The Simons Observatory (SO) will make precision temperature and polarization measurements of the cosmic
microwave background (CMB) using a series of telescopes which will cover angular scales between 1 arcminute
and tens of degrees, contain over 40,000 detectors, and sample frequencies between 27 and 270 GHz. SO will
consist of a six-meter-aperture telescope coupled to over 20,000 detectors along with an array of half-meter
aperture refractive cameras, coupled to an additional 20,000+ detectors. The unique combination of large and
small apertures in a single CMB observatory, which will be located in the Atacama Desert at an altitude of
5190 m, will allow us to sample a wide range of angular scales over a common survey area. SO will measure
fundamental cosmological parameters of our universe, find high redshift clusters via the Sunyaev-Zeldovich effect,
constrain properties of neutrinos, and seek signatures of dark matter through gravitational lensing. The complex
set of technical and science requirements for this experiment has led to innovative instrumentation solutions
which we will discuss. The large aperture telescope will couple to a cryogenic receiver that is 2.4 m in diameter
and over 2 m long, creating a number of interesting technical challenges. Concurrently, we are designing an array
of half-meter-aperture cryogenic cameras which also have compelling design challenges. We will give an overview
of the drivers for and designs of the SO telescopes and the cryogenic cameras that will house the cold optical
components and detector arrays.
The Atacama Large Millimeter/submillimeter Array (ALMA) Band 10 receiver covering 787 to 950 GHz is the highest frequency receiver of the ten bands envisioned for the ALMA Front End system. The Band 10 receivers have been undergoing installation and commissioning since 2012. After the Band 10 receiver tuning scripts (Josephson currents suppression, LO power optimization) and operation procedures had been developed and implemented, astronomical verification procedures (radio pointing, focus, beam squint, and end-to-end spectroscopic verification) were established in single dish mode at the ALMA Operations Support Facility (OSF; 2900 m elevation). Subsequently, the first Band 10 astronomical fringes were achieved at the Array Operations Site in October 2013 (AOS; 5000 m elevation). This is the highest frequency ever achieved by a radio interferometer and opens up a new window into submillimeter astrophysics.
The Atacama Large Millimeter/submillimeter Array (ALMA) will consist of at least 54 twelve-meter antennas and 12
seven-meter antennas operating as an aperture synthesis array in the (sub)millimeter wavelength range. The ALMA
System Integration Science Team (SIST) is a group of scientists and data analysts whose primary task is to verify and
characterize the astronomical performance of array elements as single dish and interferometric systems. The full set of
tasks is required for the initial construction phase verification of every array element, and these can be divided roughly
into fundamental antenna performance tests (verification of antenna surface accuracy, basic tracking, switching, and on-the-fly rastering) and astronomical radio verification tasks (radio pointing, focus, basic interferometry, and end-to-end
spectroscopic verification). These activities occur both at the Operations Support Facility (just below 3000 m elevation)
and at the Array Operations Site at 5000 m.
CℓOVER is a multi-frequency experiment optimised to measure
the Cosmic Microwave Background (CMB) polarization, in
particular the B-mode component. CℓOVER comprises two
instruments observing respectively at 97 GHz and 150/225 GHz.
The focal plane of both instruments consists of an array of
corrugated feed-horns coupled to TES detectors cooled at 100
mK. The primary science goal of CℓOVER is to be sensitive to
gravitational waves down to r ~ 0.03 (at 3σ)in two years of operations.
Submillimetre astronomy is the prime technique to unveil the birth and early evolution of stars and galaxies in the local
and distant Universe. Preliminary meteorological studies and atmospheric transmission models tend to demonstrate that
Dome C might offer atmosphere conditions that open the 200-μm atmospheric windows, and could potentially be a site
for a large ground-based telescope facility. However, Antarctic climate conditions might also severely impact and
deform any telescope mirror and hardware. We present prerequisite conditions and their associate experiments for
defining a large telescope facility for submillimetre astronomy at Dome C: (1) Whether the submm/THz atmospheric
windows open from 200 μm during a large and stable fraction of time; (2) The knowledge of thermal gradient and (3)
icing formation and their impact on a telescope mirror and hardware. This paper will present preliminary results on
current experiments that measure icing, thermal gradient and sky opacity at Dome C. We finally discuss a possible
roadmap toward the deployment of a large telescope facility at Dome C.
The Antarctic Fiber-Optic Spectrometer (AFOS) is a 30cm Newtonian optical telescope that injects light through six 30m long optical fibers onto a 240-850nm spectrograph with a 1024 x 256 pixel CCD camera. The telescope is mounted on a dual telescope altitude-azimuth mount and has been designed to measure the transperency of the atmosphere above the South Pole for astronomy in the UV and visible wavelength regions. The instrument has observed a series of bright O and B stars during the austral winters of 2002 and 2003 to probe the UV cutoff wavelength, the auroral intensity and water vapour content in the atmosphere above the plateau. AFOS is the first completely automated optical telescope on the Antarctic Plateau. This paper reports on the results of the past two austral winters of remote observing with the telescope as well as the technical and software modifications required to improve the quality and automation of the observations. The atmospheric absorption bands in the 660-900nm regions of the spectra have been fitted with MODTRAN atmospheric models and used to calculate the precipitable water vapour above the South Pole. These data are then compared to those collected concurrently by radiosonde and by a 350 μm submillimeter tipper at South Pole.