The ATLAS3D project – XX. Mass–size and mass–σ distributions of early-type galaxies: bulge fraction drives kinematics, mass-to-light ratio, molecular gas fraction and stellar initial mass function

By M. Cappellari, R. McDermid, K. Alatalo, L. Blitz, M. Bois, Frédéric Bournaud, M. Bureau, A. Crocker, Roger Davies, T. Davis and 14 more. 2012

343 citations recorded by the source corpus.

In the companion Paper XV of this series, we derive accurate total mass-to-light ratios (M/L)(JAM) approximate to (M/L)(r = R-e) within a sphere of radius r = R-e centred on the galaxy, as well as stellar (M/L)(stars) (with the dark matter removed) for the volume-limited and nearly mass-selected (stellar mass M-star greater than or similar to 6 x 10(9) M-circle dot) ATLAS(3D) sample of 260 early-type galaxies (ETGs, ellipticals Es and lenticulars S0s). Here, we use those parameters to study the two orthogonal projections (M-JAM, sigma(e)) and (M-JAM, R-e(maj)) of the thin Mass Plane (MP) (M-JAM, sigma(e), R-e(maj)) which describes the distribution of the galaxy population, where M-JAM = L x (M/L)(JAM) approximate to M-star. The distribution of galaxy properties on both projections of the MP is characterized by: (i) the same zone of exclusion (ZOE), which can be transformed from one projection to the other using the scalar virial equation. The ZOE is roughly described by two power laws, joined by a break at a characteristic mass M-JAM approximate to 3 x 10(10) M-circle dot, which corresponds to the minimum R-e and maximum stellar density. This results in a break in the mean M-JAM-sigma(e) relation with trends M-JAM proportional to sigma(2.3)(e) and M-JAM proportional to sigma(4.7)(e) at small and large sigma(e), respectively; (ii) a characteristic mass M-JAM approximate to 2 x 10(11) M-circle dot which separates a population dominated by flat fast rotator with discs and spiral galaxies at lower masses, from one dominated by quite round slow rotators at larger masses; (iii) below that mass the distribution of ETGs' properties on the two projections of the MP tends to be constant along lines of roughly constant sigma(e), or equivalently along lines with R-e(maj) proportional to M-JAM, respectively (or even better parallel to the ZOE: R-maj(e) proportional to M-JAM(0.75)); (iv) it forms a continuous and parallel sequence with the distribution of spiral galaxies; (v) at even lower masses, the distribution of fast-rotator ETGs and late spirals naturally extends to that of dwarf ETGs (Sph) and dwarf irregulars (Im), respectively. We use dynamical models to analyse our kinematic maps. We show that Sigma(e) traces the bulge fraction, which appears to be the main driver for the observed trends in the dynamical (M/L)(JAM) and in indicators of the (M/L)(pop) of the stellar population like H beta and colour, as well as in the molecular gas fraction. A similar variation along contours of Sigma(e) is also observed for the mass normalization of the stellar initial mass function (IMF), which was recently shown to vary systematically within the ETGs' population. Our preferred relation has the form log(10)[(M/L)(stars)/(M/L)(Salp)] = a + b x log(10)(sigma(e)/130 km s(-1)) with a = -0.12 +/- 0.01 and b = 0.35 +/- 0.06. Unless there are major flaws in all stellar population models, this trend implies a transition of the mean IMF from Kroupa to Salpeter in the interval log(10)(sigma(e)/km s(-1)) approximate to 1.9-2.5 (or sigma e approximate to 90-290 km s-1), with a smooth variation in between, consistently with what was shown in Cappellari et al. The observed d205 (or sigma e istribution of galaxy properties on the MP provides a clean and novel view for a number of previously reported trends, which constitute special two-dimensional projections of the more general four-dimensional parameters trends on the MP. We interpret it as due to a combination of two main effects: (i) an increase of the bulge fraction, which increases Sigma(e), decreases R-e, and greatly enhance the likelihood for a galaxy to have its star formation quenched, and (ii) dry merging, increasing galaxy mass and R-e by moving galaxies along lines of roughly constant Sigma(e) (or steeper), while leaving the population nearly unchanged.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/90652747ea14190b37f860aaf4f8848d325c862a

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In Astronomy and Astrophysics

