Opening a New Window on the Universe: High-Resolution, Long-Wavelength Radio Astronomy

2002 ◽  
Author(s):  
Namir E. Kassim ◽  
T. J. Lazio ◽  
William C. Erickson
Keyword(s):  
High Resolution ◽  
Radio Astronomy ◽  
Long Wavelength ◽  
The Universe

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 The Low-Frequency Array (LOFAR): Opening a New Window on the Universe

2002 ◽  
Vol 199 ◽  
pp. 474-483
Author(s):  
Namir E. Kassim ◽  
T. Joseph W. Lazio ◽  
William C. Erickson ◽  
Patrick C. Crane ◽  
R. A. Perley ◽  
...  
Keyword(s):  
Angular Resolution ◽  
Broad Band ◽  
Low Frequency ◽  
Electromagnetic Spectrum ◽  
Interferometric Imaging ◽  
Very Large Array ◽  
Long Wavelength ◽  
Calibration Techniques ◽  
Long Baselines ◽  
The Universe

Decametric wavelength imaging has been largely neglected in the quest for higher angular resolution because ionospheric structure limited interferometric imaging to short (< 5 km) baselines. The long wavelength (LW, 2—20 m or 15—150 MHz) portion of the electromagnetic spectrum thus remains poorly explored. The NRL-NRAO 74 MHz Very Large Array has demonstrated that self-calibration techniques can remove ionospheric distortions over arbitrarily long baselines. This has inspired the Low Frequency Array (LOFAR)—-a fully electronic, broad-band (15—150 MHz)antenna array which will provide an improvement of 2—3 orders of magnitude in resolution and sensitivity over the state of the art.

scholarly journals A Wide-Band, Active Antenna System for Long Wavelength Radio Astronomy

2012 ◽  
Vol 124 (920) ◽  
pp. 1090-1104 ◽  
Author(s):  
Brian C. Hicks ◽  
Nagini Paravastu-Dalal ◽  
Kenneth P. Stewart ◽  
William C. Erickson ◽  
Paul S. Ray ◽  
...  
Keyword(s):  
Radio Astronomy ◽  
Wide Band ◽  
Antenna System ◽  
Active Antenna ◽  
Long Wavelength

scholarly journals Low Frequency Radio Astronomy from Above the Ionosphere

2002 ◽  
Vol 199 ◽  
pp. 488-489
Author(s):  
D. L. Jones
Keyword(s):  
High Resolution ◽  
Radio Astronomy ◽  
Coronal Mass Ejections ◽  
Solar Radio ◽  
Low Frequency ◽  
Dramatic Improvement ◽  
Radio Bursts ◽  
Solar Radio Bursts ◽  
Low Frequencies ◽  
High Resolution Images

The GMRT represents a dramatic improvement in ground-based observing capabilities for low frequency radio astronomy. At sufficiently low frequencies, however, no ground-based facility will be able to produce high resolution images while looking through the ionosphere. A space-based array will be needed to explore the objects and processes which dominate the sky at the lowest radio frequencies. An imaging radio interferometer based on a large number of small, inexpensive satellites would be able to track solar radio bursts associated with coronal mass ejections out to the distance of Earth, determine the frequency and duration of early epochs of nonthermal activity in galaxies, and provide unique information about the interstellar medium.

scholarly journals The Infrared Space Observatory

1990 ◽  
Vol 123 ◽  
pp. 205-214 ◽  
Author(s):  
C.J. Cesarsky ◽  
M.F. Kessler
Keyword(s):  
Optical Sensors ◽  
European Space Agency ◽  
Space Observatory ◽  
Infrared Space Observatory ◽  
Long Wavelength ◽  
Space Agency ◽  
Pointing Accuracy ◽  
Funded Project ◽  
Astronomical Satellite ◽  
The Universe

AbstractThe Infrared Space Observatory (ISO), a fully approved and funded project of the European Space Agency (ESA), is an astronomical satellite, which will operate at wavelengths from 3–200 μm. ISO will provide astronomers with a unique facility of unprecedented sensitivity for a detailed exploration of the universe ranging from objects in the solar system right out to distant extragalactic sources. The satellite essentially consists of a large cryostat containing at launch about 2300 litres of superfluid helium to maintain the Ritchey-Chrétien telescope, the scientific instruments and the optical baffles at temperatures between 2K and 8K. The telescope has a 60-cm diameter primary mirror and is diffraction-limited at a wavelength of 5μm. A pointing accuracy of a few arc seconds is provided by a three-axis-stabilisation system consisting of reaction wheels, gyros and optical sensors. ISO’s instrument complement consists of four instruments, namely: a photo-polarimeter (3–200μm), a camera (3–17μm), a short wavelength spectrometer (3–45μm) and a long wavelength spectrometer (45–180μm). These instruments are being built by international consortia of scientific institutes and will be delivered to ESA for in-orbit operations. ISO will be launched in 1993 by an Ariane 4 into an elliptical orbit (apogee 70000km and perigee 1000km) and will be operational for at least 18 months. In keeping with ISO’s role as an observatory, two-thirds of its observing time will be made available to the european and american astronomical community.

