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Artigos de revistas sobre o tema "Stars Scintillation"

Autor: Grafiati

Publicado: 4 de junho de 2021

Última modificação: 29 de janeiro de 2023

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1

Sofieva, V. F., V. Kan, F. Dalaudier, E. Kyrölä, J. Tamminen, J. L. Bertaux, A. Hauchecorne, D. Fussen, and F. Vanhellemont. "Influence of scintillation on GOMOS ozone retrievals." Atmospheric Chemistry and Physics Discussions 9, no. 3 (May 29, 2009): 12615–43. http://dx.doi.org/10.5194/acpd-9-12615-2009.

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Abstract. The stellar light passed through the Earth atmosphere is affected by refractive effects, which should be taken into account in retrievals from stellar occultation measurements. Scintillation caused by air density irregularities is a nuisance for retrievals of atmospheric composition. In this paper, we consider the influence of scintillation on stellar occultation measurements and on quality of ozone retrievals from these measurements, based on experience of the GOMOS (Global Ozone Monitoring by Occultation of Stars) instrument on board the Envisat satellite. In the GOMOS retrievals,

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Sofieva, V. F., V. Kan, F. Dalaudier, E. Kyrölä, J. Tamminen, J. L. Bertaux, A. Hauchecorne, D. Fussen, and F. Vanhellemont. "Influence of scintillation on quality of ozone monitoring by GOMOS." Atmospheric Chemistry and Physics 9, no. 23 (December 7, 2009): 9197–207. http://dx.doi.org/10.5194/acp-9-9197-2009.

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Abstract. Stellar light passing through the Earth atmosphere is affected by refractive effects, which should be taken into account in retrievals from stellar occultation measurements. Scintillation caused by air density irregularities is a nuisance for retrievals of atmospheric composition. In this paper, we consider the influence of scintillation on stellar occultation measurements and on the quality of ozone retrievals from these measurements, based on experience of the GOMOS (Global Ozone Monitoring by Occultation of Stars) instrument on board the Envisat satellite. In GOMOS retrievals, the

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3

Melrose, D. B. "Twinkle, Twinkle Little Pulsar/Quasar." Australian Journal of Physics 52, no. 1 (1999): 1. http://dx.doi.org/10.1071/p98076.

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The twinkling of stars is a familiar example of scintillations, due to turbulence in the Earth’s atmosphere causing fluctuations in the refractive index of the air along the line of sight. Scintillations lead to time variations in the apparent position of the source, and hence to an angular broadening on integration over an observation time. Scintillations also lead to fluctuations in the intensity of the source. Pointlike astronomical radio sources such as pulsars and (the compact cores of some) quasars scintillate due to fluctuations in the electron density along the line of sight through th

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O’Brien, Sean M., Daniel Bayliss, James Osborn, Edward M. Bryant, James McCormac, Peter J. Wheatley, Jack S. Acton, et al. "Scintillation-limited photometry with the 20-cm NGTS telescopes at Paranal Observatory." Monthly Notices of the Royal Astronomical Society 509, no. 4 (November 26, 2021): 6111–18. http://dx.doi.org/10.1093/mnras/stab3399.

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ABSTRACT Ground-based photometry of bright stars is expected to be limited by atmospheric scintillation, although in practice observations are often limited by other sources of systematic noise. We analyse 122 nights of bright star (Gmag ≲ 11.5) photometry using the 20-cm telescopes of the Next-Generation Transit Survey (NGTS) at the Paranal Observatory in Chile. We compare the noise properties to theoretical noise models and we demonstrate that NGTS photometry of bright stars is indeed limited by atmospheric scintillation. We determine a median scintillation coefficient at the Paranal Observa

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5

Kan, V., V. F. Sofieva, and F. Dalaudier. "Variable anisotropy of small-scale stratospheric irregularities retrieved from stellar scintillation measurements by GOMOS/Envisat." Atmospheric Measurement Techniques 7, no. 6 (June 25, 2014): 1861–72. http://dx.doi.org/10.5194/amt-7-1861-2014.

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Abstract. In this paper, we consider possibilities for studying the anisotropy of small-scale air density irregularities using satellite observations of bi-chromatic stellar scintillations during tangential occultations. Estimation of the anisotropy coefficient (the ratio of the characteristic horizontal to vertical scales) and other atmospheric parameters is based on the comparison of simulated/theoretical and experimental auto-spectra and coherency spectra of scintillation. Our analyses exploit a 3-D model of the spectrum of atmospheric inhomogeneities, which consists of anisotropic and isot

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6

Kan, V., V. F. Sofieva, and F. Dalaudier. "Variable anisotropy of small-scale stratospheric irregularities retrieved from stellar scintillation measurements by GOMOS/Envisat." Atmospheric Measurement Techniques Discussions 7, no. 2 (February 10, 2014): 1275–304. http://dx.doi.org/10.5194/amtd-7-1275-2014.

