Broadband Imaging of a Large Sample of Irregular Galaxies

By D. Hunter, Bruce G. Elmegreen. 2005

177 citations recorded by the source corpus.

We present the results of UBV imaging of a large sample of irregular galaxies: 94 Im systems, 24 blue compact dwarfs (BCDs), and 18 Sm galaxies. We also include JHK imaging of 42 of these galaxies. The sample spans a large range in galactic parameters. Ellipse fit axial ratios, inclinations, and position angles are derived, integrated photometry and azimuthally averaged surface photometry profiles are determined, and exponential fits give the central surface brightnesses, scale lengths, and isophotal and half-power radii. These data are used to address the shapes of Im galaxies, look for clues to past interactions in large-scale peculiarities, examine the nature and consequences of bars, study color gradients and large-scale color variations, and compare the exponential disk profiles of the young and old stellar components. For example, color gradients exhibit a great variety and not all passbands are correlated. Bars are associated with higher star formation rates. Many irregulars show a double-exponential radial light profile that is steeper in the outer parts, and these are reproduced by a new model of star formation that is discussed in a companion paper. Some galaxies, primarily BCDs, have double exponentials that are steeper (and bluer) in the inner parts, presumably from centralized star formation. Im-type galaxies have thicker, less prominent dust layers than spiral galaxies because of their lower average surface densities and midplane extinctions.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/f591c52f36a983104011d4218bea8f00fac9ba34

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Citations in the corpus

Rapid Formation of Exponential Disks and Bulges at High Redshift from the Dynamical Evolution of Clump-Cluster and Chain Galaxies (2007, background): “Double-exponentials have been observed in local (e.g. Pohlen et al. 2002) and z = 0.6 − 1 spirals (Pérez 2004), as well as in local irregulars (Hunter & Elmegreen 2006).”
Beyond Inside-Out Growth: Formation and Evolution of Disk Outskirts (2007, background): “The existence of extended UV disks (e.g Thilker et al. 2007) and the lack of a clear correlation of Hα cut-offs and optical disk breaks (Pohlen et al. 2004; Hunter & Elmegreen 2006) further complicates the picture.”
THE OUTER DISKS OF EARLY-TYPE GALAXIES. I. SURFACE-BRIGHTNESS PROFILES OF BARRED GALAXIES (2007, background): “Evidence for a third general class of disk profiles has been presented by Erwin et al. (2005) for early-type disks and by Hunter & Elmegreen (2006) and Pohlen & Trujillo (2006) for late-type disks; an earlier identification of this phenomenon in extreme late-type spirals is that of Matthews &…”
HIGH-RESOLUTION DARK MATTER DENSITY PROFILES OF THINGS DWARF GALAXIES: CORRECTING FOR NONCIRCULAR MOTIONS (2008, methodology): “For NGC 2366, we used a 10% solar metallicity (Hunter & Elmegreen 2006) and a scaled Salpeter (1955) IMF.”
Evolution of galactic discs: multiple patterns, radial migration, and disc outskirts (2012, background): “…into galaxies at a range of inclinations have actually found that galactic discs do not end at the truncation, but rather exhibit a change in the exponential scale-length of the light distribu ion (e.g. Pohlen et al., 2002; Erwin et al., 2005; Pohlen and Trujillo, 2006; Hunter and Elmegreen, 2006).”
Galaxy And Mass Assembly (GAMA): the galaxy stellar mass function at z < 0.06 (2011, methodology): “For comparison, also shown are measurements of irregular galaxies (Hunter & Elmegreen 2006) using M/LV from theB − V relation of Bell et al. (2003), and Milky Way (Gilmore et al. 2007) and M31 dwarf spheroidals (e.g. McConnachie & Irwin 2006; Martin etal.”