Victor P. DebattistaSecular Evolution in Disc Galaxies

into bulge+disc to test for secular evolution of classical bulges and how this affects the MBH-e relation in the vertical direction to understand the thin/thick disc dichotomy in the Milky Way Deconstructing Galaxies

Classical vs Pseudo BulgesCLASSICAL BULGES: Mergers produce elliptical galaxies. In the early universe, disks formed around dwarf ellipticals.Predict: old stars, low rotation, short SF timescales, ellipsoidal morphology, de Vaucouleurs type profiles (Sersic index ~ 4)PSEUDO BULGES: Gas funnelled to the centre by disk processes, forming new stars and central mass concentrationPredict: younger stars, high rotation, long SF timescales, disky or boxy morphology, exponential type profile (Sersic index ~ 1)

Drory & Fisher 2007; Fisher & Drory 2008, 2010

Schawinski+ 2012Schawinski+ 2011The Evolving View of AGN HostsA sample of 140 X-ray selected AGN showed distortions (mergers) were no more likely to be ongoing than in a control sampleCisternas+ 2011

Semi-analytic models suggest that AGN in discs dominate the AGN luminosity for low massHopkins+ 13

The growth of a disk compresses a pre-existing (classical) bulge raising its velocity dispersion No disc5x Mb10x Mb15x Mb20x MbZero mass disc (for scale)20x Mb

Fitting function following Wolf et al. 2010: The parameters (,) account for the finite-thickness and assumption of fixed effective radius

Data: Gadotti & Kauffmann 2009Ellipticals Bulges Reff 8 Ellipticals Bulges 8 Mass

Data: Gadotti & Kauffmann 2009Bulges Bulges uncompressed Ellipticals

Exponential Disks?Boeker+ 2003Dutton 2009

D/B and Rd/Re correlate weakly with e. Neglecting this correlation, the M-e relation of SMBHs which start out on the relation but fail to grow with this disc is given by:

log M = log + log e 8 Rd/Reff D/B

Gltekin+ 2009Doubling requires that M grow by a factor of 16 Gadotti 09

Ellipticals No offset between bulges now and ellipticalsBulges Expected offset if SMBHs do not grow while discs reform is = -0.2 dex Gltekin+ 2009 sample = 0.08

Ellipticals Bulges Predicted initial dispersions Expected offset if SMBHs do not grow while discs reform is = -0.26 dex Beifiori+ 2009 sampleAlso no offset between bulges now and ellipticals = 0.11

Barred GalaxiesBut Beifiori et al. 2012 find no offset between barred and unbarred galaxies Graham 08Graham+ 11

Bar driven angular momentum redistribution increases the disc mass at the centre, raising e and causing an offset for the SMBHHartmann+ 14All B+D simulations are models of the MW from Widrow+ 08

Classical bulges = -0.19 0.20 Hartmann+ 14Pseudo bulges = -0.73 0.09

Sample of McConnell & Ma 1310 other galaxies with no reliable bulge classification

Sellwood & Binney 2002But negligible heating associated with the migrationFullNear circularLLRadiusRJR = (p - ) L/E = p L

RformRokar+ 08Schoenrich & Binney 09abGilmore & Reid 1983

Rokar+13Predictions from Schnrich & Binney 12

Plotted for stars 5-6 Gyr oldSolway+ 2012Thick diskThin diskAccretion: Abadi+03; thickening: Quinn+93; gas rich mergers: Brook+05; direct gas formation: Stinson+13; Bird+13; clump heating: Bournaud+07; resonant capture: Sridhar+96

Migration can give rise to a thick disc with density, kinematic, metallicity and abundance patterns not inconsistent with the observed Loebman+ 11 Rokar+ 13Ruchti+ 11

Decreasing metallicity and vrot with heightSDSS at Thin-Thick Transitionz [pc]|z| [kpc]VY [km/s]VY [km/s]Photometric [Fe/H][Fe/H]Data from SDSS Ivezic+ 08; Bond+ 10

Vy [km/s]Vy [km/s][Fe/H][Fe/H]Age [Gyr]z [kpc]Age, velocity and metallicity all correlate with height above the mid-plane.

But there is little correlation between velocity and metallicity, as found by SDSS

Stars are born on circular orbits and hence have no correlation between V and [Fe/H]. Heating brings stars into the local volume creating a correlation. Migration shuffles [Fe/H] and erases the correlationSolar nbhdLoebman+ 11[Fe/H]R [kpc]

allyoungoldGeneva-Copenhagen Survey in mid-plane after selecting non-binary stars

(Qualitatively similar results with Casagrande+ 11 ages)V/[Fe/H] = -0.5 1.5V/[Fe/H] = -1.9 1.6V/[Fe/H] = 22.1 0.8Loebman+ 11

Bovy+ 2012abcLiu & van de Ven 2012Sales+ 2009Dierickx+ 10, Wilson+ 11

Discs growing around pre-existing bulges compress them and raise their velocity dispersion. This implies SMBHs in classical bulges must grow on average by 50-80% to remain on the MBH-e relation. A comparison between the MBH-e relations of elliptical galaxies and classical bulges finds no offset. Bar evolution also compresses the bulge, and there is evidence that barred galaxies are offset from the MBH-e relation. The thick disc in the MW may have been substantially contaminated by migrated thin disc stars. A thin/thick disc dichotomy can easily arise as a result of migration. Some evidence for an unmigrated population can be recovered from the distribution of orbital eccentricities. Conclusions