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Abstract. In this paper, we consider possibilities for studying the anisotropy of small-scale air density irregularities using satellite observations of bi-chromatic stellar scintillations during tangential occultations. Estimation of the anisotropy coefficient (the ratio of the characteristic horizontal to vertical scales) and other atmospheric parameters is based on the comparison of simulated/theoretical and experimental auto-spectra and coherency spectra of scintillation. Our analyses exploit a 3-D model of the spectrum of atmospheric inhomogeneities, which consists of anisotropic and isot

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Hamacher, Duane W., John Barsa, Segar Passi, and Alo Tapim. "Indigenous use of stellar scintillation to predict weather and seasonal change." Proceedings of the Royal Society of Victoria 131, no. 1 (2019): 24. http://dx.doi.org/10.1071/rs19003.

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Indigenous peoples across the world observe the motions and positions of stars to develop seasonal calendars. Changing properties of stars, such as their brightness and colour, are also used for predicting weather. Combining archival studies with ethnographic fieldwork in Australia’s Torres Strait, we explore the various ways Indigenous peoples utilise stellar scintillation (twinkling) as an indicator for predicting weather and seasonal change, and examine the Indigenous and Western scientific underpinnings of this knowledge. By observing subtle changes in the ways the stars twinkle, Meriam pe

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Dravins, D., L. Lindegren, and E. Mezey. "Atmospheric Intensity Scintillation of Stars on Milli- and Microsecond Time Scales." International Astronomical Union Colloquium 136 (1993): 113–19. http://dx.doi.org/10.1017/s0252921100007454.

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AbstractStellar intensity scintillation on short and very short time scales (≃ 100 ms - 100 ns) was studied using an optical telescope on La Palma (Canary Islands). Photon counting detectors and real-time signal processing equipment were used to study atmospheric scintillation as function of telescope aperture size, degree of apodization, for single and double apertures, in different optical colors, at different zenith distances, times of night, and seasons of year. The statistics of temporal intensity variations can be adequately described by log-normal distributions, varying with time. The s

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Kan, V., V. F. Sofieva та F. Dalaudier. "Anisotropy of small-scale stratospheric irregularities retrieved from scintillations of a double star α-Cru observed by GOMOS/ENVISAT". Atmospheric Measurement Techniques Discussions 5, № 4 (13 липня 2012): 4881–904. http://dx.doi.org/10.5194/amtd-5-4881-2012.

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Abstract. In this paper, we discuss estimating anisotropy of air density irregularities (ratio of characteristic horizontal and vertical scales) from satellite observations of bi-chromatic scintillations of a double star whose components are not resolved by the detector. The analysis is based on fitting experimental auto- and cross-spectra of scintillations by those computed using the 3-D spectral model of atmospheric irregularities consisting of anisotropic and isotropic components. Application of the developed method to the scintillation measurements of the double star α-Cru by GOMOS (Global

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Kan, V., V. F. Sofieva та F. Dalaudier. "Anisotropy of small-scale stratospheric irregularities retrieved from scintillations of a double star α-Cru observed by GOMOS/ENVISAT". Atmospheric Measurement Techniques 5, № 11 (14 листопада 2012): 2713–22. http://dx.doi.org/10.5194/amt-5-2713-2012.

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Abstract. In this paper, we discuss estimating anisotropy of air density irregularities (ratio of characteristic horizontal and vertical scales) from satellite observations of bi-chromatic scintillations of a double star whose components are not resolved by the detector. The analysis is based on fitting experimental auto- and cross-spectra of scintillations by those computed using the 3-D spectral model of atmospheric irregularities consisting of anisotropic and isotropic components. Application of the developed method to the scintillation measurements of the double star α-Cru by GOMOS (Global

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11

Longair, Malcolm S. "Antony Hewish. 11 May 1924—13 September 2021." Biographical Memoirs of Fellows of the Royal Society 72 (March 16, 2022): 173–96. http://dx.doi.org/10.1098/rsbm.2021.0045.

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Antony (Tony) Hewish was a pioneer radio astronomer who will always be remembered as the leader of the team in 1967 that discovered the pulsars, which proved to be rapidly rotating, magnetized neutron stars. The discovery resulted from Tony's programme of systematic all-sky surveys to detect the scintillation, or flickering, of small angular diameter radio sources due to electron density fluctuations in the solar wind flowing out from the Sun. The large low-frequency 4.5-acre array was designed by Tony to find radio quasars, which often display radio scintillations, to estimate the angular siz

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Moniez, M., R. Ansari, F. Habibi, and S. Rahvar. "Search for Turbulent Gas through Interstellar Scintillation." Proceedings of the International Astronomical Union 7, S285 (September 2011): 376–78. http://dx.doi.org/10.1017/s1743921312001123.

