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

Low-redshift quasars in the SDSS Stripe 82-II. Associated companion galaxies and signature of star formation

We present optical spectroscopy of the close companions of 22 low-redshift (z < 0.5) quasars (QSO) selected from a larger sample of QSO in the SDSS Stripe82 region for which both the host galaxy and the large-scale environments have been investigated in our previous work. The new observations extend the number of QSO studied in our previous paper on close companion galaxies of 12 quasars. Our analysis here covers all 34 quasars from both this work and the previously published paper. We find that half of them (15 QSO; similar to 44 per cent) have at least one associated galaxy. Many (12 galaxies; similar to 67 per cent) of the associated companions exhibit [O II] 3727 angstrom emission line as signature of recent star formation. The star formation rate (SFR) of these galaxies is modest (median SFR similar to 4.3 M-circle dot yr(-1)). For eight QSO, we are also able to detect the starlight of the host galaxy from which three have a typical spectrum of a post-starburst galaxy. Our results suggest that quasars do not have a strong influence on the star formation of their companion galaxies

Los procedimientos dentales postnatales afectan la ganancia de peso y el bienestar de los lechones

Objective. We carried out this study to evaluate weight gain (WG), mortality, blood serum proteins (BP), facial lesions of littermates submitted to different teeth procedures. Material and Methods. The experiment was performed in a commercial breeding farm. Were used 15 sows, allotted into three groups: control, where piglets’ teeth were kept intact (IT); teeth clipping (CT); and teeth grinding using an electric grinder (GT). We evaluated WG, BS (five males/litter), mortality, low viable piglets rates and facial lesions in piglets. Additionally, we evaluated sows’ backfat thickness (P2) and teat lesion score. BP data, lesion score and WG were assessed individually. For WG, the initial weight and the litter size were used as covariates. Regarding other variables, we used the average of the litter. When there were differences, the means were compared using Duncan test (p&lt;0.05). Results. In the first week, GT piglets presented higher WG. In the second week, CT presented worst WG. In the first two weeks as in the total period, CT piglets presented worse WG than the GT. Mortality and low viable piglets rates were not influenced. After the fourth day, CT and GT treatment reduced facial lesions. There was no effect on BP. Treatments did not influence P2 and teat lesion score. Conclusions. Treatments did not have influence on mortality, low viable rates, BP of the piglets and P2 and teat lesions score. CT treatment decreased gain and IT increased face lesions score.Objetivo. Este estudio fue realizado para evaluar la ganancia de peso, mortalidad, proteínas plasmáticas (BP), lesiones faciales en los lechones y en las cerdas, grasa dorsal (P2) y lesiones en los pezones en lechigadas sometidas a diferentes manejos dentales. Materiales y métodos. La investigación fue conducida en una granja comercial de cría. Fueron utilizadas quince cerdas, divididas en tres grupos: control, en el cual los dientes de los lechones permanecieron intactos; descolmille con alicate; descolmille con limadora eléctrica. Nosotros evaluamos WG, BP (cinco machos/lechigada), mortalidad, lechones de baja viabilidad y lesiones faciales en los lechones. En las cerdas, nosotros evaluamos P2 y la escala de lesiones en los pezones. Los datos de BP, escala de lesiones y WG fueron evaluados individualmente. Para el WG, el peso inicial y el tamaño de la lechigada fueron considerados. Acerca de las otras variables, nosotros usamos el peso promedio de la lechigada. Cuando hubo diferencias, las medias fueron comparadas usando la prueba de Duncan (p&lt;0.05). Resultados. En la primera semana, los lechones del GT presentaron mayor WG. En la segunda semana el CT presentó la peor WG. En las dos primeras semanas así como en el período total, los lechones del CT presentaron peor WG de que los del GT. La mortalidad y los lechones de baja viabilidad no fueron influenciados. Después del cuarto día, el CT y el GT redujeron las lesiones faciales. No hubo efectos en BP. Los tratamientos no influenciaron P2 y las lesiones en los pezones. Conclusiones. Los tratamientos no influenciaron en la mortalidad, lechones de baja viabilidad, BP de los lechones y en la escala de lesiones en los pezones de las cerdas. CT redujo la ganancia y IT aumentó las lesiones faciales