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1.
Alessandro Marconi Roberto Maiolino Romain G. Petrov 《Astrophysics and Space Science》2003,286(1-2):245-254
Interferometry in the optical and near infrared has so far played a marginal role in Extragalactic Astronomy. Active Galactic
Nuclei are the brightest and most compact extragalactic sources, nonetheless only a very limited number could be studied with
speckle interferometry and none with long baseline interferometry. The VLTI will allow the study of moderately faint extragalactic
objects with very high spatial resolution thus opening a new window on the universe. With this paper we focus on three scientific
cases to show how AMBER and MIDI can be used to tackle open issues in extragalactic astronomy.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
2.
Webster Cash 《Experimental Astronomy》2003,16(2):91-136
For the astronomer, X-ray interferometry is the theory and practice of building dilute aperture telescopes for studying celestial X-ray sources. The short wavelengths and high surface brightness of X-ray sources will make the eventual scientific payoff very high, with direct imaging of the event horizons of black holes as the centerpiece. In this article, we review the history of X-ray interferometry and discuss the recent technical developments toward astronomical applications. We present several mission concepts and show they are achievable with todays technology. 相似文献
3.
Optical long-baseline interferometry is a unique and powerful technique for astronomical research. Since the 1980’s (with I2T, GI2T, Mark I to III, SUSI, ...), optical interferometers have produced an increasing number of scientific papers covering various fields of astrophysics. As current interferometric facilities are reaching their maturity, we take the opportunity in this paper to summarize the conclusions of a few key meetings, workshops, and conferences dedicated to interferometry. We present the most persistent recommendations related to science cases and discuss some key technological developments required to address them. In the era of extremely large telescopes, optical long-baseline interferometers will remain crucial to probe the smallest spatial scales and make breakthrough discoveries. 相似文献
4.
A. Quirrenbach 《Astrophysics and Space Science》2003,286(1-2):277-289
The scientific capabilities of the VLT Interferometer can be substantially enhanced through new focal-plane instruments. Many
interferometric techniques– astrometry, phase-referenced imaging, nulling, and differential phase measurements – require control
of the phase to ≲ 1 rad; this capability will be provided at the VLTI by the PRIMA facility. Phase-coherent operation of the
VLTI will also make it possible to perform interferometry with spectral resolution up to R ∼ 100,000 by building fiber links
to the high-resolution spectrographs UVES and CRIRES. These developments will open new approaches to fundamental problems
in fields as diverse as extra solar planets,stellar atmospheres, circumstellar matter, and active galactic nuclei.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
5.
Enrico Lorenzini Claudio Bombardelli Mario Cosmo Martin Harwit David Leisawitz Rodger Farley Stephen Rinehart David Quinn David Miller 《Astrophysics and Space Science》2006,302(1-4):225-239
Through the continuing development of improved detectors and detector arrays, far-infrared/submillimeter astronomical space
missions have had enormous successes in recent years. Despite these advances, the diffraction-limited angular resolving power
has remained virtually constant. The advent of telescopes with apertures of several meters will improve this capability, but
will still leave image resolution many orders of magnitude poorer than in most other spectral ranges. Here we point out that
the only foreseeable way to improve image quality to rival that of modern optical telescopes will be with interferometers
whose light collectors are connected by tethers. After making the scientific case for high spatial resolution far-infrared/submillimeter
imaging and the use of interferometry as the most immediate way of producing results, we discuss recent advances in dynamic
analysis and control of tethered formations, and argue that the further development and testing of tethers in space is a first
step toward providing improved far-infrared/submillimeter angular resolution and astronomical image quality. 相似文献
6.
A. Eckart T. Bertram N. Mouawad T. Viehmann C. Straubmeier J. Zuther 《Astrophysics and Space Science》2003,286(1-2):269-276
VLTI interferometry will allow imaging of galactic and extragalactic sources with milliarcsecond angular resolution. For moderately
bright sources the spectral resolution will be of the order of 10000. These capabilities will allow detailed studies of solar
system objects, stars, proto-planetary systems and the detection of hot extra-solar planets. The observations of galactic
nuclei will allow unprecedented measurements of physical parameters in these systems. VLTI will be a prime instrument to study
the immediate environment of the massive black hole at the center of the Milky Way. With the exception of a few `self-referencing'
sources the observations of extragalactic nuclei will benefit from an extended capability for simultaneous measurements of
nearby reference sources for fringe tracking. With beam combination instruments like AMBER, MIDI, PRIMA, and GENIE the VLTI
will reach full maturity at a time when other interferometric instruments at different wavelengths will be fully operational.
