Dissipation and the Fundamental Plane: Observational Tests

Hopkins, Philip F.; Cox, Thomas J.; Hernquist, Lars

doi:10.1086/592105

Cited by 95 publications

(144 citation statements)

References 188 publications

(382 reference statements)

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“…In contrast, the size-mass and FJ relations of EASK3 galaxies have shallower slopes. This agrees with the gas-rich major merger scenario modeled by Robertson et al (2006) and Hopkins et al (2008). We conclude that the rejuvenation of the central regions of the EASK3 galaxies does not seem to be caused by gas-rich major mergers.…”

Section: Eask3: Wet Minor Mergers?supporting

confidence: 88%

“…Di Matteo et al 2005). This new generation of central stars can influence the structural parameters of the galaxies and produce changes in their scaling relations (see Robertson et al 2006;Hopkins et al 2008). Therefore, we expect that elliptical galaxies built up after wet mergers, or those with a wet last merger, will have younger stellar populations at their centers than those formed by dry mergers.…”

Section: Eask3: Wet Minor Mergers?mentioning

confidence: 99%

“…These numerical simulations have also shown that the differences observed in the properties of early-type galaxies can be explained through the different physical processes taking place in such kind of mergers. This involves gas dissipation, star formation, and super-massive black hole feedback (Barnes 1992;Barnes & Hernquist 1996;Mihos & Hernquist 1996;Di Matteo et al 2005;Robertson et al 2006;Naab et al 2006aNaab et al ,b, 2007Hopkins et al 2008). In particular, the gas fraction in the galaxy progenitors could play a crucial role in shaping the final merger remnants and fix their scaling relations (see, e.g., Robertson et al 2006;Hopkins et al 2008).…”

Section: Introductionmentioning

confidence: 99%

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Dissecting the morphological and spectroscopic properties of galaxies in the local Universe

Aguerri

Huertas-Company

Alméida

et al. 2012

A&A

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Aims. We revisit the scaling relations and star-forming histories of local elliptical galaxies using a novel selection method applied to the Sloan Digital Sky Survey DR7. Methods. We combine two probability-based automated spectroscopic and morphological classifications of ∼600 000 galaxies with z < 0.25 to isolate true elliptical galaxies. Our sample selection method does not introduce artificial cuts into the parameters describing the galaxy but instead associates every object with a weight measuring the probability of being in a given spectro-morphological class. Thus, the sample minimizes the selection biases. Results. We show that morphologically defined ellipticals are basically distributed into three spectral classes, which dominate at different stellar masses. The bulk of the population (∼50%) is formed by a well-defined class of galaxies with old stellar populations that formed their stars at very early epochs in a short episode of star formation. They dominate the scaling relations of elliptical galaxies known from previous works and represent the canonical elliptical class. At the low mass end, we find a population of ellipticals with relatively large shapes and smaller velocity dispersions at fixed stellar mass, which seem to have experienced a more recent episode of star formation probably triggered by gas-rich minor mergers. The high mass end tends to be dominated by a third spectral class that is slightly more metal rich and hosts more efficient stellar formation than the reference class. This third class contributes to the curvature in the mass-size relation at high masses reported in previous works. Our method is therefore able to isolate the typical spectra of elliptical galaxies following different evolutionary pathways.

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Section: Eask3: Wet Minor Mergers?supporting

confidence: 88%

Section: Eask3: Wet Minor Mergers?mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Dissecting the morphological and spectroscopic properties of galaxies in the local Universe

Aguerri

Huertas-Company

Alméida

et al. 2012

A&A

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“…and R e in kpc) according to Hopkins et al (2008), as done in Fraix-Burnet et al (2010). This makes M dyn 5.95 * σ 2 R e .…”

