scholarly journals The Penn State Spectroscopic Survey Telescope

1984 ◽  
Vol 79 ◽  
pp. 851-860 ◽  
Author(s):  
L.W. Ramsey ◽  
D.W. Weedman
Keyword(s):  
Focal Plane ◽  
High Resolution Spectroscopy ◽  
Radius Of Curvature ◽  
Plane System ◽  
Development Costs ◽  
Large Numbers ◽  
Effective Aperture ◽  
Penn State ◽  
M Stars ◽  
The Universe

AbstractTo map the distribution of galaxies and quasars in the universe, we desire a telescope large enough to obtain spectra to about 20th magnitude in under 20 minutes integration and which is devoted entirely to such spectroscopic survey projects in dark time. We also desire extensive bright time observing to monitor large numbers of G-M stars with high-resolution spectroscopy for many years in search of solar-like activity. These projects are suited to a telescope with a large fixed primary, assembled from many spherically figured segments. We present a design for such a telescope that consists of 73 segments, each of 0.9-m diameter and 26-m radius of curvature. Mirror blanks of this size can be cut from standard Pyrex sheets. Effective aperture of the telescope exceeds 7-m; the focal plane system can track objects for 40 minutes, and sky coverage of 48 degrees is obtained by using a fixed tilt for the primary and making the entire telescope and dome rotatable. The focal plane system is lightweight and precisely pointable because spectrographs are coupled to the focus by fiber optic cables. Off-the-shelf components and existing technology are used to keep engineering and development costs low; we must remain within a budget feasible for a university. Because the telescope will be equipped with standard, minimal instrumentation and is intended for very routine observing programs, operating costs will also be low. Hardware components are now being assembled in a laboratory to develop the focal plane control system and the mirror support system.

scholarly journals The Voyage of Metals in the Universe from Cosmological to Planetary Scales: the need for a Very High-Resolution, High Throughput Soft X-ray Spectrometer

2021 ◽  
Author(s):  
F. Nicastro ◽  
J. Kaastra ◽  
C. Argiroffi ◽  
E. Behar ◽  
S. Bianchi ◽  
...  
Keyword(s):  
Chemical Composition ◽  
High Resolution ◽  
Deep Understanding ◽  
High Resolution Spectroscopy ◽  
X Ray ◽  
Viable Solution ◽  
Surrounding Space ◽  
Nuclear Processes ◽  
The Universe ◽  
Very High

AbstractMetals form an essential part of the Universe at all scales. Without metals we would not exist, and the Universe would look completely different. Metals are primarily produced via nuclear processes in stars, and spread out through winds or explosions, which pollute the surrounding space. The wanderings of metals in-and-out of astronomical objects are crucial in determining their own evolution and thus that of the Universe as a whole. Detecting metals and assessing their relative and absolute abundances and energetics can thus be used to trace the evolution of these cosmic components. The scope of this paper is to highlight the most important open astrophysical problems that will be central in the next decades and for which a deep understanding of the Universe’s wandering metals, their physical and kinematical states, and their chemical composition represents the only viable solution. The majority of these studies can only be efficiently performed through High Resolution Spectroscopy in the soft X-ray band.

scholarly journals How the Limit Values Work

2021 ◽  
Keyword(s):  
Cosmological Constant ◽  
Gravitational Radius ◽  
Limit Values ◽  
Event Horizons ◽  
Dirac Type ◽  
Large Numbers ◽  
Spatio Temporal ◽  
The Universe ◽  
Limiting Values ◽  
Physical Principles

The efficiency of limiting quantities as a tool for describing physics at various spatio-temporal scales is shown. Due to its universality, limit values allow us to establish relationships between, at first glance, distant from each other's characteristics. The article discusses specific examples of the use of limit values to establish such relationships between quantities at different scales. Based on the principle of reaching the limiting values on the event horizons, a connection was obtained between the Planck values and the values of the Universe. The resulting relation can be attributed to relations of the Dirac type - the coincidence of large numbers that emerged from empirical observations. In the article, the relationships between large numbers of the Dirac type are established proceeding, in a certain sense, from physical principles - the existence of limiting values. It is shown that this ratio is observed throughout the evolution of the Universe. An alternative way of solving the problem of the cosmological constant using limiting values and its relation to the minimum spatial scale is discussed. In addition, a one-parameter family of masses was introduced, including the mass of the Universe, the Planck mass and the mass of the graviton, which also establish relationships between quantities differing by 120 orders of magnitude. It is shown that entropic forces also obey the same universal limiting constraints as ordinary forces. Thus, the existence of limiting values extends to informational limitations in the Universe. It is fundamentally important that on any event horizon, regardless of its scale (i.e., its gravitational radius), the universal value of limit force c4/4G is realized. This allows you to relate the characteristics of the Universe related to various stages of its evolution.

