In normal spiral galaxies the arms are the main sites for star formation. This is the cause of their optical contrast compared with the rest of the disc. The...

Evidence for circumnuclear starbursts in spiral galaxies can take the form of a blue excess near the nucleus, but more frequently (because of dust extinction) H...

From published catalogs, basic physical properties including diameters, masses, and neutral hydrogen contents of spiral galaxies have been studied as a function...

The efficiency ratio of massive star formation in the arms of the spiral NGC 628 to that in the interarm region has been determined from the sizes and positions...

Observed scaling relations in galaxies between baryons and dark matter global properties are key to shed light on the process of galaxy formation and on the...

From H-alpha CCD observations taken with the 4.2-m William Herschel Telescope, a catalog of 456 H II regions of the inner zone of the spiral galaxy NGC 4321 has...

The extinction law in the well-defined dust lane of the Sombrero galaxy, NGC 4594, was studied. In the R, I, J, H, and K bands good agreement is found between...

Telescopes on La Palma and at La Silla have been used to compare dust extinction in external galaxies with our own Galaxy.