Related papers: Quantifying Bar Strength: Morphology Meets Methodo…
Our view of the properties of galaxies is strongly affected by the way in which we survey for them. I discuss some aspects of selection effects and methods to compensate for them. One result is an estimate of the surface brightness…
The morphological classification of galaxies provides vital physical information about the orbital motions of stars in galaxies, and correlates in interesting ways with star formation history, and other physical properties. Galaxy…
Aim: The aim is to study the stellar content of the bar region to constrain its formation and evolution. Methods: Line-strength indices in the bar region of a sample of 6 barred galaxies were employed to derive age and metallicity gradients…
We investigate the stellar masses of strongly barred spiral galaxies. Our analysis is based on a sample of ~14000 visually-classified nearby galaxies given in Nair & Abraham 2010(a). The fraction of barred spiral galaxies is found to be a…
A catalogue of the morphological features for the complete Spitzer Survey of Stellar Structure in Galaxies (S$^4$G), including 2352 nearby galaxies, is presented. The measurements are made using 3.6 $\mu$m images, largely tracing the old…
We aim to quantify the capability of the inhomogeneous distribution of galaxy clusters, represented by the two-point statistics in Fourier space, to retrieve information on the underlying scaling relations. We make a case study using the…
We present an observational study of the effect of bars on the gas component and on the star formation properties of their host galaxies in a statistically significant sample of resolved objects, the $Herschel$ Reference Sample. The…
I use volume- and mass-limited subsamples and recently published data from the Spitzer Survey of Stellar Structure in Galaxies (S4G) to investigate how the size of bars depends on galaxy properties. The known correlation between bar…
We propose a novel statistical method to measure cosmic birefringence and demonstrate its power in probing parity violation due to axions. Exploiting an empirical correlation between the integrated radio polarization direction of a spiral…
The morphology of a galaxy stems from secular and environmental processes during its evolutionary history. Thus galaxy morphologies have been a long used tool to gain insights on galaxy evolution. We visually classify morphologies on…
The fact that galaxy distribution exhibits fractal properties is well established since twenty years. Nowadays, the controversy concerns the range of the fractal regime, the value of the fractal dimension and the eventual presence of a…
Some years ago we proposed a new approach to the analysis of galaxy and cluster correlations based on the concepts and methods of modern statistical Physics. This led to the surprising result that galaxy correlations are fractal and not…
One third of present-day spirals host optically visible strong bars that drive their dynamical evolution. However, the fundamental question of how bars evolve over cosmological times has yet to be addressed, and even the frequency of bars…
We study in detail how the barred galaxy fraction varies as a function of luminosity, HI gas mass, morphology and color in the Virgo cluster in order to provide a well defined, statistically robust measurement of the bar fraction in the…
We present a detailed study of the morphological features of 22 rich galaxy clusters. We systematically compare cluster images and morphological parameters in an attempt to reliably identify possible substructure in both optical and X-ray…
We present first results from Galaxy Zoo 2, the second phase of the highly successful Galaxy Zoo project (www.galaxyzoo.org). Using a volume-limited sample of 13665 disk galaxies (0.01< z < 0.06 and M_r<-19.38), we study the fraction of…
While a plethora of research has been devoted to extoling the power and importance of data visualization, research on the effectiveness of data visualization methods from a human perceptual, and more generally, a cognitive standpoint…
The division of galaxies into ``barred'' (SB) and ``normal'' (S) spirals is a fundamental aspect of the Hubble galaxy classification system. This ``tuning fork'' view was revised by de Vaucouleurs, whose classification volume recognized…
We develop diagnostics to detect the presence and orientation of a bar in an edge-on disk, using its kinematical signature in the position-velocity diagram (PVD) of a spiral galaxy observed edge-on. Using a well-studied barred spiral galaxy…
Precise analyses of the statistical and scaling properties of galaxy distribution are essential to elucidate the large-scale structure of the universe. Given the ongoing debate on its statistical features, the development of statistical…