Characteristics of the defocused spherical Fabry-Pérot interferometer as a quasi-linear dispersion instrument for high resolution spectroscopy of pulsed laser sources

1968 ◽  
Vol 263 (1140) ◽  
pp. 209-223 ◽  
Keyword(s):  
Laser Beam ◽  
Optical Design ◽  
Pulsed Laser ◽  
Resolving Power ◽  
High Resolution Spectroscopy ◽  
Radius Of Curvature ◽  
Spherical Mirror ◽  
Linear Dispersion ◽  
Fabry Perot ◽  
Very High

Defocused spherical mirror Fabry—Pérot etalons, in which the mirror separation is slightly less than the common radius of curvature, produce a multiple-beam fringe pattern of concentric rings, with quasi-linear spectral dispersion over an appreciable annular region corresponding to two free spectral ranges. The characteristics of these interferograms are discussed in relation to their many advantages for pulsed laser spectroscopy. These advantages include: (i) accuracy of frequency difference measurement; (ii) high illumination of the detector with moderate energy density in the laser beam; (iii) ease of alinement and permanent adjustment of the mirrors leading to the attainment in practice of a very high instrumental finesse (N R values of up to 90 have been achieved); (iv) measurement of degree of spatial coherence of laser beam; (v) ease of matching the interferogram to the spatial resolution of the detector. A simple optical path relation determines the positions of the fringes and the location of the quasilinear dispersion region. The interfering wavefronts, formed by multiple reflexion, have been numerically computed and summed to provide information on the finesse, fringe profiles, contrast and optimum conditions of use of this new, very high resolving power (107 to 108) quasi-linear spectrographic disperser. Constructional details are described and optical design criteria are discussed, together with the various experimental arrangements for employing the instrument. Comparison is made with the equivalent confocal and plane Fabry—Pérot etalons and methods of simultaneously measuring

Testing fiber tapers for use in the SDSS-V focal plane system

2020 ◽  
Author(s):  
Sarah E. Tuttle ◽  
Emily Farr ◽  
Claire L. Poppett ◽  
Colby A. Jurgenson ◽  
José Sánchez-Gallego ◽  
...  
Keyword(s):  
Focal Plane ◽  
Plane System

scholarly journals ESO Spectroscopic Facility

2017 ◽  
Vol 13 (S334) ◽  
pp. 242-247
Author(s):  
Luca Pasquini ◽  
B. Delabre ◽  
R. S. Ellis ◽  
J. Marrero ◽  
L. Cavaller ◽  
...  
Keyword(s):  
High Resolution ◽  
Wavelength Range ◽  
Focal Plane ◽  
Working Group ◽  
Field Of View ◽  
High Resolution Spectroscopy ◽  
Wide Field ◽  
Low Resolution ◽  
Field Unit ◽  
Integral Field

AbstractWe present the concept of a novel facility dedicated to massively-multiplexed spectroscopy. The telescope has a very wide field Cassegrain focus optimised for fibre feeding. With a Field of View (FoV) of 2.5 degrees diameter and a 11.4m pupil, it will be the largest etendue telescope. The large focal plane can easily host up to 16.000 fibres. In addition, a gravity invariant focus for the central 10 arc-minutes is available to host a giant integral field unit (IFU). The 3 lenses corrector includes an ADC, and has good performance in the 360-1300 nm wavelength range. The top level science requirements were developed by a dedicated ESO working group, and one of the primary cases is high resolution spectroscopy of GAIA stars and, in general, how our Galaxy formed and evolves. The facility will therefore be equipped with both, high and low resolution spectrographs. We stress the importance of developing the telescope and instrument designs simultaneously. The most relevant R&D aspect is also briefly discussed.

