Multicomponent decompositions for a sample of S0 galaxies

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

doi:10.1111/j.1365-2966.2005.09404.x

Cited by 233 publications

(349 citation statements)

References 57 publications

(84 reference statements)

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“…On the other hand, in Dullo & Graham (2013), we argued that core-Sérsic S0s with MV (bulge) < ∼ − 21.30 mag might be assembled insideout in two stages: an earlier "dry" major merger process involving SMBHs forms their bulge component, while the surrounding disc is subsequently formed via cold gas accretion. The bulges of our small S0 galaxy sample tend to have n < ∼ 3 (Dullo & Graham 2013, see also Balcells et al 2003 andLaurikainen et al 2005), however, core-Sérsic elliptical galaxies have n > ∼ 4. As we mentioned in Section 4.1, for the same core size, these massive bulges tend to be compact (Re < ∼ 2 kpc, Fig.…”

Section: Comparison Of Core-sérsic Elliptical and Lenticular Galaxiesmentioning

confidence: 99%

Depleted cores, multicomponent fits, and structural parameter relations for luminous early-type galaxies

Dullo¹,

Graham²

2014

Monthly Notices of the Royal Astronomical Society

147

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New surface brightness profiles from 26 early-type galaxies with suspected partially depleted cores have been extracted from the full radial extent of Hubble Space Telescope images. We have carefully quantified the radial stellar distributions of the elliptical galaxies using the core-Sérsic model whereas for the lenticular galaxies a core-Sérsic bulge plus an exponential disc model gives the best representation. We additionally caution about the use of excessive multiple Sérsic functions for decomposing galaxies and compare with past fits in the literature. The structural parameters obtained from our fitted models are in general, in good agreement with our initial study using radially limited (R < ∼ 10 ′′ ) profiles, and are used here to update several "central" as well as "global" galaxy scaling relations. We find near-linear relations between the break radius R b and the spheroid luminosity L such that R b ∝ L 1.13±0.13 , and with the supermassive black hole mass. This is internally consistent with the notion that major, dry mergers add the stellar and black hole mass in equal proportion, i.e., M BH ∝ L. In addition, we observe a linear relation R b ∝ R 0.98±0.15 e for the core-Sérsic elliptical galaxies-where R e is the galaxies' effective half light radii-which is collectively consistent with the approximately-linear, bright-end of the curved L − R e relation. Finally, we measure accurate stellar mass deficits M def that are in general 0.5−4 M BH , and we identify two galaxies (NGC 1399, NGC 5061) that, due to their high M def /M BH ratio, may have experienced oscillatory core-passage by a (gravitational radiation)-kicked black hole. The galaxy scaling relations and stellar mass deficits favor core-Sérsic galaxy formation through a few "dry" major merger events involving supermassive black holes such that M def ∝ M 3.70±0.76 BH , for M BH > ∼ 2 × 10 8 M ⊙ .

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Section: Comparison Of Core-sérsic Elliptical and Lenticular Galaxiesmentioning

confidence: 99%

Depleted cores, multicomponent fits, and structural parameter relations for luminous early-type galaxies

Dullo¹,

Graham²

2014

Monthly Notices of the Royal Astronomical Society

147

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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: 99%

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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“…The galaxy light is usually modeled as the sum of the contributions of the different galactic components, i.e., bulge and disk, and eventually lenses, bars, spiral arms, and rings (Prieto et al 2001;Aguerri et al 2005). A number of two-dimensional parametric decomposition techniques have been developed to achieve this aim (e.g., Simard 1998;Khosroshahi et al 2000;Peng et al 2002;de Souza et al 2004;Laurikainen et al 2005;Pignatelli et al 2006;Méndez-Abreu et al 2008). On the other hand, the presence of the galactic disk allows us to accurately constrain the inclination of the bulge based on the assumption that the two components share the same polar axis (i.e., the equatorial plane of the disk coincides with that of the bulge).…”

Section: Intrinsic Shape Of Disk Galaxiesmentioning

confidence: 99%

Structural properties of disk galaxies

Méndez-Abreu

Simonneau

Aguerri

et al. 2010

A&A

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Context. Knowledge of the intrinsic shapes of galaxy components provides crucial information when constraining phenomena driving their formation and evolution. Aims. We analize the structural parameters of a magnitude-limited sample of 148 unbarred S0-Sb galaxies to derive the intrinsic shape of their bulges. Methods. We developed a new method to derive the intrinsic shapes of bulges based on geometrical relationships between the apparent and intrinsic shapes of bulges and disks. Bulges were assumed to be triaxial ellipsoids sharing the same center and polar axis of their surrounding disks. Disks were assumed to be circular, infinitesimally thin, and to lie on the equatorial plane of bulges. The equatorial ellipticity and intrinsic flattening of bulges were obtained from the length of the apparent major and minor semi-axes of the bulge, the twist angle between the apparent major axis of the bulge and the galaxy line of nodes, and the galaxy inclination. Results. We find that the intrinsic shape is well constrained for a subsample of 115 bulges with favorable viewing angles. A large fraction of them are characterized by an elliptical section (B/A < 0.9). This fraction is 33%, 55%, and 43% if using their maximum, mean, or median equatorial ellipticity, respectively. Most are flattened along their polar axis (C < (A + B)/2). Only 18% of the observed bulges have a probability >50% and none has a probability >90% of being elongated along the polar axis. The distribution of triaxiality is strongly bimodal. This bimodality is driven by bulges with Sérsic index n > 2, or equivalently, by the bulges of galaxies with a bulge-to-total ratio B/T > 0.3. Bulges with n ≤ 2 and with B/T ≤ 0.3 follow a similar distribution, which differs from that of bulges with n > 2 and B/T > 0.3. In particular, bulges with n ≤ 2 and B/T ≤ 0.3 exhibit a larger fraction of oblate axisymmetric (or nearly axisymmetric) bulges, a smaller fraction of triaxial bulges, and fewer prolate axisymmetric (or nearly axisymmetric) bulges with respect to bulges with n > 2 and with B/T > 0.3, respectively. No correlation is found between the intrinsic shape and either the luminosity or velocity dispersion of bulges. Conclusions. According to predictions of the numerical simulations of bulge formation, bulges with n ≤ 2, which show a high fraction of oblate axisymmetric (or nearly axisymmetric) shapes and have B/T ≤ 0.3, may be the result of dissipational minor mergers. Both major dissipational and dissipationless mergers seem to be required to explain the variety of shapes found for bulges with n > 2 and B/T > 0.3.

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Multicomponent decompositions for a sample of S0 galaxies

Cited by 233 publications

References 57 publications

Depleted cores, multicomponent fits, and structural parameter relations for luminous early-type galaxies

Depleted cores, multicomponent fits, and structural parameter relations for luminous early-type galaxies

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

Structural properties of disk galaxies

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