Emission Line Properties of Seyfert 2 Nuclei

We present a study of the global properties of Joguet's sample of 65 Seyfert 2 galaxies. We use the population synthesis models of our Paper II to derive `pure' emission-line spectra, and thus explore the statistical properties of the nuclear nebular components and their relation to the stellar populations. We find that the emission line clouds suffer substantially more extinction than the starlight, and confirm the correlations between stellar and nebular velocity dispersions and between emission line luminosity and velocity dispersions. Nuclear luminosities correlate with stellar velocity dispersions. Removing the contribution of young stars to the optical continuum produces a tighter and steeper relation, $L \propto \sigma_\star^4$, consistent with the Faber-Jackson law. Emission line ratios indicative of the gas excitation such as [OIII]/H$\beta$ and [OIII]/[OII] are statistically smaller for Seyferts with significant star-formation, implying that ionization by massive stars is responsible for a substantial, and sometimes even a dominant, fraction of the H$\beta$ and [OII] fluxes. We use our models to constrain the maximum fraction of the ionizing power that can be generated by a hidden AGN. We correlate this fraction with classical indicators of AGN photo-ionization: X-ray luminosity and nebular excitation, but find no significant correlations. Thus, while there is a strong contribution of starbursts to the excitation of the nuclear nebular emission in low-luminosity Seyferts, the contribution of the hidden AGN remains elusive even in hard X-rays. (abridged)Comment: 12 pages, 13 figures. Final version accepted for publication in MNRA

Repertorios bibliográficos (XVII) Ensayo de una bibliográfia comentada de manuales de artes, ciencias, oficios, costumbres públicas y privadas de España (Siglos XVI al XIX)

Estudio del “Ensayo de una bibliografía comentada de manuales …” realizado por Vicente Castañeda y publicado en el año 1955 por la Real Academia de la Historia. El ensayo recoge las obras que coleccionaba el autor de libros de divulgación, tratados y manuales de todo tipo sobre conocimientos populares en materia científica, artística, costumbres, diversiones y oficios manuales que se publicaban en 8º principalmente

Comment on "Properties of the recovery phase of extreme storms" by Choraghe et al. (2021)

Choraghe et al. (2021), based on a study of the recovery phase of the SYM-H index of 31 extreme geomagnetic storms, have recently concluded that the hyperbolic decay function is only able to explain the complete recovery phase of about one third of events and that both the exponential or the hyperbolic decay functions fail to explain the late recovery phase of storms. Furthermore, they propose a linear function to model the late recovery phase and claim that the proposed model could throw new light on the relative importance of different physical processes involved during the complete recovery phase of extreme storms. We assert that the Choraghe et al. (2021) conclusions regarding the recovery phase of extreme storms analysis are incorrect and in particular are based on a misunderstanding of the nature of the evolution of the SYM-H index and the energy balance of the ring current

El rol docente en la atención a la diversidad en Chile

Contradictions are observed between the Chilean educational maxims, the legal framework, the curriculum and the evaluation that is carried out to establish quality and management levels of the schools are undeniable. In legal bodies, establishes the importance of recognition, appreciation and attention to diversity, but the system works based on a homogenizing curriculum and highly standardized evaluations. The gap in the results obtained between high socioeconomic groups and the most deprived, shows that quality is not reached by everybody in the same measure. In this context, we seek to reflect on the importance of the teaching role in attending to diversity. Teachers can, based on a performance characterized by autonomy and professional responsibility, consider the cultural capital of the students as a possible wealth to incorporate into the school curriculum and teaching work in the classroom. Teachers can bring the curriculum closer to the student body and make it relevant, however, the evidence shows that teaching practice in Chile is characterized by performance focused on the official curriculum that does not know the particularities of the student body.Se observan contradicciones entre las máximas educativas chilenas, el marco legal, el currículum y la evaluación que se realiza para establecer grados de calidad y ordenación de las escuelas. En los cuerpos legales se establece la importancia del reconocimiento, la valoración y la atención de la diversidad, pero el sistema funciona a partir de un currículum homogeneizante y de evaluaciones altamente estandarizadas. La brecha en los resultados obtenidos entre los grupos socioeconómicos altos y los más desposeídos evidencia que la calidad en educación no se alcanza para todos en la misma medida. En este contexto, se buscar reflexionar sobre la importancia del rol docente en la atención a la diversidad. El profesorado puede, a partir de un desempeño caracterizado por la autonomía y la responsabilidad profesional, considerar el capital cultural del alumnado como una riqueza posible de incorporar al currículum escolar y al trabajo docente en aula. El profesorado puede acercar el currículum al estudiantado y hacerlo pertinente; sin embargo, la evidencia muestra que la práctica docente en Chile se caracteriza por un desempeño centrado en el currículum oficial que desconoce las particularidades del alumnado.

Comment on "Interplanetary conditions leading to superintense geomagnetic storms (dst ≤ -250 nt) during solar cycle 23" by E. Echer et al.

Comisión Interministerial de Ciencia y Tecnología-CICY

Forecasting intense geomagnetic activity using interplanetary magnetic field data

Southward interplanetary magnetic fields are considered traces of geoeffectiveness since they are a main agent of magnetic reconnection of solar wind and magnetosphere. The first part of this work revises the ability to forecast intense geomagnetic activity using different procedures available in the literature. The study shows that current methods do not succeed in making confident predictions. This fact led us to develop a new forecasting procedure, which provides trustworthy results in predicting large variations of Dst index over a sample of 10 years of observations and is based on the value Bz only. The proposed forecasting method appears as a worthy tool for space weather purposes because it is not affected by the lack of solar wind plasma data, which usually occurs during severe geomagnetic activity. Moreover, the results obtained guide us to provide a new interpretation of the physical mechanisms involved in the interaction between the solar wind and the magnetosphere using Faraday's law.Comisión Interministerial de Ciencia y Tecnología (CICYT

Mid-latitude double H-spikes: their properties and signatures in different geomagnetic indices

Proper assessment of geomagnetic disturbances is a key aspect of space weather as technology is often impacted by space weather activity without previous warnings or proper forecasts. Double H-spikes are a form of longitudinal asymmetry observed at midlatitudes. They are geomagnetic disturbances occurring simultaneously on the dayside and nightside as a negative/positive H-spike, which go unnoticed through common geomagnetic indices. This work presents the results of a systematic search for double H-spikes occurred over a 23-year period and analyzes characteristics of the double H-spikes such as the occurrence dependence on the solar cycle, season, intensity and phase of the geomagnetic storm. Our outcomes indicate that double H-spikes are a global phenomenon closely related with the substorm phenomenon and the ground magnetic disturbances observed at mid-latitude are remote effects of field-aligned currents (FACs). FACs would be the part of the substorm current wedge developed from the expansion onset of intense substorms whose effects have wide longitudinal extend as they are observed on the dayside and the nightside. Also mid-latitude global SYM and ASY indices are affected by FACs during those periods. Time derivatives of the SuperMAG SMR12 and SMR00 sector indices allow us to conclude that double H-spikes, as short-time high-intensity magnetic disturbances, pose a potential risk to damage ground-technological systems at midlatitudes.Agencia Estatal de InvestigaciónUniversidad de Alcal