Stationary models for the extra-planar gas in disc galaxies (2009)
Marinacci, F., Fraternali, F., Ciotti, L., Nipoti, C.
The kinematics of the extra-planar neutral and ionised gas in disc galaxies shows a systematic decline of the rotational velocity with height from the plane (vertical gradient). This feature is not...
Galaxy formation from dry and hydro simulations (2009)
The effects of dry and wet merging on the Scaling Laws (SLs) of elliptical galaxies (Es) are discussed. It is found that the galaxy SLs, possibly established at high redshift by the fast collapse of...
AGN feedback in numerical simulations (2009)
The passively evolving stellar population in elliptical galaxies (Es) provides a continuous source of fuel for accretion on the central supermassive black hole (SMBH), which is 1) extended over the...
Synchrotron Emission from Elliptical Galaxies Consequent to AGN outbursts (2009)
Ciotti, L., Ostriker, J. P., Spitkovsky, A.
Both radiative and mechanical feedback from Active Galactic Nuclei have been found to be important for the evolution of elliptical galaxies. We compute how a shock may be driven from a central black...
Pellegrini, S., Ciotti, L., Ostriker, J. P.
The centers of elliptical galaxies host supermassive black holes that significantly affect the surrounding interstellar medium through feedback resulting from the accretion process. The evolution of...
Strong Gravitational Lensing as a Probe of Gravity, Dark-Matter and Super-Massive Black Holes (2009)
Koopmans, L. V. E., Auger, M., Barnabe, M., Bolton, A., Bradac, M., Ciotti, L., ...
Whereas considerable effort has been afforded in understanding the properties of galaxies, a full physical picture, connecting their baryonic and dark-matter content, super-massive black holes, and...
Ciotti, L., Ostriker, J. P., Proga, D.
The importance of the radiative feedback from SMBHs at the centers of elliptical galaxies is not in doubt, given the well established relations among electromagnetic output, black hole mass and...
After the discovery that supermassive black holes (SMBHs) are ubiquitous at the center of stellar spheroids and that their mass Mbh, in the range 10^6-10^9 Msun, is tightly related to global...
Hydrostatic gas distributions: global estimates of temperature and abundance (2008)
Estimating the temperature and metal abundance of the intracluster and the intragroup media is crucial to determine their global metal content and to determine fundamental cosmological parameters....
Exact density-potential pairs from complex shifted axisymmetric systems (2008)
In a previous paper the complex-shift method has been applied to self-gravitating spherical systems, producing new analytical axisymmetric density-potential pairs. We now extend the treatement to the...
Dynamical friction in modified Newtonian dynamics (2008)
Nipoti, C., Ciotti, L., Binney, J., Londrillo, P.
We have tested a previous analytical estimate of the dynamical friction timescale in Modified Newtonian Dynamics (MOND) with fully non-linear N-body simulations. The simulations confirm that the...
MOTION OF A RIGID BODY IN A TIDAL FIELD An Application to Elliptical Galaxies in Clusters (2007)
Abstract. We investigate the motion, near the equilibrium configurations, of an initially spinless rigid body subject to an external tidal field. Two cases are considered: when the center of mass of...
Evolution of chemical abundances in Seyfert galaxies (2007)
Ballero, S. K., Matteucci, F., Ciotti, L., Calura, F., Padovani, P.
We computed the chemical evolution of spiral bulges hosting Seyfert nuclei, based on updated chemical and spectro-photometrical evolution models for the bulge of our Galaxy, made predictions about...
Chemical evolution of Seyfert galaxies (2007)
Ballero, S. K., Matteucci, F., Ciotti, L.
We computed the chemical evolution of Seyfert galaxies, residing in spiral bulges, based on an updated model for the Milky Way bulge with updated calculations of the Galactic potential and of the...
The importance of the radiative feedback from massive black holes at the centers of elliptical galaxies is not in doubt, given the well established relations among electromagnetic output, black hole...
Ciotti, L., Nipoti, C., Londrillo, P.
Dissipationless collapses in Modified Newtonian Dynamics (MOND) have been studied by using our MOND particle-mesh N-body code, finding that the projected density profiles of the final virialized...
Dissipationless collapses in MOND (2007)
Nipoti, C., Londrillo, P., Ciotti, L.
Dissipationless collapses in Modified Newtonian Dynamics (MOND) are studied by using a new particle-mesh N-body code based on our numerical MOND potential solver. We found that low surface-density...
Exact density-potential pairs from the holomorphic Coulomb field (2007)
We show how the complex-shift method introduced by Appell in gravity to the case of a point mass (and applied among others in electrodynamics by Newman, Carter, Lynden-Bell, and Kaiser to determine...