Most important are ALMA (in the mm- and sub-mm-domain), LOFAR and SKA (in the radio meter to centimeter domain) and of course
VLB-networks in the radio, and other – at that time –well developed interferometers in the optical. A major scientific potential
of future scientific VLTI programs will lie in an efficient combination of these high angular resolution capabilities.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
7.
Frank Przygodda O. Chesneau U. Graser Ch. Leinert S. Morel 《Astrophysics and Space Science》2003,286(1-2):85-91
MIDI, the MID-Infrared Interferometricnterferometric Instrument for ESO's Very Large Telescope Interferometer (VLTI), will be the first instrument for combining
mid-infrared light directly in order to obtain angular resolution up to 10 mas (assuming a 200 m baseline) in a wavelength
range from 8 to 13 μm. Currently in the phase of commissioning at Paranal, the start of its scientific operation is expected
for summer 2003. Direct interferometry at thermal infrared wavelengths demands special requirements on the instrument and
also on the procedures of preparation of data reduction. Hereafter MIDI's different observing modes are described and an example
for an interferometric observation is given.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
8.
The study of circumstellar disks around young stellar objects is arguably the area of astrophysics on which the technique of infrared interferometry has had the biggest impact. Here I will review the existing set of observations in this field, concentrating on disks but also including jets/winds and stellar properties. At the end, there is a brief discussion of how ongoing technical developments and observational improvements will expand the impact of infrared interferometry on the study of star formation. 相似文献
9.
Existing instruments are unable to detect planets about stars other than the Sun but such detection would be important for the theory of origin of our solar system and in the search for extraterrestrial intelligence. Infrared offers an advantage of about 105 over visible light as regards the ratio of power received from star and planet. Infrared interferometry from Earth orbit would allow discrimination against the stellar infrared by the placement of an interference null on the star and a spinning infrared interferometer would modulate the planetary emission to permit extraction by synchronous detection from the background level. The limit to sensitivity will be set by thermal emission from the zodiacal light particles near the Earth's orbit unless the interferometer is launched out of the ecliptic or out to the orbit of Jupiter, in which case instrumental limitations will dominate. Technological developments in several fields will be required as also with astrometry, spectroscopic radial velocity measurement, and direct photography from orbit, three approaches with which infrared interferometry should be carefully compared. 相似文献
10.
Intensity interferometry removes the stringent requirements on mechanical precision and atmospheric corrections that plague all amplitude interferometry techniques at the cost of severely limited sensitivity. A new idea we recently introduced, very high redundancy, alleviates this problem. It enables the relatively simple construction (∼1 cm mechanical precision) of a ground-based astronomical facility able to transform a two-dimensional field of point-like sources to a three-dimensional distribution of microarcsec resolved systems, each imaged in several optical bands. Each system will also have its high-resolution residual timing, high-quality (inside each band) spectra and light curve, emergent flux, effective temperature, polarization effects and perhaps some thermodynamic properties, all directly measured. All the above attributes can be measured in a single observation run of such a dedicated facility. We conclude that after three decades of abandonment, optical intensity interferometry deserves another review, also as a ground-based alternative to the science goals of space interferometers. 相似文献
11.
Margarita Karovska 《Astrophysics and Space Science》2006,304(1-4):379-382
UV and X-ray space-based interferometry will open unprecedented possibilities for spectral and spatial studies of a wide range of currently unresolvable interacting systems. Ultra-high angular resolution direct imaging of individual} components and transport processes in interacting binary systems is essential for detailed studies and modeling of accretion and activity. Understanding the mass loss characteristics of both components, and the dynamics of the system as a function of time, will provide key inputs to evolutionary models and will revolutionize our view and understanding of the Universe. 相似文献
12.
由于地球电离层的阻挡以及其他干扰,在地面难以进行有效的甚低频天文观测,而使用搭载于绕地或绕月轨道卫星上的甚低频天线进行干涉观测会大大提高观测灵敏度和角分辨率.卫星定位精度会影响观测数据的处理结果,进而影响成图质量,并且会大幅影响飞行项目的复杂度和总成本.首先分析卫星姿态控制精度和星间基线测量精度对绕地轨道甚低频干涉观测的影响,之后对干涉观测中信号延时误差进行仿真,研究延时误差与数据相关处理中条纹搜索范围之间的关系,并对数据计算速度需求进行估算.分析和仿真结果可以辅助相关空间甚低频观测项目总体方案的制定和工程指标的优化. 相似文献
13.