scholarly journals Cosmological constant decaying with CMB temperature

2019 ◽  
Vol 16 (06) ◽  
pp. 1950088 ◽  
Author(s):  
Tomohide Sonoda
Keyword(s):  
Cosmological Constant ◽  
Fine Tuning ◽  
Field Equations ◽  
Microwave Background ◽  
Dark Energy Density ◽  
Dimension Formula ◽  
Large Numbers ◽  
The Hierarchical Structure ◽  
The Universe ◽  
Cmb Temperature

Recent observations of the dark energy density have demonstrated the fine-tuning problem and the challenges faced by theoretical modeling. In this study, we apply the self-similar symmetry (SSS) model, describing the hierarchical structure of the universe based on the Dirac large numbers hypothesis, to Einstein’s cosmological term. We introduce a new similarity dimension, [Formula: see text], in the SSS model. Using the [Formula: see text] SSS model, the cosmological constant [Formula: see text] is simply expressed as a function of the cosmic microwave background (CMB) temperature. The result shows that both the gravitational constant [Formula: see text] and [Formula: see text] are coupled with the CMB temperature, which simplifies the solution of Einstein’s field equations for the variable [Formula: see text]–[Formula: see text] model.

scholarly journals Ensembles and Experiments in Classical and Quantum Physics

2003 ◽  
Vol 17 (16) ◽  
pp. 2937-2980
Author(s):  
Arnold Neumaier
Keyword(s):  
Quantum Mechanics ◽  
Quantum Physics ◽  
Law Of Large Numbers ◽  
Correspondence Principle ◽  
Axiomatic Approach ◽  
Mathematical Concepts ◽  
Large Numbers ◽  
The Universe ◽  
Classical And Quantum Mechanics ◽  
Elegant Solution

A philosophically consistent axiomatic approach to classical and quantum mechanics is given. The approach realizes a strong formal implementation of Bohr's correspondence principle. In all instances, classical and quantum concepts are fully parallel: the same general theory has a classical realization and a quantum realization. Extending the ''probability via expectation'' approach of Whittle to noncommuting quantities, this paper defines quantities, ensembles, and experiments as mathematical concepts and shows how to model complementarity, uncertainty, probability, nonlocality and dynamics in these terms. The approach carries no connotation of unlimited repeatability; hence it can be applied to unique systems such as the universe. Consistent experiments provide an elegant solution to the reality problem, confirming the insistence of the orthodox Copenhagen interpretation on that there is nothing but ensembles, while avoiding its elusive reality picture. The weak law of large numbers explains the emergence of classical properties for macroscopic systems.

scholarly journals Design and alignment of the MIPAS focal plane system

1996 ◽  
Author(s):  
Kees Smorenburg ◽  
Huib Visser ◽  
K. Moddemeijer
Keyword(s):  
Focal Plane ◽  
Plane System

scholarly journals Early Universe Plasma Separation and the Creation of a Dual Universe

2021 ◽  
Author(s):  
Mohammed B. Al-Fadhli
Keyword(s):  
Early Universe ◽  
Power Spectra ◽  
Free Fall ◽  
Radius Of Curvature ◽  
Second Phase ◽  
Gravitational Acceleration ◽  
Field Equations ◽  
Conformal Curvature ◽  
Cyclic Universe ◽  
The Universe

The recent Planck Legacy release confirmed the presence of an enhanced lensing amplitude in the cosmic microwave background (CMB) power spectra, which prefers a positively curved early Universe with a confidence level exceeding 99%. In this study, the pre-existing curvature is incorporated to extend the field equations where the derived wavefunction of the Universe is utilised to model Universe evolution with reference to the scale factor of the early Universe and its radius of curvature upon the emission of the CMB. The wavefunction reveals both positive and negative solutions, implying that matter and antimatter of early Universe plasma evolved in opposite directions as distinct Universe sides, corroborating the axis of CMB. The wavefunction indicates that a nascent hyperbolic expansion away from early plasma is followed by a first phase of decelerating expansion during the first 10 Gyr, and then, a second phase of accelerating expansion in reverse directions, whereby both sides free-fall towards each other under gravitational acceleration. The predicted conformal curvature evolution demonstrates the fast orbital speed of outer stars owing to external fields exerted on galaxies as they travel through conformally curved space-time. Finally, the wavefunction predicts an eventual time-reversal phase comprising rapid spatial contraction that culminates in a Big Crunch, signalling a cyclic Universe. These findings show that early plasma could be separated and evolved into distinct sides of the Universe that collectively inducing its evolution, physically explaining the effects attributed to dark energy and dark matter.

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