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S S Savchenko - One of the best experts on this subject based on the ideXlab platform.
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a multiwavelength study of spiral structure in galaxies i General Characteristics in the optical
Monthly Notices of the Royal Astronomical Society, 2020Co-Authors: S S Savchenko, Alexander Marchuk, A V Mosenkov, Konstantin GrishuninAbstract:Different spiral generation mechanisms are expected to produce different morphological and kinematic features. In this first paper in a series we carefully study the parameters of spiral structure in 155 face-on spiral galaxies, selected from the Sloan Digital Sky Survey, in the three $gri$ bands. We use a method for deriving a set of parameters of spiral structure, such as the width of the spiral arms, their fraction to the total galaxy luminosity and their colour, which have not been properly studied before. Our method is based on an analysis of a set of photometric cuts perpendicular to the direction of a spiral arm. Based on the results of our study, we compare the main three classes of spirals: grand design, multi-armed and flocculent. We conclude that: i) for the vast majority of galaxies (86\%) we observe an increase of their arm width with galactocentric distance; ii) more luminous spirals in grand design galaxies exhibit smaller variations of the pitch angle with radius than less luminous grand design spirals; iii) grand design galaxies show less difference between the pitch angles of individual arms than multi-armed galaxies. Apart from these distinctive features, all three spiral classes do not differ significantly by their pitch angle, arm width, width asymmetry, and environment. Wavelength dependence is found only for the arm fraction. Therefore, observationally we find no strong difference (except for the view and number of arms) between grand design, multi-armed and flocculent spirals in the sample galaxies.
Konstantin Grishunin - One of the best experts on this subject based on the ideXlab platform.
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a multiwavelength study of spiral structure in galaxies i General Characteristics in the optical
Monthly Notices of the Royal Astronomical Society, 2020Co-Authors: S S Savchenko, Alexander Marchuk, A V Mosenkov, Konstantin GrishuninAbstract:Different spiral generation mechanisms are expected to produce different morphological and kinematic features. In this first paper in a series we carefully study the parameters of spiral structure in 155 face-on spiral galaxies, selected from the Sloan Digital Sky Survey, in the three $gri$ bands. We use a method for deriving a set of parameters of spiral structure, such as the width of the spiral arms, their fraction to the total galaxy luminosity and their colour, which have not been properly studied before. Our method is based on an analysis of a set of photometric cuts perpendicular to the direction of a spiral arm. Based on the results of our study, we compare the main three classes of spirals: grand design, multi-armed and flocculent. We conclude that: i) for the vast majority of galaxies (86\%) we observe an increase of their arm width with galactocentric distance; ii) more luminous spirals in grand design galaxies exhibit smaller variations of the pitch angle with radius than less luminous grand design spirals; iii) grand design galaxies show less difference between the pitch angles of individual arms than multi-armed galaxies. Apart from these distinctive features, all three spiral classes do not differ significantly by their pitch angle, arm width, width asymmetry, and environment. Wavelength dependence is found only for the arm fraction. Therefore, observationally we find no strong difference (except for the view and number of arms) between grand design, multi-armed and flocculent spirals in the sample galaxies.
S. G. Medvedev - One of the best experts on this subject based on the ideXlab platform.
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Morphological diversity of the skeletal structures of fleas (Siphonaptera). Part 3: The General Characteristics and features of thoracic setation
Entomological Review, 2016Co-Authors: S. G. MedvedevAbstract:The paper continues the series of publications (Medvedev, 2015, 2016) devoted to the analysis of the structural features of fleas. In this part, the structural features of the thoracic setation are analyzed for the first time. Six characters with 53 states were distinguished in the chaetome of the pronotum, mesothorax, and metathorax. The analysis reveals some cases of the formation of externally similar states due to reduction or, by contrast, strengthening of the chaetome in some genera belonging to different superfamilies, in relation to the specific traits of parasitism. In spite of high variation in the number and arrangement of thoracic setae, some character states can be used as markers of flea taxa of the family and superfamily rank.
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morphological diversity of fleas structures siphonaptera part 3 General Characteristics and features of thoracic setation
Parazitologiia, 2015Co-Authors: S. G. MedvedevAbstract:The paper continues a series of publications (Medvedev, 2015a, b) devoted to the analysis of flea structural features. In the present publication, structural features of flea thoracic setation are analyzed for the first time. Six characters with 53 states in the structure of the chaetom of the pronotum, meso-, and metathoracic. segments are distinguished. The author analyzes the cases of the formation of similar states stipulated by processes of reduction or, by contrast, by strengthening of the chaetom in fleas of separate genera belonging to different superfamilies in relation to the type or peculiarities of parasitism in different flea species. In spite of the presence of strong variability in arrangement and number of thoracic setae, some examples of marking of groups in the range families and superfamilies by certain states of the chaetotaxy of the pronotum and metepimera are revealed.