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AbstractStars twinkle because their light propagates through the atmosphere. The same phenomenon is expected when the light of remote stars crosses a Galactic—disk or halo—refractive medium such as a molecular cloud. We present the promising results of a test performed with the ESO–NTT, and consider its potential.

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13

Lim, J., G. J. Nelson, and A. E. Vaughan. "A Multi-Purpose, Multi-Channel Radiospectrograph for the Parkes Telescope." Publications of the Astronomical Society of Australia 7, no. 2 (1987): 197–204. http://dx.doi.org/10.1017/s1323358000022207.

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AbstractThe design and scientific applications of a 96-channel filter spectrograph of 1 MHz resolution are presented. The spectrograph is currently under construction and will be installed on the Parkes telescope in 1987-1988. Its main scientific objective is dynamic spectral studies of decimetre- and metre-wavelength bursts from flare stars. However, it will also be used for performing large-scale pulsar surveys, and dynamic spectral observations of interplanetary scintillation of compact sources, interstellar scintillation of compact extragalactic sources, and interesting radio sources in ge

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Cordes, J. M. "Interstellar Scintillations and Neutron Star Kinematics." Symposium - International Astronomical Union 125 (1987): 35–46. http://dx.doi.org/10.1017/s0074180900160322.

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The interstellar scintillation technique for measuring neutron star speeds is described and results are given for 71 radio pulsars. The mean transverse neutron star speed is 100 km s−1 and the distribution extends to 300 km s−1. The transverse speed correlates with the z velocity derived independently using distance from the galactic plane, consistent with most neutron stars having been born near the galactic plane. A correlation of transverse speed with the quantity PP ∝ (magnetic moment)2 is a general property of the neutron star population. Monte Carlo simulations of the progenitors of neut

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15

Dravins, D., L. Lindegren, E. Mezey, and A. T. Young. "Atmospheric Intensity Scintillation of Stars. II. Dependence on Optical Wavelength." Publications of the Astronomical Society of the Pacific 109 (June 1997): 725. http://dx.doi.org/10.1086/133937.

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Dravins, Dainis, Lennart Lindegren, Eva Mezey, and Andrew T. Young. "Atmospheric Intensity Scintillation of Stars. III. Effects for Different Telescope Apertures." Publications of the Astronomical Society of the Pacific 110, no. 747 (May 1998): 610–33. http://dx.doi.org/10.1086/316161.

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Dravins, Dainis, Lennart Lindegren, Eva Mezey, and Andrew T. Young. "Atmospheric Intensity Scintillation of Stars, I. Statistical Distributions and Temporal Properties." Publications of the Astronomical Society of the Pacific 109 (February 1997): 173. http://dx.doi.org/10.1086/133872.

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Inoue, H. "ASCA Observations of White Dwarfs, Neutron Stars and Black Holes." Symposium - International Astronomical Union 165 (1996): 321–31. http://dx.doi.org/10.1017/s0074180900055789.

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ASCA, the fourth Japanese X-ray astronomy satellite, was launched by the Institute of Space and Astronautical Science (ISAS) on 1993 February 20. ASCA is designed to be a high-capability X-ray observatory (Tanaka et al. 1994). It is equipped with nested thin-foil mirrors which provide a large effective area over a wide energy range from 0.5 to 10 keV. Two different types of detectors, CCD cameras (SIS) and imaging gas scintillation proportional counters (GIS) are employed as the focal plane instruments.

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Rickett, Barney. "Intermittency and Anisotropy in the Ionized Interstellar Medium." Proceedings of the International Astronomical Union 13, S337 (September 2017): 283–86. http://dx.doi.org/10.1017/s1743921317009206.

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AbstractThe discovery of pulsars was closely followed by the discovery of dispersion and scattering in the interstellar plasma (ionized interstellar medium - IISM). The rich phenomena of scattering and scintillation have since been successfully modelled as propagation through a statistically uniform plasma turbulence with an isotropic Kolmogorov spectrum of density. However, this enticingly simple model fails to explain the many recent observations, that show anisotropic scattering from highly localized regions of the IISM often referred to as phase screens. I summarize the recent evidence fro

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Ashikhmin, V. V., R. I. Enikeev, A. V. Pokropivny, O. G. Ryazhskaya, and V. G. Ryasny. "Search for neutrino radiation from collapsing stars with the Artyomovsk scintillation detector." Bulletin of the Russian Academy of Sciences: Physics 77, no. 11 (November 2013): 1333–35. http://dx.doi.org/10.3103/s1062873813110051.

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Dravins, Dainis, Lennart Lindegren, Eva Mezey, and Andrew T. Young. "Atmospheric Intensity Scintillation of Stars. III. Effects for Different Telescope Apertures: Erratum." Publications of the Astronomical Society of the Pacific 110, no. 751 (September 1998): 1118. http://dx.doi.org/10.1086/316232.

