Environment and Properties of Submillimeter Galaxies

Extra-galactic surveys with large submillimeter bolometer cameras discovered a population of dust obscured starbursting galaxies at high redshifts. These submillimeter galaxies (SMGs) are crucial in the stellar build up of the Universe, and their abundance and epoch of formation place important constraints in models of galaxy evolution. Using the Max-Planck Millimeter Bolometer Array (MAMBO) on the IRAM 30 m telescope, we mapped the central 20'x20' of the COSMOS field at 1.2 mm to an rms level of 1 mJy per 11'' beam. We found 15 significant (S/N>4) millimeter sources, 11 of which have a reliable 1.4 GHz Very Large Array (VLA) radio counterpart. Ten more lower significance millimeter sources were identified based on a radio association. We used 24 um data to complement the radio identifications. Using a stacking analysis on the MAMBO map, we estimated that radio (S_nu>45 uJy), 24 um (S_nu>550 uJy) and millimeter sources (S_nu>4 mJy) contribute with about 12% of the total cosmic background radiation at 1.2 mm. About 70% of these SMGs could be classified as high-redshift star-forming galaxies based on the (B-z) and (z-K) colors and ~35% have mid-infrared (IR) colors consistent with the presence of a powerful active galactic nuclei (AGN). We find a median radio/millimeter and optical/IR photometric redshifts of 2.3 and 2.6, respectively, and a median stellar mass of 10^{11.4+/-0.4} solar masses, in agreement with previous studies of SMGs. This suggests that these galaxies are among the most massive at high-redshift. We studied the environment of our MAMBO sources by constructing projected density maps of low-redshift and high-redshift K-band selected galaxies. We found that four MAMBO sources are located at the center of strong overdensities of high-redshift galaxies. These associations are statistically likely to be real. The photometric redshifts of the galaxies in these structures are consistent with the ones of their associated SMGs, all of them being in the range z=1.5-2.0. They do not appear to be forming a red-sequence in the color-magnitude diagrams, but the SMGs are among the brightest K-band selected objects in these overdense galaxy groups. The overdensities are compact in size, typically with a diameter of ~20'', or ~170 kpc at z=1.5-2.0. This provides evidence supporting that SMGs are the progenitors of local spheroidals. Using the Plateau-du-Bureau Interferometer (PdBI), we obtained 1.3 mm continuum maps centered at the position of three significant MAMBO sources. Two of them lack significant counterparts (S/N>4) in the radio maps (J100007+021149 and J100026+021529). The other MAMBO source (J100008+02130) is embedded in a strong overdensity of high-redshift galaxies. Each of the former two MAMBO sources could be identified with single S/N>3.5 PdBI 1.3 mm sources. They could be associated with ~3 sigma radio peaks and faint optical counterparts. Their optical/IR and radio/millimeter photometric redshifts indicate that these sources are at z>3. This suggests that an important fraction of the SMGs is located at redshifts higher than the standard median value of 2.3 estimated from spectroscopic surveys of radio-selected SMGs. The MAMBO source in the strong overdensity appears to be associated with more than two PdBI 1.3 mm sources, however only one of them showed a radio counterpart. The detection of multiple millimeter components supports the picture that obscured galaxies do appear in galaxy groups. Using the IRAM 30 m telescope, we detected four carbon monoxide (CO) emission lines in one of our brightest MAMBO sources (J100038+020822). This source is a bright type-1 AGN at z=1.8275. Large velocity gradient modeling of the CO line intensities yields molecular gas (H_2) densities in the range 10^{3.5-4.0} cm^{-3} and kinetic temperatures between 50 K and 200 K. We find a dust mass of 1.2x10^9 solar masses, and a cold and hot dust temperatures of 42+/-5 K and 160+/-25 K, respectively. A comparison of its multi-wavelength SED and morphology indicates that this object shares properties of both starburst and AGN, being likely in the transition between a starbursting SMG to a QSO

Construcción socio-imaginaria de relaciones sociales: la desconfianza y el descontento en el Chile post-dictadura

From a dialogic perspective between philosophy, social sciences and social reality leading to a renewed epistemology, the article intends to comprehend: the phenomenon of citizen distrust with social institutions of the Chilean State, the distrust of the citizen against the current market logics such as the commodification of the social relations, and finally, the distrust between citizens in everyday spaces. The work is framed under the studies of sociology and anthropology, from the perspective of the social imaginaries and it is aimed to the deconstruction of mistrust in many central elements of social links in post-dictatorship Chile and their actual or potential relationship with discontent.Desde una perspectiva dialógica entre la filosofía, las ciencias sociales y la realidad social, que desemboca en una epistemología renovada, el artículo busca comprender: el fenómeno de la desconfianza del ciudadano con instituciones de la sociedad y del Estado chileno, la desconfianza del ciudadano frente a lógicas actuales del mercado como la mercantilización de las relaciones sociales y, por último, la desconfianza entre ciudadanos en espacios cotidianos. El trabajo es parte de los estudios de la sociología y de la antropología desde la perspectiva de los imaginarios sociales y se interesa en la deconstrucción de la desconfianza en tanto elemento característico central de los vínculos sociales en el Chile de la post-dictadura y de su relación potencial o real con el descontento

