Related papers: Spiral Galaxies' Disk Dominance and Testing MOND
Late-type low surface brightness galaxies (LSBs) are faint disk galaxies with central maximum stellar surface densities below 100 Msun/pc^2. The currently favored scenario for their origin is that LSBs have formed in fast-rotating halos…
The observed flaring of HI disk in the outer region of galaxies has been used in the past to determine the shape of the dark matter halo. Previous studies based on this concept suggest a slightly oblate halo (axis ratio ~ 0.8) for our…
The opacity of a spiral disk due to dust absorption influences every measurement we make of it in the UV and optical. Two separate techniques directly measure the total absorption by dust in the disk: calibrated distant galaxy counts and…
Cosmological simulations indicate that cold dark matter (CDM) halos should be triaxial. Verifying observationally this theoretical prediction is, however, less than straightforward because the assembly of galaxies is expected to modify the…
I describe how the dynamics of galactic disks can be inferred by imaging and spectroscopy. Next I demonstrate that the decomposition of the rotation curves of spiral galaxies into the contributions by the various components of the galaxies…
We present integrated H alpha measurements obtained from imaging observations of 98 late-type galaxies, primarily selected in the Coma supercluster. These data, combined with H alpha photometry from the literature, include a magnitude…
We present ultraviolet integrated and azimuthally-averaged surface photometric properties of a sample of 44 dIm, BCD, and Sm galaxies measured from archival NUV and FUV images obtained with GALEX. We compare the UV to Halpha and V-band…
In the past years a wealth of observations allowed to unravel the structural properties of the Dark Matter Halos around spirals. First, their rotation curves follow an Universal profile (URC) that can be described in terms of an exponential…
The quantity of dust in a spiral disk can be estimated using the dust's typical emission or the extinction of a known source. In this paper, we compare two techniques, one based on emission and one on absorption, applied on sections of…
When astronomers study the dark matter halos of spiral galaxies, they normally assume that the disk mass-to-light ratio is *constant*. We describe a method of analyzing the kinematics of planetary nebulae (PNe) in nearby face-on spiral…
NGC 2915 is a nearby blue compact dwarf with the HI properties of a late-type spiral. Its large, rotating HI disk (extending out to R ~ 22 B-band scale lengths) and apparent lack of stars in the outer HI disk make it a useful candidate for…
Exploiting broad- and narrow-band images of the Hubble Space Telescope from the near-UV to I-band rest frame, we study the star-forming clumps of six galaxies of the GASP sample undergoing strong ram pressure stripping. Clumps are detected…
We present new models for the formation of disk galaxies that improve upon previous models by following the detailed accretion and cooling of the baryonic mass, and by using realistic distributions of specific angular momentum. Under the…
We present a UV study of 3 extended UV (XUV) galaxies that we have observed with the UVIT and the GMRT. XUV galaxies show filamentary or diffuse star formation well beyond their optical disks, in regions where the disk surface density lies…
The formation of galactic discs and the efficiency of star formation within them are issues central to our understanding of galaxy formation. We have developed a detailed and versatile model of disc formation which combines the strengths of…
We explore the vertical light distribution as a function of galactocentric radius in the edge-on (i=88) Sd `superthin' galaxy UGC7321. UGC7321 is a low-luminosity spiral (M_B,i=-17.0) with a diffuse, low surface brightness stellar disk and…
The density-wave theory of galactic spiral-arm structure makes a striking prediction that the pitch angle of spiral arms should vary with the wavelength of the galaxy's image. The reason is that stars are born in the density wave but move…
We study the neutral hydrogen properties of a sample of 20 bulgeless disk galaxies (Sd - Sdm Hubble types), an interesting class that can be used to constrain galaxy formation and evolution, especially the role of mergers versus internal…
The DiskMass survey recently provided measurements of the vertical velocity dispersions of disk stars in a sample of nearly face-on galaxies. By setting the disk scale-heights to be equal to those of edge-on galaxies with similar…
We build a volume-limited sample of galaxies derived from the SDSS-DR7 to characterize several physical properties of the dark matter halos where LSB galaxies reside. Using an observational proxy for the assembly time, we found that LSB…