Detection of CO+ in the nucleus of M82

We present the detection of the reactive ion CO+ towards the prototypical starburst galaxy M82. This is the first secure detection of this short-lived ion in an external galaxy. Values of [CO+]/[HCO+]>0.04 are measured across the inner 650pc of the nuclear disk of M82. Such high values of the [CO+]/[HCO+] ratio had only been previously measured towards the atomic peak in the reflection nebula NGC7023. This detection corroborates that the molecular gas reservoir in the M82 disk is heavily affected by the UV radiation from the recently formed stars. Comparing the column densities measured in M82 with those found in prototypical Galactic photon-dominated regions (PDRs), we need \~20 clouds along the line of sight to explain our observations. We have completed our model of the molecular gas chemistry in the M82 nucleus. Our PDR chemical model successfully explains the [CO+]/[HCO+] ratios measured in the M~82 nucleus but fails by one order of magnitude to explain the large measured CO+ column densities (~1--4x10^{13} cm^{-2}). We explore possible routes to reconcile the chemical model and the observations.Comment: 12 pages, 2 figure

Protostellar clusters in intermediate-mass (IM) star forming regions

The transition between the low density groups of T Tauri stars and the high density clusters around massive stars occurs in the intermediate-mass (IM) range (M$_*$$\sim$2--8 M$_\odot$). High spatial resolution studies of IM young stellar objects (YSO) can provide important clues to understand the clustering in massive star forming regions. Aims: Our aim is to search for clustering in IM Class 0 protostars. The high spatial resolution and sensitivity provided by the new A configuration of the Plateau de Bure Interferometer (PdBI) allow us to study the clustering in these nearby objects. Methods: We have imaged three IM Class 0 protostars (Serpens-FIRS 1, IC 1396 N, CB 3) in the continuum at 3.3 and 1.3mm using the PdBI. The sources have been selected with different luminosity to investigate the dependence of the clustering process on the luminosity of the source. Results: Only one millimeter (mm) source is detected towards the low luminosity source Serpens--FIRS 1. Towards CB 3 and IC1396 N, we detect two compact sources separated by $\sim$0.05 pc. The 1.3mm image of IC 1396 N, which provides the highest spatial resolution, reveal that one of these cores is splitted in, at least, three individual sources.Comment: 4 pages, 3 figures, accepted for publication in Astronomy and Astrophysics Letters (Special Feature IRAM/PdB

Nueva ruralidad comunitaria y sustentabilidad : contribuciones al campo emergente de la economía-ecológica

La perspectiva ética (ecojusticia, justicia distributiva) es una vertiente en exploración en el proceso de la emergencia de la economía ecológica como campo diferenciado de la racionalidad económica ortodoxa; sobre todo para la significación de la sustentabilidad en el contexto socioambiental latinoamericano. La interacción desarrollada con diferentes grupos de trabajo en comunidades rurales de los estados mexicanos de Oaxaca y Michoacán (inmersos en procesos de una nueva ruralidad comunitaria), ofrecen referentes empíricos y analíticos en esta tarea. Estas praxis campesinas despliegan heterogéneos procesos de apropiación social de la naturaleza caracterizada por procurar una mayor articulación entre la responsabilidad social y la ambiental. De ahí la posibilidad de favorecer un diálogo de saberes como propuesta metodológica en la formulación de estrategias alternativas para la gestión sustentable de recursos. Este conjunto de estrategias se expresan a través de un modelo analítico.Ecological economics criticizes mainstream economic approaches to rationality and supports alternative models based on environmental and distributive justice concerns. As these models can be particularly relevant for analyzing environmental issues in Latin America, this study employs them to consider the interaction of several rural communities, immersed in processes of constructing new concepts and practices of communitarian rurality in the Mexican states of Oaxaca and Michoacán. We argue that the study of these processes offers valuable empirical and analytical insights, which suggest that these initiatives aim at the social appropriation of nature by incorporating the need for a greater coordination between social and environmental responsibility. Furthermore, the study of these processes can offer useful lessons for developing a methodology that can help foster a dialogue among different knowledge systems as part of the search for defining alternative strategies for sustainable resource management. Finally, we formalize this set of strategies into an analytical model

The 0.03-10Mo mass function of young open clusters

We report the present day mass functions (PDMFs) of 3 young open clusters over a mass range from 30 Jupiter masses to 10~\msunn. The PDMFs of the 3 clusters are remarkably similar, suggesting little impact of specific conditions (stellar density, metallicity, early dynamical evolution) on the mass distribution. Functional forms are provided to allow quantitative comparison with MFs derived in other environments.Comment: 6 pages, to appear in "IMF@50", Corbelli, Palla, Zinnecker ed

