The Stellar Imager (SI) project: a deep space UV/Optical Interferometer (UVOI) to observe the Universe at 0.1 milli-arcsec angular resolution

2008 ◽  
pp. 221-227 ◽  
Author(s):  
Kenneth G. Carpenter ◽  
◽  
Carolus J. Schrijver ◽  
Margarita Karovska
Keyword(s):  
Angular Resolution ◽  
Optical Interferometer ◽  
Deep Space ◽  
The Universe

scholarly journals Quantiles as Robust Probes of Non-Gaussianity in 21-cm Images

2021 ◽  
Author(s):  
Alon Banet ◽  
Rennan Barkana ◽  
Anastasia Fialkov ◽  
Or Guttman
Keyword(s):  
Galactic Halo ◽  
Angular Resolution ◽  
Research Effort ◽  
First Stars ◽  
X Ray ◽  
Global Signal ◽  
Radio Background ◽  
Halo Masses ◽  
The Universe ◽  
Cosmic History

Abstract The epoch in which the first stars and galaxies formed is among the most exciting unexplored eras of the Universe. A major research effort is focused on probing this era with the 21-cm spectral line of hydrogen. While most research focuses on statistics like the 21-cm power spectrum or the sky-averaged global signal, there are other ways to analyze tomographic 21-cm maps, which may lead to novel insights. We suggest statistics based on quantiles as a method to probe non-Gaussianities of the 21-cm signal. We show that they can be used in particular to probe the variance, skewness, and kurtosis of the temperature distribution, but are more flexible and robust than these standard statistics. We test these statistics on a range of possible astrophysical models, including different galactic halo masses, star-formation efficiencies, and spectra of the X-ray heating sources, plus an exotic model with an excess early radio background. Simulating data with angular resolution and thermal noise as expected for the Square Kilometre Array (SKA), we conclude that these statistics can be measured out to redshifts above 20 and offer a promising statistical method for probing early cosmic history.

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 NIKA: a mm camera for Sunyaev-Zel’dovich science in clusters of galaxies

2020 ◽  
Vol 228 ◽  
pp. 00016
Author(s):  
J.F. Macías-Pérez ◽  
R. Adam ◽  
P. Ade ◽  
P. André ◽  
A. Andrianasolo ◽  
...  
Keyword(s):  
Dark Matter ◽  
Angular Resolution ◽  
High Redshift ◽  
Radial Pressure ◽  
Pressure Profile ◽  
Field Of View ◽  
Dual Band ◽  
Clusters Of Galaxies ◽  
The Universe

Clusters of galaxies, the largest bound objects in the Universe, constitute a cosmological probe of choice, which is sensitive to both dark matter and dark energy. Within this framework, the Sunyaev-Zel’dovich (SZ) effect has opened a new window for the detection of clusters of galaxies and for the characterization of their physical properties such as mass, pressure and temperature. NIKA, a KID-based dual band camera installed at the IRAM 30-m telescope, was particularly well adapted in terms of frequency, angular resolution, field-of-view and sensitivity, for the mapping of the thermal and kinetic SZ effect in high-redshift clusters. In this paper, we present the NIKA cluster sample and a review of the main results obtained via the measurement of the SZ effect on those clusters: reconstruction of the cluster radial pressure profile, mass, temperature and velocity.

scholarly journals Latest results of the ANTARES neutrino telescope

2019 ◽  
Vol 209 ◽  
pp. 01022
Author(s):  
Juan-de-Dios Zornoza
Keyword(s):  
Angular Resolution ◽  
High Energy ◽  
Transient Phenomena ◽  
New Era ◽  
Neutrino Telescopes ◽  
Key Points ◽  
The Galaxy ◽  
Neutrino Astronomy ◽  
The Mediterranean ◽  
The Universe

Neutrino astronomy is in an exciting moment. The discovery of a cosmic flux of high energy neutrinos by IceCube heralds a new era in which neutrinos have finally joined the multi-messenger study of the Universe. This new important window complements more “traditional” probes (as cosmic rays or photons), given the particular combination of characteristics of neutrinos (neutral, stable and weakly interacting). The ANTARES detector, built in the Mediterranean Sea, has succeeded in two key points. First, it has shown the feasibility of the technique of underwater neutrino telescopes, which offers important advantages in terms of performance (better angular resolution, better visibility of the Galaxy if built in the Northern Hemisphere). This has paved the way for the next step, KM3NeT, already in construction. Second, the physics harvest of ANTARES is very rich, including many results that show the particular advantages of being in the Mediterranean, as mentioned above. The analyses performed include the search for point-like sources, diffuse fluxes, transient phenomena, dark matter, etc. In this talk we will review this long list of achievements.

scholarly journals A Brief Update on the CMZoom Survey

2016 ◽  
Vol 11 (S322) ◽  
pp. 90-94
Author(s):  
C. Battersby ◽  
E. Keto ◽  
Q. Zhang ◽  
S.N. Longmore ◽  
J. M. D. Kruijssen ◽  
...  
Keyword(s):  
Star Formation ◽  
Angular Resolution ◽  
Spatial Scales ◽  
Extreme Environments ◽  
Spectral Lines ◽  
Large Area ◽  
Dense Cores ◽  
Submillimeter Wavelengths ◽  
Area Survey ◽  
The Universe

AbstractThe inner few hundred parsecs of the Milky Way, the Central Molecular Zone (CMZ), is our closest laboratory for understanding star formation in the extreme environments (hot, dense, turbulent gas) that once dominated the universe. We present an update on the first large-area survey to expose the sites of star formation across the CMZ at high-resolution in submillimeter wavelengths: the CMZoom survey with the Submillimeter Array (SMA). We identify the locations of dense cores and search for signatures of embedded star formation. CMZoom is a three-year survey in its final year and is mapping out the highest column density regions of the CMZ in dust continuum and a variety of spectral lines around 1.3 mm. CMZoom combines SMA compact and subcompact configurations with single-dish data from BGPS and the APEX telescope, achieving an angular resolution of about 4″ (0.2 pc) and good image fidelity up to large spatial scales.