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Sofieva, Viktoria F., Francis Dalaudier, Alain Hauchecorne, and Valery Kan. "High-resolution temperature profiles retrieved from bichromatic stellar scintillation measurements by GOMOS/Envisat." Atmospheric Measurement Techniques 12, no. 1 (January 28, 2019): 585–98. http://dx.doi.org/10.5194/amt-12-585-2019.

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Abstract. In this paper, we describe the inversion algorithm for retrievals of high vertical resolution temperature profiles (HRTPs) using bichromatic stellar scintillation measurements in the occultation geometry. This retrieval algorithm has been improved with respect to nominal ESA processing and applied to the measurements by Global Ozone Monitoring by Occultation of Stars (GOMOS) operated on board Envisat in 2002–2012. The retrieval method exploits the chromatic refraction in the Earth's atmosphere. The bichromatic scintillations allow the determination of the refractive angle, which is p

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Kreidl, T. J. "Chaos in Pulsating Variable Stars: Preliminary Analysis of Photometric Photometry and Observational Constraints of Detection." International Astronomical Union Colloquium 139 (1993): 133. http://dx.doi.org/10.1017/s0252921100117105.

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AbstractChaos theory has been applied to a variety of variable stars, but few convincing candidates for chaos have been identified. Here, well-established analysis methods have been applied to some very extensive data sets of rapidly oscillating Ap (roAp) stars and one white dwarf. It it shown that in spite of the amount of data, the signal-to-noise ratio makes positive detection of chaos extremely difficult, especially due to scintillation noise. A new form of dimension computation is presented and discussed. Simple models were constructed to show what noise levels can be tolerated before the

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Jauncey, David L., Lucyna Kedziora-Chudczer, J. E. J. Lovell, Jean-Pierre Macquart, George D. Nicolson, Rick A. Perley, John E. Reynolds, A. K. Tzioumis, Mark A. Wieringa, and Hayley E. Bignall. "Intraday Variability and Microarcsecond Structure in Blazar Cores." Symposium - International Astronomical Union 205 (2001): 84–87. http://dx.doi.org/10.1017/s0074180900220524.

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The accumulation of evidence now strongly favours interstellar scintillation (ISS) as the principal mechanism causing intra-day variability (IDV) at cm wavelengths. While ISS reduces the implied brightness temperatures, they remain uncomfortably high. The distance to the scattering screen is an important parameter in determining the actual brightness temperature encountered. The high brightness temperatures, the presence of strong and variable circular polarization and the observed lifetimes of a decade or more for several IDV sources, pose significant problems for synchrotron theory. “The fau

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Bacchus, P. "Amateur Astronomers’ Contribution to the HIPPARCHOS Programme." International Astronomical Union Colloquium 98 (1988): 90–92. http://dx.doi.org/10.1017/s0252921100092289.

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The HIPPARCHOS satellite (High Precision Parallax Collecting Satellite) is designed to determine position, proper motion and parallax for a large number of stars. The precision expected (0.002 arcsec), and the absence of systematic errors with position in the sky arise from the following characteristics of the system: –Measurements of angular distances between stars a long way apart (58°), are by comparison with a very stable angular reference. This reference is formed by an optical block consisting of two plane mirrors, rigidly mounted, forming an angle of 29° between them, and sending two se

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Dalaudier, Francis, Valery Kan, and Alexandre S. Gurvich. "Chromatic refraction with global ozone monitoring by occultation of stars I Description and scintillation correction." Applied Optics 40, no. 6 (February 20, 2001): 866. http://dx.doi.org/10.1364/ao.40.000866.

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Belmonte, J. A., T. Roca Cortés, I. Vidal, F. X. Schmider, E. Michel, A. Baglin, M. Chevreton та ін. "Stephi: A New Approach to δ Scuti Asteroseismology". International Astronomical Union Colloquium 137 (1993): 739–42. http://dx.doi.org/10.1017/s0252921100018765.

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The STEPHI network (STEllar PHotometry International) is a multinational cooperation stablished in order to get as perfect data as possible on several δ Scuti stars, within a reasonable period of time. STEPHI is currently integrated by nearly 15 people, belonging to the first four institutions cited above. However, astronomers of other institutions have eventually contributed to the network. The idea was born in 1986 and the network has been working to full operation since August 1989. A campaign, observing one or two δ Scuties is normally undertaken every 15 months. They are usually order of

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Dietz, M., C. Lederer-Woods, O. Aberle, J. Andrzejewski, L. Audouin, M. Bacak, J. Balibrea та ін. "First Measurement of 72Ge(n, γ) at n_TOF". EPJ Web of Conferences 184 (2018): 02005. http://dx.doi.org/10.1051/epjconf/201718402005.

