Results 71 to 80 of about 202 (183)

Radial variations of the SFHs of dwarf irregular galaxies [PDF]

Proceedings of the International Astronomical Union, 2011
AbstractThe LITTLE THINGS project† has compiled multi-wavelength data (including VLA hi-line emission maps, GALEX FUV/NUV imagery, UBV, narrow-band Hα, and Spitzer images) for a representative sample of nearby dwarf irregular (dIrr) galaxies. The broadband data are used to constrain the radial variations of the star formation (SF) rate (SFR) averaged ...
Hong-Xin Zhang, Deidre A. Hunter, Bruce G. Elmegreen, Yu Gao, Andreas Schruba   +4 more
openaire   +1 more source

The Interstellar Medium in I Zw 18 Seen with JWST/MIRI. II. Warm Molecular Hydrogen and Warm Dust

The Astrophysical Journal
We present JWST/MIRI spectra from the Medium-resolution Spectrometer of I Zw 18, a nearby dwarf galaxy with a metallicity of ∼3% Solar. Here, we investigate warm molecular hydrogen, H _2 , observed in spectra extracted in ∼120 pc apertures centered on ...
L. K. Hunt, B. T. Draine, M. G. Navarro, A. Aloisi, R. J. Rickards Vaught, A. Adamo, F. Annibali, D. Calzetti, S. Hernandez, B. L. James, M. Mingozzi, R. Schneider, M. Tosi, B. Brandl, M. G. del Valle-Espinosa, F. Donnan, A. S. Hirschauer, M. Meixner, D. Rigopoulou   +18 more
doaj   +1 more source

The Interstellar Medium in I Zw 18 Seen with JWST/MIRI. I. Highly Ionized Gas

The Astrophysical Journal
We present JWST/MIRI spectra from the Medium-Resolution Spectrometer of I Zw 18, a nearby dwarf galaxy with a metallicity of ∼3% solar. Its proximity enables a detailed study of highly ionized gas that can be interpreted in the context of newly ...
L. K. Hunt, A. Aloisi, M. G. Navarro, R. J. Rickards Vaught, B. T. Draine, A. Adamo, F. Annibali, D. Calzetti, S. Hernandez, B. L. James, M. Mingozzi, R. Schneider, M. Tosi, B. Brandl, M. G. del Valle-Espinosa, F. Donnan, A. S. Hirschauer, M. Meixner, D. Rigopoulou, C. T. Richardson, J. M. Levanti, A. R. Basu-Zych   +21 more
doaj   +1 more source

Star formation in dwarf irregular galaxies NGC 6822

The Astronomical Journal, 1995
plain Tex format; for hardcopy of figures and tables 2 and 3 contact Tosi@astbo3.bo.astro.it; BAP 09-1994-023 ...
Marconi, G., Tosi, M., Greggio, L., Focardi, P.   +3 more
openaire   +2 more sources

SAGAbg. I. A Near-unity Mass-loading Factor in Low-mass Galaxies via Their Low-redshift Evolution in Stellar Mass, Oxygen Abundance, and Star Formation Rate

The Astrophysical Journal
Measuring the relation between star formation and galactic winds is observationally difficult. In this work we make an indirect measurement of the mass-loading factor (the ratio between the mass outflow rate and star formation rate) in low-mass galaxies ...
Erin Kado-Fong, Marla Geha, Yao-Yuan Mao, Mithi A. C. de los Reyes, Risa H. Wechsler, Yasmeen Asali, Nitya Kallivayalil, Ethan O. Nadler, Erik J. Tollerud, Benjamin Weiner   +9 more
doaj   +1 more source

Ultradeep Imaging of Nearby Dwarf Irregular Galaxies: Stellar Haloes and Disk Structure

The Astronomical Journal
We have examined the stellar structure of 10 nearby, low stellar mass (10 ^6 –6 × 10 ^7 M _⊙ ) dwarf irregular galaxies by fitting ellipses as a function of surface brightness on ultradeep V images. These are compared to far-ultraviolet images as tracers
Deidre A. Hunter, Bruce G. Elmegreen
doaj   +1 more source

Pressure and Star Formation in LITTLE THINGS Dwarf Irregular Galaxies

The Astrophysical Journal
The surface densities of star formation, Σ _SFR , in 24 dwarf irregular (dIrr) galaxies from the LITTLE THINGS survey are combined with gas surface densities and midplane pressures to examine the correlations found previously for spiral galaxies.
Bruce G. Elmegreen, Deidre A. Hunter, Edvige Corbelli   +2 more
doaj   +1 more source

Pervasive Cavity-rim Structure for Star Formation in Dwarf Irregular Galaxies

The Astrophysical Journal
Unsharp-mask images of H I emission from 36 dwarf irregular (dIrr) galaxies illustrate star formation in dispersed clouds and on the rims of large cavities. The cavities can extend for a radial scale length and typically have circular or slightly sheared
Bruce G. Elmegreen, Deidre A. Hunter
doaj   +1 more source

Rotationally Supported Virgo Cluster Dwarf Elliptical Galaxies: Stripped Dwarf Irregular Galaxies?

The Astronomical Journal, 2004
New observations of 16 dwarf elliptical galaxies in the Virgo Cluster indicate that at least seven dEs have significant velocity gradients along their optical major axis, with typical rotation amplitudes of 20-30 km/s. Of the remaining nine galaxies in this sample, 6 have velocity gradients less than 20 km/s kpc^{-1} while the other 3 observations had ...
van Zee, L., Skillman, E. D., Haynes, M. P.   +2 more
openaire   +2 more sources

OLD GLOBULAR CLUSTERS IN MAGELLANIC-TYPE DWARF IRREGULAR GALAXIES

The Astronomical Journal, 2008
We present a study of the old globular clusters (GC) using archival F606W and F814W HST/ACS images of 19 Magellanic-type dwarf Irregular (dIrr) galaxies found in nearby (2 - 8 Mpc) associations of only dwarf galaxies. All dIrrs have absolute magnitudes fainter than or equal to the SMC (Mv = -16.2 mag).
Georgiev, Iskren Y., Goudfrooij, Paul, Puzia, Thomas, Hilker, Michael   +3 more
openaire   +2 more sources