The IC1396N proto-cluster at a scale of 250 AU

We investigate the mm-morphology of IC1396N with unprecedented spatial resolution to analyze its dust and molecular gas properties, and draw comparisons with objects of similar mass. We have carried out sensitive observations in the most extended configurations of the IRAM Plateau de Bure interferometer, to map the thermal dust emission at 3.3 and 1.3mm, and the emission from the $J$=13$_k\to12_k$ hyperfine transitions of methyl cyanide (CH$_3$CN). We unveil the existence of a sub-cluster of hot cores in IC1396N, distributed in a direction perpendicular to the emanating outflow. The cores are embedded in a common envelope of extended and diffuse dust emission. We find striking differences in the dust properties of the cores ($\beta\simeq$ 0) and the surrounding envelope ($\beta\simeq$ 1), very likely testifying to differences in the formation and processing of dust material. The CH$_3$CN emission peaks towards the most massive hot core and is marginally extended in the outflow direction

Far infrared CO and H2_2O emission in intermediate-mass protostars

Intermediate-mass young stellar objects (YSOs) provide a link to understand how feedback from shocks and UV radiation scales from low to high-mass star forming regions. Aims: Our aim is to analyze excitation of CO and H$_2$O in deeply-embedded intermediate-mass YSOs and compare with low-mass and high-mass YSOs. Methods: Herschel/PACS spectral maps are analyzed for 6 YSOs with bolometric luminosities of $L_\mathrm{bol}\sim10^2 - 10^3$ $L_\odot$. The maps cover spatial scales of $\sim 10^4$ AU in several CO and H$_2$O lines located in the $\sim55-210$ $\mu$m range. Results: Rotational diagrams of CO show two temperature components at $T_\mathrm{rot}\sim320$ K and $T_\mathrm{rot}\sim700-800$ K, comparable to low- and high-mass protostars probed at similar spatial scales. The diagrams for H$_2$O show a single component at $T_\mathrm{rot}\sim130$ K, as seen in low-mass protostars, and about $100$ K lower than in high-mass protostars. Since the uncertainties in $T_\mathrm{rot}$ are of the same order as the difference between the intermediate and high-mass protostars, we cannot conclude whether the change in rotational temperature occurs at a specific luminosity, or whether the change is more gradual from low- to high-mass YSOs. Conclusions: Molecular excitation in intermediate-mass protostars is comparable to the central $10^{3}$ AU of low-mass protostars and consistent within the uncertainties with the high-mass protostars probed at $3\cdot10^{3}$ AU scales, suggesting similar shock conditions in all those sources.Comment: Accepted to Astronomy & Astrophysics. 4 pages, 5 figures, 3 table

Do Natural Disasters Affect Human Capital? An Assessment Based on Existing Empirical Evidence

The last few years have seen a notable increase in the number of studies investigating the causes and effects of natural disasters in many dimensions. This paper seeks to review and assess available empirical evidence on the ex-post microeconomic effects of natural disasters on the accumulation of human capital, focusing on consumption, nutrition, education and health, including mental health. Three major findings come forward from this work. First, disasters appear to bring substantial damages to human capital, including death and destruction, and produce deleterious consequences on nutrition, education, health and many income-generating processes. Furthermore, some of these detrimental effects are both large and long-lasting. Second, there is a large degree of heterogeneity in the size – but not much in the direction – of the impacts on different socioeconomic groups. Yet, an empirical regularity across natural hazards is that the poorest carry the heaviest burden of the effects of disasters across different determinants and outcomes of human capital. Finally, although the occurrence of natural hazards is mostly out of control of authorities, there still is a significant room for policy action to minimize their impacts on the accumulation of human capital. We highlight the importance of flexible safety nets as well as the double critical role of accurate and reliable information to monitor risks and vulnerabilities, and identify the impacts and responses of households once they are hit by a disaster. The paper also lays out existing knowledge gaps, particularly in regard to the need of improving our understanding of the impacts of disasters on health outcomes, the mechanisms of transmission and the persistence of the effects in the long-run.natural disasters, human capital accumulation

Physical structure of the photodissociation regions in NGC 7023: Observations of gas and dust emission with <i>Herschel</i>

The determination of the physical conditions in molecular clouds is a key step towards our understanding of their formation and evolution of associated star formation. We investigate the density, temperature, and column density of both dust and gas in the photodissociation regions (PDRs) located at the interface between the atomic and cold molecular gas of the NGC 7023 reflection nebula. We study how young stars affect the gas and dust in their environment. Our approach combining both dust and gas delivers strong constraints on the physical conditions of the PDRs. We find dense and warm molecular gas of high column density in the PDRs