The Milky Way Bulge: Observed properties and a comparison to external galaxies

The Milky Way bulge offers a unique opportunity to investigate in detail the role that different processes such as dynamical instabilities, hierarchical merging, and dissipational collapse may have played in the history of the Galaxy formation and evolution based on its resolved stellar population properties. Large observation programmes and surveys of the bulge are providing for the first time a look into the global view of the Milky Way bulge that can be compared with the bulges of other galaxies, and be used as a template for detailed comparison with models. The Milky Way has been shown to have a box/peanut (B/P) bulge and recent evidence seems to suggest the presence of an additional spheroidal component. In this review we summarise the global chemical abundances, kinematics and structural properties that allow us to disentangle these multiple components and provide constraints to understand their origin. The investigation of both detailed and global properties of the bulge now provide us with the opportunity to characterise the bulge as observed in models, and to place the mixed component bulge scenario in the general context of external galaxies. When writing this review, we considered the perspectives of researchers working with the Milky Way and researchers working with external galaxies. It is an attempt to approach both communities for a fruitful exchange of ideas.Comment: Review article to appear in "Galactic Bulges", Editors: Laurikainen E., Peletier R., Gadotti D., Springer Publishing. 36 pages, 10 figure

The CALIFA survey across the Hubble sequence: Spatially resolved stellar population properties in galaxies

© ESO, 2015. Various different physical processes contribute to the star formation and stellar mass assembly histories of galaxies. One important approach to understanding the significance of these different processes on galaxy evolution is the study of the stellar population content of today's galaxies in a spatially resolved manner. The aim of this paper is to characterize in detail the radial structure of stellar population properties of galaxies in the nearby universe, based on a uniquely large galaxy sample, considering the quality and coverage of the data. The sample under study was drawn from the CALIFA survey and contains 300 galaxies observed with integral field spectroscopy. These cover a wide range of Hubble types, from spheroids to spiral galaxies, while stellar masses range from MBlack star ∼ 109 to 7 × 1011 M⊙. We apply the fossil record method based on spectral synthesis techniques to recover the following physical properties for each spatial resolution element in our target galaxies: the stellar mass surface density (μBlack star), stellar extinction (AV), light-weighted and mass-weighted ages ('log age'L, 'log age'M), and mass-weighted metallicity ('log ZBlack star'M). To study mean trends with overall galaxy properties, the individual radial profiles are stacked in seven bins of galaxy morphology (E, S0, Sa, Sb, Sbc, Sc, and Sd). We confirm that more massive galaxies are more compact, older, more metal rich, and less reddened by dust. Additionally, we find that these trends are preserved spatially with the radial distance to the nucleus. Deviations from these relations appear correlated with Hubble type: earlier types are more compact, older, and more metal rich for a given MBlack star, which is evidence that quenching is related to morphology, but not driven by mass. Negative gradients of 'log age'L are consistent with an inside-out growth of galaxies, with the largest 'log age'L gradients in Sb-Sbc galaxies. Further, the mean stellar ages of disks and bulges are correlated and with disks covering a wider range of ages, and late-type spirals hosting younger disks. However, age gradients are only mildly negative or flat beyond R ∼ 2 HLR (half light radius), indicating that star formation is more uniformly distributed or that stellar migration is important at these distances. The gradients in stellar mass surface density depend mostly on stellar mass, in the sense that more massive galaxies are more centrally concentrated. Whatever sets the concentration indices of galaxies obviously depends less on quenching/morphology than on the depth of the potential well. There is a secondary correlation in the sense that at the same MBlack star early-type galaxies have steeper gradients. The μBlack star gradients outside 1 HLR show no dependence on Hubble type. We find mildly negative 'log ZBlack star'M gradients, which are shallower than predicted from models of galaxy evolution in isolation. In general, metallicity gradients depend on stellar mass, and less on morphology, hinting that metallicity is affected by both - the depth of the potential well and morphology/quenching.Support from the Spanish Ministerio de Economia y Competitividad, through projects AYA2010-15081 (PI R.G.D.), and Junta de Andalucia FQ1580 (PI R.G.D.), AYA2010-22111-C03-03, and AYA2010-10904E (S.F.S.). We also thank the Viabilidad, Diseno, Acceso y Mejora funding program, ICTS-2009-10, for funding the data acquisition of this project. R.C.F. thanks the hospitality of the IAA and the support of CAPES and CNPq. R.G.D. acknowledges the support of CNPq (Brazil) through Programa Ciencia sem Fronteiras (401452/2012-3). A.G. acknowledges support from EU FP7/2007-2013 under grant agreement n.267251 (AstroFIt) and from the EU Marie Curie Integration Grant >SteMaGE> Nr. PCIG12-GA-2012-326466. C.J.W. acknowledges support through the Marie Curie Career Integration Grant 303912. E.P. acknowledges support from the Guillermo Haro program at INAOE. Support for L.G. is provided by the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS. L.G. acknowledges support by CONICYT through FONDECYT grant 3140566. J.I.P. acknowledges financial support from the Spanish MINECO under grant AYA2010-21887-C04-01 and from Junta de Andalucia Excellence Project PEX2011-FQM7058. I.M., J.M. and A.d.O. acknowledge support from the project AYA2013-42227-P. RAM is funded by the Spanish program of International Campus of Excellence Moncloa (CEI). J.M. A. acknowledges support from the European Research Council Starting Grant (SEDmorph; P.I. V. Wild).Peer Reviewe

