Lyman break galaxies as young spheroids

We investigate the nature of Lyman break galaxies (LBGs) using a chemodynamical model for evolution of galaxies. Our models predict an early (the first Gyr) stage of intense star formation in the evolution of massive spheroids which could be identified to the LBGs, observed at redshift $\sim 3$ with strong ongoing star formation. In particular, we are successful in reproducing the properties of the LBG DSF 2237+116 C2 with a model describing a young $\sim L^*$ spheroid. The comparison of the predictions of our models with the observations gives support to the scenario in which LBGs are the progenitors of present-day massive spheroids, i.e. bulges of luminous early type spirals or luminous elliptical galaxies.Comment: 8 pages, 3 figures, accepted for publication in MNRA

Premature dismissal of high-redshift elliptical galaxies

It has recently been argued that single-collapse high-redshift models for elliptical galaxy formation can be rejected because they predict large numbers of very red galaxies at intermediate redshifts which are not seen in deep optical-infrared surveys. We argue, however, that this conclusion is premature since, while much effort has been invested in refining the predictions of hierarchical CDM models, only very simplistic models have been used to study the evolution of galaxies in other cosmogonies (e.g. isocurvature models). We demonstrate that the use of a more realistic multi-zone chemo-dynamical single-collapse model, yields colours at intermediate redshifts which are much bluer than inferred from the one-zone model, and indeed are comparable to those predicted by hierarchical merging despite still allowing $> 90$ of the final stellar mass of elliptical galaxies to be formed in the first Gyr of their evolution. We, therefore, conclude that the one-zone model should be avoided to predict the colours of high-redshift galaxies and that the use of realistic multi-zone models allows the existence of ellipticals at high redshift, being their dismissal premature.Comment: Submitted to MNRA

Isocyanic acid (HNCO) in the Hot Molecular Core G331.512-0.103: Observations and Chemical Modelling

The authors thank the anonymous referee for the useful comments that improved the article. CMC acknowledges the support of CNPq, Conselho Nacional de Desenvolvimento Científico e Tecnológico – Brazil, process number 41714/2016-6. This study was financed in part by the Coordenaçao de Aperfeiçoamento de Pessoal de Níıvel Su- perior – Brasil (CAPES) – Finance Code 001. LB acknowledges support from CONICYT (Comisión Nacional de Investigació Científica y Tecnolóogica) project Basal AFB-170002. EM acknowledges sup- port from the Brazilian agencies FAPESP (Fundaçao de Amparo à Pesquisa do Estado de São Paulo, grant 2014/22095-6) and CNPq (grant 150465/2019-0). MC acknowledges the financial support from the European Union’s Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement no 872081; from the Spanish National Research, Development, and Innovation plan (RDI plan) under the project PID2019-104002GB-C21; the Consejería de Conocimiento, Investigación y Universidad, Junta de Andalucía and European Regional Development Fund (ERDF), ref. SOMM17/6105/UGR; the Ministerio de Ciencia, Innovación y Universidades (ref. COOPB20364); and by the Centro de Estudios Avanzados en Física, Matemáticas y Computación (CEAFMC) of the University of Huelva

PAH lines at high redshift as galaxy evolution marker

Based in chemodynamical models for galaxy evolution,\ud we studied the formation of PAH lines at high\ud redshifts. The model considers carbon and silicon\ud grains, and also PAH molecules. It distinguishes\ud diffuse ISM the molecular clouds associated to star\ud forming regions. The PAH lines provide a good signature\ud of the evolutionary stage of galaxies, star formation\ud rate, in addition to allowing the assessment\ud the relative importance for of AGN and stellar emission\ud on the output of the galaxy. In particular, the\ud line ratio 11.3/7.7 μm is a good marker of the age\ud of high redshift galaxies. We expected that our calculations\ud provide some benchmarks both for future\ud observations both with ground and satellite instruments.\ud The ages derived in this way for high redshift\ud objects could be used to test dark energy models. In\ud addition to the cosmological applications, the observations\ud of the PAH features could be used to check\ud the charge state of PAHs. Apparently, anions and\ud neutrals are favored over cations.Resumo publicado no periódico: Revista Mexicana de Astronomía y Astrofísica. Serie de Conferencias, v. 44, p. 186, 201

Astrobiology in Brazil: early history and perspectives

This review reports the Brazilian history in astrobiology, as well as the first delineation of a vision of the future development of the field in the country, exploring its abundant biodiversity, highly capable human resources and state-of-the-art facilities, reflecting the last few years of stable governmental investments in science, technology and education, all conditions providing good perspectives on continued and steadily growing funding for astrobiology-related research. Brazil is growing steadily and fast in terms of its worldwide economic power, an effect being reflected in different areas of the Brazilian society, including industry, technology, education, social care and scientific production. In the field of astrobiology, the country has had some important landmarks, more intensely after the First Brazilian Workshop on Astrobiology in 2006. The history of astrobiology in Brazil, however, is not so recent and had its first occurrence in 1958. Since then, researchers carried out many individual initiatives across the country in astrobiology-related fields, resulting in an ever growing and expressive scientific production. The number of publications, including articles and theses, has particularly increased in the last decade, but still counting with the effort of researchers working individually. That scenario started to change in 2009, when a formal group of Brazilian researchers working with astrobiology was organized, aiming at congregating the scientific community interested in the subject and to promote the necessary interactions to achieve a multidisciplinary work, receiving facilities and funding from the University de Sao Paulo and other funding agencies. Received 29 February 2012, accepted 17 May 2012, first published online 18 July 2012Sao Paulo Research Foundation (FAPESP)FAPESP (Sao Paulo Research Foundation)National Institute of Space Research (INEspaco - MCT/CNPq)National Institute of Space Research (INEspaco MCT/CNPq)Brazilian Antarctic Program (PROANTAR - CNPq)Brazilian Antarctic Program (PROANTAR CNPq)Universidade de Sao PauloUniversidade de Sao PauloBrazilian Astrobiology Research Center (NAP-Astrobio)Brazilian Astrobiology Research Center (NAPAstrobio