Superwind evolution: the young starburst-driven wind galaxy NGC 2782

We present results from a 30 ksec Chandra observation of the important starburst galaxy NGC 2782, covering the 0.3-10keV energy band. We find evidence of a superwind of small extent, that is likely in an early stage of development. We find a total of 27 X-ray point sources within a region of radius 2$D_{25}$ of the galaxy centre and which are likely associated with the galaxy. Of these, 13 are ULXs ($L_{X}\geq 10^{39}~ erg s ^{-1}$) and a number have likely counterparts. The X-ray luminosities of the ULX candidates are $1.2-3.9\times10^{39}~ erg s ^{-1}$. NGC2782 seems to have an unusually large number of ULXs. Central diffuse X-ray emission extending to ~ 3kpc from the nuclear region has been detected. We also find an X-ray structure to the south of the nucleus, coincident with H{\alpha} filaments and with a 5 GHz radio source. We interpret this as a blow-out region of a forming superwind. This X-ray bubble has a total luminosity (0.3-10 keV) of $5\times10^{39}erg s ^{-1}$ (around $15\%$ of the total luminosity of the extended emission), and an inferred wind mass of $1.5\times10^{6}$ M$_\odot$. We also discuss the nature of the central X-ray source in NGC2782, and conclude that it is likely a low-luminosity AGN (LLAGN), with a total X-ray luminosity of $L_{X}=6\times10^{40}~erg s ^{-1}$ with strong Fe line emission at 6.4 keV.Comment: 14 pages, 14 figures, 3 tables. Accepted for publication in MNRA

The Relation between Galaxy Activity and the Dynamics of Compact Groups of Galaxies

Peer reviewe

Isotopic overabundances and the energetic particle model of solar flares

According to the energetic particle model of solar flares particles are efficiently accelerated in the magnetic field loop of an active region (AR) by hydromagnetic turbulence. It is demonstrated that the isotopic overabundances observed in some flares are not a consequence of the flare itself but are characteristic of the plasma in the AR. Only when a flare releases the plasma into the interplanetary space it is possible to observe this anomalous composition at spacecraft locations

Infrared Surface Brightness Analysis of Galaxies in Compact Groups

Images of 7 Compact groups of galaxies (CG) were obtained using the 2.1m telescope in San Pedro Martir (B.C. Mexico) equipped with the NIR camera CAMILA. The NIR images trace the mass of the galaxies, through the oldest and more evolved stellar populations. The goal of this project is to search for evidence of morphological perturbations correlated with the level of activity (AGN or star formation) of the galaxies. We find that the level of perturbation is well correlated with activity observed in optical spectrocopy (Coziol et al. 2004). Evidence for perturbations decreases from more active groups to less active groups, confirming the classification. Our analysis suggests that galaxies in more active groups are undergoing important transformations due to interaction and merging and that the whole groups is on a merger path. Galaxies in less active CG have gone through similar processes in the recent past and are either in a final merging phase or in equilibrium due to a more massive halo of dark matter.Comment: 2 pages, 1 figure, Proc. ESO Workshop "Groups of galaxies in the nearby Universe", Santiago, Chile, 5-9 Dec. 2005, ESO Astrophysics Symposia, eds. I. Saviane, V. Ivanov & J. Borissova, Springer-Verla

When giving some away makes sense to jump-start the diffusion process.

This paper uses an analytical model to examine when it makes sense to provide incentives to innovators to adopt a new product. The model allows for separate segments of innovators and imitators, each of which follows a Bass-type diffusion process. Interestingly “seeding” the market is optimal for a limited range of situations and these do not appear to include those where there is a downturn in sales (chasm) as sales move from the first to the second segment. Research has frequently identified different segments of adopters of new products. Categorizations include innovators vs imitators (Bass, 1969; Rogers, 1995; Mahahan et al., 1990; Im et al., 2003), technophiles vs “normal” people, and business vs consumer users. Further, considerable effort has gone into studying the influence of members of the first group on the second. This paper focuses on when, if ever, it makes sense for a manufacture of a new product to “seed” the market by subsidizing a few early adopters to speed the adoption process. The paper builds on earlier work by Kalish and Lilien (1983) which focused on the impact of widely available government subsidies on the adoption of socially desirable innovations (i.e. alternative energy sources) as well as the work of Jain et al. (1995). Unlike that work, we concentrate on providing subsidies (here free goods) to selective individuals in the context of a model which allows for separate segments of innovators and imitators and nests the standard Bass (1969) model.

