El origen de las galaxias esferoidales en simulaciones cosmológica

Fil: Algorry, David Gabriel Conicet Instituto de Astronomía Teórica y Experimental; Argentina.Fil:Abadi, Mario Gabriel Conicet Instituto de Astronomía Teórica y Experimental; Argentina.Fil:Abadi, Mario Gabriel Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Abstract:We use the GIMIC cosmological hydrodynamical simulations to perform a study of the properties of spheroidal galaxies formed without merger events. We select a sample of galaxies with stellar mass greater than 10 M and we classified them according to the degree of rotation support through the ratio of the rotational kinetic energy respect to the total at redshift z=0. Taken only those with κrot < 0.4 we focus on those with accreted mass fraction less than 20% to ensure that they are merger free. We found that these spheroidal galaxies have stellar mass Mgal < 10 M and have an important barred component. Interestingly; we found that in many cases the simulated galaxies present two external rings around the bar being both coplanar and counter-rotating to each other.Resumen:Utilizando las simulaciones numéricas cosmológica hidrodinámicas GIMIC realizamos un estudio de las propiedades de las galaxias esferoidales formadas sin eventos de fusión. Seleccionamos una muestra de galaxias con masa estelar mayor a 1010 M y las clasificamos de acuerdo al grado de soporte rotacional a través del cociente en energía cinética de rotación respecto del total en corrimiento al rojo z=0. Tomando sólo aquellas con κrot < 0.4, nos focalizamos en aquellas galaxias cuya fracción de masa acretada es menor al 20 % para asegurarnos que no han sufrido eventos de fusión mayores. Al analizar esta muestra encontramos que estas galaxias esferoidales poseen una masa estelar Mgal < 1011 M y poseen una componente barreada importante. Llamativamente, encontramos que en numerosos casos las galaxias simuladas presentan además dos anillos externos que rodean a la barra siendo ambos coplanares y contrarrotantes el uno respecto al otro.http://www.astronomiaargentina.org.ar/uploads/docs/baaa56.pdfAstronomía (incluye Astrofísica y Ciencias del Espacio

Accretion of galaxy groups into galaxy clusters

We study the role of group infall in the assembly and dynamics of galaxy clusters in ΛCDM. We select 10 clusters with virial mass M200 ∼1014 M from the cosmological hydrodynamical simulation Illustris and follow their galaxies with stellar mass M⊙ ≥ 1.5 × 108 M. A median of ∼38% of surviving galaxies at z = 0 is accreted as part of groups and did not infall directly from the field, albeit with significant cluster-to-cluster scatter. The evolution of these galaxy associations is quick, with observational signatures of their common origin eroding rapidly in 1-3 Gyr after infall. Substructure plays a dominant role in fostering the conditions for galaxy mergers to happen, even within the cluster environment. Integrated over time, we identify (per cluster) an average of 17 ± 9 mergers that occur in infalling galaxy associations, of which 7 ± 3 occur well within the virial radius of their cluster hosts. The number of mergers shows large dispersion from cluster to cluster, with our most massive system having 42 mergers above our mass cut-off. These mergers, which are typically gas rich for dwarfs and a combination of gas rich and gas poor for M⊙ ∼1011 $m M_odot$, may contribute significantly within ΛCDM to the formation of specific morphologies, such as lenticulars (S0) and blue compact dwarfs in groups and clusters.Fil: Benavides, José A.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Sales, Laura Virginia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentina. University of California; Estados UnidosFil: Abadi, Mario Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentin

Intra-cluster Globular Clusters in a Simulated Galaxy Cluster

Using a cosmological dark matter simulation of a galaxy-cluster halo, we follow the temporal evolution of its globular cluster population. To mimic the red and blue globular cluster populations, we select at high redshift (z ∼ 1) two sets of particles from individual galactic halos constrained by the fact that, at redshift z = 0, they have density profiles similar to observed ones. At redshift z = 0, approximately 60% of our selected globular clusters were removed from their original halos building up the intra-cluster globular cluster population, while the remaining 40% are still gravitationally bound to their original galactic halos. As the blue population is more extended than the red one, the intra-cluster globular cluster population is dominated by blue globular clusters, with a relative fraction that grows from 60% at redshift z = 0 up to 83% for redshift z ∼ 2. In agreement with observational results for the Virgo galaxy cluster, the blue intra-cluster globular cluster population is more spatially extended than the red one, pointing to a tidally disrupted origin.Fil: Ramos Almendares, Felipe Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Abadi, Mario Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Muriel, Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Coenda, Valeria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentin

Simulaciones de formación de galaxias disco barreadas

In this work we present a study of the formation and evolution of two galaxies selected from a series of numerical cosmological hydrodynamical simulations called GIMIC. The first one is a galaxy with a central bar at redshift z = 0 formed between 9 t [Gyr] 11. At this time, the galaxy accretes gas from distinct directions forming a ring located in a different plane respect to the galaxy disc. This disc transfers its angular momentum to the gas and halo decaying its pattern speed and becoming a bar. The second one is a galaxy that had a bar until a time t 10 Gyr. After this time, the bar gradually disintegrate until redshift z = 0 (t = 13.6 Gyr). This disintegration is unusual and may be due to strong perturbations originated by the proximity of a massive satellite at t 10 Gyr.En este trabajo presentamos un análisis de la formación y evolución de dos galaxias barreadas extraídas de las simulaciones numéricas cosmológicas hidrodinámicas GIMIC. La primera de ellas, es una galaxia con una barra central a redshift z = 0 que aparece a tiempo t≈10 Gyr coincidiente con el momento en que la galaxia comienza a acretar gas desde distintas derecciones formando un anillo localizado en un plano diferente respecto del disco de la galaxia. En este tiempo, el disco preexistente transfiere su momento angular al gas y a la materia oscura, decayendo su patrón de velocidad y formando la componente barreada. En contraposición la segunda galaxia presenta una barra formada desde el comienzo de la simulación que sobrevive hasta tiempo t≈10 Gyr, desintegrándose paulatinamente y dando lugar a una galaxia dominada por un disco a redshift z = 0. Esta desintegración es inusual y se debe a fuertes perturbaciones que sufre la galaxia debido a la proximidad con un satélite masivo a t ~ 10 Gry.publishedVersionFil: Abadi, Mario Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Astronomía Teórica y Experimental; Argentina.Fil: Ferrero, Santiago Ismael. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Astronomía Teórica y Experimental; Argentina.Fil: Algorry, David Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Astronomía Teórica y Experimental; Argentina.Fil: Abadi, Mario Gabriel. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Ferrero, Santiago Ismael. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Astronomía (incluye Astrofísica y Ciencias del Espacio

La abundancia de galaxias y halos de materia oscura en el universo CDM

Abstract: We use the GIMIC cosmological hydrodynamical simulations to perform a study of the properties of spheroidal galaxies formed without merger events. We select a sample of galaxies with stellar mass greater than 10 M and we classified them according to the degree of rotation support through the ratio of the rotational kinetic energy respect to the total at redshift z=0. Taken only those with ; we focus on those with accreted mass fraction less than 20 to ensure that they are merger free. We found that these spheroidal galaxies have stellar mass M M and have an important barred component. Interestingly; we found that in many cases the simulated galaxies present two external rings around the bar being both coplanar and counter-rotating to each other. FULL TEXT IN SPANISHFil: Abadi, Mario Gabriel. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Abadi, Mario Gabriel. Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.http://www.astronomiaargentina.org.ar/uploads/docs/baaa56.pdfAstronomía (incluye Astrofísica y Ciencias del Espacio

