Análisis tripartita de escurrimientos naturales: aplicación a la caracterización de sequías en el río Colorado

En este trabajo se presenta el análisis del régimen de escurrimiento natural en la cuenca del río Colorado, a la luz de lo establecido por el Tratado de 1944 entre México y Estados Unidos. Primeramente, se construye el registro mensual de escurrimiento natural anual en la estación más cercana a la frontera entre ambos países, que corresponde al sitio aguas arriba de la presa Imperial. Esto permitió contar con valores de septiembre de 1906 a diciembre de 2012, de acuerdo con la información más reciente disponible. Se calculan los estadísticos más significativos de dicho registro y se comprueba que no sigue una distribución normal. Se procede a calcular los percentiles 2.28, 15.87, 84.13 y 97.72, y con base en ellos se caracteriza el registro histórico en periodos extraordinariamente escasos, escasos, normales, abundantes y extraordinariamente abundantes. Mediante la aplicación de un análisis de Fourier, se determinan los periodos dominantes del registro. A través de una novedosa descomposición tripartita, se calculan los componentes tendenciales, cíclicos dominantes y aleatorios del registro. Se demuestra que estos últimos siguen una distribución normal y se lleva a cabo la caracterización del registro histórico en periodos muy secos, secos, normales, húmedos y muy húmedos, de acuerdo con el índice dinámico estandarizado de escurrimiento propuesto en este trabajo por el autor

Quasars: from the Physics of Line Formation to Cosmology

Quasars accreting matter at very high rates (known as extreme Population A [xA] or super-Eddington accreting massive black holes) provide a new class of distance indicators covering cosmic epochs from the present-day Universe up to less than 1 Gyr from the Big Bang. The very high accretion rate makes it possible that massive black holes hosted in xA quasars radiate at a stable, extreme luminosity-to-mass ratio. This in turns translates into stable physical and dynamical conditions of the mildly ionized gas in the quasar low-ionization line emitting region. In this contribution, we analyze the main optical and UV spectral properties of extreme Population A quasars that make them easily identifiable in large spectroscopic surveys at low-z (z < 1) and intermediate-z (2 < z < 2.6), and the physical conditions that are derived for the formation of their emission lines. Ultimately, the analysis supports the possibility of identifying a virial broadening estimator from low-ionization line widths, and the conceptual validity of the redshift-independent luminosity estimates based on virial broadening for a known luminosity-to-mass ratio.Comment: 13 pages, 5 figures. Invited lecture at SPIG 2018, Belgrade. To appear in Ato

VI Congresso Internacional de Estudios Patristicos

1. Los Congresos Internacionales de Estudios Patrísticos.2. Organización dei Congreso.3. Los congresistas.4. La Asociación Internacional de Estudios Patrísticos.1. Los Congresos Internacionales de Estudios Patrísticos.2. Organización dei Congreso.3. Los congresistas.4. La Asociación Internacional de Estudios Patrísticos

Black hole mass estimates in quasars - A comparative analysis of high- and low-ionization lines

The inter-line comparison between high- and low-ionization emission lines has yielded a wealth of information on the quasar broad line region (BLR) structure and dynamics, including perhaps the earliest unambiguous evidence in favor of a disk + wind structure in radio-quiet quasars. We carried out an analysis of the CIV 1549 and Hbeta line profiles of 28 Hamburg-ESO high luminosity quasars and of 48 low-z, low luminosity sources in order to test whether the high-ionization line CIV 1549 width could be correlated with Hbeta and be used as a virial broadening estimator. We analyze intermediate- to high-S/N, moderate resolution optical and NIR spectra covering the redshifted CIV and H$\beta$ over a broad range of luminosity log L ~ 44 - 48.5 [erg/s] and redshift (0 - 3), following an approach based on the quasar main sequence. The present analysis indicates that the line width of CIV 1549 is not immediately offering a virial broadening estimator equivalent to H$\beta$. At the same time a virialized part of the BLR appears to be preserved even at the highest luminosities. We suggest a correction to FWHM(CIV) for Eddington ratio (using the CIV blueshift as a proxy) and luminosity effects that can be applied over more than four dex in luminosity. Great care should be used in estimating high-L black hole masses from CIV 1549 line width. However, once corrected FWHM(CIV) values are used, a CIV-based scaling law can yield unbiased MBH values with respect to the ones based on H$\beta$ with sample standard deviation ~ 0.3 dex.Comment: 43 pages, 15 Figures, submitted to A&

HE0359-3959: an extremely radiating quasar

We present a multiwavelength spectral study of the quasar HE0359-3959, which has been identified as an extreme radiating source at intermediate redshift (z=1.5209). Along the spectral range, the different ionic species give information about the substructures in the broad line region. The presence of a powerful outflow with an extreme blueshifted velocity of $\sim$-6000$\pm$500 km s$^{-1}$ is shown in the CIV{\lambda}1549 emission line. A prominent blueshifted component is also associated with the 1900{\AA} blend, resembling the one observed in CIV{\lambda}1549. We detect a strong contribution of very the low-ionization lines, FeII and Near-Infrared CaII triplet. We find that the physical conditions for the low, intermediate and high-ionization emission lines are different, which indicate that the emission lines are emitted in different zones of the broad line region. The asymmetries shown by the profiles reveal different forces over emitter zones. The high-ionization region is strongly dominated by radiation forces, which also affect the low and intermediate-ionization emitter region, commonly governed by virial motions. These results support the idea that highly radiating sources host a slim disk.Comment: 10 pages, 3 figure