Rapid developments in the techniques of interferometry at millimeter wavelengths now permit the use of telescope arrays similar to the Very Large Array at microwave wavelengths. These new arrays represent improvements of orders of magnitude in the spatial resolution and sensitivity of millimeter observations of the Sun, and will allow us to map the solar chromosphere at high spatial resolution and to study solar radio burst sources at millimeter wavelengths with high spatial and temporal resolution. Here we discuss the emission mechanisms at millimeter wavelengths and the phenomena which we expect will be the focus of such studies. We show that the flare observations study the most energetic electrons produced in solar flares, and can be used to constrain models for electron acceleration. We discuss the advantages and disadvantages of millimeter interferometry, and in particular focus on the use of and techniques for arrays of small numbers of telescopes.Paper presented at the 4th CESRA Workshop in Ouranopolis (Greece) 1991. 相似文献
14.
15.
《Experimental Astronomy》2009,23(1):221-244
Millimetron is a Russian-led 12 m diameter submillimeter and far-infrared space observatory which is included in the Space
Plan of the Russian Federation for launch around 2017. With its large collecting area and state-of-the-art receivers, it will
enable unique science and allow at least one order of magnitude improvement with respect to the Herschel Space Observatory.
Millimetron will be operated in two basic observing modes: as a single-dish observatory, and as an element of a ground-space
very long baseline interferometry (VLBI) system. As single-dish, angular resolutions on the order of 3 to 12 arc sec will
be achieved and spectral resolutions of up to a million employing heterodyne techniques. As VLBI antenna, the chosen elliptical
orbit will provide extremely large VLBI baselines (beyond 300,000 km) resulting in micro-arc second angular resolution. 相似文献
16.
Michael Shao 《Astrophysics and Space Science》1996,241(1):105-110
This paper summarizes the limits of ground-based interferometry for differential astrometry as well as ground-based interferometry for direct detection of exo-planets and exo-zodi dust levels. For direct detection, ground-based interferometry at near IR wavelengths using large telescopes with adaptive optics offers a significant advantage over single telescopes with adaptive optics. Ground-based differential astrometry for exo-planet detection is extremely accurate with sufficient accuracy to detect Neptune mass planets around 400–600 nearby stars. Ground-based interferometry using large (>6m) telescopes is also capable of detecting the 10 m emission of the zodiacal light around nearby stars with zodi levels similar to our solar system 相似文献
17.
R. P. Korechoff D. J. Diner E. F. Tubbs S. L. Gaiser 《Astrophysics and Space Science》1994,212(1-2):369-383
This paper discusses the concept of extrasolar planet detection using a large-aperture infrared imaging telescope. Coronagraphic stellar apodization techniques are less efficient at infrared wavelengths compared to the visible, as a result of practical limitations on aperture dimensions, thus necessitating additional starlight suppression to make planet detection feasible in this spectral domain. We have been investigating the use of rotational shearing interferometry to provide up to three orders of magnitude of starlight suppression over broad spectral bandwidths. We present a theoretical analysis of the system performance requirements needed to make this a viable instrument for planet detection, including specifications on the interferometer design and telescope aperture characteristics. The concept of using rotational shearing interferometry as a wavefront error detector, thus providing a signal that can be used to adaptively correct the wavefront, will be discussed. We also present the status of laboratory studies of on-axis source suppression using a recently constructed rotational shearing interferometer that currently operates in the visible.Paper presented at the Conference onPlanetary Systems: Formation, Evolution, and Detection held 7–10 December, 1992 at CalTech, Pasadena, California, U.S.A. 相似文献
18.
19.
F. Malbet 《Astrophysics and Space Science》2003,286(1-2):131-144
The study of Young Stellar Objects (YSOs) is one of the most exciting topics that can be undertaken by long baseline optical
interferometry. The magnitudes of these objects are at the edge of capabilities of current optical interferometers, limiting
the studies to a few dozen, but are well within the capability of coming large aperture interferometers like the VLT Interferometer,
the Keck Interferometer, the Large Binocular Telescope or 'OHANA. The milli-arcsecond spatial resolution reached by interferometry
probes the very close environment of young stars, down to a tenth of an astronomical unit. In this paper, I review the different
aspects of star formation that can be tackled by interferometry: circumstellar disks, multiplicity, jets. I present recent
observations performed with operational infrared interferometers, IOTA, PTI and ISI, and I show why in the next future one
will extend these studies with large aperture interferometers.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
20.
Browne Patnaik Wilkinson & Wrobel 《Monthly notices of the Royal Astronomical Society》1998,293(3):257-287
We present a catalogue of 781 compact radio sources in the declination range 0° ≤ δB1950 ≤ +20° whose positions have been measured to an rms accuracy of about 14 mas with the Very Large Array (VLA). These sources are primarily intended for use as phase calibration sources for the Jodrell Bank MERLIN. However, they will also be suitable as phase calibrators for the VLA and can be considered as candidate phase calibrators for very long-baseline interferometry (VLBI) networks. 相似文献