Evaluation of public and private health care systems

Indexación: ScieloBackground: There is a great degree of dissatisfaction with the Chilean health care system. Aim: To investigate which are the most relevant perceived factors when the health care system is evaluated. Material and Methods: Analysis of a survey about the Chilean health care system carried out during 2011, 2012 and 2013, involving 2,801 respondents. Results: The response capacity of emergency systems was the main factor considered for the evaluation of public and private health care systems. Respondents who were affiliated to private insurance systems also took into consideration the quality of medical infrastructure. Conclusions: There are different factors considered when public or private health care systems are evaluated. Key words: Delivery of health care; Public Health; Public Opinion; Chile

La producción de contenidos para radios comunitarias

La implementación de la Ley de Servicios de Comunicación Audiovisual hizo fundamental la formación de nuevos actores que intenten capacitarse para producir y generar contenido de calidad y que sea una alternativa hacia la reconstrucción del tejido social, la legitimación del conocimiento y la democratización de la comunicación. Este trabajo constituye el desarrollo de una herramienta que se encuentre al alcance de la mayor cantidad de comunidades posibles y que construya desde todos los actores y se repiense según vaya cambiando los intereses y necesidades que las radios comunitarias encuentren como prioritarias en relación a la generación de contenidos y capacitación de sus trabajadores. Este Trabajo de Integración Final (TIF) pretende ser un espacio donde se pueda aprender a producir contenido, que invite a reflexionar acerca de cómo pensar este medio tan maravilloso que es la radio. Pero no solo eso, sino que también actúe como intercambio de experiencias y de ideas, que aporte la construcción de una sociedad con pluralidad de voces.Facultad de Periodismo y Comunicación Socia

JVLA 1.5GHz continuum observation of CLASH clusters I: radio properties of the BCGs

We present high-resolution ($\sim 1"$), 1.5 GHz continuum observations of the brightest cluster galaxies (BCGs) of 13 CLASH (Cluster Lensing And Supernova survey with Hubble) clusters at $0.18<z<0.69$ with the Karl G. Jansky Very Large Array (JVLA). Radio emission is clearly detected and characterized for 11 BCGs, while for two of them we obtain only upper limits to their radio flux ($<0.1$ mJy at 5$\sigma$ confidence level). We also consider five additional clusters whose BCG is detected in FIRST or NVSS. We find radio powers in the range from $2\times 10^{23}$ to $\sim 10^{26}$ $W~Hz^{-1}$ and radio spectral indices $\alpha_{1.5}^{30}$ (defined as the slope between 1.5 and 30 GHz) distributed from $\sim -1$ to $-0.25$ around the central value $\langle \alpha \rangle= - 0.68$. The radio emission from the BCGs is resolved in three cases (Abell 383, MACS J1931, and RX J2129), and unresolved or marginally resolved in the remaining eight cases observed with JVLA. In all the cases the BCGs are consistent with being powered by active galactic nuclei (AGN). The radio power shows a positive correlation with the BCG star formation rate, and a negative correlation with the central entropy of the surrounding intracluster medium (ICM) except in two cases (MACS J1206 and CL J1226). Finally, over the restricted range in radio power sampled by the CLASH BCGs, we observe a significant scatter between the radio power and the average mechanical power stored in the ICM cavities.Comment: 19 pages, 11 figures, significantly improved following referee's comments. Accepted by Ap

AGN and Star-Formation Properties of Inside-out Assembled Galaxy Candidates at z<0.1

We study a sample of 48127 galaxies selected from the SDSS MPA-JHU catalogue, with $\log M_{\star}/M_{\odot} = 10.73 - 11.03$ and $z<0.1$. Local galaxies in this stellar mass range have been shown to have systematically shorter assembly times within their inner regions ($<0.5~R_{50}$) when compared to that of the galaxy as a whole, contrary to lower or higher mass galaxies which show consistent assembly times at all radii. Hence, we refer to these galaxies as Inside-Out Assembled Galaxy (IOAG) candidates. We find that the majority of IOAG candidates with well-detected emission lines are classified as either AGN (40%) or composite (40%) in the BPT diagram. We also find that the majority of our sources are located below the main sequence of star formation, and within the green valley or red sequence. Most BPT-classified star-forming IOAG candidates have spiral morphologies and are in the main sequence, whereas Seyfert 2 and composites have mostly spiral morphologies but quiescent star formation rates (SFRs). We argue that a high fraction of IOAG candidates seem to be in the process of quenching, moving from the blue cloud to the red sequence. Those classified as AGN have systematically lower SFRs than star-forming galaxies suggesting that AGN activity may be related to this quenching. However, the spiral morphology of these galaxies remains in place, suggesting that the central star-formation is suppressed before the morphological transformation occurs.Comment: 11 pages, 9 figure, accepted for publication in MNRAS. A video description can be seen here https://youtu.be/oxfjbqMqeQ