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Bloodsucking dipteran insects (Diptera) attacking humans and animals (the “gnus” complex) in northwestern Russia: I. General Characteristics of the fauna
Entomological Review, 2007Co-Authors: S. G. Medvedev, N K Brodskaya, S. V. Aibulatova, L. A. Bespyatova, E. V. Panyukova, A. V. Khalin, A. V. YankovskyAbstract:The fauna of bloodsucking Diptera of northwestern Russia comprises 226 species of mosquitoes (Culicidae), biting midges (Ceratopogonidae), black flies (Simuliidae) and horseflies (Tabanidae). In particular, Culicidae include 41 species from 10 subgenera of 5 genera of 2 subfamilies. Simuliidae are represented by 110 species of 23 genera, belonging to 6 tribes of 2 subfamilies; the genus Culicoides of the Ceratopogonidae, by 31 species; and Tabanidae, by 44 species of 7 genera from 2 subfamilies. There is a necessity of elaboration and application of more advanced forms of information storage and field data standardization. In the Zoological Institute, Russian Academy of Sciences, a special database on the bloodsucking insects of Russia is created in the DBMS Access. A list of abundant bloodsucking species of mosquitoes, biting midges, black flies and horseflies is included. A brief synopsis of bibliography of investigations of the bloodsucking dipterans from northwestern Russia is given, provided with a list of more then 190 publication.
A V Mosenkov - One of the best experts on this subject based on the ideXlab platform.
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a multiwavelength study of spiral structure in galaxies i General Characteristics in the optical
Monthly Notices of the Royal Astronomical Society, 2020Co-Authors: S S Savchenko, Alexander Marchuk, A V Mosenkov, Konstantin GrishuninAbstract:Different spiral generation mechanisms are expected to produce different morphological and kinematic features. In this first paper in a series we carefully study the parameters of spiral structure in 155 face-on spiral galaxies, selected from the Sloan Digital Sky Survey, in the three $gri$ bands. We use a method for deriving a set of parameters of spiral structure, such as the width of the spiral arms, their fraction to the total galaxy luminosity and their colour, which have not been properly studied before. Our method is based on an analysis of a set of photometric cuts perpendicular to the direction of a spiral arm. Based on the results of our study, we compare the main three classes of spirals: grand design, multi-armed and flocculent. We conclude that: i) for the vast majority of galaxies (86\%) we observe an increase of their arm width with galactocentric distance; ii) more luminous spirals in grand design galaxies exhibit smaller variations of the pitch angle with radius than less luminous grand design spirals; iii) grand design galaxies show less difference between the pitch angles of individual arms than multi-armed galaxies. Apart from these distinctive features, all three spiral classes do not differ significantly by their pitch angle, arm width, width asymmetry, and environment. Wavelength dependence is found only for the arm fraction. Therefore, observationally we find no strong difference (except for the view and number of arms) between grand design, multi-armed and flocculent spirals in the sample galaxies.
Alexander Marchuk - One of the best experts on this subject based on the ideXlab platform.
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a multiwavelength study of spiral structure in galaxies i General Characteristics in the optical
Monthly Notices of the Royal Astronomical Society, 2020Co-Authors: S S Savchenko, Alexander Marchuk, A V Mosenkov, Konstantin GrishuninAbstract:Different spiral generation mechanisms are expected to produce different morphological and kinematic features. In this first paper in a series we carefully study the parameters of spiral structure in 155 face-on spiral galaxies, selected from the Sloan Digital Sky Survey, in the three $gri$ bands. We use a method for deriving a set of parameters of spiral structure, such as the width of the spiral arms, their fraction to the total galaxy luminosity and their colour, which have not been properly studied before. Our method is based on an analysis of a set of photometric cuts perpendicular to the direction of a spiral arm. Based on the results of our study, we compare the main three classes of spirals: grand design, multi-armed and flocculent. We conclude that: i) for the vast majority of galaxies (86\%) we observe an increase of their arm width with galactocentric distance; ii) more luminous spirals in grand design galaxies exhibit smaller variations of the pitch angle with radius than less luminous grand design spirals; iii) grand design galaxies show less difference between the pitch angles of individual arms than multi-armed galaxies. Apart from these distinctive features, all three spiral classes do not differ significantly by their pitch angle, arm width, width asymmetry, and environment. Wavelength dependence is found only for the arm fraction. Therefore, observationally we find no strong difference (except for the view and number of arms) between grand design, multi-armed and flocculent spirals in the sample galaxies.