Wavelets: a powerful tool for studying rotation, activity, and pulsation in Kepler and CoRoT stellar light curves

Aims. The wavelet transform has been used as a powerful tool for treating several problems in astrophysics. In this work, we show that the time-frequency analysis of stellar light curves using the wavelet transform is a practical tool for identifying rotation, magnetic activity, and pulsation signatures. We present the wavelet spectral composition and multiscale variations of the time series for four classes of stars: targets dominated by magnetic activity, stars with transiting planets, those with binary transits, and pulsating stars. Methods. We applied the Morlet wavelet (6th order), which offers high time and frequency resolution. By applying the wavelet transform to the signal, we obtain the wavelet local and global power spectra. The first is interpreted as energy distribution of the signal in time-frequency space, and the second is obtained by time integration of the local map. Results. Since the wavelet transform is a useful mathematical tool for nonstationary signals, this technique applied to Kepler and CoRoT light curves allows us to clearly identify particular signatures for different phenomena. In particular, patterns were identified for the temporal evolution of the rotation period and other periodicity due to active regions affecting these light curves. In addition, a beat-pattern signature in the local wavelet map of pulsating stars over the entire time span was also detected.Comment: Accepted for publication on A&

Determinantes del desempeño adaptativo en el contexto de sistemas de información

Hoy en día las organizaciones están caracterizadas por el cambio y expuestas a contextos dinámicos lo cual pone de manifiesto cada vez más la necesidad de empleados adaptativos. En este sentido, la conceptualización del desempeño ha sido extendida. El desempeño tradicionalmente ha sido definido como la suficiencia con la que se ejecutan las tareas centrales del empleado. Ahora comprende aquella dimensión que se relaciona con la capacidad del individuo a adaptarse a cambios en el ambiente de trabajo. Más aún, el creciente trabajo mediado por computadores motiva una comprensión acerca de los factores que explican la adaptación en el contexto de sistemas de información. El desempeño adaptativo se entiende como el comportamiento del individuo conducente a modificar la tecnología o incrementar el dominio del sistema por parte de la persona. Esta temática está en pleno desarrollo, sin embargo, son todavía escasos los modelos explicativos en la literatura. Fundamentado en la teoría de la migración, el cambio de proveedor de servicios del marketing y el cambio de tecnología, el artículo propone un modelo de desempeño adaptativo donde se identifican tres constructos de segundo orden: empuje, atracción y enganche. Factor de empuje comprende aquellos aspectos negativos que resultan del actual dominio del sistema de información (insatisfacción, disconformidad); el factor de atracción comprende los aspectos positivos de mejorar mi actual dominio (ventaja relativa) y el factor de enganche comprende los factores barrera (y en extenso facilitadores) del comportamiento adaptativo (actitud, norma subjetiva, autoeficacia e inercia y costos de cambio). Se presentan, además, los lineamientos del método para su evaluación empírica

Automating and informating : roles to examine in technology's impact on performance

La calidad de la información y la calidad del sistema se consideran factores claves para determinar la utilidad de los sistemas. Sin embargo, estudios anteriores han arrojado resultados mixtos. En este artículo se sostiene que la asistencia del sistema (el grado de la asistencia proporcionada por un sistema a través de sus dos funciones: la automatización e “informating”) media en esta relación y puede ayudar a explicar estos resultados mixtos. Por otra parte, se sostiene que el nivel del sistema de intervención ( grado en que la tecnología participa en la realización de las tareas) es otro factor clave para determinar su utilidad, especialmente a través de la función de automatización. Se recogieron datos de 246 usuarios de diferentes jerarquías y funciones. Los resultados muestran que la calidad de la información y el nivel de intervención del sistema explican la utilidad de ambas funciones. La calidad del sistema explica la utilidad mediante el rol del “informating”, pero no mediante el papel de la automatización. Los efectos diferenciados de los factores a través de cada rol pueden ayudar a los gerentes para establecer criterios y prioridades más eficaces en las diferentes etapas del ciclo de vida de un sistema de información.Information quality and system quality are considered key factors in determining the usefulness of systems. However, prior studies have yielded mixed results. This article holds that the system’s assistance (the degree of the assistance provided by a system through its two roles: automating and informating) mediates in this relationship and may help to explain such mixed results. Furthermore, it holds that the system’s level of intervention (the degree to which technology participates in carrying out the tasks) is another key factor in determining its usefulness, especially through the automating role. Data from 246 users filling different hierarchies and functional areas were collected. Results show that information quality and system’s level of intervention explain usefulness through both roles. System quality explains usefulness through the informating role, but not through the automating role. The factors’ differentiated effects through each role may help managers to establish more effective criteria and priorities in the different stages of an information system’s life cycle

Utilizing Real Objects to Increase Reading Comprehension in Students with Significant Cognitive Disabilities

This poster presents the results of a study conducted to evaluate the effects of pairing read-alouds with real objects related to stories read to students with significant cognitive disabilities to increase reading comprehension skills. The participants are four elementary students. The target audience is special education teachers