The Astronomical Low-Frequency Array (ALFA)
نویسندگان
چکیده
منابع مشابه
Passive Radar and the Low Frequency Array
The proposed Low Frequency Array will be a powerful new radio telescope operating in the 15 to 240 MHz range. LOFAR will be a fully digital instrument with tens of thousands of antennas and receivers. In the currently proposed configuration LOFAR will also be capable of operating as a high performance passive radar system using FM radio stations as signals of opportunity. In this mode of operat...
متن کاملAstronomical Image Processing with Array Detectors
We address the question of astronomical image processing from data obtained with array detectors. We define and analyze the cases of evenly, regularly, and irregularly sampled maps for idealized (i.e., infinite) and realistic (i.e., finite) detectors. We concentrate on the effect of interpolation on the maps, and the choice of the kernel used to accomplish this task. We show how the normalizati...
متن کاملThe Very Large Array Low-frequency Sky Survey Redux (VLSSr)
We present the results of a recent re-reduction of the data from the Very Large Array (VLA) Low-frequency Sky Survey (VLSS). We used the VLSS catalog as a sky model to correct the ionospheric distortions in the data and create a new set of sky maps and corresponding catalog at 73.8 MHz. The VLSS Redux (VLSSr) has a resolution of 75 arcsec, and an average map RMS noise level of σ ∼ 0.1 Jy beam. ...
متن کاملLaser frequency combs for astronomical observations.
A direct measurement of the universe's expansion history could be made by observing in real time the evolution of the cosmological redshift of distant objects. However, this would require measurements of Doppler velocity drifts of approximately 1 centimeter per second per year, and astronomical spectrographs have not yet been calibrated to this tolerance. We demonstrated the first use of a lase...
متن کاملCalibrating Astronomical Spectrographs with Frequency Combs
This thesis reports on the development of a frequency comb to improve the calibration of astronomical spectrographs. In 1999, the invention of the frequency comb initiated a revolution in the field of precision spectroscopy. It enabled measurement of transitions in atomic and molecular systems with unprecedented accuracy, and in recognition of this achievement, the Nobel Prize was later awarded...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: International Astronomical Union Colloquium
سال: 1998
ISSN: 0252-9211
DOI: 10.1017/s0252921100046091