecture is similar to that of the Spitzer Space Telescope and requires very few deployments after launch, while the cryothermal system design leverages James Webb Space Telescope technology and experience. A combination of current-state-of-the-art cryocoolers and next-generation detector technology will enable Origins’ natural background-limited sensitivity.
The Large Millimeter Telescope (LMT) Alfonso Serrano is a 50m-diameter single-dish radio telescope constructed at an altitude of 4600 meters on the summit of Volcan Sierra Negra, an extinct volcano in the Mexican state of Puebla. The LMT is a bi-national scientific collaboration between Mexico and the USA, led by the Instituto Nacional de Astrofisica, Optica y Electronica (INAOE) and the University of Massachusetts at Amherst. The telescope currently operates at wavelengths from 4mm to 1mm, and during the dry winter months the LMT site provides the highest levels of atmospheric transmission and potential future access to submillimeter observing windows. This paper describes the current status and scientific performance of the LMT, the suite of scientific instrumentation and future engineering upgrades that will optimize the optical efficiency of the telescope and increase its scientific productivity.
TolTEC is a three-band imaging polarimeter for the Large Millimeter Telescope. Simultaneously observing with passbands at 1.1mm, 1.4mm and 2.0mm, TolTEC has diffraction-limited beams with FWHM of 5, 7, and 11 arcsec, respectively. Over the coming decade, TolTEC will perform a combination of PI-led and Open-access Legacy Survey projects. Herein we provide an overview of the instrument and give the first quantitative measures of its performance in the lab prior to shipping to the telescope in 2021.
The Origins Space Telescope will trace the history of our origins from the time dust and heavy elements permanently altered the cosmic landscape to present-day life. How did galaxies evolve from the earliest galactic systems to those found in the universe today? How do habitable planets form? How common are life-bearing worlds? To answer these alluring questions, Origins will operate at mid- and far-infrared wavelengths and offer powerful spectroscopic instruments and sensitivity three orders of magnitude better than that of Herschel, the largest telescope flown in space to date. After a 3 ½ year study, the Origins Science and Technology Definition Team will recommend to the Decadal Survey a concept for Origins with a 5.9-m diameter telescope cryocooled to 4.5 K and equipped with three scientific instruments. A mid-infrared instrument (MISC-T) will measure the spectra of transiting exoplanets in the 2.8 – 20 μm wavelength range and offer unprecedented sensitivity, enabling definitive biosignature detections. The Far-IR Imager Polarimeter (FIP) will be able to survey thousands of square degrees with broadband imaging at 50 and 250 μm. The Origins Survey Spectrometer (OSS) will cover wavelengths from 25 – 588 μm, make wide-area and deep spectroscopic surveys with spectral resolving power R ~ 300, and pointed observations at R ~ 40,000 and 300,000 with selectable instrument modes. Origins was designed to minimize complexity. The telescope has a Spitzer-like architecture and requires very few deployments after launch. The cryo-thermal system design leverages JWST technology and experience. A combination of current-state-of-the-art cryocoolers and next-generation detector technology will enable Origins’ natural backgroundlimited sensitivity.
The OSS on the Origins Space Telescope is designed to decode the cosmic history of nucleosynthesis, star formation, and supermassive black hole growth with wide-area spatial-spectral 3-D surveys across the full 25 to 590 micron band. Six wideband grating modules combine to cover the full band at R=300, each couples a long slit with 60-190 beams on the sky. OSS will have a total of 120,000 background-limited detector pixels in the six 2-D arrays which provide spatial and spectral coverage. The suite of grating modules can be used for pointed observations of targets of interest, and are particularly powerful for 3-D spectral spectral surveys. To chart the transition from interstellar material, particularly water, to planetary systems, two high-spectral-resolution modes are included. The first incorporates a Fourier-transform spectrometer (FTS) in front of the gratings providing resolving power of 25,000 (δv = 12 km/s) at 179 µm to resolve water emission in protoplanetary disk spectra. The second boosts the FTS capability with an additional etalon (Fabry-Perot interferometer) to provide 2 km/s resolution in this line to enable detailed structural studies of disks in the various water and HD lines. Optical, thermal, and mechanical designs are presented, and the system approach to the detector readout enabling the large formats is described.
The Origins Space Telescope (OST) is the mission concept for the Far-Infrared Surveyor, one of the four science and technology definition studies of NASA Headquarters for the 2020 Astronomy and Astrophysics Decadal survey. "Concept-1" is a cold (4 K) 9 m space telescope with five instruments, while "concept 2" consists of a cold 5.9 m telescope and four instruments, providing imaging and spectroscopic capabilities between 5μm and 600μm. The sensitivity provided by the observatory will be a three to four orders of magnitude improvement over currently achieved observational capabilities, allowing to address a wide range of new and so far inaccessible scientific questions, ranging from bio-signatures in the atmospheres of exo-planets to the production of the first metals in the universe right after the end of re-ionization. Here we present the Far Infrared Imager and Polarimeter (FIP) for OST. The camera will cover four bands, 50μm, 100μm, 250μm, and 500μm. In the "concept 1" version of the instrument, FIP will allow for differential polarimetry with the ability to observe two colors simultaneously, while all four bands can be observed simultaneously in total power mode. The confusion limit in the total power mode will be reached in only 8 ms at 500μm, while at 50μm the source density in the sky is so low that at OST's angular resolution of (see manuscript for symbol) 2" in this band the source confusion limit will only be reached after about two hours of integration with the "concept-2" version of FIP ("concept-1" FIP will not be confusion limited at 50m, no matter how long it integrates). Science topics that can be addressed by the camera include, but are not limited to, galactic and extragalactic magnetic field studies, deep galaxy surveys, and outer Solar System objects.
