Publications by Michele Cappellari


SALPETER NORMALIZATION OF THE STELLAR INITIAL MASS FUNCTION FOR MASSIVE GALAXIES AT z similar to 1

ASTROPHYSICAL JOURNAL LETTERS 786 (2014) ARTN L10

S Shetty, M Cappellari


Identification of old tidal dwarfs near early-type galaxies from deep imaging and H i observations

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 440 (2014) 1458-1469

P-A Duc, S Paudel, RM McDermid, J-C Cuillandre, P Serra, F Bournaud, M Cappellari, E Emsellem


Kinematics of superdense galaxies in clusters

GALAXIES IN 3D ACROSS THE UNIVERSE 10 (2014) 219-220

A Moretti, B Poggianti, D Bettoni, M Cappellari, G Fasano, WINGS Team


NGC 1266 as a local candidate for rapid cessation of star formation

Astrophysical Journal 780 (2014)

K Alatalo, K Nyland, G Graves, S Deustua, KS Griffin, PA Duc, M Cappellari, RM McDermid, TA Davis, AF Crocker, LM Young, P Chang, N Scott, SL Cales, E Bayet, L Blitz, M Bois, F Bournaud, M Bureau, RL Davies, PT De Zeeuw, E Emsellem, S Khochfar, D Krajnović, H Kuntschner, R Morganti, T Naab, T Oosterloo, M Sarzi, P Serra, AM Weijmans

We present new Spectrographic Areal Unit for Research on Optical Nebulae (SAURON) integral-field spectroscopy and Swift Ultraviolet Optical Telescope (UVOT) observations of molecular outflow host galaxy NGC 1266 that indicate NGC 1266 has experienced a rapid cessation of star formation. Both the SAURON maps of stellar population age and the Swift UVOT observations demonstrate the presence of young (<1 Gyr) stellar populations within the central 1 kpc, while existing Combined Array for Research in Millimeter-Wave Astronomy CO(1-0) maps indicate that the sites of current star formation are constrained to only the inner few hundred parsecs of the galaxy. The optical spectrum of NGC 1266 from Moustakas & Kennicutt reveal a characteristic poststarburst (K+A) stellar population, and Davis et al. confirm that ionized gas emission in the system originate from a shock. Galaxies with K+A spectra and shock-like ionized gas line ratios may comprise an important, overlooked segment of the poststarburst population, containing exactly those objects in which the active galactic nucleus (AGN) is actively expelling the star-forming material. While AGN activity is not the likely driver of the poststarburst event that occurred 500 Myr ago, the faint spiral structure seen in the Hubble Space Telescope Wide-field Camera 3 Y-, J- and H-band imaging seems to point to the possibility of gravitational torques being the culprit. If the molecular gas were driven into the center at the same time as the larger scale galaxy disk underwent quenching, the AGN might be able to sustain the presence of molecular gas for ≳ 1 Gyr by cyclically injecting turbulent energy into the dense molecular gas via a radio jet, inhibiting star formation. © 2014. The American Astronomical Society. All rights reserved.


Galaxy masses

REVIEWS OF MODERN PHYSICS 86 (2014) 47-119

S Courteau, M Cappellari, RS de Jong, AA Dutton, E Emsellem, H Hoekstra, LVE Koopmans, GA Mamon, C Maraston, T Treu, LM Widrow


Distribution of slow and fast rotators in the Fornax cluster

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 441 (2014) 274-288

N Scott, RL Davies, RCW Houghton, M Cappellari, AW Graham, KA Pimbblet


CONNECTION BETWEEN DYNAMICALLY DERIVED INITIAL MASS FUNCTION NORMALIZATION AND STELLAR POPULATION PARAMETERS

ASTROPHYSICAL JOURNAL LETTERS 792 (2014) ARTN L37

RM McDermid, M Cappellari, K Alatalo, E Bayet, L Blitz, M Bois, F Bournaud, M Bureau, AF Crocker, RL Davies, TA Davis, PT de Zeeuw, P-A Duc, E Emsellem, S Khochfar, D Krajnovic, H Kuntschner, R Morganti, T Naab, T Oosterloo, M Sarzi, N Scott, P Serra, A-M Weijmans, LM Young


KMOS Clusters and VIRIAL GTO Surveys

GALAXIES IN 3D ACROSS THE UNIVERSE 10 (2014) 293-294

D Wilman, R Bender, RL Davies, JT Mendel, J Chan, A Beifiori, R Houghton, R Saglia, NF Schreiber, S Wuyts, P van Dokkum, M Cappellari, J Stott, R Smith, M Fossati, S Kulkarni, S Seitz, M Fabricius, R Sharples, G Brammer, E Nelson, I Momcheva, M Wegner, I Lewis