Extreme quasars at high redshift

Context:Quasars radiating at extreme Eddington ratios (xA) are likely a prime mover of galactic evolution and have been hailed as potential distance indicators. Their properties are still scarcely known. Aims:We test the effectiveness of the selection criteria defined on the 4D Eigenvector 1 (4DE1) for identifying xA sources. We provide a quantitative description of their UV spectra in the redshift range 2<z<2.9. Methods:19 extreme quasar candidates were identified using 4DE1 selection criteria applied to SDSS spectra: AlIII1860/SiIII]1892>0.5 and CIII]1909/SiIII]1892<1. The emission line spectra was studied using multicomponent fits of deep spectroscopic observations obtained with the OSIRIS-GTC. Results:Spectra confirm that almost all of these quasars are xA sources with very similar properties. We provide spectrophotometric and line profile measurements for the SiIV1397+OIV]1402, CIV1549+HeII1640, and the 1900A blend composed by AlIII1860, SiIII]1892, FeIII and a weak CIII]1909. The spectra can be characterized as very low ionization (logU~-3), a condition that explains the significant FeIII emission. CIV1549 shows low equivalent width (<30 A for the most sources), and high or extreme blueshift amplitudes (-5000<c(1/2)<-1000 kms-1). Weak-lined quasars appear as extreme xA quasars and not as an independent class. The CIV1549 high amplitude blueshifts coexists in all cases save one with symmetric and narrower AlIII and SiIII] profiles. Estimates of the Eddington ratio using the AlIII FWHM as a virial broadening estimator are consistent with the ones of a previous xA sample. Conclusions:It is now feasible to assemble large samples of xA quasars from the latest data releases of the SDSS. We provide evidence that AlIII1860 could be associated with a low-ionization virialized sub-system, supporting previous suggestions that AlIII is a reliable virial broadening estimator.Comment: 36 pages, 31 figures, 12 tables. Manuscript accepted for publication, A&A. Corrected titl

Narrow-line Seyfert 1s: what is wrong in a name?

Narrow-line Seyfert 1s (NLSy1s) are an ill-defined class. Work done over the past 20 years as well as recent analyses show a continuity in properties (e.g., Balmer line profiles, blueshifts of high-ionization lines) between sources with FWHM above and below 2000 km/s, the defining boundary of NLSy1s. This finding alone suggests that comparisons between samples of NLSy1s and rest of broad-line AGNs are most likely biased. NLSy1s can be properly contextualized by their location on the quasar main sequence originally defined by Sulentic et al 2000. At one end, NLSy1s encompass sources with strong FeII emission and associated with high Eddington ratio that hold the promise of becoming useful distance indicators; at the other end, at least some of them are sources with broad profiles seen face-on. Any rigid FWHM limit gives rise to some physical ambiguity, as the FWHM of low-ionization lines depends in a complex way on mass, Eddington ratio, orientation, and luminosity. In addition, if the scaling derived from luminosity and virial dynamics applies to the broad line regions, NLSy1s at luminosity higher than 1E47 erg/s become physically impossible. Therefore, in a broader context, a proper subdivision of two distinct classes of AGNs and quasars may be achieved by the distinction between Pop. A and B with boundary at = 4000 km/s in samples at z < 1, or on the basis of spectrophotometric properties which may ultimately be related to differences in accretion modes if high-luminosity quasars are considered.Comment: Contribution presented at the meeting Revisiting narrow-line Seyfert 1 galaxies and their place in the Universe, held at the Padova Botanical Garden, Italy, on 9-13 April 201

Automatic multiscale vascular image segmentation algorithm for coronary angiography

[Abstract] Cardiovascular diseases, particularly severe stenosis, are the main cause of death in the western world. The primary method of diagnosis, considered to be the standard in the detection and quantification of stenotic lesions, is a coronary angiography. This article proposes a new automatic multiscale segmentation algorithm for the study of coronary trees that offers results comparable to the best existing semi-automatic method. According to the state-of-the-art, a representative number of coronary angiography images that ensures the generalisation capacity of the algorithm has been used. All these images were selected by clinics from an Haemodynamics Unit. An exhaustive statistical analysis was performed in terms of sensitivity, specificity and Jaccard. Algorithm improvements imply that the clinician can perform tests on the patient and, bypassing the images through the system, can verify, in that moment, the intervention of existing differences in a coronary tree from a previous test, in such a way that it could change its clinical intra-intervention criteria.Galicia. Consellería de Cultura, Educación e Ordenación Universitaria; GRC2014/049Ministerio de Economía y Competitividad; TIN2015-70648-