Multiple populations in young clusters detected by Gaia.

The second release of Gaia is revolutionizing the study of star formation and young clusters. In this talk I discussed the potential in detecting multiple populations in young clusters, and the importance of a membership well defined as a starting point. I presented, as an example, the results on the multiple population of one of the closest low-mass star forming region, the Chamaeloen I. Using the Gaia data we found the region to be at slightly higher distance than previously thought. We confirmed the presence of two populations with a peculiar spatial distribution, which might be influenced by the filamentary molecular cloud present in the region. Presenting the method applied to find kinematically the multiple populations, I discussed the effect on the results of taking into account the correlations between parallaxes and proper motions. I finally presented the impact of the refined distance of young stars and clusters using the Gaia data on other fields of star formation, e.g. the study of the evolution of protoplanetary disks and the disk structure

The double population of Chamaeleon I detected by Gaia DR2

Context. Chamaeleon I represents an ideal laboratory to study the cluster formation in a low-mass environment. Recently, two sub clusters spatially located in the northern and southern parts of Chamaeleon I were found with different ages and radial velocities. Aims. In this letter we report new insights into the structural properties, age, and distance of Chamaeleon I based on the astrometric parameters from Gaia data-release 2 (DR2). Methods. We identified 140 sources with a reliable counterpart in the Gaia DR2 archive. We determined the median distance of the cluster using Gaia parallaxes and fitted the distribution of parallaxes and proper motions assuming the presence of two clusters. We derived the probability of each single source of belonging to the northern or southern sub-clusters, and compared the HR diagram of the most probable members to pre-main sequences isochrones. Results. The median distance of Chamaeleon I is ~190 pc. This is about 20 pc larger than the value commonly adopted in the literature. From a Kolmogorov-Smirnov test of the parallaxes and proper-motion distributions we conclude that the northern and southern clusters do not belong to the same parent population. The northern population has a distance dN = 192.7+/-0.4 pc, while the southern one dS = 186.5+/-0.7 pc. The two sub-clusters appear coeval, at variance with literature results, and most of the sources are younger than 3 Myr. The northern cluster is more elongated and extends towards the southern direction partially overlapping with the more compact cluster located in the south. A hint of a relative rotation between the two sub-clusters is also found.Comment: Letter accepted by A&

Orientaciones globales para la formulación de una estrategia de ordenación territorial.

Sin resume

On two South-West Atlantic Diastylis (Cumacea: Crustacea), D. obliquisulcata n. sp. and D. geocostae, with remarks on this speciose genus.

A new species, Diastylis obliquisulcata from eastern Patagonia, is fully described and illustrated based on specimens collected in shallow waters. Diastylis obliquisulcata shares with 14 other species of this genus an opercular maxilliped 3, a short telson and rudimentary exopods on pereopods 3 and 4 in the females. Diastylis obliquisulcata can be easily distinguished from all these species by the females having an oblique groove or sulcus on each side of the carapace. The taxonomic position of this group of species in the genus Diastylis is discussed. The adult male of Diastylis geocostae is described for the first time, the adult female briefly redescribed, and its distribution, up to now known from the type locality only (Cabo Frio, Rio de Janeiro State), is extended to off Rawson, Argentina. Within this species there are reported ontogenetic changes in the carapace ornamentation, in the chaetotaxy of the telson, and in the length ratio between the telson and the uropod peduncle.Fil: Alberico, Natalia Andrea. Universidad de Buenos Aires. Departamento de Ciencias Exactas; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria; ArgentinaFil: Roccatagliata, Daniel Carlos. Universidad de Buenos Aires. Departamento de Ciencias Exactas; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria; Argentin

Two new species of the genus Munnogonium (Isopoda: Asellota: Paramunnidae) from Argentina

Two new species of paramunnid isopods from Argentina are described: Munnogonium quequensis n. sp. from Buenos Aires Province (Quequén) and M. diplonychia n. sp. from Patagonia (Comodoro Rivadavia, Rada Tilly and Puerto Deseado). Both species are distinguished from their congeners by having a tight tuft of setae on the frontal margin. These setae have been discovered after examining the specimens under scanning electron microscope; under dissecting microscope they look like a short blunt median projection. M. diplonychia n. sp. differs from M. quequensis n. sp. by having bifid claws on pereopods II–IV. Eighty of the 92 specimens of M. quequensis n. sp. examined were found attached to the sea star Astropecten brasiliensis, a fact that suggests an association between these two species.Fil: Doti, Brenda Lía. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biologia Experimental. Laboratorio de Invertebrados Ii; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biologia Experimental y Aplicada; ArgentinaFil: Roccatagliata, Daniel Carlos. Universidad de Buenos Aires. Facultad de Cs.exactas y Naturales. Departamento de Biodiversidad y Biologia Experimental. Laboratorio de Invertebrados Ii; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Oficina de Coordinacion Administrativa Ciudad Universitaria. Instituto de Biodiversidad y Biologia Experimental y Aplicada; Argentin

A Herschel view of IC 1396 A: Unveiling the different sequences of star formation