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The slow neutron capture process (s-process) is responsible for producing about half of the elemental abundances heavier than iron in the universe. Neutron capture cross sections on stable isotopes are a key nuclear physics input for s-process studies. The 72Ge(n, γ) cross section has an important influence on production of isotopes between Ge and Zr during s-process in massive stars and therefore experimental data are urgently required. 72Ge(n, γ) was measured at the neutron time-of-flight facility n_TOF (CERN) for the first time at stellar energies. The measurement was performed using an enr

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Tamminen, J., E. Kyrölä, V. F. Sofieva, M. Laine, J. L. Bertaux, A. Hauchecorne, F. Dalaudier, et al. "GOMOS data characterization and error estimation." Atmospheric Chemistry and Physics Discussions 10, no. 3 (March 11, 2010): 6755–96. http://dx.doi.org/10.5194/acpd-10-6755-2010.

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Abstract. The Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument uses stellar occultation technique for monitoring ozone and other trace gases in the stratosphere and mesosphere. The self-calibrating measurement principle of GOMOS together with a relatively simple data retrieval where only minimal use of a priori data is required, provides excellent possibilities for long term monitoring of atmospheric composition. GOMOS uses about 180 brightest stars as the light source. Depending on the individual spectral characteristics of the stars, the signal-to-noise ratio of GOMOS is ch

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Tamminen, J., E. Kyrölä, V. F. Sofieva, M. Laine, J. L. Bertaux, A. Hauchecorne, F. Dalaudier, et al. "GOMOS data characterisation and error estimation." Atmospheric Chemistry and Physics 10, no. 19 (October 8, 2010): 9505–19. http://dx.doi.org/10.5194/acp-10-9505-2010.

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Abstract. The Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument uses stellar occultation technique for monitoring ozone, other trace gases and aerosols in the stratosphere and mesosphere. The self-calibrating measurement principle of GOMOS together with a relatively simple data retrieval where only minimal use of a priori data is required provides excellent possibilities for long-term monitoring of atmospheric composition. GOMOS uses about 180 of the brightest stars as its light source. Depending on the individual spectral characteristics of the stars, the signal-to-noise rati

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Bradt, H. V., A. M. Levine, E. H. Morgan, R. A. Remillard, J. H. Swank, B. L. Dingus, S. S. Holt, et al. "The X-Ray Timing Explorer." International Astronomical Union Colloquium 123 (1990): 89–110. http://dx.doi.org/10.1017/s0252921100076946.

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AbstractThe capabilities of the X-ray Timing Explorer (XTE) are described with particular attention paid to current scientific problems it will address from galactic neutron star systems to active galactic nuclei. It features a low-background continuous 2-200 keV response with large apertures (a 0.63-m2 proportional counter array and a 0.16-m2 dual rocking NaI/CsI scintillation array). Rapid response (in hours) to temporal phenomena, e.g. transients, is obtained by virtue of a scanning all-sky monitor and rapid maneuverability. XTE will carry out detailed energy-resolved studies of phenomena c

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Wlodarczyk-Sroka, B. S., M. A. Garrett, and A. P. V. Siemion. "Extending the Breakthrough Listen nearby star survey to other stellar objects in the field." Monthly Notices of the Royal Astronomical Society 498, no. 4 (September 8, 2020): 5720–29. http://dx.doi.org/10.1093/mnras/staa2672.

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ABSTRACT We extend the source sample recently observed by the Breakthrough Listen (BL) Initiative by including additional stars (with parallaxes measured by Gaia) that also reside within the full width at half-maximum of the Green Bank 100-m Telescope and Parkes radio telescope target fields. These stars have estimated distances as listed in the extensions of the Gaia DR2 catalogue. Enlarging the sample from 1327 to 288 315 stellar objects permits us to achieve substantially better Continuous Waveform Transmitter Rate Figures of Merit (CWTFM) than any previous analysis, and allows us to place

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Bryant, Edward M., Daniel Bayliss, James McCormac, Peter J. Wheatley, Jack S. Acton, David R. Anderson, David J. Armstrong, et al. "Simultaneous TESS and NGTS transit observations of WASP-166 b." Monthly Notices of the Royal Astronomical Society 494, no. 4 (April 24, 2020): 5872–81. http://dx.doi.org/10.1093/mnras/staa1075.

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ABSTRACT We observed a transit of WASP-166 b using nine Next Generation Transit Survey (NGTS) telescopes simultaneously with the Transiting Exoplanet Survey Satellite (TESS) observations of the same transit. We achieved a photometric precision of 152 ppm per 30 min with the nine NGTS telescopes combined, matching the precision reached by TESS for the transit event around this bright (T = 8.87) star. The individual NGTS light-curve noise is found to be dominated by scintillation noise and appears free from any time-correlated noise or any correlation between telescope systems. We fit the NGTS d

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Querci, François R. "Network of Oriental Robotic Telescopes." Highlights of Astronomy 10 (1995): 677–79. http://dx.doi.org/10.1017/s1539299600012557.