Radioastron: Main results of the implementation of the early science program in studies of astronomical objects in the universe with ultra-high angular resolution

2015 ◽  
Vol 49 (7) ◽  
pp. 573-579 ◽  
Author(s):  
N. S. Kardashev ◽  
A. V. Alakoz ◽  
Y. Y. Kovalev ◽  
M. V. Popov ◽  
A. M. Sobolev ◽  
...  
Keyword(s):  
Angular Resolution ◽  
High Angular Resolution ◽  
Science Program ◽  
The Universe

scholarly journals Stellar Masses from Double Star Observations with the Mark III Interferometer

1992 ◽  
Vol 135 ◽  
pp. 492-501
Author(s):  
J.T. Armstrong
Keyword(s):  
Angular Resolution ◽  
Speckle Interferometry ◽  
Precise Determination ◽  
Double Star ◽  
Optical Interferometer ◽  
Imaging Interferometer ◽  
Calibration Uncertainty ◽  
Element System ◽  
Stellar Masses ◽  
Magnitude Difference

AbstractBy improving on the angular resolution possible with conventional telescopes, speckle interferometry has been adding to the list of known masses, resolving binaries with separations of 30 mas. Interferometry with separate apertures offers the possibility of going to much higher resolution.The Mark III Optical Interferometer on Mt. Wilson has been used for astrometry, for stellar diameter measurements, and for binary observations since routine operations began in late 1988. The fringe visibilty calibration uncertainty is ~1% for m < 4m at λ800 nm with good seeing, so that both binary components can be detected when the magnitude difference is 3.5m to 4m.From Mark III data, masses of eight stars have been determined. The most precise determination is for the components of the ϕ Cygni system: 2.545 ± 0.085 and 2.445 ± 0.081 M⊙. To improve on this measurement, more precise spectroscopic data are needed, as is the case for most of the systems for which we have orbits or preliminary orbits.The NRL/USNO Optical Interferometer Project is currently designing two more capable instruments: a four–element system for astrometric observations, and a six–element system for imaging. The ultimate 430-m maximum baseline and 35-cm apertures of the imaging interferometer will allow observations to 8th to 10th mag and resolution of binary components separated by as little as ≈ 200 µas.

scholarly journals SOFIA: Stratospheric Observatory for Infrared Astronomy

1994 ◽  
Vol 140 ◽  
pp. 428-429
Author(s):  
J. A. Davidson ◽  
E. F. Erickson
Keyword(s):  
Infrared Spectrum ◽  
Peer Review ◽  
Community Participation ◽  
Infrared Radiation ◽  
Angular Resolution ◽  
State Of The Art ◽  
Infrared Astronomy ◽  
The Past ◽  
Hands On ◽  
The Universe

SOFIA will be a 2.5 meter telescope installed in a Boeing 747 aircraft. It will replace NASA’s smaller Kuiper Airborne Observatory (KAO), which for the past 18 years has provided the only routine access to most of the vital infrared spectrum (1 - 1000 µm). The aircraft platform opens a valuable window to the universe by enabling measurements of infrared radiation from celestial sources which the Earth’s atmosphere absorbs at lower altitudes. SOFIA will have 10 times the sensitivity and 3 times the angular resolution of the KAO throughout most of the infrared spectrum.SOFIA will be operated during its 20 year lifetime as an international facility for astronomy. It would fly 160 astronomy missions per year for about 50 science teams, selected by annual peer review. Nearly a third of these teams will furnish the observatory with specialized instrumentation, including array cameras, polarimeters, and several types of spectrometers. The frequent flight opportunities with state-of-the-art instruments guarantee extensive community participation and hands-on training of young scientists.

scholarly journals VLBI from the Moon

1998 ◽  
Vol 11 (2) ◽  
pp. 985-987
Author(s):  
L. I. Gurvits
Keyword(s):  
Radio Astronomy ◽  
Very Long Baseline Interferometry ◽  
Angular Resolution ◽  
High Angular Resolution ◽  
The Moon ◽  
Next Generation ◽  
Space Observatory ◽  
Long Baseline ◽  
The Earth ◽  
The Universe

Very Long Baseline Interferometry (VLBI) technique occupies a special place among tools for studying the Universe due to its record high angular resolution. The latter is in the inverse proportion to the length of interferometer baseline at any given wavelength. Until recently, the available angular resolution in radio domain of about 1 milliarcsecond at centimeter wavelengths was limited by the diameter of the Earth. However, many astrophysical problems require a higher angular resolution. The only way to achieve this at a given wavelength is to create an interferometer with the baseline larger than the Earth’s diameter by placing at least one telescope in space. In February 1997, the first dedicated Space VLBI mission, VLBI Space Observatory Program (VSOP), led by the Institute of Space and Astronautical Sciences (Japan) has been launched (Hirabayashi 1997). The VSOP mission opens a new dimension in the development of radio astronomy of extremely high angular resolution and will be followed by other Space VLBI missions. A review of scientific drives and technological challenges of the next generation Space VLBI mission have been discussed, for example, by Gurvits et al. (1996) and Ulvestad et al. (1997).

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