We present the kinematics and stellar population properties of a sample of 53 galaxies (50 are Early-Type galaxies, ETGs) with Counter-Rotating Disks (CRD) extracted from a sample of about 4000 galaxies of all morphological types in the MaNGA survey
(DR16). The kinematic maps were used to select galaxies based on evidence of counter-rotation in the velocity maps or two peaks in the velocity dispersion maps. For about 1/3 of the sample, the counter-rotating components can also be separated spectroscopically. We then produced the age and metallicity maps, and compared the stellar population properties to those of the general ETGs population. We found that CRDs have similar trends in age and metallicity, but they are generally less metallic at low masses. The metallicity gradients are similar; instead, age gradients are typically flatter and confined within a smaller range of values. We compared the velocity fields of the ionized gas and the stars, and found that in 25 cases the gas corotates with either the inner (13 cases) or the outer (12 cases) disk, and in 9 cases the gaseous and stellar disks are misaligned. With one exception, all misaligned cases have stellar masses less than $3 times 10^{10}$M$_odot$. We also compared stellar and gaseous disks with age maps and found that in most cases the gas corotates with the younger disk. We looked for evidences of multimodality in the stellar populations, and found it in 25 galaxies, plus 11 cases with evidences of ongoing star formation, and the latter are the youngest and least massive galaxies; 13 galaxies, instead, exhibit unimodality, and are the oldest and most massive CRDs. As a general result, our work supports different formation scenarios for the kinematic class of counter-rotators.
In the $(lambda_{rm R}, varepsilon)$ and $(V/sigma, varepsilon)$ diagrams for characterizing dynamical states, the fast-rotator galaxies (both early-type and spirals) are distributed within a well-defined leaf-shaped envelope. This was explained as d
ue to an upper limit to the orbital anisotropy increasing with galaxy intrinsic flattening. However, a physical explanation for this empirical trend was missing. Here we construct Jeans Anisotropic Models (JAM), with either cylindrically or spherically aligned velocity ellipsoid (two extreme assumptions), and each with either spatially-constant or -variable anisotropy. We use JAM to build mock samples of axisymmetric galaxies, assuming on average an oblate shape for the velocity ellipsoid (as required to reproduce the rotation of real galaxies), and limiting the radial anisotropy $beta$ to the range allowed by physical solutions. We find that all four mock samples naturally predict the observed galaxy distribution on the $(lambda_{rm R}, varepsilon)$ and $(V/sigma, varepsilon)$ diagrams, without further assumptions. Given the similarity of the results from quite different models, we conclude that the empirical anisotropy upper limit in real galaxies, and the corresponding observed distributions in the $(lambda_{rm R}, varepsilon)$ and $(V/sigma, varepsilon)$ diagrams, are due to the lack of physical axisymmetric equilibrium solutions at high $beta$ anisotropy when the velocity ellipsoid is close to oblate.
Galaxy properties are known to correlate most tightly with the galaxy effective stellar velocity dispersion $sigma_{rm e}$. Here we look for {em additional} trends at fixed $sigma_{rm e}$ using 1339 galaxies ($M_ast gtrsim 6times10^9$ M$_odot$) with
different morphologies in the MaNGA (DR14) sample with integral-field spectroscopy data. We focus on the gradients ($gamma_{rm rms} equiv sigma(R_{rm e}/4)/sigma_{rm e}$) of the stellar root-mean-square velocity ($V_{rm rms} equiv sqrt{V^2 + sigma^2}$), which we show traces the total mass density gradient $gamma_{rm tot}$ derived from dynamical models and, more weakly, the bulge fraction. We confirm that $gamma_{rm rms}$ increases with $sigma_{rm e}$, age and metallicity. We additionally find that these correlations still exist at fixed $sigma_{rm e}$, where galaxies with larger $gamma_{rm rms}$ are found to be older and more metal-rich. It means that mass density gradients contain information of the stellar population which is not fully accounted for by $sigma_{rm e}$. This result puts an extra constraint on our understanding of galaxy quenching. We compare our results with galaxies in the IllustrisTNG hydrodynamical simulations and find that, at fixed $sigma_{rm e}$, similar trends exist with age, the bulge fraction, and the total mass density slope but, unlike observations, no correlation with metallicity can be detected in the simulations.