1. M. Cappellari
2. P. Hopkins
3. L. Hernquist
4. T. Naab
5. C. Conroy
6. Volker Springel
7. M. Sarzi
8. Thomas J. Cox

In Instrumentation

1. M. Cappellari
2. P. Hopkins
3. T. Naab
4. L. Hernquist
5. M. Sarzi
6. C. Conroy
7. Eric Emsellem
8. Roger Davies

Citations in the corpus

• Dusty Star Forming Galaxies at High Redshift (2014, result): “…the stellarmass to light ratio from kinematics have suggested a similar result (e.g. Auger et al., 2010; Treu et al., 2010; Spiniello et al., 2011; Cappellari et al., 2012, 2013; Brewer et al., 2012; Dutton et al., 2013; Tortora et al., 2013), though we note that increased mass to light ratios…”
• The AIMSS Project I: bridging the star cluster, galaxy divide (2014, methodology): “The quoted central (Re/8) velocity dispersions are from Cappellari et al. (2013a).”
• The ATLAS3D Project – XXX. Star formation histories and stellar population scaling relations of early-type galaxies (2015, methodology): “The mass MJAM is derived applying equation 3 of Cappellari et al. (2013b), using the (M/L)JAM and r-band luminosity given in table 1 of Cappellari et al. (2013a), columns 6 and 15, respectively.”
• simba: Cosmological simulations with black hole growth and feedback (2019, background): “There is also the issue of the stellar initial mass function (IMF) – stellar population (Conroy et al. 2013) and dynamical (Cappellari et al. 2013) studies suggest that the most massive galaxies have bottom-heavy IMFs relative to Milky Way-like galaxies, which can result in the stellar mass being…”
• The CALIFA survey across the Hubble sequence: Spatially resolved stellar population properties in galaxies (2015, background): “In this scheme, S0’s are a transition between spirals and ellipticals (Cappellari et al. 2013), and the bulge/disk ratio increases from late to early type spirals.”
• The ATLAS3D Project – XXVIII. Dynamically driven star formation suppression in early-type galaxies (2014, methodology): “This average fraction appearsto decrease with increasing galaxy bulge fraction (Cappellari et al. 2013a, hereafter Paper XX; see also Saintonge et al. 2012).”
• Selection bias in dynamically measured supermassive black hole samples: its consequences and the quest for the most fundamental relation (2016, result): “Cappellari et al. (2013) claim a slight massdependent aperture correction, as expected in pressure-supported systems (Graham & Colless 1997), though still, on average, in good agreement with Equation 1.”
• AGN-driven quenching of star formation: morphological and dynamical implications for early-type galaxies (2013, methodology): “…(Grillo et al. 2008; Auger et al. 2010; Grillo & Gobat 2010; Treu et al. 2010; Spiniello et al. 2011; Thomas et al. 2011; Sonnenfeld et al. 2012; Cappellari et al. 2013) or spectroscopy (Conroy & van Dokkum 2012; Spiniello et al. 2012), the IMF is considered to be more bottom-heavy for the most…”
• The ATLAS3D project - XXIX. The new look of early-type galaxies and surrounding fields disclosed by extremely deep optical images (2014, background): “7 tabulated in Table 1, column 10 of Cappellari et al. (2013).”
• Improving the full spectrum fitting method: accurate convolution with Gauss-Hermite functions (2016, methodology): “Dynamical models based on IFS kinematics allow one to infer galaxy mass distributions to study scaling relations (e.g. Cappellari et al. 2013a; Scott et al. 2015), the stellar and dark matter content (e.g. Cappellari et al. 2012, 2015), or measure black hole masses (e.g. Krajnović et al. 2009;…”
• The distribution of dark matter in galaxies (2018, methodology): “This has clearly emerged in Cappellari et al. (2013): they started with the FP which reads as log ( L L ,r ) = a+ b log ( σe 130 kms ) + c log ( Re 2 kpc ) , (44) σe and Re are normalized to the median values found in sample under study.”
• Stellar Mass—Halo Mass Relation and Star Formation Efficiency in High-Mass Halos (2014, methodology): “5 of Cappellari et al. (2013) and associated parameters to convert velocity dispersion to stellar mass and obtain the corresponding variation of the mass-to-light ratio as a function of stellar mass for early type galaxies.”