The two Ultraluminous X-ray sources in the galaxy NGC 925

NGC 925 ULX-1 and ULX-2 are two ultraluminous X-ray sources in the galaxy NGC 925, at a distance of 8.5 Mpc. For the first time, we analyzed high quality, simultaneous XMM-Newton and NuSTAR data of both sources. Although at a first glance ULX-1 resembles an intermediate mass black hole candidate (IMBH) because of its high X-ray luminosity ($(2$$-$$4)\times10^{40}$ erg s$^{-1}$) and its spectral/temporal features, a closer inspection shows that its properties are more similar to those of a typical super-Eddington accreting stellar black hole and we classify it as a `broadened disc' ultraluminous X-ray source. Based on the physical interpretation of this spectral state, we suggest that ULX-1 is seen at small inclination angles, possibly through the evacuated cone of a powerful wind originating in the accretion disc. The spectral classification of ULX-2 is less certain, but we disfavour an IMBH accreting at sub-Eddington rates as none of its spectral/temporal properties can be associated to either the soft or hard state of Galactic accreting black hole binaries.Comment: Accepted on MNRAS with very minor comments, 7 pages, 5 figures, 1 tabl

High redshift BL Lac objects: spectroscopy of candidates

We report on 16 BL Lacertae objects that were proposed to be at z > 1. We present spectroscopic observations secured at the 10.4m GTC that allowed us to assess the redshift of these sources. In particular, for five objects we disprove the previous value of the redshift reported in literature and found that they lie at z < 1. Moreover, two of them exhibit broad emission lines that are not characteristic of BL Lacertae object. On the other hand, for eight targets we improve the tentative value of z, previously based on only one feature, by detecting a number emission lines. Finally, in three cases we detect onset of Ly-{\alpha} forest at z > 2.50. Based on the new high quality spectra we found that only half of the observed objects can be classified as bona-fine BL Lacs.Comment: Accepted for publication in Ap

MAD Adaptive Optics Imaging of High Luminosity Quasars: A Pilot Project

We present near-IR images of five luminous quasars at z~2 and one at z~4 obtained with an experimental adaptive optics instrument at the ESO Very Large Telescope. The observations are part of a program aimed at demonstrating the capabilities of multi-conjugated adaptive optics imaging combined with the use of natural guide stars for high spatial resolution studies on large telescopes. The observations were mostly obtained under poor seeing conditions but in two cases. In spite of these non optimal conditions, the resulting images of point sources have cores of FWHM ~0.2 arcsec. We are able to characterize the host galaxy properties for 2 sources and set stringent upper limits to the galaxy luminosity for the others. We also report on the expected capabilities for investigating the host galaxies of distant quasars with adaptive optics systems coupled with future Extremely Large Telescopes. Detailed simulations show that it will be possible to characterize compact (2-3 kpc) quasar host galaxies for QSOs at z = 2 with nucleus K-magnitude spanning from 15 to 20 (corresponding to absolute magnitude -31 to -26) and host galaxies that are 4 mag fainter than their nuclei.Comment: 19 pages, 12 figures, accepted for pubblication in The Astronomical Journa

Behavioral disorders in elementary school children and their relationship with family structure

The increase in behavioral disorders in children and adolescents is a factor of concern for health professionals. During the internship of nursing students in a public school, it was observed that 15 elementary students presented a medical diagnosis of mental disorder and/or were taking controlled medication. The present study aimed to characterize those students, and to identify the existence of risk factors for mental health problems, as well as their relationship with family structure and characteristics. The informers were 11 parents of students who agreed to participate in the study. Data were collected in June 2006, through a semi-structured interview that was conducted in the child's home. Results showed that the mental disorder is present in children/adolescents of both sexes and in different age groups. Most of the families were of a nuclear type and the average family income was of 3 to 5 minimum wages. The most frequent medical diagnosis was ADHD, 76% of the children presented family antecedents of mental disorder, 72% had difficulties at school, and a great number of them was exposed to humiliating situations. It was concluded that the characteristics of the studied families can be considered a risk factor for behavioral disorders, especially in relation to family antecedents and to inadequate educational practices. Further studies are needed on the theme in order to subsidize the elaboration of public policies of mental health.O aumento da incidência do distúrbios de conduta em crianças e adolescentes é um fator de preocupação para os profissionais de saúde. Durante as atividades de estágio de alunos de enfermagem em uma escola pública foi detectado que 15 alunos do ensino fundamental apresentavam diagnóstico médico de distúrbios de conduta e/ou tomava medicação controlada. O presente estudo teve como objetivo caracterizar estes alunos, identificar a existência de fatores de risco para problemas de saúde mental e sua relação com a estrutura e a característica familiar. Os participantes foram 11 pais de alunos que concordaram em participar do estudo. Os dados foram coletados por entrevista semi-estruturada realizada no domicílio da criança. Os resultados mostraram que o transtorno mental está presente em crianças / adolescentes de ambos os sexos e em diferentes faixas etárias. A maioria das famílias era do tipo nuclear e a renda familiar média era de 3 a 5 salários-mínimos. O diagnóstico médico mais freqüente era de transtorno de déficit de atenção/hiperatividade (TDAH); a maioria das crianças (76%) possuía antecedentes familiares de transtorno mental e apresentavam dificuldade escolar (72%); e boa parte das crianças era exposta a situações de humilhação. Conclui-se que as características das famílias estudadas podem ser consideradas um fator de risco para o distúrbio de conduta, especialmente em relação aos antecedentes familiares e a práticas educativas inapropriadas. Há necessidade de novos estudos sobre o tema que possam subsidiar a elaboração de políticas públicas de saúde mental

Detection of bridge emission above 50 GeV from the Crab pulsar with the MAGIC telescopes

The Crab pulsar is the only astronomical pulsed source detected at very high energy (VHE, E>100GeV) gamma-rays. The emission mechanism of VHE pulsation is not yet fully understood, although several theoretical models have been proposed. In order to test the new models, we measured the light curve and the spectra of the Crab pulsar with high precision by means of deep observations. We analyzed 135 hours of selected MAGIC data taken between 2009 and 2013 in stereoscopic mode. In order to discuss the spectral shape in connection with lower energies, 4.6 years of {\it Fermi}-LAT data were also analyzed. The known two pulses per period were detected with a significance of $8.0 \sigma$ and $12.6 \sigma$. In addition, significant emission was found between the two pulses with $6.2 \sigma$. We discovered the bridge emission above 50 GeV between the two main pulses. This emission can not be explained with the existing theories. These data can be used for testing new theoretical models.Comment: 5 pages, 4 figure