The importance of dry and wet merging on the formation and evolution of elliptical galaxies (2006)
Ciotti, L., Lanzoni, B., Volonteri, M.
With the aid of a simple yet robust approach we investigate the influence of dissipationless and dissipative merging on galaxy structure, and the consequent effects on the scaling laws followed by...
Reconciling optical and X-ray mass estimates: the case of the elliptical galaxy NGC3379 (2006)
NGC3379 is a well studied nearby elliptical for which optical investigations have claimed a little dark matter content, or even no dark matter. Recently, its total mass profile M(r) has been derived...
Dissipationless collapse, weak homology and central cores of elliptical galaxies (2006)
Nipoti, C., Londrillo, P., Ciotti, L.
By means of high-resolution N-body simulations we revisited the dissipationless collapse scenario for galaxy formation. We considered both single-component collapses and collapses of a cold stellar...
Axisymmetric and triaxial MOND density-potential pairs (2005)
Ciotti, L., Londrillo, P., Nipoti, C.
We present a simple method, based on the deformation of spherically symmetric potentials, to construct explicit axisymmetric and triaxial MOND density-potential pairs. General guidelines to the...
Hydrostatic models for the rotation of extra-planar gas in disk galaxies (2005)
Sancisi, R., Fraternali, F., Ciotti, L., Barnabe, M.
Published in: Phys. Lett., B 624 (2005) 186-194 Abstract: We show that fluid stationary models are able to reproduce the observed, negative vertical gradient of the rotation velocity of the...
Hydrostatic models for the rotation of extra-planar gas in disk galaxies (2005)
Barnabè, M., Ciotti, L., Fraternali, F., Sancisi, R.
We show that fluid stationary models are able to reproduce the observed, negative vertical gradient of the rotation velocity of the extra-planar gas in spiral galaxies. We have constructed models...
The contribution of rotational velocity to the FP of elliptical galaxies (2005)
Riciputi, A., Lanzoni, B., Bonoli, S., Ciotti, L.
The contribution of ordered rotation to the observed tilt and thickness of the Fundamental Plane of elliptical galaxies is studied by means of oblate, two-integrals cuspy galaxy models with...
The evolution of early-type galaxies at z~1 from the K20 survey (2005)
Alighieri, S. Di Serego, Vernet, J., Cimatti, A., Lanzoni, B., Cassata, P., Ciotti, L., ...
We have performed VLT spectroscopy of an almost complete sample of 18 early-type galaxies with 0.88 < z < 1.3 plus two at z=0.67, selected from the K20 survey, and derived the velocity dispersion for...
Radiative feedback from quasars and the growth of massive black holes in stellar spheroids (2005)
Sazonov, S. Yu., Ostriker, J. P., Ciotti, L., Sunyaev, R. A.
Radiative feedback from quasars and the growth of massive black holes in stellar spheroids (2004)
Sazonov, S. Yu., Ostriker, J. P., Ciotti, L., Sunyaev, R. A.
We discuss the importance of feedback via photoionization and Compton heating on the co-evolution of massive black holes (MBHs) at the center of spheroidal galaxies and their stellar and gaseous...
Radiative Feedback from Quasars and the Growth of Supermassive Black Holes (2004)
Sazonov, S. Yu., Ostriker, J. P., Ciotti, L., Sunyaev, R. A.
We discuss the role of feedback via photoionization and Compton heating in the co-evolution of massive black holes at the center of spheroidal galaxies and their stellar and gaseous components. We...
Stationary fluid models for the extra-planar gas in spiral galaxies (2004)
Barnabe', M., Ciotti, L., Fraternali, F., Sancisi, R.
We show how to construct families of stationary hydrodynamical configurations that reproduce the observed vertical gradient of the rotation velocity of the extra-planar gas in spiral galaxies. We...
A physically motivated toy model for the BH-spheroid coevolution (2004)
Ciotti, L., Ostriker, J. P., Sazonov, S. Yu.
We present a summary of the results obtained with a time-dependent, one-zone toy model aimed at exploring the importance of radiative feedback on the co-evolution of massive black holes (MBHs) at the...
Active Galaxies and Radiative Heating (2004)
There is abundant evidence that heating processes in the central regions of elliptical galaxies has both prevented large-scale cooling flows and assisted in the expulsion of metal rich gas. We now...
By means of simple numerical models we discuss whether "collisionless stellar evaporation" from cluster elliptical galaxies could be an effective mechanism for the production of intracluster stellar...
Two-body relaxation in modified Newtonian dynamics (2004)
A naive extension to MOND of the standard computation of the two-body relaxation time Tb implies that Tb is comparable to the crossing time regardless of the number N of stars in the system. This...
