Results 271 to 280 of about 954,000 (309)

Primordial Rotating Disk Composed of ≥15 Star Forming Clumps at Cosmic Dawn

open access: yes
Fujimoto S   +45 more
europepmc   +1 more source

Abundances in Galaxies

Astrophysics and Space Science, 2001
To start things going, the following topics were suggested:* 1. Reliability of abundances Stars vs H ii regions H ii classical diagnostics Effects of shocks and inhomogeneities on H ii-region diagnostics H n new diagnostics Can reliable H ii-region diagnostics be developed for high metallicity?
B. E. J. Pagel, M. G. Edmunds
openaire   +1 more source

Dust Formation in a Galaxy with Primitive Abundances [PDF]

open access: yesScience, 2009
Interstellar dust plays a crucial role in the evolution of galaxies. It governs the chemistry and physics of the interstellar medium. In the local universe, dust forms primarily in the ejecta from stars, but its composition and origin in galaxies at very early times remain controversial.
G. Sloan   +8 more
semanticscholar   +5 more sources

Abundances in dwarf galaxies

AIP Conference Proceedings, 1989
In an attempt to discover regions of very low heavy element abundance, we have observed H II regions in 7 nearby, very low luminosity dwarf irregular galaxies. All yield oxygen abundances of less than one‐tenth of the solar value, and three are within a factor of two of the lowest oxygen abundance ever detected in an H II region.
Evan D. Skillman, R. C. Kennicutt
openaire   +1 more source

Molecular Abundances in Galaxies

AIP Conference Proceedings, 2006
Two topics are discussed here. The first is an observational study on molecular abundance in nearby (< 10 Mpc) gas‐rich galaxies based on our ammonia survey and on data in literature. As a result, a systematically peculiar molecular abundance was found in a famous starburst galaxy M 82 regarding the formation mechanisms of molecules.
openaire   +1 more source

Chemical Abundances in Galaxies

1988
This article is intended as a brief overview of chemical abundances in galaxies other than our own. Attention is concentrated on global properties of ellipticals and spirals, and the methods by which abundances are estimated. References are predominantly to work which has appeared since the review of Pagel and Edmunds (1981).
openaire   +1 more source

Nebulae and abundances in galaxies

Publications of the Astronomical Society of the Pacific, 1986
Some current problems related to abundances in H II regions are briefly reviewed. For H II regions with measured electron temperatures, the discrepancy in O/H between the sun and the Orion Nebula is stressed. Studies of abundance and temperature variations within H II regions in NGC 604 are summarized.
openaire   +1 more source

Abundances in dwarf irregular galaxies

Publications of the Astronomical Society of the Pacific, 1986
The results of abundance studies of dwarf irregular galaxies and similar objects are reviewed with special attention to variations in the CNO element group. Observations of the forbidden N II and semiforbidden C III lines in the most metal-poor galaxy known, IZw 18, are presented for the first time and CNO abundances are derived via a photoionization ...
openaire   +1 more source

Abundance Gradients in Spiral Galaxies

1997
The study of HII regions in the disks of spiral galaxies has given us important information about their physical conditions. In particular the study of their chemical abundances soon showed the existence of negative gradients with higher abundance towards the centre of a galaxy (e.g. Pagel and Edmunds 1981; McCall 1982; Diaz 1989; Dinerstein 1990).
openaire   +1 more source

Interstellar Abundances in External Galaxies

1977
This field has been excellently reviewed recently by Peimbert (1975), Burbidge and Burbidge (1975) and Searle (1975). The present discussion will cover work since these and in particular the evidence for composition gradients across galaxies and the systematics with galactic type.
openaire   +1 more source

Home - About - Disclaimer - Privacy