54 research outputs found
Red-channel (6000-8000 {\AA}) nuclear spectra of 376 local galaxies
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
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
An infrared survey of the central 650 arcmin of the Coma cluster is used
to determine the band luminosity function for the cluster. Redshifts are
available for all galaxies in the survey with , and for this sample
we obtain a good fit to a Schechter function with and
. 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
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 , with slope .Comment: 15 pages, 2 figures Accepted by ApJ Letter
The properties of quasar hosts at the peak of the quasar activity
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 Photometry of Galaxies in the Coma Cluster
We present a set of photometry for 745 band selected
objects in a 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 . 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
( mag in and less than in , or ).
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 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
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 -band luminosity function of galaxies in clusters to
We derive the rest-frame -band luminosity function for galaxies in 32
clusters at using deep m and m 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 ) are fully assembled at least at 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 .Comment: Accepted for publication in AJ; includes data table of k-correction
The Environmental Dependence of the Luminosity-Size Relation for Galaxies
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
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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