Far-ultraviolet radiation from disk globular clusters

1993 ◽  
Vol 406 ◽  
pp. 489 ◽  
Author(s):  
R. M. Rich ◽  
Dante Minniti ◽  
James Liebert
Keyword(s):  
Ultraviolet Radiation ◽  
Globular Clusters ◽  
Far Ultraviolet

scholarly journals Solar Extreme and Far Ultraviolet Radiation Modeling for Aeronomic Calculations

2021 ◽  
Vol 13 (8) ◽  
pp. 1454
Author(s):  
Anatoliy A. Nusinov ◽  
Tamara V. Kazachevskaya ◽  
Valeriya V. Katyushina
Keyword(s):  
Ultraviolet Radiation ◽  
Input Parameter ◽  
Solar Spectrum ◽  
Upper Atmosphere ◽  
Model Calculations ◽  
Radiation Fluxes ◽  
Main Components ◽  
Comparison Of The Results ◽  
Far Ultraviolet ◽  
Radiation Modeling

Modeling the upper atmosphere and ionospheres on the basis of a mathematical description of physical processes requires knowledge of ultraviolet radiation fluxes from the Sun as an integral part of the model. Aeronomic models of variations in the radiation flux in the region of extreme (EUV) and far (FUV) radiation, based mainly on the data of the last TIMED mission measurements of the solar spectrum, are proposed. The EUVT model describes variations in the 5–105 nm spectral region, which are responsible for the ionization of the main components of the earth’s atmosphere. The FUVT model describes the flux changes in the 115–242 nm region, which determines heating of the upper atmosphere and the dissociation of molecular oxygen. Both models use the intensity of the hydrogen Lyman-alpha line as an input parameter, which can currently be considered as one of the main indices of solar activity and can be measured with relatively simpler photometers. A comparison of the results of model calculations with observations shows that the model error does not exceed 1–2% for the FUVT model, and 5.5% for EUVT, which is sufficient for calculating the parameters of the ionosphere and thermosphere.

scholarly journals Globular clusters in the outer halo of M 31

2019 ◽  
Vol 623 ◽  
pp. A65 ◽  
Author(s):  
Song Wang ◽  
Jun Ma ◽  
Jifeng Liu
Keyword(s):  
Globular Clusters ◽  
Selection Effect ◽  
Population Synthesis ◽  
Clear Trend ◽  
Intermediate Band ◽  
Near Ultraviolet ◽  
Poor Group ◽  
History Of ◽  
M 31 ◽  
Far Ultraviolet

In this paper, we present photometry of 53 globular clusters (GCs) in the M 31 outer halo, including the GALEX far-ultraviolet (FUV) and near-ultraviolet (NUV), SDSS ugriz, 15 intermediate-band filters of BATC, and 2MASS JHKs bands. By comparing the multicolour photometry with stellar population synthesis models, we determine the metallicities, ages, and masses for these GCs, aiming to probe the merging/accretion history of M 31. We find no clear trend of metallicity and mass with the de-projected radius. The halo GCs younger than ∼8 Gyr are mostly located at the de-projected radii around 100 kpc, but this may be due to a selection effect. We also find that the halo GCs have consistent metallicities with their spatially associated substructures, which provides further evidence of the physical association between them. Both the disc and halo GCs in M 31 show a bimodal luminosity distribution. However, we should emphasise that there are more faint halo GCs which are not seen in the disc. The bimodal luminosity function of the halo GCs may reflect a different origin or evolution environment in their original hosts. The M 31 halo GCs include one intermediate metallicity group (−1.5 < [Fe/H] < −0.4) and one metal-poor group ([Fe/H] < −1.5), while the disc GCs have one metal-rich group more. There are considerable differences between the halo GCs in M 31 and the Milky Way (MW). The total number of GCs in M 31 is approximately three times greater than in the MW, however M 31 has about six times more halo GCs than the MW. Compared to the halo GCs of M 31, those of the MW are mostly metal-poor. Both the numerous halo GCs and the higher-metallicity component are suggestive of an active merger history of M 31.

Coloration of KC1 and KBr crystals by far ultraviolet radiation

1970 ◽  
Vol 8 (11) ◽  
pp. 893-896 ◽  
Author(s):  
Mart Elango ◽  
Christian Gähwiller ◽  
Frederick C. Brown
Keyword(s):  
Ultraviolet Radiation ◽  
Far Ultraviolet

Photolysis of O2 dispersed in solid neon with far-ultraviolet radiation

2018 ◽  
Vol 20 (11) ◽  
pp. 7730-7738 ◽  
Author(s):  
Sheng-Lung Chou ◽  
Jen-Iu Lo ◽  
Yu-Chain Peng ◽  
Hsiao-Chi Lu ◽  
Bing-Ming Cheng ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Emission Spectra ◽  
Spectral Lines ◽  
Absorption And Emission ◽  
Absorption And Emission Spectra ◽  
Far Ultraviolet

Irradiation of O2 dispersed in solid Ne near 4 K at 173 or 143 nm produced many new spectral lines of O, O2 and O3 in absorption and emission spectra.

scholarly journals THE INFLUENCE OF FAR-ULTRAVIOLET RADIATION ON THE PROPERTIES OF MOLECULAR CLOUDS IN THE 30 DOR REGION OF THE LARGE MAGELLANIC CLOUD

2009 ◽  
Vol 703 (1) ◽  
pp. 736-751 ◽  
Author(s):  
Jorge L. Pineda ◽  
Jürgen Ott ◽  
Ulrich Klein ◽  
Tony Wong ◽  
Erik Muller ◽  
...  
Keyword(s):  
Ultraviolet Radiation ◽  
Molecular Clouds ◽  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Far Ultraviolet

Qualitative and quantitative effects of radiation on pycnidial formation by Dendrophoma obscurans

1976 ◽  
Vol 54 (7) ◽  
pp. 566-571 ◽  
Author(s):  
Frank L. Binder ◽  
V. G. Lilly
Keyword(s):  
Ultraviolet Radiation ◽  
Casein Hydrolysate ◽  
Qualitative And Quantitative ◽  
Near Ultraviolet ◽  
Blue Radiation ◽  
Age Dependent ◽  
Dendrophoma Obscurans ◽  
Effects Of Radiation ◽  
Far Ultraviolet

Cultures of Dendrophoma obscurans grown on a 10:2 glucose: casein hydrolysate medium require radiation for sporulation. Far-ultraviolet (253.7 nm), near-ultraviolet (300–425 nm), and blue radiation (400–525 nm) were effective in initiating pycnidial formation. Exposure of cultures to radiation from 500 to 850 nm did not induce sporulation. Pycnidial formation was found to be photoinduced and age dependent. Low intensities of near-ultraviolet radiation administered over long durations were more effective than high intensities of short durations for inducing pycnidial formation.

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