Efectos de mareas en cúmulos globulares

Abstract. Using an N-body numerical simulation in the framework of the ΛCDM cosmological model we study the globular cluster population in a simulated galaxy cluster. We select particles that trace the bimodal (red and blue) globular cluster system of each individual dark matter halo prior to their incorporation to the cluster virial radius. We found that the blue population is more prone to be removed from the halo than the red one. This result suggests that globular clusters are tidally disrupted, being the blue (more extended) population easily removed.Resumen. Hemos utilizado una simulación cosmológica de N-cuerpos, en el marco del modelo cosmológico ΛCDM, para estudiar la población de cúmulos globulares (CGs) en un cúmulo de galaxias. Hemos seleccionado partıculas trazadoras de los sistemas de CG de cada halo de materia oscura en el momento previo a entrar al radio virial del cúmulo, teniendo en cuenta la distribución bimodal de la población de CGs. Encontramos que la población de CGs azul es mas fácilmente removida del halo que la población roja. Este resultado sugiere que los CGs son afectados por interacciones de marea, siendo la población mas extendida (la azul) mayormente afectada.Fil: Coenda, Valeria Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Coenda, Valeria Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.Fil: Muriel, Hernán Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Muriel, Hernán Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.Fil:Abadi, Mario Gabriel. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; Argentina.Fil: Abadi, Mario Gabriel Conicet. Instituto de Astronomía Teórica y Experimental; Argentina.http://www.astronomiaargentina.org.ar/b56/BAAA56_v15_final.pdfpublishedVersionAstronomía (incluye Astrofísica y Ciencias del Espacio

A unified scenario for the origin of spiral and elliptical galaxy structural scaling laws

Elliptical (E) and spiral (S) galaxies follow tight, but different, scaling laws that link their stellar masses, radii, and characteristic velocities. Mass and velocity, for example, scale tightly in spirals with little dependence on galaxy radius (the 'Tully-Fisher relation'; TFR). On the other hand, ellipticals appear to trace a 2D surface in size-mass-velocity space (the 'Fundamental Plane'; FP). Over the years, a number of studies have attempted to understand these empirical relations, usually in terms of variations of the virial theorem for E galaxies and in terms of the scaling relations of dark matter halos for spirals. We use Lambda cold dark matter (ΛCDM) cosmological hydrodynamical simulations to show that the scaling relations of both ellipticals and spirals arise as the result of (i) a tight galaxy mass-dark halo mass relation and (ii) the self-similar mass profile of cold dark matter halos. In this interpretation, E and S galaxies of a given stellar mass inhabit halos of similar masses, and their different scaling laws result from the varying amounts of dark matter enclosed within their luminous radii. This scenario suggests a new galaxy distance indicator applicable to galaxies of all morphologies and provides simple and intuitive explanations for long-standing puzzles, such as why the TFR is independent of surface brightness, or what causes the 'tilt' in the FP. Our results provide strong support for the predictions of ΛCDM in the strongly non-linear regime, as well as guidance for further improvements to cosmological simulations of galaxy formation.Fil: Ferrero, Santiago Ismael. University of Oslo; NoruegaFil: Navarro, Julio F.. University of Victoria; CanadáFil: Abadi, Mario Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Benavides Blanco, Jose Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Mast, Damian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentin

Properties of subhalos in the interacting dark matter scenario

One possible and natural derivation fromthe collisionless cold dark matter (CDM) standard cosmological framework is the assumption of the existence of interactions between dark matter (DM) and photons or neutrinos. Such a possible interacting dark matter (IDM) model would imply a suppression of small-scale structures due to a large collisional damping effect, even though the weakly-interacting massive particle (WIMP) can still be the DM candidate. Because of this, IDM models can help alleviate alleged tensions between standard CDM predictions and observations at small mass scales. In this work, we investigate the properties of the DM halo substructure or subhalos formed in a high-resolution cosmological N-body simulation specifically run within these alternative models. We also run its CDM counterpart, which allowed us to compare subhalo properties in both cosmologies. We show that, in the lower mass range covered by our simulation runs, both subhalo concentrations and abundances are systematically lower in IDM compared to the CDM scenario. Yet, as in CDM, we find that median IDM subhalo concentration values increase towards the innermost regions of their hosts for the same mass subhalos. Similarly to CDM, we find IDM subhalos to be more concentrated than field halos of the same mass. Our work has a direct application to studies aimed at the indirect detection of DM where subhalos are expected to boost the DM signal of their host halos significantly. From our results, we conclude that the role of the halo substructure in DM searches will be less important in interacting scenarios than in CDM, but is nevertheless far from being negligible.Fil: Moliné, Ángeles. Universidad Autónoma de Madrid; España. Consejo Superior de Investigaciones Científicas; EspañaFil: Schewtschenko, Jascha A.. University of Portsmouth; Reino UnidoFil: Sánchez Conde, Miguel A.. Universidad Autónoma de Madrid; EspañaFil: Aguirre Santaella, Alejandra. Universidad Autónoma de Madrid; EspañaFil: Cora, Sofia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Abadi, Mario Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentin

