54 research outputs found

    Red-channel (6000-8000 {\AA}) nuclear spectra of 376 local galaxies

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    We obtained long-slit optical spectra of the nuclear regions of 376 galaxies in the local Universe using the 1.5m Cassini telescope of Bologna Observatory. Of these spectra, 164 were either never taken before by the Sloan Digital Sky Survey (SDSS), or given by the Nasa Extragalactic Database (NED). With these new spectra, we contribute investigating the occurrence of active galactic nuclei (AGNs). Nevertheless, we stress that the present sample is by no means complete, thus, it cannot be used to perform any demographic study. Following the method presented in Gavazzi et al. (2011), we classify the nuclear spectra using a six bin scheme: SEY (Seyfert), sAGN (strong AGN), and wAGN (weak AGN) represent active galactic nuclei of different levels of activity; HII accounts for star-forming nuclei; RET (retired) and PAS (passive) refer to nuclei with poor or no star-formation activity. The spectral classification is performed using the ratio of 6584 {\lambda} [NII] to H{\alpha} lines and the equivalent width (EW) of H{\alpha} versus [NII]/H{\alpha} (WHAN diagnostic introduced by Cid Fernandes and collaborators) after correcting H{\alpha} for underlying absorption. The obtained spectra are made available in machine readable format via the Strasbourg Astronomical Data Center (CDS) and NED.Comment: 8 pages, 6 Figures, 4 Tables, accepted for publication in Astronomy & Astrophysic

    Panarteritis nodosa cutánea, presentación de un caso con lesiones en localización atípica

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    La Panarteritis Nodosa Cutánea es una rara entidad caracterizada por nódulos subcutáneos, de curso crónico, benigno y recurrente. La mayoría de los pacientes presentan lesiones en miembros inferiores, y un tercio en los miembros superiores. Además existen manifestaciones extracutáneas como miositis o artritis. Presentamos el caso de una paciente que fue internada por tumefacción, debilidad muscular y dolor incapacitante en ambos hombros y nódulos subcutáneos en hombros y cara, a quien le habían diagnosticado panarteritis nodosa en la infancia, pero que siempre presentó lesiones en localizaciones atípicas, respetando los miembros inferiores

    The Infrared Luminosity Function of Galaxies in the Coma Cluster

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    An infrared survey of the central 650 arcmin2^2 of the Coma cluster is used to determine the HH band luminosity function for the cluster. Redshifts are available for all galaxies in the survey with H<14.5H < 14.5, and for this sample we obtain a good fit to a Schechter function with H=11.13H^*=11.13 and α=0.78\alpha=-0.78. These luminosity function parameters are similar to those measured for field galaxies in the infrared, which is surprising considering the very different environmental densities and, presumably, merger histories for field galaxies. For fainter galaxies, we use two independent techniques to correct for field galaxy contamination in the cluster population: the BRB-R color-magnitude relation and an estimate for the level of background and foreground contamination from the literature. Using either method we find a steep upturn for galaxies with 14<H<1614 < H < 16, with slope α1.7\alpha \simeq 1.7.Comment: 15 pages, 2 figures Accepted by ApJ Letter

    The properties of quasar hosts at the peak of the quasar activity

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    We present near-infrared imaging obtained with ESO VLT/ISAAC of a sample of 16 low luminosity radio-quiet quasars at the epoch around the peak of the quasar activity (2 < z < 3), aimed at investigating their host galaxies. For 11 quasars, we are able to detect the host galaxies and derive their properties, while for the other five quasars, upper limits to the host luminosity are estimated. The luminosities of the host galaxies of radio-quiet quasars at high redshift are in the range of those of massive inactive elliptical galaxies. This work complements our previous systematic study of quasar hosts aimed to trace the cosmological luminosity evolution of the host galaxies up to z ~2 and extends our pilot study of a few luminous quasars at z > 2. The luminosity trend with cosmic epoch resembles that observed for massive inactive galaxies, suggesting a similar star formation history. In particular, both quasar host galaxies and massive inactive galaxies appear mostly assembled already at the peak age of the quasar activity. This result is of key importance for testing the models of joint formation and evolution of galaxies and their active nuclei.Comment: 27 pages, 8 figures, 2 tables. Accepted for publication in Ap

    Multiaperture UBVRIzJHKUBVRIzJHK Photometry of Galaxies in the Coma Cluster

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    We present a set of UBVRIzJHKsUBVRIzJHK_s photometry for 745 J+HJ+H band selected objects in a 22.5×29.222.5' \times 29.2' region centered on the core of the Coma cluster. This includes 516 galaxies and is at least 80% complete to H=16, with a spectroscopically complete sample of 111 cluster members (nearly all with morphological classification) for H<14.5H < 14.5. For each object we present total \cite{kron80} magnitudes and aperture photometry. As an example, we use these data to derive color-magnitude relations for Coma early-type galaxies, measure the intrinsic scatter of these relations and its dependence on galaxy mass, and address the issue of color gradients. We find that the color gradients are mild and that the intrinsic scatter about the color-magnitude relation is small (0.05\sim 0.05 mag in UVU-V and less than 0.03\sim 0.03 in BRB-R, VIV-I or JKJ-K). There is no evidence that the intrinsic scatter varies with galaxy luminosity, suggesting that the cluster red sequence is established at early epochs over a range of 100\sim 100 in stellar mass.Comment: 41 pages, 5 figures, 18 data tables attached to source files or available on request from R. De propris. Accepted for publication in Astrophysical Journal Supplement Serie

