Fresh Activity in Old Systems: Radio AGN in Fossil Groups of Galaxies

We present the first systematic 1.4 GHz Very Large Array radio continuum survey of fossil galaxy group candidates. These are virialized systems believed to have assembled over a gigayear in the past through the merging of galaxy group members into a single, isolated, massive elliptical galaxy and featuring an extended hot X-ray halo. We use new photometric and spectroscopic data from SDSS Data Release 7 to determine that three of the candidates are clearly not fossil groups. Of the remaining 30 candidates, 67% contain a radio-loud (L_1.4GHz > 10^23 W Hz^-1) active galactic nucleus (AGN) at the center of their dominant elliptical galaxy. We find a weak correlation between the radio luminosity of the AGN and the X-ray luminosity of the halo suggesting that the AGN contributes to energy deposition into the intragroup medium. We only find a correlation between the radio and optical luminosity of the central elliptical galaxy when we include X-ray selected, elliptically dominated non-fossil groups, indicating a weak relationship between AGN strength and the mass assembly history of the groups. The dominant elliptical galaxy of fossil groups is on average roughly an order of magnitude more luminous than normal group elliptical galaxies in optical, X-ray, and radio luminosities and our findings are consistent with previous results that the radio-loud fraction in elliptical galaxies is linked to the stellar mass of a population. The current level of activity in fossil groups suggests that AGN fueling continues long after the last major merger. We discuss several possibilities for fueling the AGN at the present epoch.Comment: Accepted for publication in A

Inteligencias múltiples en terapia ocupacional en relación con la intervención en niños y niñas de 6 a 10 años con diagnóstico de trastorno por déficit atencional con hiperactividad

Tesis (Licenciado en Terapia Ocupacional)La presente investigación, se encuentra enmarcada en el desarrollo del Seminario de Investigación de Pregrado, el cual tiene como objetivo conocer si los/as Terapeutas Ocupacionales de distintas comunas y ciudades de Chile utilizan las Inteligencias Múltiples en el proceso de intervención con niños/as de entre 6 a 10 años diagnosticados con Trastorno por déficit atencional con hiperactividad (TDAH), tanto de forma directa como indirecta. Este estudio se sitúa desde el paradigma interpretativo, utilizando además un diseño de investigación de tipo cualitativo. La estrategia de muestreo es de tipo no probabilístico por conveniencia. Mientras que la técnica de recolección de datos utilizada corresponde a entrevistas semiestructuradas, las cuales debido al contexto de pandemia por COVID-19 se llevaron a cabo de manera virtual. En cuanto al análisis cualitativo de la información obtenida, se realizó bajo la Teoría fundamentada. Con respecto a los resultados obtenidos, estos dan cuenta que no existe un conocimiento acabado sobre la teoría de las Inteligencias Múltiples por parte de los/as Terapeutas Ocupacionales entrevistados/as, no conocen los principios básicos de la teoría y no definen de manera articulada cada uno de los 8 tipos de inteligencias que menciona la misma. Por otra parte, la información existente sobre la teoría de las Inteligencias Múltiples está ligada en su mayoría a lo teórico, teniendo muy limitada la información con respecto a la aplicación de la misma. A pesar de que la mayoría de los Terapeutas Ocupacionales no conocían a cabalidad las Inteligencias Múltiples, se determina a modo de conclusión que las intervenciones de terapia ocupacional pueden ser beneficiadas si en ellas se utiliza la teoría de las Inteligencias Múltiples en relación con el TDAH, además de esta forma se abre la posibilidad de establecer un nuevo paradigma dentro del área de educación en el cual el Terapeuta Ocupacional puede ser protagonista y de esta forma validar y visibilizar las contribuciones, labor e identidad y lograr la valoración de la profesión.The present research is framed in the development of the Undergraduate Research Seminar, which aims to know if Occupational Therapists from different communes and cities of Chile use multiple intelligences in the process of intervention with children between 6 and 10 years old diagnosed with Attention Deficit Hyperactivity Disorder (ADHD), both directly and indirectly. This study is situated from the Interpretative paradigm, and also using a qualitative research design. The sampling strategy is of non-probabilistic type for convenience. While the data collection technique used corresponds to semi-structured interviews, which due to the context of pandemic by COVID-19 were conducted virtually. As for the qualitative analysis of the information obtained, it was carried out under the Grounded Theory. Regarding to the results obtained, they show that there is no finished knowledge about the multiple intelligences´ theory on the part of the Occupational Therapists interviewed, they do not know the basic principles of the theory and they do not define in an articulated way each one of the 8 types of intelligences mentioned in it. On the other hand, the existing information on the theory of multiple intelligences is mostly linked to the theoretical, having very limited information regarding its application. Even though most occupational therapists were not fully aware of multiple intelligences, it is determined as a conclusion that occupational therapy interventions can be benefited if it is used the theory of multiple intelligences in relation to ADHD. In addition, this opens up the possibility of establishing a new paradigm within the area of education in which the occupational therapist can be a protagonist and, in this way, validate and make visible the contributions, work and identity and achieve the valuation of the profession

Cosmological Evolution of Supermassive Black Holes. II. Evidence for Downsizing of Spin Evolution

