64 research outputs found
Metal Enrichment of the ICM: a 3-D Picture of Chemical and Dynamical Properties
We develop a model for the metal enrichment of the intracluster medium (ICM)
that combines a cosmological non-radiative hydrodynamical N-Body/SPH simulation
of a cluster of galaxies, and a semi-analytic model of galaxy formation. The
novel feature of our hybrid model is that the chemical properties of the
diffuse gas in the underlying simulation are dynamically and consistently
generated from stars in the galaxies. We follow the production of several
chemical elements, provided by low- and intermediate-mass stars, core collapse
and type Ia supernovae. We analyse the spatial distribution of metals in the
ICM, investigate the way in which the chemical enrichment proceeds, and use
iron emissivity as a tracer of gas motions. Fe and O radial abundance profiles
are enhanced in the inner 100 h^-1 kpc in the last Gyr because of the
convergence of enriched gas clumps to the cluster centre. Our results support a
scenario in which part of the central intracluster gas comes from gas clumps
that, in the redshift range of z~0.2 to ~0.5, have been enriched to solar
values and are at large distances from the cluster centre (from ~1 to ~6 h^-1
Mpc) moving at very high velocities (from ~1300 to ~2500 km s^-1). The
turbulent gas motions within the cluster, originated in the inhomogeneous gas
infall during the cluster assembly, are manifested in emission-weighted
velocity maps as gradients that can be as large as ~1000 km s^-1 over distances
of a few hundred kpc. Gradients of this magnitude are also seen in velocity
distributions along sightlines through the cluster centre. Doppler shifting and
broadening suffered by the Fe K 6.7 keV emission line along such sightlines
could be used to probe these gas large-scale motions when they are produced
within an area characterised by high iron line emissivity.Comment: 24 pages, 13 figures, accepted for publication in MNRA
Modeling the Color Magnitude Relation for Galaxy Clusters
We investigate the origin of the colour-magnitude relation (CMR) observed in
cluster galaxies by using a combination of a cosmological N-body simulation of
a cluster of galaxies and a semi-analytic model of galaxy formation. The
departure of galaxies in the bright end of the CMR with respect to the trend
denoted by less luminous galaxies could be explained by the influence of minor
mergersComment: ASP Conference, Galaxies in Isolation; Exploring Nature vs. Nurture;
201
Semi-analytic galaxies - II. Revealing the role of environmental and mass quenching in galaxy formation
We use the semi-analytic model of galaxy formation sag to study the relevance of mass and environmental quenching on satellite galaxies. We find that environmental processes dominate the star formation (SF) quenching of low-mass satellites (M? . 1010.5 M ), whereas high-mass galaxies typically quench as centrals. High-mass galaxies that remain actively forming stars while being accreted are found to be mainly affected by mass quenching after their first infall. For a given stellar mass, our model predicts SF quenching to be less efficient in low-mass haloes both before and after infall, in contradiction with common interpretations of observational data. Our model supports a two-stage scenario to explain the SF quenching. Initially, the SF of satellites resembles that of centrals until the gas cooling rate is reduced to approximately half its value at infall. Then, the SF fades through secular processes that exhaust the cold gas reservoir. This reservoir is not replenished efficiently due to the action of either ram-pressure stripping (RPS) of the hot gas in low-mass satellites, or feedback from the active galactic nucleus (AGN) in high-mass satellites. The delay times for the onset of SF quenching are found to range from ≈ 3 Gyr to ≈ 1 Gyr for low-mass (M? ≈ 1010 M ) and high-mass (M? ≈ 1011 M ) satellites, respectively. SF fades in ≈ 1.5 Gyr, largely independent of stellar mass. We find that the SF quenching of lowmass satellites supports the so-called delay-then-rapid quenching scenario. However, the SF history of z = 0 passive satellites of any stellar mass is better described by a delay-then-fade quenching scenario.Fil: 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; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Observatorio Astronómico de La Plata - Sede Central; ArgentinaFil: Hough, Tomas. 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; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Observatorio Astronómico de La Plata - Sede Central; ArgentinaFil: Vega Martínez, Cristian Antonio. 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: Orsi, Álvaro A.. Centro de Estudios de Física del Cosmos de Aragón; Españ
Local metallicity in simulated galaxies
En la ultima década, la espectroscopia de campo integrado ha expandido nuestra comprensión de la evolución química de las galaxias, dando evidencia de un gradiente radial de la metalicidad de la fase gaseosa. En este trabajo, usamos la simulación cosmologica hidrodinamica eagle para estudiar las propiedades localmente resueltas de las galaxias. Mostramos que la metalicidad local del gas correlaciona con la densidad superficial de masa estelar y anticorrelaciona con la acrecion de gas. Los perfiles de metalicidad resueltos actúan como buenos estimadores de la acrecion de gas, y pueden ser usados para entender los cambios en el enriquecimiento químico de las galaxiasIn the last decade, integral field spectroscopy has expanded our understanding of chemical evolution of galaxies, giving evidence of a radial gradient of gas-phase metallicity. In this work, we use the state-of-art hydrodynamical simulation EAGLE to study the resolved, local properties of galaxies. We show that the local gas metallicity correlates with the stellar mass surface density and anti-correlates with the gas accretion. Resolved metallicity profiles acts as a good estimator of gas accretion, and can be used to understand the changes in the chemical enrichment of galaxies.Fil: Collacchioni, Florencia. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. 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: Correa, C. A.. University of Western Australia; AustraliaFil: Lagos, C .D. P.. Universidad de Copenhagen; DinamarcaFil: 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; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina62° Reunión Anual de la Asociación Argentina de AstronomíaRosarioArgentinaAsociación Argentina de Astronomí
