Double Bars, Inner Disks, and Nuclear Rings in Early-Type Disk Galaxies

By P. Erwin, L. Sparke. 2002

138 citations recorded by the source corpus.

We present results from a survey of an unbiased sample of 38 early-type (S0–Sa), low-inclination, optically barred galaxies in the field, using images both from the ground and from space. Our goal was to find and characterize central stellar and gaseous structures: secondary bars, inner disks, and nuclear rings. We find that bars inside bars are surprisingly common: at least one-quarter of the sample galaxies (possibly as many as 40%) are double barred, with no preference for Hubble type or the strength of the primary bar. A typical secondary bar is ∼12% of the size of its primary bar and extends to 240–750 pc in radius. Secondary bars are not systematically either parallel or perpendicular to the primary; we see cases where they lead the primary bar in rotation and others where they trail, which supports the hypothesis that the two bars of a double-bar system rotate independently. We see no significant effect of secondary bars on nuclear activity: our double-barred galaxies are no more likely to harbor a Seyfert or LINER nucleus than our single-barred galaxies. We find kiloparsec-scale inner disks in at least 20% of our sample; they occur almost exclusively in S0 galaxies. These disks are on average 20% the size of their host bar and show a wider range of relative sizes than do secondary bars. Nuclear rings are present in about a third of our sample. Most of these rings are dusty, sites of current or recent star formation, or both; such rings are preferentially found in Sa galaxies. Three S0 galaxies (8% of the sample, but 15% of the S0's) appear to have purely stellar nuclear rings, with no evidence for dust or recent star formation. The fact that these central stellar structures are so common indicates that the inner regions of early-type barred galaxies typically contain dynamically cool and disklike structures. This is especially true for S0 galaxies, where secondary bars, inner disks, and/or stellar nuclear rings are present at least two-thirds of the time. If we interpret nuclear rings, secondary bars, and (possibly) inner disks and nuclear spirals as signs of inner Lindblad resonances (ILRs), then between one and two-thirds of barred S0–Sa galaxies show evidence for ILRs.

Subfields: Astronomy and Astrophysics, Instrumentation, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/f3d68b3be3b7112e2ab6835532c6fa8a49cded20

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Citations in the corpus

Photometric scaling relations of lenticular and spiral galaxies (2010, background): “Moreover the disks in most S0 galaxies are not featureless: bars are known to be prominent in S0s, nuclear bars are frequent (Erwin & Sparke 2002; Laine et al. 2002; Laurikainen et al. 2009), and even a large majority of non-barred S0s have ovals or lenses (Laurikainen et al. 2009).”
Massive Black Hole Binary Evolution (2004, background): “Furthermore imaging of galaxy centers on parsec scales reveals a wealth of features in the stellar distribution that are not consistent with axisymmetry, including bars, nuclear spirals, and other misaligned features [221, 164, 40].”
Circumnuclear Dust in Nearby Active and Inactive Galaxies. II. Bars, Nuclear Spirals, and the Fueling of Active Galactic Nuclei (2002, background): “…bars in only ∼ 25% of all Seyferts (Regan & Mulchaey 1999; Martini et al. 2001) and studies of Seyfert and control samples have found similar fractions of double bars in samples of active and inactive galaxies with large-scale bars (Márquez et al. 2000; Laine et al. 2002; Erwin & Sparke 2002).”
Secular Evolution and the Formation of Pseudobulges in Disk Galaxies (2004, background): “Erwin & Sparke (2002) find nuclear bars in 26± 7% of their sample of 38 SB galaxies.”
Double-Barred Galaxies I. A Catalog of Barred Galaxies with Stellar Secondary Bars and Inner Disks (2003, background): “NGC 2685: Erwin & Sparke (2002, 2003) listed this among their inner-disk galaxies.”
Gas flow models in the Milky Way embedded bars (2008, background): “Around 28% of barred galaxies have a secondary bar (Erwin & Sparke 2002; Laine et al. 2002).”
THE STRUCTURE OF CLASSICAL BULGES AND PSEUDOBULGES: THE LINK BETWEEN PSEUDOBULGES AND SÉRSIC INDEX (2008, background): “…outer disk (Fathi & Peletier 2003; Kormendy 1993); mid-IR colors of the bulge are similar to those of the outer disk (Fisher 2006); nuclear bar (Erwin & Sparke 2002); nuclear ring and/or nuclear spiral (Carollo et al. 1997); near-exponential surface brightness profiles (Andredakis & Sanders…”
BULGES OF NEARBY GALAXIES WITH SPITZER: SCALING RELATIONS IN PSEUDOBULGES AND CLASSICAL BULGES (2010, background): “…(Peletier & Balcells 1996), the bulge has a nearly exponential surface brightness profile (Andredakis & Sanders 1994), flattening similar to that of their outer disk (Fathi & Peletier 2003; Kormendy 1993), nuclear bar (Erwin & Sparke 2002), nuclear ring, and/or nuclear spiral (Carollo et al. 1997).”
BUDDA: A New Two-dimensional Bulge/Disk Decomposition Code for Detailed Structural Analysis of Galaxies (2004, methodology): “To a lesser extent, a similar analysis can be performed via unsharp masking and color maps (see, e.g., Erwin & Sparke 2002 for a recent application).”
AINUR: Atlas of Images of NUclear Rings (2009, background): “We have not included the possible nuclear ring in NGC 3489 (Erwin & Sparke 2002) because it is too inclined for us to be completely sure about its nature.”