Bibcode
DOI
Vila-Vilaró, B.; Cepa, J.; Butner, H. M.
Bibliographical reference
The Astrophysical Journal, Volume 594, Issue 1, pp. 232-246.
Advertised on:
9
2003
Journal
Citations
14
Refereed citations
14
Description
We present Heinrich Hertz Telescope CO (3-2) observations of a sample of
10 early-type galaxies detected both in far-infrared (IRAS) and in CO
(1-0). Six of the objects (i.e., 60% of the sample) were detected in the
CO (3-2) transition. Comparison of the beam-matched CO (3-2)/CO (1-0)
and CO (2-1)/CO (1-0) intensity ratios with simple large velocity
gradient and photodissociation region models reveals that early-type
objects can be broadly classified into two categories. The majority of
objects have a molecular interstellar medium of moderate density
(nH2<=1000 cm-3) and temperature
(T<=30 K). Two objects, NGC 3593 and NGC 4691, show indications of
quite denser and warmer environments, as well as gradients in their
physical properties, compatible with their classification as starbursts.
The heating source of the molecular gas and dust in all the objects in
our sample appears to be ongoing star formation.