Published data for large amplitude asymptotic giant branch variables in the Large Magellanic Cloud are re-analysed to establish the constants for an infrared (K) periodluminosity relation of the form: MK = ρ[logP − 2.38]+ δ. A slope of ρ = −3.51± 0.20 and a zero point of δ = −7.15 ± 0.06 are found for oxygen-rich Miras (if a distance modulus of 18.39 ± 0.05 is used for the LMC). Assuming this s...

We present the comparison between theoretical and empirical PL relations in V and I bands for the Large Magellanic Cloud. We found that, within the current intrinsic dispersions, theoretical predictions are in remarkable agreement with observational data. We also discuss the PLC relations in (V,B-V) and (V,V-I) as well as the dependence of distance determinations on uncertainties in colors, in ...

We discuss the impact of possible differences in the slope of the Cepheid Period-Luminosity relation on the determination of extragalactic distances in the context of recent studies that suggest changes in this slope. We show that the Wesenheit function W = V −R×((V −I), widely used for the determination of Cepheid distances, is expected to be highly insensitive to changes in the slope of the u...

A globular cluster distance scale based on Hipparcos parallaxes of subdwarfs has been used to derive estimates of MK for cluster Miras, including one in the SMC globular cluster NGC121. These lead to a zero-point of the Mira infrared period-luminosity relation, PL(K), in good agreement with that derived from Hipparcos parallaxes of nearby field Miras. The mean of these two estimates together wi...

Abstract The period–luminosity relations (PLRs) of Milky Way δ Scuti ( Sct) stars have been described to the present day by a linear relation. However, when studying extragalactic systems such as Magellanic Clouds and several dwarf galaxies, we notice for first time nonlinear behavior in PLR Sct stars. Using largest sample ∼3700 from data available literature—mainly based on Optical Gravitation...

The effects of axial stellar rotation on the wind–momentum relation (WLR) for determining the extragalactic distances are investigated. Despite the fact that the mass loss rates grow quite a lot with rotation, remarkably the effects on the WLR are found to be very small on the average. As an example, for an average orientation angle between the rotation axis and the line of sight, the luminosit...

The distance to NGC3982, host galaxy to the Type Ia supernova SN1998aq, is derived using 32 Cepheids discovered in archival multi-epoch Hubble Space Telescope observations. Employing recent Large Magellanic Cloud Cepheid period-luminosity relations and absolute zero point, we find a distance to NGC3982 of 20.5±0.8 (r)±1.7 (s)Mpc, including both random (r) and systematic (s) uncertainties, and i...

We investigate the Luminosity – Metallicity (L − Z) relation in the local universe (0 < z < 0.15) using spectra of 6 387 star-forming galaxies extracted from the 2dF Galaxy Redshift Survey. This sample is by far the largest to date used to perform such a study. We distinguish star-forming galaxies from AGNs using “standard” diagnostic diagrams to build a homogeneous sample of starburst galaxies...

We use a complete sample of about 140,000 galaxies from the Sloan Digital Sky Survey (SDSS) to study the size distribution of galaxies and its dependence on their luminosity, stellar mass, and morphological type. The large SDSS database provides statistics of unprecedented accuracy. For each type of galaxy, the size distribution at given luminosity (or stellar mass) is well described by a log-n...

I review the connection between dynamics and the baryonic mass distribution in rotationally-supported galaxies. The enclosed dynamical mass-to-light ratio increases with decreasing galaxy luminosity and surface brightness. The correlation with surface brightness appears to be the more fundamental, with the dependence on luminosity following simply from the weaker correlation between luminosity ...