37 research outputs found
3D Spectroscopy of Blue Compact Galaxies. Diagnostic Diagrams
Here we present the analysis of 3D spectroscopic data of three Blue Compact
Galaxies (Mrk324, Mrk370, and IIIZw102). Each of the more than 22500 spectra
obtained for each galaxy has been fitted by a single gaussian from which we
have inferred the velocity dispersion (sigma), the peak intensity (Ipeak), and
the central wavelength (lambda_c). The analysis shows that the sigma vs Ipeak
diagrams look remarkably similar to those obtained for giant extragalactic HII
regions. They all present a supersonic narrow horizontal band that extends
across all the range of intensities and that result from the massive nuclear
star-forming regions of every galaxy. The sigma vs Ipeak diagrams present also
several inclined bands of lower intensity and an even larger sigma, arising
from the large galactic volumes that surround the main central emitting knots.
Here we also show that the sigma vs lambda_c and lambda_c vs Ipeak diagrams,
are powerful tools able to unveil the presence of high and low mass stellar
clusters, and thus allow for the possibility of inferring the star formation
activity of distant galaxies, even if these are not spatially resolved.Comment: 15 pages, 3 figures, accepted for publication in The Astronomical
Journa
Star-forming complexes in the polar ring galaxy NGC660
Galaxies with polar rings consist of two subsystems, a disk and a ring, which
rotate almost in orthogonal planes. In this paper, we analyze the parameters
characterizing the composition of the interstellar medium and star formation in
star-forming complexes, belonging to a polar ring galaxy NGC660. We show that
star-forming regions in the ring of the galaxy are distinctively different from
those in the galaxy disk. They possess substantially lower infrared
luminosities, indicative of less dust mass in these regions than in a typical
disk star-forming region. UV and H luminosities also appear to be lower
in the ring, probably, being a consequence of its relatively recent formation.Comment: Accepted for publication in Open Astronomy, 6 figure