High resolution radio astronomy at 13.5 meters.

1955 ◽  
Vol 60 ◽  
pp. 155 ◽  
Author(s):  
B. F. Burke ◽  
R. L. Franklin
Keyword(s):  
High Resolution ◽  
Radio Astronomy

Parkes: Thirty Years of Radio Astronomy

1994 ◽  
Author(s):  
DK Milne
Keyword(s):  
Radio Telescope ◽  
Radio Astronomy ◽  
International Research ◽  
Subsequent Development ◽  
Technical Staff ◽  
The Past ◽  
Fresh Perspective ◽  
Australian Science ◽  
The Universe ◽  
Work And Life

The opening of the Parkes radio telescope in October 1961 placed Australia at the forefront of international research in radio astronomy and ushered in an era of rapid developments in our understanding of the origin and nature of the Universe and our place within it. Thirty years later, the scientists, engineers and technical staff involved in the establishment, operation and subsequent development of this most successful of Australian research instruments gathered to review and reflect on their achievements, and to recount many of the human stories that were so intimately bound up with this extraordinarily productive period in Australia's scientific history. This book presents their accounts of the work and life at Parkes, and provides a fresh perspective on the growth of Australian science over the past three decades.

scholarly journals Division X: Radio Astronomy

2001 ◽  
Vol 24 (2) ◽  
pp. 223-227
Author(s):  
James M. Moran
Keyword(s):  
Solar System ◽  
Radio Astronomy ◽  
Radio Galaxies ◽  
Big Bang ◽  
Common Theme ◽  
Radar Measurements ◽  
The Big Bang ◽  
The Universe ◽  
Vast Range

Division X provides a common theme for astronomers using radio techniques to study a vast range of phenomena in the Universe, from exploring the Earth’s ionosphere or making radar measurements in the solar system, via mapping the distribution of gas and molecules in our own and other galaxies, to the study of previous vast explosive processes in radio galaxies and QSOs and the faint afterglow of the Big Bang itself.

scholarly journals The Chemical Evolution of the Universe

2001 ◽  
Vol 204 ◽  
pp. 323-331
Author(s):  
Antoinette Songaila ◽  
Lennox L. Cowie
Keyword(s):  
High Resolution ◽  
Chemical Evolution ◽  
Metal Contamination ◽  
Metal Distribution ◽  
Absorption Lines ◽  
Low Density ◽  
Intergalactic Gas ◽  
Quasar Absorption Lines ◽  
Future Work ◽  
The Universe

We still know relatively little about the local metal density outside of galaxies and clusters, but at high redshifts (z ~ 3) the advent of highly efficient high-resolution spectrographs on the new 8–10m telescopes has revolutionized the study of quasar absorption lines. This allows us to track the bulk of the baryons in the Universe, which are in highly observable form at this redshift, and to determine the metal density of the gas that contains most of the baryonic material. One of the more surprising results that has emerged is how uniformly the intergalactic gas at redshifts 2–4 is pervaded by metals, and we discuss current limits on such metal contamination of the low density gas. These measurements will be useful in understanding and calibrating feedback processes in early generations of small galaxies. Future work will track the metal distribution at higher redshift using bright z = 5 SDSS quasars.

scholarly journals The Redshift Distribution of Ly α Forest Lines in Spectra of QSOs

1994 ◽  
Vol 159 ◽  
pp. 509-510
Author(s):  
Huang Keliang ◽  
Zhou Hongnan
Keyword(s):  
High Resolution ◽  
Early Universe ◽  
Equivalent Width ◽  
Large Scale ◽  
Strong Line ◽  
Redshift Distribution ◽  
Medium Resolution ◽  
The Universe ◽  
Larger Sample ◽  
Line Sample

Numerous narrow absorption lines in the region of wavelength shorter than 1216(1+zem) (zem is the emission redshift), i.e. so-called Ly α forest lines, detected in QSO spectra are usually thought to be produced in intervening primeval clouds. The study of Ly α clouds may reveal how matter distributes in space and how it evolves with time at the early universe and provide valuable information about the large scale structure of the universe and its evolution. Based on intermediate resolution (1 ∼ 2 A) spectra, many authors (e.g. Lu et al. 1991) deduced that the evolutionary index γ ∼ 2, (dN/dz ∼ (1 + z)γ, dN/dz is the number of clouds per unit redshift interval at redshift z). It means that Ly α clouds have strong cosmological evolution. In recent years, there appear high-resolution (< 30km/sec) spectra of QSOs. High resolution spectra may provide more information than medium resolution spectra. Hence, it is necessary to study the evolution of Ly α clouds, using the spectra with higher resolution. Carswell et al. (1987) found γ=1 in the redshift interval 1.9–3.8. But Rauch et al. (1992) found γ=2.1 for the line sample with logN(HI) ≥ 13.75. It is more interesting that Giallongo (1991) found a differential evolution: γ is depended on the equivalent width W of line and no evolution for the strong line sample with 0.5 > W > 0.3. However, these studies involved very few QSOs (three or four). In this paper, we use a larger sample of QSOs to study the evolution of Ly α clouds.

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