Section: Group Propertiesmentioning

confidence: 99%

A six-parameter space to describe galaxy diversification

Fraix-Burnet

Chattopadhyay

et al. 2012

A&A

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Context. The diversification of galaxies is caused by transforming events such as accretion, interaction, or mergers. These explain the formation and evolution of galaxies, which can now be described by many observables. Multivariate analyses are the obvious tools to tackle the available datasets and understand the differences between different kinds of objects. However, depending on the method used, redundancies, incompatibilities, or subjective choices of the parameters can diminish the usefulness of these analyses. The behaviour of the available parameters should be analysed before any objective reduction in the dimensionality and any subsequent clustering analyses can be undertaken, especially in an evolutionary context. Aims. We study a sample of 424 early-type galaxies described by 25 parameters, 10 of which are Lick indices, to identify the most discriminant parameters and construct an evolutionary classification of these objects. Methods. Four independent statistical methods are used to investigate the discriminant properties of the observables and the partitioning of the 424 galaxies: principal component analysis, K-means cluster analysis, minimum contradiction analysis, and Cladistics. Results. The methods agree in terms of six parameters: central velocity dispersion, disc-to-bulge ratio, effective surface brightness, metallicity, and the line indices NaD and OIII. The partitioning found using these six parameters, when projected onto the fundamental plane, looks very similar to the partitioning obtained previously for a totally different sample and based only on the parameters of the fundamental plane. Two additional groups are identified here, and we are able to provide some more constraints on the assembly history of galaxies within each group thanks to the larger number of parameters. We also identify another "fundamental plane" with the absolute K magnitude, the linear diameter, and the Lick index Hβ. We confirm that the Mg b vs. velocity dispersion correlation is very probably an evolutionary correlation, in addition to several other scaling relations. Finally, combining the results of our two papers, we obtain a classification of galaxies that is based on the transforming processes that are at the origin of the different groups. Conclusions. By taking into account that galaxies are evolving complex objects and using appropriate tools, we are able to derive an explanatory classification of galaxies, based on the physical causes of the diverse properties of galaxies, as opposed to the descriptive classifications that are quite common in astrophysics.

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“…Guyon et al 2006;Dasyra et al 2007;Silverman et al 2008;Bennert et al 2008;Liu et al 2009;Veilleux et al 2009;Letawe et al 2010;Koss et al 2010Koss et al , 2012, and references therein). Such encounters also convert disks into spheroids and further grow the bulge via centrally concentrated gas inflows in a merger-induced starburst (Mihos & Hernquist 1994;Hibbard & Yun 1999;Robertson et al 2006b; Naab * E-mail:phopkins@caltech.edu Cox et al 2006;Hopkins et al 2008aHopkins et al ,b, 2009a. As argued in Hopkins et al (2007a); ; Snyder et al (2011b), this deepens the central potential, so a merger both directly strips gas of angular momentum (providing a BH fuel source) and also increases the binding energy of that material (and bulge mass/velocity dispersion), meaning the BH will grow larger even if strong feedback "resists" inflows, before "catching up" to the BH-host relations and self-regulating.…”

Section: Introductionmentioning

confidence: 99%

Do we expect most AGN to live in discs?

Hopkins¹,

Kocevski²,

Bundy³

2014

Monthly Notices of the Royal Astronomical Society

Self Cite

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Recent observations have indicated that a large fraction of the low to intermediate luminosity AGN population lives in disk-dominated hosts, while the more luminous quasars live in bulge-dominated hosts (that may or may not be major merger remnants), in conflict with some previous model predictions. We therefore build and compare a semi-empirical model for AGN fueling which accounts for both merger and non-merger "triggering." In particular, we show that the "stochastic accretion" model -in which fueling in disk galaxies is essentially a random process arising whenever dense gas clouds reach the nucleusprovides a good match to the present observations at low/intermediate luminosities. However it falls short of the high-luminosity population. We combine this with models for major merger-induced AGN fueling, which lead to rarer but more luminous events, and predict the resulting abundance of disk-dominated and bulge-dominated AGN host galaxies as a function of luminosity and redshift. We compile and compare observational constraints from z ∼ 0 − 2. The models and observations generically show a transition from disk to bulge dominance in hosts near the Seyfert-quasar transition, at all redshifts. "Stochastic" fueling dominates AGN by number (dominant at low luminosity), and dominates BH growth below the "knee" in the present-day BH mass function ( 10 7 M ). However it accounts for just ∼ 10% of BH mass growth at masses 10 8 M . In total, fueling in disky hosts accounts for ∼ 30% of the total AGN luminosity density/BH mass density. The combined model also accurately predicts the AGN luminosity function and clustering/bias as a function of luminosity and redshift; however, we argue that these are not sensitive probes of BH fueling mechanisms.

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Dissipation and the Fundamental Plane: Observational Tests

Cited by 95 publications

References 188 publications

Dissecting the morphological and spectroscopic properties of galaxies in the local Universe

Dissecting the morphological and spectroscopic properties of galaxies in the local Universe

A six-parameter space to describe galaxy diversification

Do we expect most AGN to live in discs?

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