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81.
82.
Noah Brosch 《Astrophysics and Space Science》2009,320(1-3):207-215
After considering a number of historical but somewhat “forgotten” UV astronomy experiments, I discuss a number of ways of non-conventional astronomy in the ultraviolet that, on first considerations, could be viable alternatives and valuable complements to classical space observations. These are (a) UV astronomy from the Antarctic or the Arctic regions that take advantage of the “ozone hole”, (b) the use of high-altitude stratospheric balloon-borne telescopes, and (c) the operation of UV telescopes on the Moon. The advantages of these options are discussed and evaluated against the costs of each option and, one by one, are mostly rejected as not fully justifying the specific alternative. The possibility to achieve valuable (but limited) UV science, such as imaging at ~2000 Å, using long-duration stratospheric balloons is described. The option of lunar UV observatories is retained to be implemented for the case of a UV interferometer, where the stability of the lunar regolith is seen as a significant advantage in comparison to free-flying interferometers. A location beyond the main asteroid belt, where the background due zodiacal light may be negligible, is advocated as an ideal location for a UV observatory in the Solar System. 相似文献
83.
Elhanan Almoznino Noah Brosch Ido Finkelman Hagai Netzer Erez R. Yacoby Jeremy Topaz Nachman Saar 《Astrophysics and Space Science》2009,320(4):321-341
We describe in detail the procedures used for the ground testing and calibration of the flight model of the TAUVEX space telescope.
We present the measurements done for this purpose, the various assumptions adopted during the ground calibration process,
the results obtained, and provide a first approximation to the real performance of the experiment.
The results of the ground-based calibration are that the system complies with the predicted performance in all aspects except
for the total throughput, which is a factor of ∼5 smaller than expected. However, the instrument sensitivity measurement is
highly uncertain due to known limitations of the available equipment and a more accurate calibration will be performed in
orbit. 相似文献
84.
85.
We show that present day observational techniques make it possible to detect diffuse gas masses down to ~1010 M ⊙ in cosmic voids with linear sizes of ~1 Mpc or larger. The observations consist of searches for absorption lines, similar in character to those produced in galactic interstellar clouds, in the spectra of high-redshift objects located beyond previously identified voids adjoining nearby superclusters. 相似文献
86.
Ofer Lahav Noah Brosch Evgeny Goldberg George K. T. Hau Renée C. Kraan-Korteweg & Andy J. Loan 《Monthly notices of the Royal Astronomical Society》1998,299(1):24-30
Motivated by recent discoveries of nearby galaxies in the Zone of Avoidance (ZOA), we conducted a pilot study of galaxy candidates at low galactic latitude, near galactic longitude l ∼ 135°, where the Supergalactic plane is crossed by the Galactic plane. We observed with the 1-m Wise Observatory in the l band 17 of the 'promising' candidates identified by visual examination of Palomar red plates by Hau et al. A few candidates were also observed in R or B bands, or had spectroscopic observations performed at the Isaac Newton Telescope and at the Wise Observatory. Our study suggests that there are probably 10 galaxies in this sample. We also identify a probable planetary nebula. The final confirmation of the nature of these sources must await the availability of full spectroscopic information. The success rate of ∼ 50 per cent in identifying galaxies at galactic latitude | b | < 5° indicates that the ZOA is a promising region to discover new galaxies. 相似文献
87.
Elchanan Almoznino & Noah Brosch 《Monthly notices of the Royal Astronomical Society》1998,298(3):920-930
We selected samples of late-type dwarf galaxies in the Virgo cluster with H i information. The galaxies were observed at the Wise Observatory using several broad-band and Hα bandpasses. UV measurements were carried out with the IUE Observatory from VILSPA, and with the FAUST shuttle-borne UV telescope. We describe the observations in detail, paying particular attention to the determination of measurement errors, and present the observational results together with published data and far-infrared information from IRAS . The sample will be analysed in subsequent papers, in order to study star formation mechanisms in galaxies. 相似文献
88.
Noah Brosch Eran O. Ofek Elhanan Almoznino Timothy Sasseen Michael Lampton & Stuart Bowyer 《Monthly notices of the Royal Astronomical Society》1998,295(4):959-969
We analyse an ultraviolet observation toward the Coma cluster by means of the FAUST shuttle-borne telescope. We detect 56 candidate sources to a signal-to-noise ratio of 6.5. Most sources have optical counterparts in existing catalogues and are stars. 10 sources with no listed counterparts were observed at the Wise Observatory. We present identifications based on low-resolution spectrophotometry, and discuss the foreground stars and the galaxies, all in the foreground of the Coma cluster. The FAUST image yields a higher fraction of hot evolved stars than either of the North Galactic Pole or the Virgo regions, analysed previously. We identify these tentatively as cooling white dwarfs in the Coma Berenices (Mel 111) open cluster. 相似文献
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90.