Results 1 to 10 of about 722,598 (307)

Dark Matter and the Chemical Evolution of Irregular Galaxies [PDF]

The Astrophysical Journal, 1998
We present three types of chemical evolution models for irregular galaxies: closed-box with continuous star formation rates (SFRs), closed-box with bursting SFRs, and O-rich outflow with continuous SFRs. We discuss the chemical evolution of the irregular galaxies NGC 1560 and II Zw 33, and a ``typical'' irregular galaxy.
Arimoto N., Bajaja E., Balkowski C., Brinks E., Broeils A. H., Burlak A. N., Carigi L., Esteban C., Ferrano F. R., Gottesman S. T., Gottesman S. T., Hindman J. V., Israel F. P., Kroupa P., Kunkel W. E., L. Carigi, Lequeux J., M. Peimbert, Maeder A., P. Colin, Peimbert M., Petrosian A. R., Renzini A., Schaller G., Shostak G. S., Staveley-Smith L.   +25 more
arxiv   +9 more sources

Oxygen abundances in dwarf irregular galaxies and the metallicity - luminosity relationship [PDF]

, 2001
The low-luminosity dwarf irregular galaxies are considered. The oxygen abundances in HII regions of dwarf irregular galaxies were recalculated from published spectra through the recently suggested P - method. It has been found that the metallicity of low-luminosity dwarf irregular galaxies, with a few exceptions, correlates well with galaxy luminosity.
Pilyugin, L. S.
arxiv   +6 more sources

Diffuse Ionized Gas in the Dwarf Irregular Galaxy DDO 53 [PDF]

Astron.J.134:1447-1458,2007, 2007
The spectral characteristics throughout the dwarf irregular galaxy DDO 53 are studied. The results are very similar to those for other irregular galaxies: high excitation and low values of the [SII]/Halpha ratio. The most likely ionization source is photon leakage from the classical HII regions, without any other source, although the interstellar ...
A. M. Hidalgo-Gámez, Begum A., Benvenuti P., Caplan J., Dopita M. A., Hidalgo-Gamez A. M., Moles M., Olofsson K., Otte B., Pagel B. E. J., Pilyugin L. S., Schuster W. J., Stasinska G.   +12 more
arxiv   +3 more sources

Cosmic-ray driven dynamo in the medium of irregular galaxy [PDF]

, 2009
We investigate the cosmic ray driven dynamo in the interstellar medium of irregular galaxy. The observations (Chyzy et al. 2000, 2003) show that the magnetic field in irregular galaxies is present and its value reaches the same level as in spiral galaxies.
Chyży, Chyży, Dominik Bomans, Hanasz, Hubert Siejkowski, Katarzyna Otmianowska-Mazur, Marian Soida, Michał Hanasz   +7 more
arxiv   +11 more sources

Magnetic Fields in Irregular Galaxies [PDF]

, 2007
Magnetic fields are an important component of the interstellar medium, especially in low-mass galaxies like irregulars where the magnetic pressure may be significant. However, few irregular galaxies have observed magnetic field structures. Using the VLA, the GBT, and the ATCA, we have observed several irregular galaxies in the radio continuum to ...
Timothy Robishaw, S. Muehle, Eric M. Wilcots, Ellen G. Zweibel, John E. Everett, Carl Heiles, Amanda A. Kepley   +6 more
arxiv   +5 more sources

The oxygen abundance deficiency in irregular galaxies [PDF]

New Astronomy Reviews, 2000
The observed oxygen abundances in a number of irregular galaxies have been compared with predictions of the closed-box model of chemical and photometric evolution of galaxies. Oxygen is found to be deficient with respect to the predicted abundances. This
Ferrini, F., Pilyugin, L. S.
core   +6 more sources

Lopsidedness in dwarf irregular galaxies [PDF]

Monthly Notices of the Royal Astronomical Society, 2000
42 pages, LaTex.
Ana Heller, N. Brosch, E. Almoznino, Liese van Zee, John J. Salzer   +4 more
openalex   +4 more sources

