Pub Date : 2019-11-21DOI: 10.17721/2227-1481.10.7-11
B. Etma'nski, M. Schmidt, R. Szczerba
The HIFI instrument on board of the Herschel Space Observatory (HSO) has been very successful in detecting molecular lines from the circumstellar envelopes around evolved stars, like massive red supergiants, Asymptotic Giant Branch (AGB) and post-AGB stars, as well as the planetary nebulae. Among others, ammonia have been found in the circumstellar envelopes of C-rich AGB stars in amounts that significantly exceeded the theoretical predictions for C-rich stars. Few scenarios have been proposed to resolve this problem: formation of ammonia behind the shock front and photochemical processes in the inner part of the envelope partly transparent to UV background radiation due to the clumpy structure of the gas and formation of ammonia on dust grains. Careful analysis of observations may help to put the constraints on one or another mechanism of ammonia formation. Here, we present results of the non-LTE radiative transfer modeling of ammonia transitions including the crucial process of radiative pumping via the v2=1 vibrational band (at ∼10 μm) for V Cyg. Only the ground-based ammonia transition NH3 J = 10-00 at 572.5 GHz has been observed by HIFI. Therefore, to determine the abundance of ammonia we estimate the photodissociation radius of NH3 using chemical model of the envelope consistent with the dust grain properties concluded from the spectral energy distribution.
{"title":"Ammonia in circumstellar environment of V Cyg","authors":"B. Etma'nski, M. Schmidt, R. Szczerba","doi":"10.17721/2227-1481.10.7-11","DOIUrl":"https://doi.org/10.17721/2227-1481.10.7-11","url":null,"abstract":"The HIFI instrument on board of the Herschel Space Observatory (HSO) has been very successful in detecting molecular lines from the circumstellar envelopes around evolved stars, like massive red supergiants, Asymptotic Giant Branch (AGB) and post-AGB stars, as well as the planetary nebulae. Among others, ammonia have been found in the circumstellar envelopes of C-rich AGB stars in amounts that significantly exceeded the theoretical predictions for C-rich stars. Few scenarios have been proposed to resolve this problem: formation of ammonia behind the shock front and photochemical processes in the inner part of the envelope partly transparent to UV background radiation due to the clumpy structure of the gas and formation of ammonia on dust grains. Careful analysis of observations may help to put the constraints on one or another mechanism of ammonia formation. Here, we present results of the non-LTE radiative transfer modeling of ammonia transitions including the crucial process of radiative pumping via the v2=1 vibrational band (at ∼10 μm) for V Cyg. Only the ground-based ammonia transition NH3 J = 10-00 at 572.5 GHz has been observed by HIFI. Therefore, to determine the abundance of ammonia we estimate the photodissociation radius of NH3 using chemical model of the envelope consistent with the dust grain properties concluded from the spectral energy distribution.","PeriodicalId":52077,"journal":{"name":"Advances in Astronomy and Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46538261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-01DOI: 10.17721/2227-1481.9.3-7
E. Musiichuk, S. Borysenko
Periodic comets of different dynamical groups with orbits at 2–5 AU still occasionally active. The observed dust activity of such objects can be connected with the processes of water ice sublimation (MBCs) or crystallisation of amorphous water ice (QHCs) as well as with external causes. Despite the absence of connections between cometary flares and cyclic variations of solar activity indexes, some individual solar flares can affect the brightness of comets. Cometary objects in the main asteroid belt have lower statistic of flares than comets at orbits similar to quasi-Hilda objects.
{"title":"Some peculiarities of activity for comets with orbits\u0000on 2–5 AU","authors":"E. Musiichuk, S. Borysenko","doi":"10.17721/2227-1481.9.3-7","DOIUrl":"https://doi.org/10.17721/2227-1481.9.3-7","url":null,"abstract":"Periodic comets of different dynamical groups with orbits at 2–5 AU still occasionally active. The observed dust activity of such objects can be connected with the processes of water ice sublimation (MBCs) or crystallisation of amorphous water ice (QHCs) as well as with external causes. Despite the absence of connections between cometary flares and cyclic variations of solar activity indexes, some individual solar flares can affect the brightness of comets. Cometary objects in the main asteroid belt have lower statistic of flares than comets at orbits similar to quasi-Hilda objects.","PeriodicalId":52077,"journal":{"name":"Advances in Astronomy and Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46142291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-09-01DOI: 10.17721/2227-1481.9.8-13
I. Babyk
We present the X-ray scaling relations of a sample of elliptical galaxies using X-ray Chandra observations. We use a single β-model to reconstruct the density gas profile and the hydrostatic equation to measure the total mass. We build X-ray scaling relations between temperature, luminosity and total mass at 5Re. Our sample in- cludes gas-poor objects that help us to extend already published LX − T , M − T and LX − M scaling relations to lower magnitudes. The derived slopes for all three relations are much steeper than those for galaxy clusters and groups, and are extreme compared to self-similar models considering gravity only. This increase of steepness from clusters to galaxies indicates that non-thermal processes (e.g. AGN feedback) have a stronger influence on the small-scale systems. Our results indicate that the hot interstellar medium of gas-poor early-type galaxies is not in the wind/outflow state as suggested by recent hydrodynamical simulations. We also discuss the possible biases of our calculations and compare our results to recent papers.