The ATLAS(3D) Project - XXVIII. Dynamically driven star formation suppression in early-type galaxies

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 444 (2014) 3427-3445

TA Davis, LM Young, AF Crocker, M Bureau, L Blitz, K Alatalo, E Emsellem, T Naab, E Bayet, M Bois, F Bournaud, M Cappellari, RL Davies, PT de Zeeuw, P-A Duc, S Khochfar, D Krajnovic, H Kuntschner, RM McDermid, R Morganti, T Oosterloo, M Sarzi, N Scott, P Serra, A-M Weijmans


The ATLAS(3D) project - XXIV. The intrinsic shape distribution of early-type galaxies

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 444 (2014) 3340-3356

A-M Weijmans, PT de Zeeuw, E Emsellem, D Krajnovic, P-Y Lablanche, K Alatalo, L Blitz, M Bois, F Bournaud, M Bureau, M Cappellari, AF Crocker, RL Davies, TA Davis, P-A Duc, S Khochfar, H Kuntschner, RM McDermid, R Morganti, T Naab, T Oosterloo, M Sarzi, N Scott, P Serra, GV Kleijn, LM Young


The ATLAS(3D) project - XXVII. Cold gas and the colours and ages of early-type galaxies

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 444 (2014) 3408-3426

LM Young, N Scott, P Serra, K Alatalo, E Bayet, L Blitz, M Bois, F Bournaud, M Bureau, AF Crocker, M Cappellari, RL Davies, TA Davis, PT de Zeeuw, P-A Duc, E Emsellem, S Khochfar, D Krajnovic, H Kuntschner, RM McDermid, R Morganti, T Naab, T Oosterloo, M Sarzi, A-M Weijmans


The ATLAS(3D) project - XXV. Two-dimensional kinematic analysis of simulated galaxies and the cosmological origin of fast and slow rotators

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 444 (2014) 3357-3387

T Naab, L Oser, E Emsellem, M Cappellari, D Krajnovic, RM McDermid, K Alatalo, E Bayet, L Blitz, M Bois, F Bournaud, M Bureau, A Crocker, RL Davies, TA Davis, PT de Zeeuw, P-A Duc, M Hirschmann, PH Johansson, S Khochfar, H Kuntschner, R Morganti, T Oosterloo, M Sarzi, N Scott, P Serra, G van de Ven, A Weijmans, LM Young


The ATLAS(3D) project - XXVI. H I discs in real and simulated fast and slow rotators

MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY 444 (2014) 3388-3407

P Serra, L Oser, D Krajnovic, T Naab, T Oosterloo, R Morganti, M Cappellari, E Emsellem, LM Young, L Blitz, TA Davis, P-A Duc, M Hirschmann, A-M Weijmans, K Alatalo, E Bayet, M Bois, F Bournaud, M Bureau, AF Crocker, RL Davies, PT de Zeeuw, S Khochfar, H Kuntschner, P-Y Lablanche, RM McDermid, M Sarzi, N Scott


Chronos: a NIR spectroscopic galaxy survey. From the formation of Galaxies to the peak of activity

Cosmic Vision ESA (2013)

I Ferreras, R Sharples, JS Dunlop, A Pasquali, FL Barbera, A Vazdekis, S Khochfar, M Cropper, A Cimatti, M Cirasuolo, R Bower, J Brinchmann, B Burningham, M Cappellari, S Charlot, CJ Conselice, E Daddi, EK Grebel, R Ivison, MJ Jarvis, D Kawata, RC Kennicutt, T Kitching, O Lahav, R Maiolino

<p style="text-align:justify;"> Chronos is our response to ESA's call for white papers to define the science for the future L2, L3 missions. Chronos targets the formation and evolution of galaxies, by collecting the deepest NIR spectroscopic data, from the formation of the first galaxies at z~10 to the peak of formation activity at z~1-3. The strong emission from the atmospheric background makes this type of survey impossible from a ground-based observatory. The spectra of galaxies represent the equivalent of a DNA fingerprint, containing information about the past history of star formation and chemical enrichment. The proposed survey will allow us to dissect the formation process of galaxies including the timescales of quenching triggered by star formation or AGN activity, the effect of environment, the role of infall/outflow processes, or the connection between the galaxies and their underlying dark matter haloes. To provide these data, the mission requires a 2.5m space telescope optimised for a campaign of very deep NIR spectroscopy. A combination of a high multiplex and very long integration times will result in the deepest, largest, high-quality spectroscopic dataset of galaxies from z=1 to 12, spanning the history of the Universe, from 400 million to 6 billion years after the big bang, i.e. covering the most active half of cosmic history. </p>


