198 research outputs found
Asymmetrical structure of ionization and kinematics in the Seyfert galaxy NGC 5033
We present integral field spectroscopy of NGC 5033, a low luminosity Seyfert
galaxy. The observations were made with INTEGRAL, a fiber based system
operating at the WHT. The intensity map of the H emission line
represents a spiral or ring-like pattern of HII regions. On the contrary, the
[OIII] intensity map morphology is markedly anisotropic. The strong
morphological differences imply that the [OIII] emitters represent highly
ionized gas illuminated by the central source. The [OIII] map morphology is
compatible with a biconical structure of ionization induced by strong
extinction in the galaxy disc that also obscures half of the spheroidal stellar
bulge. We identify the spectrum corresponding to the Seyfert 1 nucleus from the
presence of H broad emission lines. This spectrum is located in a region
where strong extinction is expected but exhibits the bluest spectral energy
distribution. The Seyfert 1 nucleus seems to be offcenter with respect to the
stellar rotation center. This result has been also found in other Seyfert
galaxies and interpreted in terms of a past merger. The offcentering could
indicate the presence of nonsymmetric departures in the gravitational potential
which could be fueling the active nucleus. The kinematics of the [OIII]
emitters show important deviations at a kpc scale with respect to the stellar
velocity field and show features related to the asymmetrical morphology of the
high ionization region.Comment: 9 pages, accepted for publication in Astronomy and Astrophysics.
Figures 1 and 7 are attached as .gif file
Does perceived restorativeness mediate the effects of perceived biodiversity and perceived naturalness on emotional well-being following group walks in nature?
Natural environments are associated with positive health and well-being. However, little is known about the influence of environmental qualities on well-being and the mechanisms underlying this association. This study explored whether perceived restorativeness and it subscales would mediate the effects of perceived biodiversity, perceived naturalness, walk duration and perceived intensity on emotional well-being.
Participants (n = 127) of a national walking program in England completed pre- and post-walk questionnaires (n = 1009) for each group walk attended within a 13-week period. Multilevel mediation examined the hypothesised indirect effects.
Perceived restorativeness mediated the effects of perceived bird biodiversity, perceived naturalness, and perceived walk intensity on positive affect, happiness and negative affect. The effect of walk duration on happiness was also mediated by perceived restorativeness. Perceived walk intensity had a direct effect on positive affect and happiness.
Findings have implications for theory development, future biodiversity-health research and practitioners interested in designing restorative environments
Axisymmetrical Gas Inflow in the Central Region of NGC 7331
New Integral Field Spectroscopy of the central region of NGC 7331 reveals
strong H emission in the well-known CO and HI ring of NGC 7331. The
[NII]/H ratio indicates that a large scale stellar formation process is
taken place at the ring in agreement with previous hypothesis about the
exhaustion of gas in the inner to the ring region. The dynamics of stars and
gas are not coupled. There is a ring of peculiar velocities in the ionized gas
velocity map. These peculiar velocities can be well interpreted by the presence
of an axisymmetric inflow of 40 km/s at the inner boundary of the large-scale
gaseous ring. We infer an inwards total flux of 1.6 Myr. This
value is typical of the accretion rates in hypothetical {\bf large} nuclear
black holes. Despite the large differences in the scales of the nucleus and the
gas ring of NGC 7331, we suggest that this inwards flux is feeding the nucleus.Comment: 5 pages, 3 figures, to be published in Astronomy and Astrophysic
Non-circular motion evidences in the circumnuclear region of M100 (NGC 4321)
We analyse new integral field spectroscopy of the inner region (central 2.5
kpc) of the spiral galaxy NGC 4321 to study the peculiar kinematics of this
region. Fourier analysis of the velocity residuals obtained by subtracting an
axisymmetric rotation model from the velocity field, indicates
that the distortions are {\em global} features generated by an
perturbation of the gravitational potential which can be explained by the
nuclear bar. This bar has been previously observed in the near-infrared but not
in the optical continuum dominated by star formation. We detect the optical
counterpart of this bar in the 2D distribution of the old stellar population
(inferred from the equivalent width map of the stellar absorption lines). We
apply the Tremaine--Weinberg method to the stellar velocity field to calculate
the pattern speed of the inner bar, obtaining a value of