    the safety transformation in the future internet domain

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    Public Safety is nowadays a priority, cornerstone and major concern for governments, majors and policy makers in current (and future) smart cities. Notwithstanding the foregoing, large advances in ICT technologies are foretold to revolutionize our society and enhance our feeling of safety (and hopefully, wellbeing). This chapter presents an introduction to three of the most promising technological pillars considered to be spearheads in this transformation: Internet of things, understood as the data capillarity through billions of sensors, Intelligent Video Analytics and Data Mining Intelligence, the latter two enabling smarter contextual awareness and prediction of potential threats leading to proactive prevention of them. The associated horizontal economic implications of this evolution and its impact into the societal and economic fabric are also tackled. Part of the results and analysis produced in this chapter are the outcome of the work carried out in the FP7 EU project SafeCity, one of the eight Use Cases of the FI Programme

    The rest-frame KK-band luminosity function of galaxies in clusters to z=1.3z=1.3

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    We derive the rest-frame KK-band luminosity function for galaxies in 32 clusters at 0.6<z<1.30.6 < z < 1.3 using deep 3.6μ3.6\mum and 4.5μ4.5\mum imaging from the Spitzer Space Telescope InfraRed Array Camera (IRAC). The luminosity functions approximate the stellar mass function of the cluster galaxies. Their dependence on redshift indicates that massive cluster galaxies (to the characteristic luminosity MKM^*_K) are fully assembled at least at z1.3z \sim 1.3 and that little significant accretion takes place at later times. The existence of massive, highly evolved galaxies at these epochs is likely to represent a significant challenge to theories of hierarchical structure formation where such objects are formed by the late accretion of spheroidal systems at z<1z < 1.Comment: Accepted for publication in AJ; includes data table of k-correction

    The Environmental Dependence of the Luminosity-Size Relation for Galaxies

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    We have examined the luminosity-size relationship as a function of environment for 12150 SDSS galaxies with precise visual classifications from the catalog of Nair & Abraham (2010a). Our analysis is subdivided into investigations of early-type galaxies and late-type galaxies. Early-type galaxies reveal a surprisingly tight luminosity-size relation. The dispersion in luminosity about the fiducial relation is only ~0.14 dex (0.35 mag), even though the sample contains galaxies which differ by a factor of almost 100 in luminosity. The dispersion about the luminosity-size relation is comparable to the dispersion about the fundamental plane, even though the luminosity-size relation is fundamentally simpler and computed using purely photometric parameters. The key contributors to the dispersion about the luminosity-size relation are found to be color and central concentration. Expanding our analysis to the full range of morphological types, we show that the slope, zero point, and scatter about the luminosity-size relation is independent of environmental density. Our study thus indicates that whatever process is building galaxies is doing so in a way that preserves fundamental scaling laws even as the typical luminosity of galaxies changes with environment. However, the distribution of galaxies along the luminosity-size relation is found to be strongly dependent on galaxy environment. This variation is in the sense that, at a given morphology, larger and more luminous galaxies are rarer in sparser environments. Our analysis of late-type galaxy morphologies reveals that scatter increases towards later Hubble types. Taken together, these results place strong constraints on conventional hierarchical models in which galaxies are built up in an essentially stochastic way.Comment: 20 pages, 10 figures, 5 tables, Submitted Nov 5, 2009; Accepted by ApJ April 6, 2010 Higher resolution versions of the figures can be found at: http://www.bo.astro.it/~nair/Morphology

    The Next Generation Virgo Cluster Survey - Infrared (NGVS-IR): I. A new Near-UV/Optical/Near-IR Globular Cluster selection tool

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    The NGVS-IR project (Next Generation Virgo Survey - Infrared) is a contiguous near-infrared imaging survey of the Virgo cluster of galaxies. It complements the optical wide-field survey of Virgo (NGVS). The current state of NGVS-IR consists of Ks-band imaging of 4 deg^2 centered on M87, and J and Ks-band imaging of 16 deg^2 covering the region between M49 and M87. In this paper, we present the observations of the central 4 deg^2 centered on Virgo's core region. The data were acquired with WIRCam on the Canada-France-Hawaii Telescope and the total integration time was 41 hours distributed in 34 contiguous tiles. A survey-specific strategy was designed to account for extended galaxies while still measuring accurate sky brightness within the survey area. The average 5\sigma limiting magnitude is Ks=24.4 AB mag and the 50% completeness limit is Ks=23.75 AB mag for point source detections, when using only images with better than 0.7" seeing (median seeing 0.54"). Star clusters are marginally resolved in these image stacks, and Virgo galaxies with \mu_Ks=24.4 AB mag arcsec^-2 are detected. Combining the Ks data with optical and ultraviolet data, we build the uiK color-color diagram which allows a very clean color-based selection of globular clusters in Virgo. This diagnostic plot will provide reliable globular cluster candidates for spectroscopic follow-up campaigns needed to continue the exploration of Virgo's photometric and kinematic sub-structures, and will help the design of future searches for globular clusters in extragalactic systems. Equipped with this powerful new tool, future NGVS-IR investigations based on the uiK diagram will address the mapping and analysis of extended structures and compact stellar systems in and around Virgo galaxies.Comment: 23 pages, 18 figures. Accepted for publication in ApJ
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