It is well known that when measuring electron densities in H II regions locally via emission line ratios the values observed are 100cm-3, but gobal values...

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...

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...

Using CCD observations in the narrow band filters in Hα , Hβ , [O Ii], [O Iii], [S Ii] and [S Iii] lines we have compiled a catalogue of 338 H Ii regions for...

Observations carried out with a 8-13 micron grating-spectrometer of Mrk 231 and NGC 4151 are reported. The Mrk 231 data can be fitted to various thermal dust...

Following the observational and theoretical evidence that points at core-collapse supernovae (SNe) as major producers of dust, here we calculate the...

The present study estimates the efficiency ratio for massive star formation between the arms and the interarm disks of three grand design spirals. The estimate...

We quantify the energy radiated through all the collisional lines in a photoionized nebula in the presence of temperature fluctuations in the form of hot spots...

This paper presents examples of star-forming phenomena in the discs of spirals which show symptoms of phase-coherence over kpc scales. Cases are found where...