=160. This value is considerably la
rger than the one obtained when a simple bar model is considered. However the
uncertainties in the pattern speed determination prevent us to give support to
alternative scenarios.Comment: 11 pages, 11 figures, accepted for publication in MNRA
Integral field optical spectroscopy of a representative sample of ULIRGs: I. The Data
We present a project aimed at studying the structure, dust distribution,
ionization state, and kinematics of a representative sample of 22 ULIRGs. The
galaxies in the sample undergo different merger phases (they are evenly divided
between pre- and post-coalescence systems) and ionization stages (27% HII, 32%
LINER, 18% Seyfert, and 23% mixed classifications) over a wide infrared
luminosity range (11.8<Lir/Lsun<12.6), which also includes some galaxies of low
luminosity. The main aims of this paper are to present the sample and discuss
the structure of the stellar and ionized gas components. Our results imply that
evolution caused by a merger is occurring in the ionized gas structure of
ULIRGs. The present study relies on the use of integral field optical
spectroscopy data obtained with the INTEGRAL instrument at the 4.2 m William
Herschel Telescope.Comment: To appear in A&A. Paper with higher quality images can be found at
http://hera.ph1.uni-koeln.de/ftpspace/maca/Catalog
Integral Field Spectroscopy of the Central Regions of 3C 120: Evidence of a Past Merging Event
IFS combined with HST WFPC imaging were used to characterize the central
regions of the Seyfert 1 radio galaxy 3C 120. We carried out the analysis of
the data, deriving intensity maps of different emission lines and the continua
at different wavelengths from the observed spectra. Applying a 2D modeling to
the HST images we decoupled the nucleus and the host galaxy, and analyzed the
host morphology. The host is a highly distorted bulge dominated galaxy, rich in
substructures. We developed a new technique to model the IFS data extending the
2D modeling. Using this technique we separated the Seyfert nucleus and the host
galaxy spectra, and derived a residual data cube with spectral and spatial
information of the different structures in 3C 120. Three continuum-dominated
structures (named A, B, and C) and other three extended emission line regions
(EELRs, named E1, E2 and E3) are found in 3C 120 which does not follow the
general behavior of a bulge dominated galaxy. We also found shells in the
central kpc that may be remnants of a past merging event in this galaxy. The
origin of E1 is most probably due to the interaction of the radio-jet of 3C 120
with the intergalactic medium. Structures A, B, and the shell at the southeast
of the nucleus seem to correspond to a larger morphological clumpy structure
that may be a tidal tail, consequence of the past merging event. We found a
bright EELR (E2) in the innermost part of this tidal tail, nearby the nucleus,
which shows a high ionization level. The kinematics of the E2 region and its
connection to the tidal tail suggest that the tail has channeled gas from the
outer regions to the center.Comment: 55 pages, 18 figures and 5 tables Accepted by AP
PMAS Optical Integral Field Spectroscopy of Luminous Infrared Galaxies. II.-- Spatially resolved stellar populations and excitation conditions
The general properties of luminous and ultraluminous infrared galaxies (LIRGs
and ULIRGs) in the local universe are well known since large samples of these
objects have been the subject of numerous spectroscopic works. There are,
however, relatively few studies of large samples of LIRGs and ULIRGs using
integral field spectroscopy (IFS). We analyze optical (3800-7200A) IFS data
taken with the Potsdam Multi-Aperture Spectrophotometer (PMAS) of the central
few kiloparsecs of 11 LIRGs. To study the stellar populations we fit the
optical stellar continuum and the hydrogen recombination lines of selected
regions. We analyze the excitation conditions of the gas using the spatially
resolved properties of the brightest optical emission lines. The optical
continua of the selected regions are well fitted with a combination of evolved
(~0.7-10Gyr) and ionizing (1-20Myr) stellar populations. The latter is more
obscured than the evolved population, and has visual extinctions in good
agreement with those obtained from the Balmer decrement. Except for NGC 7771,
there is no clear evidence for an important contribution to the optical light
from an intermediate-aged population (~100-500Myr). Even after correcting for
the presence of stellar absorption, a large fraction of spaxels with low
observed equivalent widths of Halpha in emission still show enhanced
[NII]/Halpha and [SII]/Halpha ratios. These ratios are likely to be produced by
a combination of photoionization in HII regions and diffuse emission. These
regions of enhanced ratios are generally coincident with low surface brightness
HII regions and diffuse emission detected in the Halpha and Pa-alpha images.