On the use of X-rays to determine dynamical properties of elliptical galaxies (2004)
The X-ray emitting interstellar medium of early type galaxies is often used as a tool to determine their total mass M and stellar orbital anisotropy beta profiles, based on the hypothesis of...
Self-consistent stellar dynamical tori (2003)
Ciotti, L., Bertin, G., Londrillo, P.
We present preliminary results on a new family of distribution functions that are able to generate axisymmetric, truncated (i.e., finite size) stellar dynamical models characterized by toroidal...
Free-free absorption effects on Eddington luminosity (2003)
In standard treatments the Eddington luminosity is calculated by assuming that the electron-photon cross section is well described by the Thomson cross section which is gray (frequency independent)....
The role of Compton heating in cluster cooling flows (2003)
Ciotti, L., Ostriker, J. P., Pellegrini, S.
Recent observations by Chandra and XMM-Newton demonstrate that the central gas in "cooling flow" galaxy clusters has a mass cooling rate that decreases rapidly with decreasing temperature. This...
Clues on galaxy and cluster formation from their scaling relations (2003)
Lanzoni, B., Ciotti, L., Cappi, A., Tormen, G., Zamorani, G.
By means of high-resolution N-body simulations in a LambdaCDM cosmology, we verify that scaling relations similar to those observed for nearby galaxy clusters are also defined by their dark matter...
Nipoti, C., Stiavelli, M., Ciotti, L., Treu, T., Rosati, P.
The X-ray cluster C0337-2522 at redshift $z=0.59$ hosts in its core a group of five elliptical galaxies. Using N-body simulations we show that a multiple merging event among the five galaxies is...
The scaling relations of galaxy clusters and their dark matter halos (2003)
Lanzoni, B., Ciotti, L., Cappi, A., Tormen, G., Zamorani, G.
Like early-type galaxies, also nearby galaxy clusters define a Fundamental Plane, a luminosity-radius, and a luminosity-velocity dispersion relations, whose physical origin is still unclear. By means...
Galactic cannibalism in the galaxy cluster C0337-2522 at z=0.59 (2003)
Nipoti, C., Stiavelli, M., Ciotti, L., Treu, T., Rosati, P.
According to the galactic cannibalism model, cD galaxies are formed in the center of galaxy clusters by merging of massive galaxies and accretion of smaller stellar systems: however, observational...
Projection effects on the FP thickness: a Monte-Carlo exploration (2003)
We study the contribution of projection effects to the intrinsic thickness of the Fundamental Plane (FP) of elliptical galaxies. The Monte-Carlo mapping technique between model properties and...
Galaxy merging, the Fundamental Plane of elliptical galaxies, and the Mbh-sigma relation (2003)
Nipoti, C., Londrillo, P., Ciotti, L.
We explore the effects of dissipationless merging on the Fundamental Plane of elliptical galaxies by using a N-body code based on a new, high performance numerical scheme (Dehnen 2002). We...
Collisionless evaporation from cluster elliptical galaxies (2003)
We describe a particular aspect of the effects of the parent cluster tidal field (CTF) on stellar orbits inside cluster Elliptical galaxies. In particular we discuss, with the aid of a simple...
A parallel implementation of a new fast algorithm for N-body simulations (2002)
Londrillo, P., Nipoti, C., Ciotti, L.
A new, momentum preserving fast Poisson solver for N-body systems sharing effective O(N) computational complexity, has been recently developed by Dehnen (2000, 2002). We have implemented the proposed...
Lanzoni, B., Cappi, A., Ciotti, L.
Pure N-body high-resolution re-simulations of 13 massive dark matter halos in a Lambda-CDM cosmology are presented. The resulting sample is used to investigate the physical origin of the Fundamental...
With the aid of simple numerical models, we discuss a particular aspect of the interaction between stellar orbital periods inside elliptical galaxies (Es) and the parent cluster tidal field (CTF),...
Weak homology of elliptical galaxies (2002)
Bertin, G., Ciotti, L., Del Principe, M.
We start by studying a small set of objects characterized by photometric profiles that have been pointed out to deviate significantly from the standard R^{1/4} law. For these objects we confirm that...
The Mbh-sigma relation as a constraint on the formation of elliptical galaxies (2001)
Most elliptical galaxies contain central black holes, whose masses scale proportionally to the observed central velocity dispersions of the host galaxies according to the so-called Mbh-sigma...
Cooling flows and quasars: II. Detailed models of feedback modulated accretion flows (1999)
Most elliptical galaxies contain central black holes (BHs), and most also contain significant amounts of hot gas capable of accreting on to the central BH due to cooling times short compared to the...
Analytical properties of the R^(1/m) luminosity law (1999)
In this paper we describe some analytical properties of the R^{1/m} law proposed by Sersic (1968) to categorize the photometric profiles of elliptical galaxies. In particular, we present the full...