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
The effect of gas accretion on the radial gas metallicity profile of simulated galaxies
We study the effect of the gas accretion rate (M˙ accr) on the radial gas metallicity profile (RMP) of galaxies using the EAGLE cosmological hydrodynamic simulations, focusing on central galaxies of stellar mass M 109 M at z ≤ 1. We find clear relations between M˙ accr and the slope of the RMP (measured within an effective radius), where higher M˙ accr are associated with more negative slopes. The slope of the RMPs depends more strongly on M˙ accr than on stellar mass, star formation rate (SFR), or gas fraction, suggesting M˙ accr to be a more fundamental driver of the RMP slope of galaxies. We find that eliminating the dependence on stellar mass is essential for pinning down the properties that shape the slope of the RMP. Although M˙ accr is the main property modulating the slope of the RMP, we find that it causes other correlations that are more easily testable observationally: At fixed stellar mass, galaxies with more negative RMP slopes tend to have higher gas fractions and SFRs, while galaxies with lower gas fractions and SFRs tend to have flatter metallicity profiles within an effective radius.Fil: Collacchioni, Florencia. 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: Lagos, Claudia D.P.. University of Western Australia; Australia. Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions; Australia. Universidad de Copenhagen; DinamarcaFil: Mitchell, Peter D.. Leiden University; Países Bajos. Université Claude Bernard Lyon 1; FranciaFil: Schaye, Joop. Leiden University; Países BajosFil: Wisnioski, Emily. Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions; Australia. Australian National University. Research School of Astronomy and Astrophysics; AustraliaFil: 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: Correa, Camila A.. Leiden University; Países Bajo
Associations of common breast cancer susceptibility alleles with risk of breast cancer subtypes in BRCA1 and BRCA2 mutation carriers
Introduction: More than 70 common alleles are known to be involved in breast cancer (BC) susceptibility, and several exhibit significant heterogeneity in their associations with different BC subtypes. Although there are differences in the association patterns between BRCA1 and BRCA2 mutation carriers and the general population for several loci, no study has comprehensively evaluated the associations of all known BC susceptibility alleles with risk of BC subtypes in BRCA1 and BRCA2 carriers. Methods: We used data from 15,252 BRCA1 and 8,211 BRCA2 carriers to analyze the associations between approximately 200,000 genetic variants on the iCOGS array and risk of BC subtypes defined by estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (HER2) and triple-negative- (TN) status; morphologic subtypes; histological grade; and nodal involvement. Results: The estimated BC hazard ratios (HRs) for the 74 known BC alleles in BRCA1 carriers exhibited moderate correlations with the corresponding odds ratios from the general population. However, their associations with ER-positive BC in BRCA1 carriers were more consistent with the ER-positive as
Exploring Cosmic Origins with CORE: Cosmological Parameters
We forecast the main cosmological parameter constraints achievable with theCORE space mission which is dedicated to mapping the polarisation of the CosmicMicrowave Background (CMB). CORE was recently submitted in response to ESA'sfifth call for medium-sized mission proposals (M5). Here we report the resultsfrom our pre-submission study of the impact of various instrumental options, inparticular the telescope size and sensitivity level, and review the great,transformative potential of the mission as proposed. Specifically, we assessthe impact on a broad range of fundamental parameters of our Universe as afunction of the expected CMB characteristics, with other papers in the seriesfocusing on controlling astrophysical and instrumental residual systematics. Inthis paper, we assume that only a few central CORE frequency channels areusable for our purpose, all others being devoted to the cleaning ofastrophysical contaminants. On the theoretical side, we assume LCDM as ourgeneral framework and quantify the improvement provided by CORE over thecurrent constraints from the Planck 2015 release. We also study the jointsensitivity of CORE and of future Baryon Acoustic Oscillation and Large ScaleStructure experiments like DESI and Euclid. Specific constraints on the physicsof inflation are presented in another paper of the series. In addition to thesix parameters of the base LCDM, which describe the matter content of aspatially flat universe with adiabatic and scalar primordial fluctuations frominflation, we derive the precision achievable on parameters like thosedescribing curvature, neutrino physics, extra light relics, primordial heliumabundance, dark matter annihilation, recombination physics, variation offundamental constants, dark energy, modified gravity, reionization and cosmicbirefringence. (ABRIDGED
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