Bars, Ovals, and Lenses in Early-Type Disk Galaxies: Probes of Galaxy Evolution

Laurikainen, Eija; Salo, H.; Buta, Ronald J.; Knapen, Johan H.

doi:10.1088/0004-637x/692/1/l34

Cited by 105 publications

(183 citation statements)

References 48 publications

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“…The incidence of bars in our Sy and control galaxy sample is similar: (49 ± 8)% 6 and (46 ± 8)%, respectively. These percentages may be lower than in other studies in the optical, owing to the large share of S0 galaxies that tend to show a lower incidence of bars, relative to later types (Ho et al 1997;Knapen et al 2000;Laurikainen et al 2009;Aguerri et al 2009). Given our morphological mix and the distribution of bar fractions with Hubble type in Ho et al (1997), based on RC3 classification, and in Aguerri et al (2009), based on ellipse fitting, we estimated the expected bar fraction of our combined (Sy and control) sample to be 50% for the former and 44% for the latter authors, which is similar to our fractions.…”

Section: Bar Fractioncontrasting

confidence: 60%

Optical multiband surface photometry of a sample of Seyfert galaxies

Slavcheva-Mihova

Mihov

2010

A&A

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Context. Parallel analysis of the large-scale morphology and local environment of matched active and control galaxy samples plays an important role in studies of the fueling of active galactic nuclei. Aims. We carry out a detailed morphological characterization of a sample of 35 Seyfert galaxies and a matched sample of inactive galaxies in order to compare the evidence of non-axisymmetric perturbation of the potential and, in the second part of this paper, to be able to perform a multicomponent photometric decomposition of the Seyfert galaxies. Methods. We constructed contour maps, BVR C I C profiles of the surface brightness, ellipticity, and position angle, as well as colour index profiles. We further used colour index images, residual images, and structure maps, which helped clarify the morphology of the galaxies. We studied the presence of close companions using literature data. Results. By straightening out the morphological status of some of the objects, we derived an improved morphological classification and built a solid basis for a further multicomponent decomposition of the Seyfert sample. We report hitherto undetected (to our knowledge) structural components in some Seyfert galaxies -a bar (Ark 479), an oval/lens (Mrk 595), rings (Ark 120, Mrk 376), a nuclear bar and ring (Mrk 352), and nuclear dust lanes (Mrk 590). We compared the large-scale morphology and local environment of the Seyfert sample to those of the control one and found that (1) the two samples show similar incidences of bars, rings, asymmetries, and close companions; (2) the Seyfert bars are generally weaker than the bars of the control galaxies; (3) the bulk of the two samples shows morphological evidence of non-axisymmetric perturbations of the potential or close companions; (4) the fueling of Seyfert nuclei is not directly related to the large-scale morphology and local environment of their host galaxies.

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Section: Bar Fractioncontrasting

confidence: 60%

Optical multiband surface photometry of a sample of Seyfert galaxies

Slavcheva-Mihova

Mihov

2010

A&A

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“…There are other mechanisms that can lead to the formation of an S0 galaxy, for instance internal secular processes such as bars or strong gas outflows and inflows induced by torques and nuclear activity (Laurikainen et al 2009(Laurikainen et al , 2013De Rossi et al 2012). Furthermore, some studies argue that the mechanisms producing S0 galaxies do not mainly depend on the environment, but on the mass of the galaxy (e.g.…”