A Revised Parallel-Sequence Morphological Classification of Galaxies: Structure and Formation of S0 and Spheroidal Galaxies [PDF]

, 2011
We update van den Bergh's parallel sequence galaxy classification in which S0 galaxies form a sequence S0a-S0b-S0c that parallels the sequence Sa-Sb-Sc of spiral galaxies. The ratio B/T of bulge to total light defines the position of a galaxy in each sequence. Our classification makes one improvement.
Abramson, Arnaboldi, Arnaboldi, Arnaboldi, Arnaboldi, Arnaboldi, Baggett, Baldry, Bell, Bender, Bender, Bender, Bender, Bender, Bender, Bender, Bernardi, Binggeli, Binggeli, Binggeli, Blanton, Blanton, Boselli, Bullock, Buta, Buta, Buta, Buta, Buta, Böker, Böker, Chen, Chiboukas, Chung, Chung, Combes, Courteau, Côté, Da Costa, Davé, De Rijcke, de Souza, de Vaucouleurs, Djorgovski, Dressler, Faber, Ferguson, Ferrarese, Fisher, Freeland, Gavazzi, Geha, Geha, Geisler, Glass, Gonzalez, Graham, Graham, Graham, Grebel, Hamabe, Hinz, Hogg, Hogg, Hopkins, Hopkins, Hopkins, Hubble, Hurley-Keller, Ibata, Ibata, Ibata, Irwin, Jerjen, Jerjen, Jerjen, John Kormendy, Jørgensen, Karachentsev, Kazantzidis, Kelson, Kenney, Kenney, Kenney, Kirby, Komatsu, Kormendy, Kormendy, Kormendy, Kormendy, Kormendy, Kormendy, Kormendy, Kormendy, Kormendy, Kormendy, Kormendy, Kormendy, Kormendy, Kormendy, Kormendy, Kormendy, Kormendy, Krajnović, Krick, Lake, Larson, Laurikainen, Laurikainen, Li, Lisker, Lisker, Martin, Mateo, Mayer, Mayer, Mei, Merritt, Mihos, Mihos, Mihos, Milosavljević, Moore, Moore, Morgan, Mori, Naab, Neistein, Okamura, Oser, Oser, Peng, Pildis, Press, Ralf Bender, Robertson, Saglia, Saito, Sandage, Sandage, Sandage, Sandage, Sandage, Scorza, Sellwood, Shetrone, Shetrone, Shetrone, Shetrone, Simard, Strateva, Sérsic, Temi, Tolstoy, Tonnesen, Tonnesen, Tonnesen, Tonnesen, Tremaine, Tully, van Albada, van den Bergh, van den Bergh, van den Bergh, van den Bergh, van Dokkum, van Driel, van Gorkom, van Woerden, van Zee, Veilleux, Venn, Venn, Vikhlinin, Watt, Weinzirl, Weisz, Weisz, Welch, Williams, Williams, Wilman, Yoshida   +182 more
arxiv   +6 more sources

Supernova Remnants in the Irregular Galaxy NGC 4449

The Astrophysical Journal, 2023
The nearby irregular galaxy NGC 4449 has a star formation rate of ∼0.4 M _☉ yr ^−1 and should host of order 70 supernova remnants (SNRs) younger than 20,000 yr, a typical age for SNRs expanding into an interstellar medium (ISM) with a density of 1 cm ^−3
P. Frank Winkler, Knox S. Long, William P. Blair   +2 more
doaj   +3 more sources

Stellar Structure of Irregular Galaxies. Edge-On Galaxies [PDF]

Astron.Rep. 50 (2006) 517-525, 2006
Stellar photometry obtained using the Hubble Space Telescope is used to study the distributions of the number densities of stars of various ages in 12 irregular and dwarf spiral galaxies viewed edge-on. Two subsystems can be distinguished in all the galaxies: a thin disk comprised of young stars and a thick disk containing a large fraction of the old ...
arxiv   +7 more sources