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We should like to report on the Network of Oriental Robotic Telescopes, otherwise the ORT network. Our objective is non-stop observations of variable stars by collaboration with other networks of automated photometric telescopes, complementary to the ORT network in longitude and latitude intervals, such as the GNAT in the U.S.A., the Chilean cordillera stations, the South African stations, etc. As a first step we will deal with photometric telescopes, then we will extend them to spectroscopy.From 12-year archives of meteorological satellites, it appeared that sites located around the north lat

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Koay, J. Y., D. L. Jauncey, T. Hovatta, S. Kiehlmann, H. E. Bignall, W. Max-Moerbeck, T. J. Pearson, et al. "The presence of interstellar scintillation in the 15 GHz interday variability of 1158 OVRO-monitored blazars." Monthly Notices of the Royal Astronomical Society 489, no. 4 (September 7, 2019): 5365–80. http://dx.doi.org/10.1093/mnras/stz2488.

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ABSTRACT We have conducted the first systematic search for interday variability in a large sample of extragalactic radio sources at 15 GHz. From the sample of 1158 radio-selected blazars monitored over an ∼10 yr span by the Owens Valley Radio Observatory 40-m telescope, we identified 20 sources exhibiting significant flux density variations on 4-d time-scales. The sky distribution of the variable sources is strongly dependent on the line-of-sight Galactic H α intensities from the Wisconsin H α Mapper Survey, demonstrating the contribution of interstellar scintillation (ISS) to their interday v

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Cesarsky, C. J., R. A. Sunyaev, G. W. Clark, R. Giacconi, Vin-Yue Qu, E. E. Salpeter, P. A. Scheuer, et al. "Commission N°48: High Energy Astrophysics (Astrophysique Des Hautes Energies)." Transactions of the International Astronomical Union 20, no. 1 (1988): 671–75. http://dx.doi.org/10.1017/s0251107x00007549.

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The european X-ray observatory (EXOSAT), which was launched in 1983 and which finished operations in April 1986, has brought a rich harvest of results in the period 1984-1987, surveyed here. The EXOSAT payload consisted of three sets of instruments: two low energy imaging telescopes (LE:E<2 KeV), a medium-energy experiment (ME:E=l-50KeV) and a gas scintillation proportional counter (GSPC:E=2-20KeV). Over most of the energy range covered, EXOSAT was not more sensitive than its predecessor, the american EINSTEIN satellite. But the EINSTEIN satellite is far from having exhausted the treasures

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Djuric, N., and L. Field. "On the detectability of intelligent civilizations in the galaxy." Serbian Astronomical Journal, no. 167 (2003): 1–10. http://dx.doi.org/10.2298/saj0367001d.

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In this paper we argue for the possibility that even in the event of a Galaxy teeming with extraterrestrial intelligence (ETI) the probability of receiving recognizable signals from the ETIs may be very low. There are two majors factors that may limit our ability to detect other civilizations. (i) Evolutionary mismatches may cause difficulties analogous to humans attempting to communicate with lower primates. (ii) Independent evolutionary paths resulting from differing planetary/stellar environments may result in life whose cognitive processes and consequent perceptions of the universe are ver

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Kan, Valery, Francis Dalaudier, and Alexandre S. Gurvich. "Chromatic refraction with global ozone monitoring by occultation of stars II Statistical properties of scintillations." Applied Optics 40, no. 6 (February 20, 2001): 878. http://dx.doi.org/10.1364/ao.40.000878.

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Kyrölä, E., J. Tamminen, V. Sofieva, J. L. Bertaux, A. Hauchecorne, F. Dalaudier, D. Fussen, et al. "Retrieval of atmospheric parameters from GOMOS data." Atmospheric Chemistry and Physics Discussions 10, no. 4 (April 19, 2010): 10145–217. http://dx.doi.org/10.5194/acpd-10-10145-2010.

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Abstract. The Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument on board the European Space Agency's ENVISAT satellite measures attenuation of stellar light in occultation geometry. Daytime measurements also record scattered solar light from the atmosphere. The wavelength regions are the ultraviolet-visible band 248–690 nm and two infrared bands at 755–774 nm and at 926–954 nm. From UV-Visible and IR spectra the vertical profiles of O3, NO2, NO3, H2O, O2 and aerosols can be retrieved. In addition there are two 1 kHz photometers at blue 473–527 nm and red 646–698 nm. Photometer

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Kyrölä, E., J. Tamminen, V. Sofieva, J. L. Bertaux, A. Hauchecorne, F. Dalaudier, D. Fussen, et al. "Retrieval of atmospheric parameters from GOMOS data." Atmospheric Chemistry and Physics 10, no. 23 (December 14, 2010): 11881–903. http://dx.doi.org/10.5194/acp-10-11881-2010.

