2,051 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
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
A detailed two-dimensional stellar population study of M32
We present Two-Dimensional Spectroscopy of the 9x12 arcsec^2 central region
of M32 obtained with the 2D_FIS fibre spectrograph installed at the William
Herschel Telescope. From these spectra line strength maps have been
reconstructed for about 20 absorption lines, mostly belonging to the Lick
system. We find good agreement with long-slit line strength profiles in the
literature. In contrast with previous studies, indices were azimuthally
averaged along continuum isophotes of M32. A remarkable result is that no
gradients are presented in the spectral indices. So, we have fitted the mean
values of each spectral index and central colours to the models of Vazdekis et
al. (1996) and Worthey (1994), finding that an intermediate age (~4 Gyr) and
metallicity similar to solar (Z=0.02) are the best fitted values for the
innermost region of M32.Comment: accepted in MNRA
Spatially resolved kinematics, galactic wind, and quenching of star formation in the luminous infrared galaxy IRAS F11506-3851
We present a multi-wavelength integral field spectroscopic study of the low-z
LIRG IRAS F11506-3851, on the basis of VIMOS and SINFONI (ESO-VLT)
observations. The morphology and the 2D kinematics of the gaseous (neutral and
ionized) and stellar components have been mapped using the NaD doublet, the
H line, and the near-IR CO(2-0) and CO(3-1) bands. The kinematics of
the ionized gas and the stars are dominated by rotation, with large observed
velocity amplitudes and centrally peaked velocity dispersion maps. The stars
lag behind the warm gas and represent a dynamically hotter system, as indicated
by the observed dynamical ratios. Thanks to these IFS data we have disentangled
the contribution of the stars and the ISM to the NaD feature, finding that it
is dominated by the absorption of neutral gas clouds in the ISM. The neutral
gas 2D kinematics shows a complex structure dominated by two components. On the
one hand, the thick slowly rotating disk lags significantly compared to the
ionized gas and the stars, with an irregular and off-center velocity dispersion
map. On the other hand, a kpc-scale neutral gas outflow is observed along the
semi-minor axis of the galaxy, as revealed by large blueshifted velocities
(30-154 km/s). We derive an outflowing mass rate in neutral gas of about 48
/yr. Although this implies a global mass loading factor of
1.4, the 2D distribution of the ongoing SF suggests a much larger value of mass
loading factor associated with the inner regions (R200 pc), where the
current SF represents only 3 percent of the total. All together these results
strongly suggest that we are witnessing (nuclear) quenching due to SF feedback
in IRAS F11506-3851. However, the relatively large mass of molecular gas
detected in the nuclear region via the H2 1-0 S(1) line suggests that further
episodes of SF may take place again
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
Sandstone petrofacies in the northwestern sector of the Iberian Basin
During the most active rifting stages in the northwestern sector of the Iberian Basin (Cameros Basin and Aragonese Branch of the Iberian Range), thick sequences of continental clastic deposits were generated. Sandstone records from Rift cycle 1 (Permo-Triassic) and Rift cycle 2 (Late Jurassic-Early Cretaceous) show similarities in composition. Based on the most recent data, this paper describes sandstone petrofacies developed during both rifting periods. Six petrofacies can be distinguished: two associated with Rift cycle 1 (PT-1 and PT-2) and four with Rift cycle 2 (JC-1 to JC-4). All six petrofacies can be classifi ed as sedimentoclastic or plutoniclastic. Sedimentoclastic petrofacies developed during early rifting stages either through the recycling of pre-rift sediments or signifi cant palaeogeographical changes. These facies comprise a thin succession (<100 m) of clastic deposits with mature quartzose and quartzolithic sandstones containing sedimentary and metasedimentary rock fragments. Carbonate diagenesis is more common than clay mineral diagenesis. Sedimentoclastic petrofacies have been identifi ed in Rift cycle 1 (Saxonian facies, PT-1) and Rift cycle 2 (JC-1 and JC-3; Tithonian and Valanginian, respectively). In the absence of the pre-rift sedimentary cover, metasedimentoclastic petrofacies sometimes develop as a product of the erosion of the low- to medium-grade metamorphic substratum (Petrofacies JC-2, Tithonian-Berriasian). Plutoniclastic petrofacies were generated during periods of high tectonic activity and accompanied by substantial denudation and the erosion of plutonites. Forming thick stratigraphic successions (1000 to 4000 m), these feldspar-rich petrofacies show a rigid framework and clay mineral diagenesis. In Rift cycle 1, plutoniclastic petrofacies (PT-2) are associated with the Buntsandstein. This type of petrofacies also developed in Rift cycle 2 in the Cameros Basin (JC-4) from DS-5 to DS-8 (Hauterivian-Early Albian), and represents the main basin fi ll interval. Sedimentoclastic and plutoniclastic petrofacies can be grouped into three pairs of basic petrofacies. Each pair represents a ‘provenance cycle’ that records a complete clastic cycle within a rifting period. Petrofacies PT-1 and PT-2 represent the ‘provenance cycle’ during Rift-1. In the Cameros Basin, two provenance cycles may be discerned during Rift cycle 2, related both to the Tithonian-Berriasian and the Valanginian-Early Albian megasequences. Tectonics is the main factor controlling petrofacies. Other factors (e.g., maturation during transport, local supply) may modulate the compositional signatures of the petrofacies yet their main character persists and even outlines he hierarchy of the main bounding surfaces between depositional sequences in the intracontinental Iberian Rift Basin.Durante las fases de rifting más activas en el sector noroccidental de la Cuenca Ibérica (Cuenca de Cameros y Rama Aragonesa de la Cordillera Ibérica), se generaron potentes sucesiones detríticas de depósitos continentales. Los registros arenosos del ciclo Rift 1 (Permo-Triásico) y Rift-2 (Jurásico Superior-Cretácico Inferior) muestran similitudes en cuanto a su composición. El presente rabajo describe las petrofacies arenosas desarrolladas durante los dos períodos de rifting. Es osible establecer un total de seis petrofacies: dos relacionadas con el Rift-1 (PT-1 y PT-2) y cuatro con el Rift-2 (JC-1 a JC-4). Todas estas petrofacies pueden ser consideradas bien como sedimentoclásticas o como plutoniclásticas. Las petrofacies sedimentoclásticas se desarrollaron durante las etapas iniciales de rifting debido al reciclado del registro sedimentario rerift, o por importantes cambios paleogeográfi cos. Aparecen constituyendo sucesiones de depósitos clásticos poco potentes
Estudio tecnológico de los moluscos marinos perforados de los yacimientos de Lumentxa y Santa Catalina (Lekeitio, Bizkaia)
La colección de moluscos perforados tardiglaciares de los yacimientos de Lumentxa y Santa Catalina, aunque no muy abundante, presenta una importante variedad de especies y formas. En este artículo se revisan los objetos ya publicados y se añaden otros inéditos. De entre éstos destaca una Chlamys islándica de Santa Catalina excepcional tanto por lo infrecuente de su presencia en yacimientos cantábricos como por la decoración geométrica que tiene en el interior de la valva. El estudio tecnológico incluye la observación microscópica de las piezas y la realización de un programa experimental adecuado, lo que nos ha permitido acercarnos a las técnicas empleadas en su realización
FeNi-based magnetoimpedance multilayers: Tailoring of the softness by magnetic spacers
The microstructure and magnetic properties of sputtered permalloy films and FeNi(170 nm)/X/FeNi(170 nm) (X=Co, Fe, Gd, Gd-Co) sandwiches were studied. Laminating of the thick FeNi film with various spacers was done in order to control the magnetic softness of FeNi-based multilayers. In contrast to the Co and Fe spacers, Gd and Gd-Co magnetic spacers improved the softness of the FeNi/X/FeNi sandwiches. The magnetoimpedance responses were measured for [FeNi/Ti(6 nm)] 2/FeNi and [FeNi/Gd(2 nm)] 2/FeNi multilayers in a frequency range of 1-500 MHz: for all frequencies under consideration the highest magnetoimpedance variation was observed for [FeNi/Gd(2 nm)] 2/FeNi multilayers. © 2012 American Institute of Physics
Three-year durable efficacy of dolutegravir plus lamivudine in antiretroviral therapy - naive adults with hiv-1 infection
Objective:To assess efficacy and safety of dolutegravir (DTG) + lamivudine (3TC) vs. DTG + tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) in treatment-naive adults with HIV-1 in the prespecified 144-week secondary analyses of GEMINI-1 and GEMINI-2.Design:Identical, multicenter, phase III, randomized, non-inferiority studies (double-blind through 96 weeks).Methods:Participants with HIV-1 RNA ≤500 000 copies/ml and no major viral resistance mutations to nucleoside reverse transcriptase inhibitors, nonnucleoside reverse transcriptase inhibitors, or protease inhibitors were randomized 1:1 to once-daily DTG + 3TC or DTG + TDF/FTC.Results:At week 144, DTG + 3TC (N = 716) was noninferior to DTG + TDF/FTC (N = 717) in proportion of participants achieving HIV-1 RNA <50 copies/ml (Snapshot algorithm) in the pooled analysis (82% vs. 84%, respectively; adjusted treatment difference [95% confidence interval (CI)], -1.8% [-5.8, 2.1]), GEMINI-1 (-3.6% [-9.4, 2.1]), and GEMINI-2 (0.0% [-5.3, 5.3]). Twelve DTG + 3TC participants and nine DTG + TDF/FTC participants met protocol-defined confirmed virologic withdrawal (CVW) criteria; none developed treatment-emergent resistance. One DTG + 3TC participant who did not meet CVW criteria developed M184V at week 132 and R263R/K at week 144, conferring a 1.8-fold change in susceptibility to DTG; non-adherence to therapy was reported. Significantly fewer drug-related adverse events occurred with DTG + 3TC vs. DTG + TDF/FTC (20% vs. 27%; relative risk [95% CI], 0.76 [0.63-0.92]). Renal and bone biomarker changes favored DTG + 3TC.Conclusions:Three-year durable efficacy, long-term tolerability, and high barrier to resistance support first-line use of DTG + 3TC for HIV-1 treatment (see Supplemental Digital Content 1, http://links.lww.com/QAD/C297; video abstract)This study was funded by ViiV Healthcar
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