The ATLAS<sup>3D</sup> Project - XXIII. Angular momentum and nuclear surface brightness profiles

Monthly Notices of the Royal Astronomical Society 433 (2013) 2812-2839

D Krajnović, AM Karick, RL Davies, T Naab, M Sarzi, E Emsellem, M Cappellari, P Serra, PT de Zeeuw, N Scott, RM McDermid, AM Weijmans, TA Davis, K Alatalo, L Blitz, M Bois, M Bureau, F Bournaud, A Crocker, PA Duc, S Khochfar, H Kuntschner, R Morganti, T Oosterloo, LM Young

We investigate nuclear light profiles in 135 ATLAS3D galaxies for which the Hubble Space Telescope (HST) imaging is available and compare them to the large-scale kinematics obtained with the SAURONintegral-field spectrograph. Specific angular momentum, λR, correlateswith the shape of nuclear light profiles, where, as suggested by previous studies, cores are typically found in slow rotators and core-less galaxies are fast rotators. As also shown before, cores are found only in massive galaxies and only in systems with the stellar mass (measured via dynamical models) M ≳ 8 × 1010 M· Based on our sample, we, however, see no evidence for a bimodal distribution of nuclear slopes. The best predictor for finding a core is based on the stellar velocity dispersion within an effective radius, se, and specific angular momentum, where cores are found for λR ≲ 0.25 and σe ≳ 160 kms-1. We estimate that only about 10 per cent of nearby early-type galaxies contain cores. Furthermore, we show that there is a genuine population of fast rotators with cores. We also show that core fast rotators are morphologically, kinematically and dynamically different from core slow rotators. The cores of fast rotators, however, could harbour black holes of similar masses to those in core slow rotators, but typically more massive than those found in core-less fast rotators. Cores of both fast and slow rotators are made of old stars and found in galaxies typically lacking molecular or atomic gas (with a few exceptions). Core-less galaxies, and especially core-less fast rotators, are underluminous in the diffuse X-ray emission, but the presence of a core does not imply high X-ray luminosities. Additionally, we postulate (as many of these galaxies lack HST imaging) a possible population of core-less galaxies among slow rotators, which cannot be explained as face-on discs, but comprise a genuine sub-population of slow rotators. These galaxies are typically less massive and flatter than core slow rotators, and show evidence for dynamical cold structures and exponential photometric components. Based on our findings, major nondissipative (gas-poor) mergers together with black hole binary evolution may not be the only path for formation of cores in early-type galaxies. We discuss possible processes for formation of cores and their subsequent preservation. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.


The ATLAS<sup>3D</sup> project - XVI. Physical parameters and spectral line energy distributions of the molecular gas in gas-rich early-type galaxies

Monthly Notices of the Royal Astronomical Society 432 (2013) 1742-1767

E Bayet, M Bureau, TA Davis, LM Young, AF Crocker, K Alatalo, L Blitz, M Bois, F Bournaud, M Cappellari, RL Davies, PT de Zeeuw, PA Duc, E Emsellem, S Khochfar, D Krajnović, H Kuntschner, RM McDermid, R Morganti, T Naab, T Oosterloo, M Sarzi, N Scott, P Serra, AM Weijmans