We study the link between the kinematic-morphology of galaxies, as inferred from integral-field stellar kinematics, and their relation between mass and star formation rate (SFR). Our sample consists of $sim 3200$ galaxies with integral-field spectros
copic data from the MaNGA survey with available determinations of their effective stellar angular momentum within the half-light radius $lambda_{R_e}$. We find that for star-forming galaxies, namely along the star formation main sequence (SFMS), the $lambda_{R_e}$ values remain large and almost unchanged over about two orders of magnitude in stellar mass, with the exception of the lowest masses $mathcal{M}_{star}lesssim2times10^{9} mathcal{M}_{odot}$, where $lambda_{R_e}$ slightly decreases. The SFMS is dominated by spiral galaxies with small bulges. Below the SFMS, but above the characteristic stellar mass $mathcal{M}_{rm crit}approx2times10^{11} mathcal{M}_{odot}$, there is a sharp decrease in $lambda_{R_e}$ with decreasing star formation rate: massive galaxies well below the SFMS are mainly slow-rotator early-type galaxies, namely genuinely spheroidal galaxies without disks. Below the SFMS and below $mathcal{M}_{rm crit}$ the decrease of $lambda_{R_e}$ with decreasing SFR becomes modest or nearly absent: low-mass galaxies well below the SFMS, are fast-rotator early-type galaxies, and contain fast-rotating stellar disks like their star-forming counterparts. We also find a small but clear environmental dependence for the massive galaxies: in the mass range $10^{10.9}-10^{11.5} mathcal{M}_{odot}$, galaxies in rich groups or denser regions or classified as central galaxies have lower values of $lambda_{R_e}$. While no environmental dependence is found for galaxies of lower mass. We discuss how our results can be understood as due to the different star formation and mass assembly histories of galaxies with varying mass.
I present a flexible solution for the axisymmetric Jeans equations of stellar hydrodynamics under the assumption of an anisotropic (three-integral) velocity ellipsoid aligned with the spherical polar coordinate system. I describe and test a robust an
d efficient algorithm for its numerical computation. I outline the evaluation of the intrinsic velocity moments and the projection of all first and second velocity moments, including both the line-of-sight velocities and the proper motions. This spherically-aligned Jeans Anisotropic Modelling (JAM_sph) method can describe in detail the photometry and kinematics of real galaxies. It allows for a spatially-varying anisotropy, or stellar mass-to-light ratios gradients, as well as for the inclusion of general dark matter distributions and supermassive black holes. The JAM_sph method complements my previously derived cylindrically-aligned JAM_cyl and spherical Jeans solutions, which I also summarize in this paper. Comparisons between results obtained with either JAM_sph or JAM_cyl can be used to asses the robustness of inferred dynamical quantities. As an illustration, I modelled the Atlas3D sample of 260 early-type galaxies with high-quality integral-field spectroscopy, using both methods. I found that they provide statistically indistinguishable total-density logarithmic slopes. This may explain the previously-reported success of the JAM method in recovering density profiles of real or simulated galaxies. A reference software implementation of JAM_sph is included in the publicly-available JAM software package.
Different massive black hole mass - host galaxy scaling relations suggest that the growth of massive black holes is entangled with the evolution of their host galaxies. The number of measured black hole masses is still limited, and additional measure
ments are necessary to understand the underlying physics of this apparent co-evolution. We add six new black hole mass (MBH) measurements of nearby fast rotating early-type galaxies to the known black hole mass sample, namely NGC 584, NGC 2784, NGC 3640, NGC 4570, NGC 4281 and NGC 7049. Our target galaxies have effective velocity dispersions ({sigma}e) between 170 and 245 km s^(-1), and thus this work provides additional insight into the black hole properties of intermediate-mass early-type galaxies. We combine high-resolution adaptive-optics SINFONI data with large-scale MUSE, VIMOS and SAURON data from ATLAS3D to derive two-dimensional stellar kinematics maps. We then build both Jeans Anisotropic Models and axisymmetric Schwarzschild models to measure the central black hole masses. Our Schwarzschild models provide black hole masses which are consistent with recent MBH-{sigma}e scaling relations. NGC 3640 has a velocity dispersion dip and NGC 7049 a constant velocity dispersion in the center, but we can clearly constrain their lower black hole mass limit. We conclude our analysis with a test on NGC 4570 taking into account a variable mass-to-light ratio (M/L) when constructing dynamical models. When considering M/L variations linked mostly to radial changes in the stellar metallicity, we find that the dynamically determined black hole mass from NGC 4570 decreases by 30%. Further investigations are needed in the future to account for the impact of radial M/L gradients on dynamical modeling.
Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) is acquiring integral-field spectroscopy for the largest sample of galaxies to date. By 2020, the MaNGA Survey --- one of three core programs in the fourth-generation Sloan Digital Sky Surve
y (SDSS-IV) --- will have observed a statistically representative sample of 10$^4$ galaxies in the local Universe ($zlesssim0.15$). In addition to a robust data-reduction pipeline (DRP), MaNGA has developed a data-analysis pipeline (DAP) that provides higher-level data products. To accompany the first public release of its code base and data products, we provide an overview of the MaNGA DAP, including its software design, workflow, measurement procedures and algorithms, performance, and output data model. In conjunction with our companion paper Belfiore et al., we also assess the DAP output provided for 4718 observations of 4648 unique galaxies in the recent SDSS Data Release 15 (DR15). These analysis products focus on measurements that are close to the data and require minimal model-based assumptions. Namely, we provide stellar kinematics (velocity and velocity dispersion), emission-line properties (kinematics, fluxes, and equivalent widths), and spectral indices (e.g., D4000 and the Lick indices). We find that the DAP provides robust measurements and errors for the vast majority ($>$99%) of analyzed spectra. We summarize assessments of the precision and accuracy of our measurements as a function of signal-to-noise, and provide specific guidance to users regarding the limitations of the data. The MaNGA DAP software is publicly available and we encourage community involvement in its development.
We investigate the variation of black hole masses (Mbh) as a function of their host galaxy stellar mass (Mstar) and half-light radius (Re). We confirm that the scatter in Mbh within this plane is essentially the same as that in the Mbh - sigma relati
on, as expected from the negligible scatter reported in the virial mass estimator sigma_v^2=GxMstar/(5xRe). All variation in Mbh happens along lines of constant sigma_v on the (Mstar, Re) plane, or Mstar $propto$ Re for Mstar <2x10^11 Msun. This trend is qualitatively the same as those previously reported for galaxy properties related to stellar populations, like age, metallicity, alpha enhancement, mass-to-light ratio and gas content. We find evidence for a change in the Mbh variation above the critical mass of Mcrit ~ 2x10^11 Msun. This behaviour can be explained assuming that Mbh in galaxies less massive than Mcrit can be predicted by the Mbh - sigma relation, while Mbh in more massive galaxies follow a modified relation which is also dependent on Mstar once Mstar >Mcrit. This is consistent with the scenario where the majority of galaxies grow through star formation, while the most massive galaxies undergo a sequence of dissipation-less mergers. In both channels black holes and galaxies grow synchronously, giving rise to the black hole - host galaxy scaling relations, but there is no underlying single relation that is universal across the full range of galaxy masses.
I start by providing an updated summary of the penalized pixel-fitting (pPXF) method, which is used to extract the stellar and gas kinematics, as well as the stellar population of galaxies, via full spectrum fitting. I then focus on the problem of ex
tracting the kinematic when the velocity dispersion $sigma$ is smaller than the velocity sampling $Delta V$, which is generally, by design, close to the instrumental dispersion $sigma_{rm inst}$. The standard approach consists of convolving templates with a discretized kernel, while fitting for its parameters. This is obviously very inaccurate when $sigma<Delta V/2$, due to undersampling. Oversampling can prevent this, but it has drawbacks. Here I present a more accurate and efficient alternative. It avoids the evaluation of the under-sampled kernel, and instead directly computes its well-sampled analytic Fourier transform, for use with the convolution theorem. A simple analytic transform exists when the kernel is described by the popular Gauss-Hermite parametrization (which includes the Gaussian as special case) for the line-of-sight velocity distribution. I describe how this idea was implemented in a significant upgrade to the publicly available pPXF software. The key advantage of the new approach is that it provides accurate velocities regardless of $sigma$. This is important e.g. for spectroscopic surveys targeting galaxies with $sigmallsigma_{rm inst}$, for galaxy redshift determinations, or for measuring line-of-sight velocities of individual stars. The proposed method could also be used to fix Gaussian convolution algorithms used in todays popular software packages.
The dark matter (DM) haloes around spiral galaxies appear to conspire with their baryonic content: empirically, significant amounts of DM are inferred only below a universal characteristic acceleration scale. Moreover, the discrepancy between the bar
yonic and dynamical mass, which is usually interpreted as the presence of DM, follows a very tight mass discrepancy acceleration (MDA) relation. Its universality, and its tightness in spiral galaxies, poses a challenge for the DM interpretation and was used to argue in favour of MOdified Newtonian Dynamics (MOND). Here, we test whether or not this applies to early-type galaxies. We use the dynamical models of fast-rotator early-type galaxies by Cappellari et al. based on ATLAS$^{3D}$ and SLUGGS data, which was the first homogenous study of this kind, reaching ~4 $R_e$, where DM begins to dominate the total mass budget. We find the early-type galaxies to follow an MDA relation similar to spiral galaxies, but systematically offset. Also, while the slopes of the mass density profiles inferred from galaxy dynamics show consistency with those expected from their stellar content assuming MOND, some profiles of individual galaxies show discrepancies.