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Abstract. The Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument on board the European Space Agency's ENVISAT satellite measures attenuation of stellar light in occultation geometry. Daytime measurements also record scattered solar light from the atmosphere. The wavelength regions are the ultraviolet-visible band 248–690 nm and two infrared bands at 755–774 nm and at 926–954 nm. From UV-Visible and IR spectra the vertical profiles of O3, NO2, NO3, H2O, O2 and aerosols can be retrieved. In addition there are two 1 kHz photometers at blue 473–527 nm and red 646–698 nm. Photometer

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Amaducci, Simone, Nicola Colonna, Luigi Cosentino, Sergio Cristallo, Paolo Finocchiaro, Milan Krtička, Cristian Massimi та ін. "First Results of the 140Ce(n,γ)141Ce Cross-Section Measurement at n_TOF". Universe 7, № 6 (17 червня 2021): 200. http://dx.doi.org/10.3390/universe7060200.

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An accurate measurement of the 140Ce(n,γ) energy-dependent cross-section was performed at the n_TOF facility at CERN. This cross-section is of great importance because it represents a bottleneck for the s-process nucleosynthesis and determines to a large extent the cerium abundance in stars. The measurement was motivated by the significant difference between the cerium abundance measured in globular clusters and the value predicted by theoretical stellar models. This discrepancy can be ascribed to an overestimation of the 140Ce capture cross-section due to a lack of accurate nuclear data. For

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Bertaux, J. L., E. Kyrölä, D. Fussen, A. Hauchecorne, F. Dalaudier, V. Sofieva, J. Tamminen, et al. "Global ozone monitoring by occultation of stars: an overview of GOMOS measurements on ENVISAT." Atmospheric Chemistry and Physics Discussions 10, no. 4 (April 16, 2010): 9917–10076. http://dx.doi.org/10.5194/acpd-10-9917-2010.

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Abstract. GOMOS on ENVISAT (launched in February, 2002) is the first space instrument dedicated to the study of the atmosphere of the Earth by the technique of stellar occultations (Global Ozone Monitoring by Occultation of Stars). From a polar orbit, it allows to have a good latitude coverage. Because it is self-calibrated, it is particularly well adapted to the long time trend monitoring of stratospheric species. With 4 spectrometers the wavelength coverage of 248 nm to 942 nm allows to monitor ozone, H2O, NO2, NO3, air, aerosols, and O2. Two additional fast photometers (1 kHz sampling rate)

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Bertaux, J. L., E. Kyrölä, D. Fussen, A. Hauchecorne, F. Dalaudier, V. Sofieva, J. Tamminen, et al. "Global ozone monitoring by occultation of stars: an overview of GOMOS measurements on ENVISAT." Atmospheric Chemistry and Physics 10, no. 24 (December 20, 2010): 12091–148. http://dx.doi.org/10.5194/acp-10-12091-2010.

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Abstract. GOMOS on ENVISAT (launched in February, 2002) is the first space instrument dedicated to the study of the atmosphere of the Earth by the technique of stellar occultations (Global Ozone Monitoring by Occultation of Stars). Its polar orbit makes good latitude coverage possible. Because it is self-calibrating, it is particularly well adapted to long time trend monitoring of stratospheric species. With 4 spectrometers, the wavelength coverage of 248 nm to 942 nm enables monitoring ozone, H2O, NO2, NO3, air density, aerosol extinction, and O2. Two additional fast photometers (with 1 kHz s

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Sullivan, Woodruff T., Kelvin J. Wellington, G. Seth Shostak, Peter R. Backus, and James M. Cordes. "A Galactic Center Search for Extraterrestrial Intelligent Signals." International Astronomical Union Colloquium 161 (January 1997): 653–56. http://dx.doi.org/10.1017/s0252921100015190.

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AbstractIn June 1995 we used the Parkes 64-m radio telescope to search for narrowband or pulsing signals of extraterrestrial intelligent (ETI) origin from the direction of the galactic center. This strategy was chosen so as to maximize the number of possibly detectable ETI signals within the beam, assuming that they are associated with stars and that their luminosity function is such that they can be detected at a distance of at least a few kiloparsecs. A total of 190 1.2–minute integrations were taken in a region of size 5.0° × 0.6° centered on the galactic center. Many positions in this regi

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Нарожный, Анатолий Николаевич. "КОСМІЧНЕ МІКРОХВИЛЬОВЕ ВИПРОМІНЮВАННЯ І ТЕМНА МАТЕРІЯ". Open Information and Computer Integrated Technologies, № 82 (19 грудня 2018): 83–101. http://dx.doi.org/10.32620/oikit.2018.82.07.