The spin is an important but poorly constrained parameter for describing supermassive black holes (SMBHs). Using the continuity equation of SMBH number density, we explicitly obtain the mass-dependent cosmological evolution of the radiative efficiency for accretion, which serves as a proxy for SMBH spin. Our calculations make use of the SMBH mass function of active and inactive galaxies (derived in the first paper of this series), the bolometric luminosity function of active galactic nuclei (AGNs), corrected for the contribution from Compton-thick sources, and the observed Eddington ratio distribution. We find that the radiative efficiency generally increases with increasing black hole mass at high redshifts (z>~1), roughly as \eta \propto M_bh^0.5, while the trend reverses at lower redshifts, such that the highest efficiencies are attained by the lowest mass black holes. Black holes with M_bh>~10^8.5M_sun maintain radiative efficiencies as high as \eta~0.3-0.4 at high redshifts, near the maximum for rapidly spinning systems, but their efficiencies drop dramatically (by an order of magnitude) by z~0. The pattern for lower mass holes is somewhat more complicated but qualitatively similar. Assuming that the standard accretion disk model applies, we suggest that the accretion history of SMBHs and their accompanying spins evolve in two distinct regimes: an early phase of prolonged accretion, plausibly driven by major mergers, during which the black hole spins up, then switching to a period of random, episodic accretion, governed by minor mergers and internal secular processes, during which the hole spins down. The transition epoch depends on mass, mirroring other evidence for "cosmic downsizing" in the AGN population; it occurs at z~2 for high-mass black holes, and somewhat later, at z~1, for lower-mass systems.Comment: To appear in the ApJ, 11 pages and 9 figure

On the non-evolution of the dependence of black hole masses on bolometric luminosities for QSOs

There are extremely luminous quasi stellar objects (QSOs) at high redshift which are absent at low redshift. The lower luminosities at low redshifts can be understood as the external manifestation of either a lower Eddington ratio or a lower mass. To distinguish between both effects, we determine the possible dependence of masses and Eddington ratios of QSOs with a fixed luminosity as a function of redshifts; this avoids the Malmquist bias or any other selection effect. For the masses and Eddington ratios derived for a sample of QSOs in the Sloan Digital Sky Survey, we model their evolution by a double linear fit separating the dependence on redshifts and luminosities. The validity of the fits and possible systematic effects were tested by the use of different estimators of masses or bolometric luminosities, and possible intergalactic extinction effects. The results do not show any significant evolution of black hole masses or Eddington ratios for equal luminosity QSOs. The black hole mass only depends on the bolometric luminosity without significant dependence on the redshift as M_{BH}(10^9 M_sun) = 3.4[L_{bol}(10^{47} erg/s})]^{0.65} on average for z<5. This must not be confused with the possible evolution in the formation of black holes in QSOs. The variations of environment might influence the formation of the black holes but not its subsequent accretion. It also leaves a question to be solved: Why are there not QSOs with very high mass at low redshift? A brief discussion of the possible reasons for this is tentatively pointed out.Comment: Accepted to be published in RA

The Chandra COSMOS Survey: III. Optical and Infrared Identification of X-ray Point Sources

The Chandra COSMOS Survey (C-COSMOS) is a large, 1.8 Ms, Chandra program that has imaged the central 0.9 deg^2 of the COSMOS field down to limiting depths of 1.9 10^-16 erg cm^-2 s-1 in the 0.5-2 keV band, 7.3 10^-16 erg cm^-2 s^-1 in the 2-10 keV band, and 5.7 10^-16 erg cm^-2 s-1 in the 0.5-10 keV band. In this paper we report the i, K and 3.6micron identifications of the 1761 X-ray point sources. We use the likelihood ratio technique to derive the association of optical/infrared counterparts for 97% of the X-ray sources. For most of the remaining 3%, the presence of multiple counterparts or the faintness of the possible counterpart prevented a unique association. For only 10 X-ray sources we were not able to associate a counterpart, mostly due to the presence of a very bright field source close by. Only 2 sources are truly empty fields. Making use of the large number of X-ray sources, we update the "classic locus" of AGN and define a new locus containing 90% of the AGN in the survey with full band luminosity >10^42 erg/s. We present the linear fit between the total i band magnitude and the X-ray flux in the soft and hard band, drawn over 2 orders of magnitude in X-ray flux, obtained using the combined C-COSMOS and XMM-COSMOS samples. We focus on the X-ray to optical flux ratio (X/O) and we test its known correlation with redshift and luminosity, and a recently introduced anti-correlation with the concentration index (C). We find a strong anti-correlation (though the dispersion is of the order of 0.5 dex) between C and X/O, computed in the hard band, and that 90% of the obscured AGN in the sample with morphological information live in galaxies with regular morphology (bulgy and disky/spiral), suggesting that secular processes govern a significant fraction of the BH growth at X-ray luminosities of 10^43- 10^44.5 erg/s.Comment: 21 pages, 17 figures, 4 tables; accepted for publication in ApJS. The catalog is available at the urls listed in the pape

Contraction amplitude is a relevant predictor of bolus transit during sitting viscous solution swallows in healthy individuals : preliminary results of a multicenter study using high resolution impedance manometry (HRIM)

Q1Q1https://orcid.org/0000-0002-9219-4548https://orcid.org/0000-0003-1222-0636https://orcid.org/0000-0002-4523-7947Revista Internacional - Indexad