J/psi production as a function of charged-particle pseudorapidity density in p-Pb collisions at root s(NN)=5.02 TeV

We report measurements of the inclusive J/ψ yield and average transverse momentum as a function of charged-particle pseudorapidity density dNch/dη in p–Pb collisions at sNN=5.02TeV with ALICE at the LHC. The observables are normalised to their corresponding averages in non-single diffractive events. An increase of the normalised J/ψ yield with normalised dNch/dη, measured at mid-rapidity, is observed at mid-rapidity and backward rapidity. At forward rapidity, a saturation of the relative yield is observed for high charged-particle multiplicities. The normalised average transverse momentum at forward and backward rapidities increases with multiplicity at low multiplicities and saturates beyond moderate multiplicities. In addition, the forward-to-backward nuclear modification factor ratio is also reported, showing an increasing suppression of J/ψ production at forward rapidity with respect to backward rapidity for increasing charged-particle multiplicity

Efeito da seleção para peso pós-desmama sobre indicadores da eficiência produtiva de vacas da raça Nelore Effects of selection for post weaning weight on Nellore cow productivity efficiency indicators

O objetivo deste estudo foi avaliar indicadores da eficiência produtiva de vacas Nelore selecionadas para peso pós-desmama, enfocados nas relações peso bezerro e peso da vaca, nos rebanhos controle (NeC), não-selecionados para peso pós-desmama, seleção (NeS) e tradicional (NeT). As análises envolveram 3929 e 3906 pesos dos bezerros aos 120 (P120) e 210 (P210) dias de idade, respectivamente. Os pesos das vacas àquelas idades também foram considerados, obtendo-se 3824 (PV120) e 3777 (PV210) registros, respectivamente, para 120 e 210 dias. A análise incluiu 183, 375 e 554 vacas dos rebanhos NeC, NeS e NeT, respectivamente. Para as análises utilizou-se o procedimento GLM/SAS, em modelos que incluíram os efeitos fixos de rebanho, ano e mês de nascimento, sexo do bezerro, idade da vaca ao parto e as interações rebanho x ano de nascimento e ano x mês de nascimento. Todos os efeitos foram significativos. Os resultados mostraram respostas correlacionadas positivas na seleção para peso pós-desmama nos pesos dos bezerros e, em menor magnitude, no peso das vacas. As relações peso bezerro e peso da vaca apresentaram valores médios ajustados de 249,0±2,1; 253,7±1,6; e 255,8±1,2 g/kg para R120 e 362,9±2,8; 368,5±2,1; e 374,6±1,7 para NeC, NeS e NeT em R210, respectivamente, indicando que, nas duas idades, os rebanhos NeS e NeT produziram mais quilogramas de bezerro por quilogramas de vaca, quando comparados ao NeC.<br>The objective of this study was to evaluate the productivity efficiency indicators of cows selected for post-weaning weight, with emphasis in the calf-cow weight ratios, in a controlled herd (NeC), unselected for post-weaning weight, selection (NeS) and conventional (NeT). The analysis involved 3929 and 3906 calves weights at the 120 (P120) and 210 (P210) days of age, respectively. The cow weights at those ages were also considered, and the recorded numbers were 3824 (PV120) and 3777 (PV210), respectively, for 120 and 210 days. The analysis included 183, 375 and 554 cows from NeC, NeS and NeT, respectively. The SAS/GLM procedure was used in the data analyses. The model included the effects of herd, year and month of birth, and sex of calf, age of cow at calving, and the interactions herd x year, and year x month of birth. All effects were significant. The results showed a positive correlated response in the selection for post weaning on the calf weights and, low response, on cow weights. The calf weight/cow weight ratios showed average adjusted values of 249.0±2.1, 253.7±1.6 and 255.8±1.2 g/kg for R120, and 362.9±2.8, 368.5±2.1 and 374.6±1.7 g/kg for NeC, NeS and NeT at R210, respectively, and indicated that, at both ages, the NeS and NeT herds produced more kg of calf by kg of cow when compared to NeC

First measurement of jet mass in PbâPb and pâPb collisions at the LHC

This letter presents the first measurement of jet mass in Pb–Pb and p–Pb collisions at sNN=2.76 TeV and sNN=5.02 TeV, respectively. Both the jet energy and the jet mass are expected to be sensitive to jet quenching in the hot Quantum Chromodynamics (QCD) matter created in nuclear collisions at collider energies. Jets are reconstructed from charged particles using the anti-kT jet algorithm and resolution parameter R=0.4. The jets are measured in the pseudorapidity range |ηjet|<0.5 and in three intervals of transverse momentum between 60 GeV/c and 120 GeV/c. The measurement of the jet mass in central Pb–Pb collisions is compared to the jet mass as measured in p–Pb reference collisions, to vacuum event generators, and to models including jet quenching. It is observed that the jet mass in central Pb–Pb collisions is consistent within uncertainties with p–Pb reference measurements. Furthermore, the measured jet mass in Pb–Pb collisions is not reproduced by the quenching models considered in this letter and is found to be consistent with PYTHIA expectations within systematic uncertainties