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The question of the possible origin of one of the components of dark matter filling the galaxies is considered. The analysis of the “fate” of stellar electromagnetic radiation under the conditions of the eternal Universe is taken as a starting point. Based on a comparison of the average lifetime of a star in the active phase and the lifetime of the non-absorbed part of its radiation, it is concluded that the Universe is filled with stellar electromagnetic radiation. However, based on existing concepts, as well as the red shift found in the spectra of distant galaxies, the addition of new radia

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Belousov, Maksim, Maksim Gorbunov, Oleg Ignat'ev, Andrey Krymov, Anton Kupchinskiy, Sergey Morozov, and Aleksey Pulin. "Perspectives of CsI:Tl Crystals in g-Spectrometers." ANRI, no. 2 (June 29, 2021): 24–40. http://dx.doi.org/10.37414/2075-1338-2021-105-2-24-40.

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The article describes the problems of creating a scintillation spectrometer with a CsI:Tl crystal to replace spectrometers with NaI:Tl crystals which are widely used at nuclear power plants (NPPs) to monitor the activity of air, waste water and adjacent territories. The advantages of CsI:Tl-spectrometers are in the best energy resolution; much greater resistance to mechanical and electromagnetic influences due to the use of silicon photomultipliers (SiPM) instead of vacuum photomultiplier tubes (VPMT); much greater durability due to the very low hygroscopicity of the material. The strong misma

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Penek, Ö., M. Agostini, K. Altenmüller, S. Appel, V. Atroshchenko, Z. Bagdasarian, D. Basilico, et al. "Observation of CNO cycle solar neutrinos in Borexino." Journal of Physics: Conference Series 2156, no. 1 (December 1, 2021): 012128. http://dx.doi.org/10.1088/1742-6596/2156/1/012128.

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Abstract The Borexino detector, located at the Laboratori Nazionali del Gran Sasso in Italy, is a radiopure 280 ton liquid scintillator detector with a primary goal to measure low-energy solar neutrinos created in the core of the Sun. These neutrinos are a consequence of nuclear fusion reactions in the solar core where Hydrogen is burned into Helium and provide a direct probe of the energy production processes, namely the proton-proton (pp) chain and the Carbon-Nitrogen-Oxygen (CNO) cycle. The fusion of Hydrogen in the case of the CNO cycle, which is expected to contribute in the order of less

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Bignall, Hayley E., Artem V. Tuntsov, Jamie Stevens, Keith Bannister, Mark A. Walker, and Cormac Reynolds. "The annual cycle in scintillation timescale of PMN J1726+0639." Monthly Notices of the Royal Astronomical Society, April 18, 2022. http://dx.doi.org/10.1093/mnras/stac1051.

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Abstract We discovered rapid intra-day variability in radio source PMN J1726+0639 at GHz frequencies, during a survey to search for such variability with the Australia Telescope Compact Array. Follow-up observations were conducted over two years and revealed a clear, repeating annual cycle in the rate, or characteristic timescale, of variability, showing that the observed variations can be attributed to scintillations from interstellar plasma inhomogeneities. The strong annual cycle includes an apparent ‘standstill’ in April and another in September. We fit kinematic models to the data, allowi

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"The physics of pulsar scintillation." Philosophical Transactions of the Royal Society of London. Series A: Physical and Engineering Sciences 341, no. 1660 (October 15, 1992): 151–65. http://dx.doi.org/10.1098/rsta.1992.0090.

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Scintillation is a well-known phenomenon in astronomy, e.g. twinkling of stars due to scattering in the Earth’s atmosphere, and variability of compact radio sources due to scattering in the ionosphere and the solar wind. These examples correspond to the so-called regime of weak scattering. Radio pulsars scintillate as a result of scattering in the ionized interstellar medium, but in contrast to the previous cases, the physical régime corresponds to strong scattering. Pulsars exhibit two distinct kinds of variability, called diffractive scintillation and refractive scintillation, on timescales

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Luo, Rui, George Hobbs, Suk Yee Yong, Andrew Zic, Lawrence Toomey, Shi Dai, Alex Dunning, et al. "Simulating high-time resolution radio-telescope observations." Monthly Notices of the Royal Astronomical Society, April 29, 2022. http://dx.doi.org/10.1093/mnras/stac1168.

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Abstract We describe a new software package for simulating channelised, high-time resolution data streams from radio telescopes. The software simulates data from the telescope and observing system taking into account the observation strategy, receiver system and digitisation. The signatures of pulsars, fast radio bursts and flare stars are modelled, including frequency-dependent effects such as scattering and scintillation. We also simulate more generic signals using spline curves and images. Models of radio frequency interference include signals from satellites, terrestrial transmitters and i

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