We present a detailed study of the physical properties of the molecular gas in a sample of 18 molecular gas-rich early-type galaxies (ETGs) from the ATLAS3D sample. Our goal is to better understand the star formation processes occurring in those galaxies, starting here with the dense star-forming gas. We use existing integrated 12CO (1-0, 2-1), 13CO (1-0, 2-1), HCN (1-0) and HCO+ (1-0) observations and new 12 CO (3-2) single-dish data. From these, we derive for the first time the average kinetic temperature, H2 volume density and column density of the emitting gas in a significant sample of ETGs, using a non-local thermodynamical equilibrium theoretical model. Since the CO lines trace different physical conditions than of those the HCN and HCO+ lines, the two sets of lines are treated separately. For most of the molecular gas-rich ETGs studied here, the CO transitions can be reproduced with kinetic temperatures of 10-20 K, H2 volume densities of 103-4 cm-3 and CO column densities of 1018-20 cm-2. The physical conditions corresponding to the HCN and HCO+ gas component have large uncertainties and must be considered as indicative only. We also compare for the first time the predicted CO spectral line energy distributions and gas properties of our molecular gas-rich ETGs with those of a sample of nearby well-studied disc galaxies. The gas excitation conditions in 13 of our 18 ETGs appear analogous to those in the centre of theMilky Way, hence the star formation activity driving these conditions is likely of a similar strength and nature. Such results have never been obtained before for ETGs and open a new window to explore further star-formation processes in the Universe. The conclusions drawn should nevertheless be considered carefully, as they are based on a limited number of observations and on a simple model. In the near future, with higher CO transition observations, it should be possible to better identify the various gas components present in ETGs, as well as more precisely determine their associated physical conditions. To achieve these goals, we show here from our theoretical study, that mid-J CO lines [such as the 12CO (6-5) line] are particularly useful. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.


Effect of environment on galaxies mass-size distribution: unveiling the transition from outside-in to inside-out evolution

The Astrophysical Journal Letters (2013)

M Cappellari


The ATLAS<sup>3D</sup> project - XXII. Low-efficiency star formation in early-type galaxies: Hydrodynamic models and observations

Monthly Notices of the Royal Astronomical Society 432 (2013) 1914-1927

M Martig, AF Crocker, F Bournaud, E Emsellem, JM Gabor, K Alatalo, L Blitz, M Bois, M Bureau, M Cappellari, RL Davies, TA Davis, A Dekel, PT de Zeeuw, PA Duc, J Falcón-Barroso, S Khochfar, D Krajnović, H Kuntschner, R Morganti, RM McDermid, T Naab, T Oosterloo, M Sarzi, N Scott, P Serra, KS Griffin, R Teyssier, AM Weijmans, LM Young

We study the global efficiency of star formation in high-resolution hydrodynamical simulations of gas discs embedded in isolated early-type and spiral galaxies. Despite using a universal local law to form stars in the simulations, we find that the early-type galaxies are offset from the spirals on the large-scale Kennicutt relation, and form stars two to five times less efficiently. This offset is in agreement with previous results on morphological quenching: gas discs are more stable against star formation when embedded in early-type galaxies due to the lower disc self-gravity and increased shear. As a result, these gas discs do not fragment into dense clumps and do not reach as high densities as in the spiral galaxies. Even if some molecular gas is present, the fraction of very dense gas (typically above 104 cm-3) is significantly reduced, which explains the overall lower star formation efficiency. We also analyse a sample of local early-type and spiral galaxies, measuring their CO and HI surface densities and their star formation rates as determined by their non-stellar 8 μm emission. As predicted by the simulations, we find that the early-type galaxies are offset from the Kennicutt relation compared to the spirals, with a twice lower efficiency. Finally, we validate our approach by performing a direct comparison between models and observations. We run a simulation designed to mimic the stellar and gaseous properties of NGC 524, a local lenticular galaxy, and find a gas disc structure and global star formation rate in good agreement with the observations. Morphological quenching thus seems to be a robust mechanism, and is also consistent with other observations of a reduced star formation efficiency in early-type galaxies in the COLD GASS survey. This lower efficiency of star formation is not enough to explain the formation of the whole red sequence, but can contribute to the reddening of some galaxies. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.


The ATLAS<sup>3D</sup> project - XVII. Linking photometric and kinematic signatures of stellar discs in early-type galaxies

Monthly Notices of the Royal Astronomical Society 432 (2013) 1768-1795

D Krajnović, K Alatalo, L Blitz, M Bois, F Bournaud, M Bureau, M Cappellari, RL Davies, TA Davis, PT de Zeeuw, PA Duc, E Emsellem, S Khochfar, H Kuntschner, RM McDermid, R Morganti, T Naab, T Oosterloo, M Sarzi, N Scott, P Serra, AM Weijmans, LM Young