{"title":"X-ray scaling relations of elliptical galaxies","authors":"I. Babyk","doi":"10.17721/2227-1481.9.8-13","DOIUrl":"https://doi.org/10.17721/2227-1481.9.8-13","url":null,"abstract":"We present the X-ray scaling relations of a sample of elliptical galaxies using X-ray Chandra observations. We use a single β-model to reconstruct the density gas profile and the hydrostatic equation to measure the total mass. We build X-ray scaling relations between temperature, luminosity and total mass at 5Re. Our sample in- cludes gas-poor objects that help us to extend already published LX − T , M − T and LX − M scaling relations to lower magnitudes. The derived slopes for all three relations are much steeper than those for galaxy clusters and groups, and are extreme compared to self-similar models considering gravity only. This increase of steepness from clusters to galaxies indicates that non-thermal processes (e.g. AGN feedback) have a stronger influence on the small-scale systems. Our results indicate that the hot interstellar medium of gas-poor early-type galaxies is not in the wind/outflow state as suggested by recent hydrodynamical simulations. We also discuss the possible biases of our calculations and compare our results to recent papers.","PeriodicalId":52077,"journal":{"name":"Advances in Astronomy and Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46995771","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.17721/2227-1481.9.28-32
M. Vasiuta, M. Medvedsky
The purpose of this work is to develop and assemble the real-time in-sky safety system for SLR (Satellite Laser Ranging) system. It is based on receiving ADS-B protocol aircraft data via RTL-SDR device. This solution represents an asynchronous service in the SLR laser control system. It instantly inhibits SLR laser pulses in order to prevent illumination of an aircraft. The service is ready at the SLR station ‘Golosiiv’ (Ukraine) (EUROLAS Data Center ID – 1824).
{"title":"Creation of in-sky safety system using ADS-B radar receiver based on RTL-SDR device for SLR station Golosiiv","authors":"M. Vasiuta, M. Medvedsky","doi":"10.17721/2227-1481.9.28-32","DOIUrl":"https://doi.org/10.17721/2227-1481.9.28-32","url":null,"abstract":"The purpose of this work is to develop and assemble the real-time in-sky safety system for SLR (Satellite Laser Ranging) system. It is based on receiving ADS-B protocol aircraft data via RTL-SDR device. This solution represents an asynchronous service in the SLR laser control system. It instantly inhibits SLR laser pulses in order to prevent illumination of an aircraft. The service is ready at the SLR station ‘Golosiiv’ (Ukraine) (EUROLAS Data Center ID – 1824).","PeriodicalId":52077,"journal":{"name":"Advances in Astronomy and Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67430860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2019-01-01DOI: 10.17721/2227-1481.9.20-27
A. Paznukhov, A. Soina, G. Milinevsky, Y. Yampolsky
To investigate weekly cycle in aerosol parameters using recent AERONET data, we analyse the 7-days periodicity in the different regions that vary in the level of the industrial aerosol load. In the paper we are looking for the weekly cycle in atmosphere aerosol optical thickness at 440 and 870 nm (AOT440, AOT870), measured by AERONE sun-photometers in the industrial regions: Europe and North America. The possible appearance of the weekly cycle in Antarctica, where the lowest industrial aerosol load expected, was investigated as well. For each of the AERONET stations, the analysis was provided using the 8-year continuous measurement sequences data in the 2009–2016 period. Due to AERONET sun-photometers provided aerosol measurements in the daytime and cloudless conditions only, we use the weekly data overlay technique for analysis. According to this method, the initial sequence of the measurements was divided into the 7-days data segments, corresponding to a week period. The 8-year averaged values and standard deviation were calculated for an each day of week. The average Europe and North America weekend effect in the percent difference of AOT440 in the weekdays and in the weekend in the atmosphere over North America is equal 7.2%, over Europe - 4.2%. The lowest AOT values observed on Sunday and Monday the highest values are seen from Wednesday till Saturday. To reveal seasonal dependence of the weekend effect, the weekly variations of seasonally separated AOT440 and AOT870 data over Europe have been analysed. The results exhibit the maximum AOT values in working days and minimum in weekend similar to seasonally averaged results.
