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Titolo:
SHORT 21-CM WSRT OBSERVATIONS OF SPIRAL AND IRREGULAR GALAXIES - HI PROPERTIES
Autore:
BROEILS AH; RHEE MH;
Indirizzi:
STOCKHOLM OBSERV S-13336 SALTSJOBADEN SWEDEN KAPTEYN ASTRON INST NL-9700 AV GRONINGEN NETHERLANDS
Titolo Testata:
Astronomy and astrophysics
fascicolo: 3, volume: 324, anno: 1997,
pagine: 877 - 887
SICI:
0004-6361(1997)324:3<877:S2WOOS>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
NEARBY GALAXIES; PARAMETERS; CATALOG;
Keywords:
GALAXIES, FUNDAMENTAL PARAMETERS; GALAXIES, STRUCTURE; GALAXIES, KINEMATICS AND DYNAMICS; GALAXIES, SPIRAL; RADIO LINES, GALAXIES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
32
Recensione:
Indirizzi per estratti:
Citazione:
A.H. Broeils e M.H. Rhee, "SHORT 21-CM WSRT OBSERVATIONS OF SPIRAL AND IRREGULAR GALAXIES - HI PROPERTIES", Astronomy and astrophysics, 324(3), 1997, pp. 877-887

Abstract

We present the analysis of neutral hydrogen properties of 108 galaxies, based on short 21-cm observations with the Westerbork Synthesis Radio Telescope (WSRT). The results of two H I surveys are analysed to investigate the existence of relations between optical and H I properties, like diameters, hydrogen masses and average surface densities. For all galaxies in our sample we find that the H I diameter, defined at asurface density level of 1 M. pc(-2), is larger than the optical diameter, defined at the 25(th) mag arcsec-2 isophotal level. The H I-to-optical-diameter ratio does not depend on morphological type or luminosity. The strongest, physically meaningful, correlation for the sample of 108 galaxies is the one between log M-H I and log D-H I, With a slope of 2. This implies that the H I surface density averaged over the whole H I disc is constant from galaxy to galaxy, independent of luminosity or type. The radial H I surface density profiles are studied using the technique of principal component analysis. We find that about 81% of the variation in the density profiles of galaxies can be explained by two dimensions. The most dominant component can be related to ''scale'' and the second principal component accounts for the variance inthe behaviour of the radial profile in the central parts of galaxies (i.e. ''peak or depression''). The third component accounts for 7% of the variation and is most likely responsible for bumps and wiggles in the observed density profiles.

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Documento generato il 22/09/20 alle ore 19:48:53