Effects of tidal interactions on the gas flows of elliptical galaxies (1999)
D'Ercole, A., Recchi, S., Ciotti, L.
During a Hubble time, cluster galaxies may undergo several mutual encounters close enough to gravitationally perturb their hot, X-ray emitting gas flows. We ran several 2D, time dependent...
Phase-space constraints on visible and dark matter distributions in elliptical galaxies (1999)
There are observational and theoretical indications that both the visible (stars) and the dark matter density distributions in elliptical galaxies increase significantly up to the galactic center. I...
Analytical properties of the R^{1/m} law (1999)
In this paper we describe some analytical properties of the R^{1/m} law proposed by Sersic to categorize the photometric profiles of elliptical galaxies. In particular, we present the full asymptotic...
In the context of the study of the properties of the mutual mass distribution of the bright and dark matter in elliptical galaxies, present a family of two-component, spherical, self-consistent...
Inversion of the Abel equation for toroidal density distributions (1999)
In this paper I present three new results of astronomical interest concerning the theory of Abel inversion. 1) I show that in the case of a spatial emissivity that is constant on toroidal surfaces...
Two-component galaxy models: phase-space constraints (1998)
The properties of the analitycal phase--space distribution function of two-component spherical self-consistent galaxy models, where one density distribution follows the Hernquist profile, and the...
Decoupled hot gas flows in elliptical galaxies (1998)
We present the results of a new set of hydrodynamical simulations of hot gas flows in model elliptical galaxies with the following characteristics: the spatial luminosity distribution approaches a...
Motion of a rigid body in a tidal field: an application to elliptical galaxies in clusters (1998)
We investigate the motion, near the equilibrium configurations, of an initially spinless rigid body subject to an external tidal field. Two cases are considered: when the center of mass of the body...
Decoupled and inhomogeneous gas flows in S0 galaxies (1997)
A recent analysis of the "Einstein" sample of early-type galaxies has revealed that at any fixed optical luminosity Lb S0 galaxies have lower mean X-ray luminosity Lx per unit Lb than ellipticals....
Cooling flows and quasars: different aspects of the same phenomenon? I. Concepts (1997)
We present a new class of solutions for the gas flows in elliptical galaxies containing massive central black holes (BH). Modified King model galaxies are assumed. Two source terms operate: mass loss...
Five contributions to the 3rd ESO-VLT Workshop ``Galaxy Scaling Relations'' (1996)
Cappi, A., Ciotti, L., Lanzoni, B., Maraston, C., Maurogordato, S., Pellegrini, S.
In the first contribution the basic problems posed by the existence of the Fundamental Plane (FP), and its relations with the Virial Theorem are discussed. Various possibilities are presented that...
X-ray emission and internal kinematics in early-type galaxies. I. Observations (1996)
Pellegrini, S., Held, E. V., Ciotti, L.
Long slit spectroscopic data for 7 early-type galaxies with X-ray emission have been analyzed to derive velocity dispersion and radial velocity profiles. Major axis rotation curves out to $R\sim R_e$...
We study the dynamical properties of spherical galaxies with surface luminosity profile described by the R^{1/m}-law, in which a variable degree of orbital anisotropy is allowed. The parameter m for...
The Tilt of the Fundamental Plane of Elliptical Galaxies: I. Dynamical and Structural Effects (1996)
Ciotti, L., Lanzoni, B., Renzini, A.
In this paper we explore several structural and dynamical effects on the projected velocity dispersion as possible causes of the fundamental plane (FP) tilt of elliptical galaxies. Specifically, we...
The energetics of flat and rotating early-type galaxies and their X-ray luminosity (1995)
The global energy budget of the hot gas flows in early-type galaxies is used to explain the recent observational results that S0 galaxies have lower mean X-ray luminosity $L_X$ per unit optical...
RECOVERING THE INTRINSIC METALLICITY DISTRIBUTION OF ELLIPTICAL GALAXIES (1995)
Ciotti, L., Stiavelli, M., Braccesi, A.
We address the problem of deriving, from the observed projected metallicity gradients, the intrinsic metallicity distribution of elliptical galaxies as a function of their integrals of motion. The...
Tomography of Collisionless Stellar Systems (1994)
In this paper the concept of tomography of a collisionless stellar system of general shape is introduced, and a generalization of the Projected Virial Theorem is obtained. Applying the tomographic...
Alignment and morphology of elliptical galaxies: the influence of the cluster tidal field (1994)
We investigate two possible effects of the tidal field induced by a spherical cluster on its elliptical galaxy members: the modification of the ellipticity of a spherical galaxy and the isophotal...