The IC1396A globule in the young cluster Tr37, hosting many young stars and protostars, is assumed to be a site of triggered star formation. We mapped IC1396A with Herschel/PACS at 70 and 160 micron. The Herschel maps trace in great detail the very embedded protostellar objects and the structure of the cloud. PACS data reveal a previously unknown Class 0 object (IC1396A-PACS-1) located behind the ionization front. IC1396A-PACS-1 is not detectable with Spitzer, but shows marginal X-ray emission. The data also allowed to study three of the Class I intermediate-mass objects within the cloud. We derived approximate cloud temperatures to study the effect and potential interactions between the protostars and the cloud. The Class 0 object is associated with the densest and colder part of IC1396A. Heating in the cloud is dominated by the winds and radiation of the O6.5 star HD 206267 and, to a lesser extent, by the effects of the Herbig Ae star V 390 Cep. The surroundings of the Class I and Class II objects embedded in the cloud also appear warmer than the sourceless areas, although most of the low-mass objects cannot be individually extracted due to distance and beam dilution. The observations suggest that at least two episodes of star formation have occurred in IC1396A. One would have originated the known, ~1 Myr-old Class I and II objects in the cloud, and a new wave of star formation would have produced the Class 0 source at the tip of the brigth-rimmed cloud. From its location and properties, IC1396A-PACS-1 is consistent with triggering via radiative driven implosion (RDI) induced by HD 206267. The mechanisms behind the formation of the more evolved population of Class I/II/III objects in the cloud are uncertain. Heating of most of the remaining cloud by Class I/Class II objects and by HD 206267 itself may preclude further star formation in the region.Comment: Accepted by A&A, 9 pages, 5 figure

Representación del HIV-SIDA y performatividad de género en <i>Continuadísimo</i> de Naty Menstrual

Naty Menstrual es una artista trans multifacética: poeta, performer, actriz, escritora. Colaboró en diversos suplementos como Las 12 y Soy, forma parte del equipo de la redacción de El Teje (primer periódico travesti latinoamericano) y lleva adelante un blog (Naty Menstrual Blog. Literatura Travesti Trash) en donde publica sus poemas, crónicas y relatos. Nos vamos a concentrar aquí en los relatos del capítulo “Camarada Kaposi” de Continuadísimo, porque son aquellos en los que ficción y VIH-SIDA se entrelazan.Centro Interdisciplinario de Investigaciones en Géner

Representación del HIV-SIDA y performatividad de género en <i>Continuadísimo</i> de Naty Menstrual

Naty Menstrual es una artista trans multifacética: poeta, performer, actriz, escritora. Colaboró en diversos suplementos como Las 12 y Soy, forma parte del equipo de la redacción de El Teje (primer periódico travesti latinoamericano) y lleva adelante un blog (Naty Menstrual Blog. Literatura Travesti Trash) en donde publica sus poemas, crónicas y relatos. Nos vamos a concentrar aquí en los relatos del capítulo “Camarada Kaposi” de Continuadísimo, porque son aquellos en los que ficción y VIH-SIDA se entrelazan.Centro Interdisciplinario de Investigaciones en Géner

Netflix is burning: countersexuality and HIV-Aids in Pose

El artículo se propone reflexionar acerca de los modos en que Pose, serie emitida por FX (y luego incluida en la plataforma de streaming Netflix), cuestiona los dispositivos hegemónicos que configuran el orden de género e identidad en la sociedad estadounidense de fines de los 80s bajo el gobierno de Ronald Reagan. Esos modos y gestos deconstructivos quiebran los cimientos sobre los que se sostiene la matriz cisheteronormativa, y proponen una sociedad contrasexual en la que el deseo se libera (o al menos intenta hacerlo) de las estrictas ataduras socioculturales que lo delimitan. Por otro lado, se analizará la representación del VIH-Sida en la serie, y cómo esa representación puede ser entendida como una denuncia a las políticas neoliberales y neoconservadoras que se desentendieron de la pandemia y sometieron a miles de vidas al más nefasto abandono y olvido.The article focus on the reflection about the ways in which Pose, a series firstly broadcasted by FX (and then available on Netflix streaming platform), questions the hegemonic mechanisms that set up the gender and identity order within the U.S. society by the end of the 80s during Ronald Reagan government. These deconstructive ways and gestures shake the foundation over which the cisheteronormative matrix sustains itself, and it also propose a countersexual society, in which desire is released (at least it tries to) out of the strictest socio-cultural ties limiting it. Otherwise, it will be analyzed the VIH-Aids representation in the series, and how it may be read as a denouncement of neoconservative and neoliberal policies, which put a blind eye on the pandemic and submitted thousands of lives to the most disastrous abandonment and oblivion.Fil: Roccatagliata, Camila. Universidad Nacional de La Plata. Facultad de Humanidades y Ciencias de la Educación; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentin

Multi-wavelength studies of protoplanetary discs

The early evolutionary stages of a pre-main sequence star are characterised by the formation of a dense accretion disc. These discs provide the environment and material in and from which planets are expected to form. At this epoch circumstellar material is accreting onto the central star, while small dust grains in the disc interior coagulate into larger objects and gravitationally settle into the mid-plane. These are the first steps of planet formation. The study of the dust properties (e.g. grain size distribution, dissipation timescale) in protoplanetary discs is then fundamental to understand how planets form. In this thesis I present three works aimed at studying the formation, dissipation and long term evolution of protoplanetary discs, respectively. The first project investigates the properties of the young binary system Haro~6-10. I present the results of multi-wavelength high spatial resolution observations of Haro 6-10 aimed at characterising the large- and small-scale structures of the binary system. The second project is a combined infrared (Spitzer/IRAC) and X-ray (Chandra/ACIS) survey of the OB association IC~1795. This program is aimed at studying the evolution of protoplanetary discs in regions of massive star formation. The last project is the deepest single dish millimetre survey of debris discs around solar-type stars to date. The aim of this work is to study the evolution of the debris dust mass with time and to characterise the structure of these discs