No Arabic abstract
The current STELLA Echelle spectrograph (SES), which records 390nm to 870nm in one shot at a spectral resolution of 55000, will be replaced by a suite of specialized spectrographs in three spectral bands. The UV will be covered by a newly designed H&K spectrograph covering 380nm to 470nm (SES-H&K), the visual band (470nm - 690nm) will be covered by SES-VIS, which is a vacuum-stabilized spectrograph designed for high radial-velocity accuracy, and the NIR will be covered by the current SES spectrograph from 690nm to 1050nm. In order to improve the UV transmission, and to accommodate three different fibre-feeds, the prime focus corrector of the telescope will be refurbished, leading to an optical system with the f/2 1200mm spherical primary, a 4-lens collimator with 2 arcsec aperture, atmospheric dispersion corrector (ADC), and two dichroic beam splitters, feeding 3 separate fibre feeds for the three bands. The newly designed H&K spectrograph will be an Echelle spectrograph, based on a R4-grating with 41.6 l/mm and 110mmx420mm, using a f/5 camera and the cross-disperser in double pass (as in TRAFICOS, MIKE, KPF), using 21 spectral orders. The spectral resolution of all three spectrographs will be comparable to the 55000 of the current SES.
In this Chapter we review the challenges of, and opportunities for, 3D spectroscopy, and how these have lead to new and different approaches to sampling astronomical information. We describe and categorize existing instruments on 4m and 10m telescopes. Our primary focus is on grating-dispersed spectrographs. We discuss how to optimize dispersive elements, such as VPH gratings, to achieve adequate spectral resolution, high throughput, and efficient data packing to maximize spatial sampling for 3D spectroscopy. We review and compare the various coupling methods that make these spectrographs ``3D, including fibers, lenslets, slicers, and filtered multi-slits. We also describe Fabry-Perot and spatial-heterodyne interferometers, pointing out their advantages as field-widened systems relative to conventional, grating-dispersed spectrographs. We explore the parameter space all these instruments sample, highlighting regimes open for exploitation. Present instruments provide a foil for future development. We give an overview of plans for such future instruments on todays large telescopes, in space, and in the coming era of extremely large telescopes. Currently-planned instruments open new domains, but also leave significant areas of parameter space vacant, beckoning further development.
The IceCube Neutrino Observatory is a cubic-kilometer-scale high-energy neutrino detector built into the ice at the South Pole. Construction of IceCube, the largest neutrino detector built to date, was completed in 2011 and enabled the discovery of high-energy astrophysical neutrinos. We describe here the design, production, and calibration of the IceCube digital optical module (DOM), the cable systems, computing hardware, and our methodology for drilling and deployment. We also describe the online triggering and data filtering systems that select candidate neutrino and cosmic ray events for analysis. Due to a rigorous pre-deployment protocol, 98.4% of the DOMs in the deep ice are operating and collecting data. IceCube routinely achieves a detector uptime of 99% by emphasizing software stability and monitoring. Detector operations have been stable since construction was completed, and the detector is expected to operate at least until the end of the next decade.
The Calar Alto Observatory, located at 2168m height above the sea level in continental Europe, holds a significant number of astronomical telescopes and experiments, covering a large range of the electromagnetic domain, from gamma-ray to near-infrared. It is a very well characterized site, with excellent logistics. Its main telescopes includes a large suite of instruments. At the present time, new instruments, namely CAFE, PANIC and Carmenes, are under development. We are also planning a new operational scheme in order to optimize the observatory resources.
High-multiplex and deep spectroscopic follow-up of upcoming panoramic deep-imaging surveys like LSST, Euclid, and WFIRST is a widely recognized and increasingly urgent necessity. No current or planned facility at a U.S. observatory meets the sensitivity, multiplex, and rapid-response time needed to exploit these future datasets. FOBOS, the Fiber-Optic Broadband Optical Spectrograph, is a near-term fiber-based facility that addresses these spectroscopic needs by optimizing depth over area and exploiting the aperture advantage of the existing 10m Keck II Telescope. The result is an instrument with a uniquely blue-sensitive wavelength range (0.31-1.0 um) at R~3500, high-multiplex (1800 fibers), and a factor 1.7 greater survey speed and order-of-magnitude greater sampling density than Subarus Prime Focus Spectrograph (PFS). In the era of panoramic deep imaging, FOBOS will excel at building the deep, spectroscopic reference data sets needed to interpret vast imaging data. At the same time, its flexible focal plane, including a mode with 25 deployable integral-field units (IFUs) across a 20 arcmin diameter field, enables an expansive range of scientific investigations. Its key programmatic areas include (1) nested stellar-parameter training sets that enable studies of the Milky Way and M31 halo sub-structure, as well as local group dwarf galaxies, (2) a comprehensive picture of galaxy formation thanks to detailed mapping of the baryonic environment at z~2 and statistical linking of evolving populations to the present day, and (3) dramatic enhancements in cosmological constraints via precise photometric redshifts and determined redshift distributions. In combination with Keck I instrumentation, FOBOS also provides instant access to medium-resolution spectroscopy for transient sources with full coverage from the UV to the K-band.
FRAM (F/Photometric Robotic Atmospheric Monitor) is a robotic telescope operated at the Pierre Auger Observatory in Argentina for the purposes of atmospheric monitoring using stellar photometry. As a passive system which does not produce any light that could interfere with the observations of the fluorescence telescopes of the observatory, it complements the active monitoring systems that use lasers. We discuss the applications of stellar photometry for atmospheric monitoring at optical observatories in general and the particular modes of operation employed by the Auger FRAM. We describe in detail the technical aspects of FRAM, the hardware and software requirements for a successful operation of a robotic telescope for such a purpose and their implementation within the FRAM system.