{"title":"Weekly cycle in the atmosphere aerosol variations for\u0000industrial regions","authors":"A. Paznukhov, A. Soina, G. Milinevsky, Y. Yampolsky","doi":"10.17721/2227-1481.9.20-27","DOIUrl":"https://doi.org/10.17721/2227-1481.9.20-27","url":null,"abstract":"To investigate weekly cycle in aerosol parameters using recent AERONET data, we analyse the 7-days periodicity in the different regions that vary in the level of the industrial aerosol load. In the paper we are looking for the weekly cycle in atmosphere aerosol optical thickness at 440 and 870 nm (AOT440, AOT870), measured by AERONE sun-photometers in the industrial regions: Europe and North America. The possible appearance of the weekly cycle in Antarctica, where the lowest industrial aerosol load expected, was investigated as well. For each of the AERONET stations, the analysis was provided using the 8-year continuous measurement sequences data in the 2009–2016 period. Due to AERONET sun-photometers provided aerosol measurements in the daytime and cloudless conditions only, we use the weekly data overlay technique for analysis. According to this method, the initial sequence of the measurements was divided into the 7-days data segments, corresponding to a week period. The 8-year averaged values and standard deviation were calculated for an each day of week. The average Europe and North America weekend effect in the percent difference of AOT440 in the weekdays and in the weekend in the atmosphere over North America is equal 7.2%, over Europe - 4.2%. The lowest AOT values observed on Sunday and Monday the highest values are seen from Wednesday till Saturday. To reveal seasonal dependence of the weekend effect, the weekly variations of seasonally separated AOT440 and AOT870 data over Europe have been analysed. The results exhibit the maximum AOT values in working days and minimum in weekend similar to seasonally averaged results.","PeriodicalId":52077,"journal":{"name":"Advances in Astronomy and Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2019-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67430612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2018-11-11DOI: 10.17721/2227-1481.9.14-19
O. Sergijenko
For dynamical dark energy with the barotropic equation of state we determine the mean values of parameters and their confidence ranges together with other cosmological parameters on the basis of different combined datasets. The used observations include Planck data on CMB temperature anisotropy, E-mode polarisation and lensing, BICEP2/Keck Array data on B-mode polarisation, BAO from SDSS and 6dFGS, power spectrum of galaxies from WiggleZ, weak lensing from CFHTLenS and SN Ia data from the JLA compilation. We find that all but one mean models are phantom, mean values of the equation of state parameter at current epoch are close to −1 and constraints on the adiabatic sound speed of dark energy are weak. We investigate the effect of CMB polarisation data on the dark energy parameters estimation. We discuss also which type of data on the large scale structure of the Universe allows to determine the dark energy parameters most precisely.
{"title":"Constraints on the dark energy with barotropic equation\u0000of state: assessing the importance of different observations","authors":"O. Sergijenko","doi":"10.17721/2227-1481.9.14-19","DOIUrl":"https://doi.org/10.17721/2227-1481.9.14-19","url":null,"abstract":"For dynamical dark energy with the barotropic equation of state we determine the mean values of parameters and their confidence ranges together with other cosmological parameters on the basis of different combined datasets. The used observations include Planck data on CMB temperature anisotropy, E-mode polarisation and lensing, BICEP2/Keck Array data on B-mode polarisation, BAO from SDSS and 6dFGS, power spectrum of galaxies from WiggleZ, weak lensing from CFHTLenS and SN Ia data from the JLA compilation. We find that all but one mean models are phantom, mean values of the equation of state parameter at current epoch are close to −1 and constraints on the adiabatic sound speed of dark energy are weak. We investigate the effect of CMB polarisation data on the dark energy parameters estimation. We discuss also which type of data on the large scale structure of the Universe allows to determine the dark energy parameters most precisely.","PeriodicalId":52077,"journal":{"name":"Advances in Astronomy and Space Physics","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2018-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43073577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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