Simulating the spatial distribution and kinematics of globular clusters within galaxy clusters in illustris

We study the assembly of globular clusters (GCs) in 9 galaxy clusters using the cosmological simulation Illustris. GCs are tagged to individual galaxies at their infall time. The tidal removal of GCs from their galaxies and the distribution of the GCs within the cluster is later followed self-consistently by the simulation. The method relies on the simple assumption of a single power-law relation between halo mass (Mvir) and mass in GCs (MGC) as found in observations. We find that the GCs specific frequency SN as a function of V-band magnitude naturally reproduces the observed ‘U’-shape due to the combination of the power law MGC–Mvir relation and the non-linear stellar mass (M∗)–halo mass relation from the simulation. Additional scatter in the SN values is traced back to galaxies with early infall times due to the evolution of the M∗–Mvir relation with redshift. GCs that have been tidally removed from their galaxies form the present-day intracluster component, from which about ∼60 per cent were brought in by galaxies that currently orbit within the cluster potential. The remaining ‘orphan’ GCs are contributed by satellite galaxies with a wide range of stellar masses that are fully tidally disrupted at z = 0. This intracluster component is a good dynamical tracer of the dark matter potential. As a consequence of the accreted nature of most intracluster GCs, their orbits are fairly radial with a predicted orbital anisotropy β ≥ 0.5. However, local tangential motions may appear as a consequence of localized substructure, providing a possible interpretation to the β < 0 values suggested in observations of M87.Fil: Ramos Almendares, Felipe Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Sales, Laura Virginia. University of California; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Abadi, Mario Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; ArgentinaFil: Muriel, Hernan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Astronomía Teórica y Experimental. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Instituto de Astronomía Teórica y Experimental; Argentina. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba; ArgentinaFil: Doppel, Jessica E.. University of California; Estados UnidosFil: Peng, Eric W.. Peking University; Chin

Globular clusters as tracers of the dark matter content of dwarfs in galaxy clusters

Globular clusters (GCs) are often used to estimate the dark matter content of galaxies, especially dwarfs, where other kinematic tracers are lacking. These estimates typically assume spherical symmetry and dynamical equilibrium, assumptions that may not hold for the sparse GC population of dwarfs in galaxy clusters. We use a catalog of GCs tagged onto the Illustris simulation to study the accuracy of GC-based mass estimates. We focus on galaxies in the stellar mass range 10$^{8} - 10^{11.8}$ M$_{\odot}$ identified in $9$ simulated Virgo-like clusters. Our results indicate that mass estimates are, on average, quite accurate in systems with GC numbers $N_{\rm GC} \geq 10$ and where the uncertainty of individual GC line-of-sight velocities is smaller than the inferred velocity dispersion, $\sigma_{\rm GC}$. In cases where $N_{\rm GC} \leq 10$, however, biases may result depending on how $\sigma_{\rm GC}$ is computed. We provide calibrations that may help alleviate these biases in methods widely used in the literature. As an application, we find a number of dwarfs with $M_{*} \sim 10^{8.5}\, M_{\odot}$ (comparable to the ultradiffuse galaxy DF2, notable for the low $\sigma_{GC}$ of its $10$ GCs) with $\sigma_{\rm GC} \sim 7$ - $15\; \rm km \rm s^{-1}$. These DF2 analogs correspond to relatively massive systems at their infall time ($M_{200} \sim 1$ - $3 \times 10^{11}$ $M_{\odot}$) which have retained only $3$-$17$ GCs and have been stripped of more than 95$\%$ of their dark matter. Our results suggest that extreme tidal mass loss in otherwise normal dwarf galaxies may be a possible formation channel for ultradiffuse objects like DF2.Comment: 19 pages, 15 figures. Accepted to MNRAS Dec. 11 202