We analyse the morphological structures in galaxies of the ATLAS3D sample by fitting a single Sérsic profile and decomposing all non-barred objects (180 of 260 objects) in two components parametrized by an exponential and a general Sérsic function. The aim of this analysis is to look for signatures of discs in light distributions of nearby early-type galaxies and compare them to kinematic properties. Using Sérsic index from single-component fits for a distinction between slow and fast rotators, or even late- and early-type galaxies, is not recommended. Assuming that objects with n > 3 are slow rotators (or ellipticals), there is only a 22 per cent probability to correctly classify objects as slow rotators (or 37 per cent of previously classified as ellipticals). We show that exponential sub-components, as well as light profiles fitted with only a single component of a low Sérsic index, can be linked with the kinematic evidence for discs in early-type galaxies. The median disc-to-total light ratio for fast and slow rotators is 0.41 and 0.0, respectively. Similarly, the median Sérsic indices of the bulge (general Sérsic component) are 1.7 and 4.8 for fast and slow rotators, respectively. Overall, discs or disc-like structures are present in 83 per cent of early-type galaxies which do not have bars, and they show a full range of disc-to-total light ratios. Discs in early-type galaxies contribute with about 40 per cent to the total mass of the analysed (non-barred) objects. The decomposition into discs and bulges can be used as a rough approximation for the separation between fast and slow rotators, but it is not a substitute, as there is only a 59 per cent probability to correctly recognize slow rotators. We find trends between the angular momentum and the disc-to-total light ratios and the Sérsic index of the bulge, in the sense that high angular momentum galaxies have large disc-to-total light ratios and small bulge indices, but there is none between the angular momentum and the global Sérsic index. We investigate the inclination effects on the decomposition results and confirm that strong exponential profiles can be distinguished even at low inclinations, but medium-size discs are difficult to quantify using photometry alone at inclinations lower than ∼50°. Kinematics (i.e. projected angular momentum) remains the best approach to mitigate the influence of the inclination effects.We also find weak trends with mass and environmental density, where disc-dominated galaxies are typically less massive and found at all densities, including the densest region sampled by the ATLAS3D sample. © 2012 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.


The ATLAS<sup>3D</sup> project - XIX. The hot gas content of early-type galaxies: Fast versus slow rotators

Monthly Notices of the Royal Astronomical Society 432 (2013) 1845-1861

M Sarzi, K Alatalo, L Blitz, M Bois, F Bournaud, M Bureau, M Cappellari, A Crocker, RL Davies, TA Davis, PT de Zeeuw, PA Duc, E Emsellem, S Khochfar, D Krajnović, H Kuntschner, PY Lablanche, RM McDermid, R Morganti, T Naab, T Oosterloo, N Scott, P Serra, LM Young, AM Weijmans

For early-type galaxies, the ability to sustain a corona of hot, X-ray-emitting gas could have played a key role in quenching their star formation history. A halo of hot gas may act as an effective shield against the acquisition of cold gas and can quickly absorb stellar mass loss material. Yet, since the discovery by the Einstein Observatory of such X-ray haloes around early-type galaxies, the precise amount of hot gas around these galaxies still remains a matter of debate. By combining homogeneously derived photometric and spectroscopic measurements for the early-type galaxies observed as part of the ATLAS3D integral field survey with measurements of their X-ray luminosity based on X-ray data of both low and high spatial resolution (for 47 and 19 objects, respectively) we conclude that the hot gas content of early-type galaxies can depend on their dynamical structure. Specifically, whereas slow rotators generally have X-ray haloes with luminosity LX, gas and temperature T values that are well in line with what is expected if the hot gas emission is sustained by the thermalization of the kinetic energy carried by the stellar mass loss material, fast rotators tend to display LX, gas values that fall consistently below the prediction of thismodel, with similar T values that do not scale with the stellar kinetic energy (traced by the stellar velocity dispersion) as observed in the case of slow rotators. Such a discrepancy between the hot gas content of slow and fast rotators would appear to reduce, or even disappear, for large values of the dynamical mass (above ∼3× 1011Mȯ), with younger fast rotators displaying also somewhat larger LX, gas values possibly owing to the additional energy input from recent supernovae explosions. Considering that fast rotators are likely to be intrinsically flatter than slow rotators, and that the few LX, gas-deficient slow rotators also happen to be relatively flat, the observed LX, gas deficiency in these objects would support the hypothesis whereby flatter galaxies have a harder time in retaining their hot gas, although we suggest that the degree of rotational support could further hamper the efficiency with which the kinetic energy of the stellar mass loss material is thermalized in the hot gas. We discuss the implications that a different hot gas content could have on the fate of both acquired and internally produced gaseous material, considering in particular how the LX, gas deficiency of fast rotators would make them more capable to recycle the stellar mass loss material into new stars than slow rotators. This would be consistent with the finding that molecular gas and young stellar populations are detected only in fast rotators across the entire ATLAS3D sample, and that fast rotators tend to have a larger specific dust mass content than slow rotators. © 2013 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society.

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