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Surface Brightness Profiles of Seyfert Galaxies  [PDF]
A. V. Tugay,S. L. Shihov
Physics , 2014,
Abstract: We built r-band surface brightness profiles by SDSS data for 16 Seyfert galaxies observed in Crimean Astrophysical Observatory. Obtained profiles can be used for finding more accurate lightcurves for these galaxies.
Dark Matter in Low Surface Brightness Galaxies  [PDF]
W. J. G. de Blok,Stacy McGaugh
Physics , 1996,
Abstract: Low Surface Brightness (LSB) galaxies form a large population of disc galaxies that extend the Hubble sequence towards extreme late-types. They are only slowly evolving, and still in an early evolutionary state. The Tully-Fisher relation and rotation curves of LSB galaxies both show that LSB galaxies are very dark-matter dominated with respect to ``normal'' high surface brightness (HSB) galaxies. Mass models derived from the rotation curves of LSB and HSB galaxies show that LSB galaxies inhabit less dense and more extended halos. Mass density, which changes with surface brightness, is as important in determining the evolution of a galaxy as total mass is.
Dwarf and Low Surface Brightness Galaxies  [PDF]
Stacy S. McGaugh
Physics , 1995,
Abstract: I review the evolutionary status of the field populations of starbursting dwarf galaxies and low surface brightness spirals. Particular attention is paid to the long standing problem of the progenitors for star burst galaxies, which may be related to a population of small, low surface brightness dwarfs. Larger low surface brightness spirals are known to evolve slowly, converting little of their gas mass into stars and metals in a Hubble time. Their slow evolution is controlled by their low densities, which arise naturally from formation by late collapse of low amplitude perturbations in the initial density field.
Gas, Stars and Baryons in Low Surface Brightness Galaxies  [PDF]
K. O'Neil
Physics , 2000,
Abstract: Recent surveys have discovered hundreds of low surface brightness galaxies in the local (z < 0.1) Universe. Plots of the surface brightness distribution (the space density of galaxies plotted against central surface brightness) show a flat distribution from the bright-end cutoff of 21.65 through the current observational limit of 25.0 B mag arcsec^{-2}. As no trend is seen to indicate the size or mass of galaxies decreases with decreasing central surface brightness, it is likely that a significant percentage of the baryon content in the universe is contained in these diffuse systems. In this paper I briefly review the known properties of low surface brightness galaxies, and describe some current theories on the baryonic mass fraction of low surface brightness systems and their consequences.
Surface brightness measurements for APM galaxies  [PDF]
Z. Shao,S. J. Maddox,J. B. Jones,P. Coles
Physics , 2002, DOI: 10.1046/j.1365-8711.2003.06018.x
Abstract: This paper considers some simple surface brightness (SB) estimates for galaxies in the Automated Plate Measuring Machine (APM) catalogue in order to derive homogeneous SB data for a very large sample of faint galaxies. The isophotal magnitude and area are used to estimate the central surface brightness and total magnitude based on the assumption of an exponential SB profile. The surface brightness measurements are corrected for field effects on each UK Schmidt plate and the zero-point of each plate is adjusted to give a uniform sample of SB and total magnitude estimates over the whole survey. Results are obtained for 2.4 million galaxies with blue photographic magnitudes brighter than b_J = 20.5 covering 4300 deg^2 in the region of the south galactic cap. Almost all galaxies in our sample have central surface brightness in the range 20 to 24 b_J mag per arcsec^2. The SB measurements we obtain are compared to previous SB measurements and we find an acceptable level of error of +/- 0.2 b_J mag per arcsec^2. The distribution of SB profiles is considered for different galaxy morphologies for the bright APM galaxies. We find that early-type galaxies have more centrally concentrated profiles.
Massive Disks in Low Surface Brightness Galaxies  [PDF]
B. Fuchs
Physics , 2002, DOI: 10.1023/A:1024011601885
Abstract: An update of the set of low surface brightness galaxies is presented which can be used to set constraints on the otherwise ambiguous decompositions of their rotation curves into contributions due to the various components of the galaxies. The selected galaxies show all clear spiral structure and arguments of density wave theory of galactic spiral arms are used to estimate the masses of the galactic disks. Again these estimates seem to indicate that the disks of low surface brightness galaxies might be much more massive than currently thought. This puzzling result contradicts stellar population synthesis models. This would mean also that low surface brightness galaxies are not dominated by dark matter in their inner parts.
Dim Matter in the Disks of Low Surface Brightness Galaxies  [PDF]
B. Fuchs
Physics , 2002,
Abstract: An attempt is made to set constraints on the otherwise ambiguous decomposition of the rotation curves of low surface brightness galaxies into contributions due to the various components of the galaxies. For this purpose galaxies are selected which show clear spiral structure. Arguments of density wave theory of galactic spiral arms are then used to estimate the masses of the galactic disks. These estimates seem to indicate that the disks of low surface brightness galaxies might be much more massive than currently thought. This unexpected result contradicts stellar population synthesis models. This would also mean that low surface brightness galaxies are not dominated by dark matter in their inner parts.
From Spirals to Low Surface Brightness galaxies  [PDF]
S. Boissier,D. Monnier Ragaigne,N. Prantzos,W. van Driel,C. Balkowski
Physics , 2002, DOI: 10.1023/A:1024039404689
Abstract: We show that simple models of the chemical and spectrophotometric evolution of galaxies can be used to explore the properties of present-day galaxies and especially the causes of the observed variety among disc galaxies. We focus on the link between ``classical'' spirals and Low Surface Brightness galaxies.
The Molecular ISM in Low Surface Brightness Disk Galaxies  [PDF]
Chris Mihos,Marco Spaans,Stacy McGaugh
Physics , 1998,
Abstract: We present models for the interstellar medium in disk galaxies. In particular, we investigate whether the ISM in low surface brightness galaxies can support a significant fraction of molecular gas given their low metallicity and surface density. It is found that the abundance and line brightness of CO in LSB galaxies is small and typically below current observational limits. Still, depending on physical details of the ISM, the fraction of gas in the form of molecular hydrogen can be significant in the inner few kpc of a low surface brightness galaxy. This molecular gas would be at temperatures of $\sim$ 30 -- 50 K, rather higher than in high surface brightness galaxies. These results may help explain the star forming properties and inferred evolutionary history of LSB galaxies.
The Morphology of Low Surface Brightness Disk Galaxies  [PDF]
Stacy McGaugh,Jim Schombert,Greg Bothun
Physics , 1995, DOI: 10.1086/117427
Abstract: We present $UBVI$ and H$\alpha$ images of a sample of Low Surface Brightness (LSB) disk galaxies. These galaxies are generally late types, if they can be sensibly classified at all. However, they are not dwarfs, being intrinsically large and luminous. The morphology of LSB galaxies is discussed in terms of the physical interpretation of the Hubble sequence. Galaxies with high contrast relative to the sky background are subject to being more finely typed than those which appear merely as fuzzy blobs on photographic plates. This causes the stages of the Hubble sequence to be nonlinear in the sense that large morphological type distinctions are made between high surface brightness spirals when only small physical differences exist, and small morphological distinctions are made between low surface brightness galaxies even when large physical differences exist. Many LSB galaxies lack the old red disk conspicuous in higher surface brightness spirals. Their morphology is strikingly similar in all bands from $U$ to $I$, suggesting farily homogeneous stellar populations lacking a well developed giant branch. These properties, together with their very blue colors, suggest that LSB galaxies are relatively younger than their high surface brightness counterparts. A few of these LSB galaxies appear to be very young ($\simlt 1$~Gyr), and as such may represent local examples of protogalaxies.
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