Using the PMAS line ratios and the NICMOS Pa-alpha photometry of HII regions we
find that the fraction of diffuse emission in LIRGs varies from galaxy to
galaxy, and it is generally less than 60% as found in other starburst galaxies.
(Abridged)Comment: Accepted for publication in A&
Integral Field Spectroscopy Of The Brightest Knots Of Hh 223 In L723
HH 223 is the optical counterpart of a larger scale H2 outflow, driven by the
protostellar source VLA 2A, in L723. Its poorly collimated and rather chaotic
morphology suggested the Integral Field Spectroscopy (IFS) as an appropriate
option to map the emission for deriving the physical conditions and the
kinematics. Here we present new results based on the IFS observations made with
the INTEGRAL system at the WHT. The brightest knots of HH 223 (\sim16 arcsec,
0.02 pc at a distance of 300 pc) were mapped with a single pointing in the
spectral range 6200-7700 A. We obtained the emission-line intensity maps for
Halpha, [NII] 6584 A and [SII] 6716, 6731 A, and explored the distribution of
the excitation and electron density from [NII]/Halpha, [SII]/Halpha, and [SII]
6716/6731 line-ratio maps. Maps of the radial velocity field were obtained. We
analysed the 3D-kinematics by combining the knot radial velocities, derived
from IFS data, with the knot proper motions derived from multi-epoch,
narrow-band images. The intensity maps built from IFS data reproduced well the
morphology found in the narrow-band images. We checked the results obtained
from previous long-slit observations with those derived from IFS spectra
extracted with a similar spatial sampling. At the positions intersected by the
slit, the physical conditions and kinematics derived from IFS are compatible
with those derived from long-slit data. In contrast, significant discrepancies
were found when the results from long-slit data were compared with the ones
derived from IFS spectra extracted at positions shifted a few arcsec from those
intersected by the slit. This clearly revealed IFS observations as the best
choice to get a reliable picture of the HH emission properties.Comment: 9 pages, 8 figures; Accepted for MNRA
TP97 299. Experiencia en el uso de válvula aórtica biológica freedom solo en endocarditis
IntroducciónLas válvulas aórticas biológicas sin soporte Sorin Freedom Solo (FS) han demostrado una mejoría en el aumento del orificio de área efectivo, así como un mejor perfil en los gradientes transvalvulares, fracción de eyección del ventrículo izquierdo (FEVI) y regresión de la hipertrofia ventricular izquierda. También, se ha comprobado una reducción en los tiempos de isquemia miocárdica y de circulación extracorpórea. Sin embargo no hay mucha información sobre su comportamiento en el contexto de endocarditis valvular.Material y métodosDesde noviembre de 2006 – septiembre 2011, se implantaron 17 prótesis FS en 16 pacientes (50% hombres, 60,2±15 años) por endocarditis bacteriana. Se determinó la cantidad de plaquetas en el día 5 postimplante, así como la fracción de eyección (FE) y los gradientes transvalvulares posquirúrgicos. Seguimiento medio de 22,5±26 meses.ResultadosLa prevalencia de trombocitopenia (< 150.000 plaquetas) y trombocitopenia grave (< 50.000 plaquetas) ha sido de 68,8 y 31,3%, respectivamente. Hubo un total de 4 muertes hospitalarias (25%), 2 intraoperatorias. Gradiente transvalvular medio de 22±18mmHg, FEVI postoperatoria media de 52,4±10,3%. Tres pacientes fueron reintervenidos, 2 por deterioro precoz (16%), 1 por nueva endocarditis (8%).ConclusiónLa prótesis aórtica biológica sin soporte FS muestra un buen perfil hemodinámico, mejorando significati-vamente los gradientes transvalvulares.Nuestra prevalencia de trombocitopenia al quinto día y durabilidad de la válvula se encuentran en valores similares a lo publicado en la literatura.El uso de dicha prótesis en endocarditis aórtica debe considerarse una alternativa eficaz al demostrarse baja tasa de reincidencia de endocarditis
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