Section: Discussionmentioning

confidence: 99%

Formation of S0 galaxies through mergers

Tapia

Eliche‐Moral

Aceves

et al. 2017

A&A

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Context. Lenticular (S0) galaxies are known to derive from spiral galaxies. The fact that S0s nearly obey the Tully-Fisher relation (TFR) at z ∼ 0 (as spirals have done in the last ∼9 Gyr) is considered an argument against their major-merger origin because equal mergers of two disc galaxies produce remnants that are outliers of the TFR. Aims. We explore whether a scenario that combines an origin by mergers at z ∼ 1.8 − 1.5 with a subsequent passive evolution of the resulting S0 remnants since z ∼ 0.8-1 is compatible with observational data of S0s in the TFR both at z ∼ 0.8 and z ∼ 0. Methods. We studied a set of major and minor merger experiments from the GalMer database that generate massive S0 remnants that are dynamically relaxed and have realistic properties. We analysed the location of these remnants in the photometric and stellar TFRs assuming that they correspond to z ∼ 0.8 galaxies. We then estimated their evolution in these planes over the last ∼ 7 Gyr considering that they have evolved passively in isolation. The results were compared with data of real S0s and spirals at different redshifts. We also tested how the use of V circ or V rot,max affects the results. Results. Just after ∼ 1-2 Gyr of coalescence, major mergers generate S0 remnants that are outliers of the local photometric and stellar TFRs (as already stated in previous studies), in good agreement with observations at z ∼ 0.8. After ∼ 4 -7 Gyr of passive evolution in isolation, the S0 remnants move towards the local TFR, although the initial scatter among them persists. This scatter is sensitive to the indicator used for the rotation velocity: V circ values yield a lower scatter than when V rot,max values are considered instead. In the planes involving V rot,max , a clear segregation of the S0 remnants in terms of the spin-orbit coupling of the model is observed, in which the remnants of retrograde encounters overlap with local S0s hosting counter-rotating discs. The location of the S0 remnants at z ∼ 0 agrees well with the observed distribution of local S0 galaxies in the σ 0 -M K , V circ -σ 0 , and V rot,max -σ 0 planes. Conclusions. Massive S0 galaxies may have been formed through major mergers that occurred at high redshift and have later evolved towards the local TFR through passive evolution in relative isolation, a mechanism that would also contribute to the scatter observed in this relation.

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“…Because the models lack gas (and thus star formation), the ovals are weak. But nevertheless they are very frequent subcomponents of real S0 galaxies (Laurikainen et al 2005(Laurikainen et al , 2009(Laurikainen et al , 2013. The most noticeable changes in the B semi-axis correspond to the models with small original primary bulges (S0c) and to the models with original S0b galaxies that have long-pericentre retrograde orbits and the lowest mass ratios.…”

Section: Shape Of the Remnant Bulgesmentioning

confidence: 97%

Evolution induced by dry minor mergers onto fast-rotator S0 galaxies

Tapia

Eliche‐Moral

Balcells

et al. 2014

A&A

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Context. Numerical studies have shown that the properties of the S0 galaxies with kinematics intermediate between fast and slow rotators are difficult to explain by a scenario of major mergers. Aims. We investigate whether the smoother perturbation induced by minor mergers can reproduce these systems. Methods. We analysed collisionless N-body simulations of intermediate and minor dry mergers onto S0s to determine the structural and kinematic evolution induced by the encounters. The original primary galaxies represent gas-poor fast-rotator S0b and S0c galaxies with high intrinsic ellipticities. The original bulges are intrinsically spherical and have low rotation. Different mass ratios, parent bulges, density ratios, and orbits were studied. Results. Minor mergers induce a lower decrease of the global rotational support (as provided by λ e ) than encounters of lower mass ratios, which results in S0s with properties intermediate between fast and slow rotators. The resulting remnants are intrinsically more triaxial, less flattened, and span the whole range of apparent ellipticities up to e ∼ 0.8. They do not show lower apparent ellipticities in random projections than initially; on the contrary, the formation of oval distortions and the disc thickening increase the percentage of projections at 0.4 < e < 0.7. In the experiments with S0b progenitor galaxies, minor mergers tend to spin up the bulge and to slightly decrease its intrinsic ellipticity, whereas in the cases of primary S0c galaxies they keep the rotational support of the bulge nearly constant and significantly decrease its intrinsic ellipticity. The remnant bulges remain nearly spherical (B/A ∼ C/A > 0.9), but exhibit a wide range of triaxialities (0.20 < T < 1.00). In the plane of global anisotropy of velocities (δ) vs. intrinsic ellipticity ( e,intr ), some of our models extend the linear trend found in previous major merger simulations towards higher e,intr values, while others clearly depart from it (depending on the progenitor S0). This is consistent with the wide dispersion exhibited by real S0s in this diagram compared with ellipticals, which follow the linear trend drawn by major merger simulations. Conclusions. The smoother changes induced by minor mergers can explain the existence of S0s with intermediate kinematic properties between fast and slow rotators that are difficult to explain with major mergers. The different trends exhibited by ellipticals and S0 galaxies in the δ -e diagram may be pointing to the different role played by major mergers in the build-up of each morphological type.

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Bars, Ovals, and Lenses in Early-Type Disk Galaxies: Probes of Galaxy Evolution

Cited by 105 publications

References 48 publications

Optical multiband surface photometry of a sample of Seyfert galaxies

Optical multiband surface photometry of a sample of Seyfert galaxies

Formation of S0 galaxies through mergers

Evolution induced by dry minor mergers onto fast-rotator S0 galaxies

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