The Origins Space Telescope (OST) will trace the history of our origins from the time dust and heavy elements permanently altered the cosmic landscape to present-day life. How did the universe evolve in response to its changing ingredients? How common are life-bearing planets? To accomplish its scientific objectives, OST will operate at mid- and far-infrared wavelengths and offer superlative sensitivity and new spectroscopic capabilities. The OST study team will present a scientifically compelling, executable mission concept to the 2020 Decadal Survey in Astrophysics. To understand the concept solution space, our team studied two alternative mission concepts. We report on the study approach and describe both of these concepts, give the rationale for major design decisions, and briefly describe the mission-enabling technology.
The Origins Space Telescope (OST) mission concept study is the subject of one of the four science and technology definition studies supported by NASA Headquarters to prepare for the 2020 Astronomy and Astrophysics Decadal Survey. OST will survey the most distant galaxies to discern the rise of metals and dust and to unveil the co-evolution of galaxy and blackhole formation, study the Milky Way to follow the path of water from the interstellar medium to habitable worlds in planetary systems, and measure biosignatures from exoplanets. This paper describes the science drivers and how they drove key requirements for OST Mission Concept 2, which will operate between ~5 and ~600 microns with a JWST sized telescope. Mission Concept 2 for the OST study optimizes the engineering for the key science cases into a powerful and more economical observatory compared to Mission Concept 1.
The Large Millimeter Telescope (LMT) Alfonso Serrano is a bi-national (Mexico and USA) telescope facility operated by the Instituto Nacional de Astrofisica, Optica y Electronica (INAOE) and the University of Massachusetts. The LMT is designed as a 50-m diameter single-dish millimeter-wavelength telescope that is optimized to conduct scientific observations at frequencies between ~70 and 350 GHz. The LMT is constructed on the summit of Sierra Negra at an altitude of 4600m in the Mexican state of Puebla. The site offers excellent mm-wavelength atmospheric transparency all-year round, and the opportunity to conduct submillimeter wavelength observations during the winter months. Following first-light observations in mid-2011, the LMT began regular scientific operations in 2014 with a shared-risk Early Science observing program using the inner 32-m diameter of the primary reflector with an active surface control system. The LMT has already performed successful VLBI observations at 3mm with the High Sensitivity Array and also at 1.3mm as part of the Event Horizon Telescope. Since early 2018 the LMT has begun full scientific operations as a 50-m diameter telescope, making the LMT 50-m the world´s largest single-dish telescope operating at 1.1mm. I will describe the current status of the telescope project, including the early scientific results from the LMT 50-m, as well the instrumentation development program, the plan to improve the overall performance of the telescope, and the on-going transition towards the formation of the LMT Observatory to support the scientific community in their use of the LMT to study the formation and evolution of structure at all cosmic epochs.
The mm-wavelength sky reveals the initial phase of structure formation, at all spatial scales, over the entire observable history of the Universe. Over the past 20 years, advances in mm-wavelength detectors and camera systems have allowed the field to take enormous strides forward – particularly in the study of the Cosmic Microwave Background – but limitations in mapping speeds, sensitivity and resolution have plagued studies of astrophysical phenomena. In fact, limitations due to inherent biases in the ground-based mm-wavelength surveys conducted over the last 2 decades continue to motivate the need for deeper and wider-area maps made with increased angular resolution. TolTEC is a new camera that will fill the focal plane of the 50m diameter Large Millimeter Telescope (LMT) and provide simultaneous, polarization-sensitive imaging at 2.0, 1.4, and 1.1mm wavelengths. The instrument, now under construction, is a cryogenically cooled receiver housing three separate kilo-pixel arrays of Kinetic Inductance Detectors (KIDs) that are coupled to the telescope through a series of silicon lenses and dichroic splitters. TolTEC will be installed and commissioned on the LMT in early 2019 where it will become both a facility instrument and also perform a series of 100 hour “Legacy Surveys” whose data will be publicly available. The initial four surveys in this series: the Clouds to Cores Legacy Survey, the Fields in Filaments Legacy Survey, the Ultra-Deep Legacy Survey and the Large Scale Structure Survey are currently being defined in public working groups of astronomers coordinated by TolTEC Science Team members. Data collection for these surveys will begin in late 2019 with data releases planned for late 2020 and 2021. Herein we describe the instrument concept, provide performance data for key subsystems, and provide an overview of the science, schedule and plans for the initial four Legacy Survey concepts.
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