Abstract
Boxy/peanut bulges are considered to be part of the same stellar structure as bars and both could be linked through the buckling instability. The Milky Way is our closest example. The goal ...of this Letter is to determine if the mass assembly of the different components leaves an imprint in their stellar populations allowing the estimation the time of bar formation and its evolution. To this aim, we use integral field spectroscopy to derive the stellar age distributions, SADs, along the bar and disc of NGC 6032. The analysis clearly shows different SADs for the different bar areas. There is an underlying old (≥12 Gyr) stellar population for the whole galaxy. The bulge shows star formation happening at all times. The inner bar structure shows stars of ages older than 6 Gyr with a deficit of younger populations. The outer bar region presents an SAD similar to that of the disc. To interpret our results, we use a generic numerical simulation of a barred galaxy. Thus, we constrain, for the first time, the epoch of bar formation, the buckling instability period and the posterior growth from disc material. We establish that the bar of NGC 6032 is old, formed around 10 Gyr ago while the buckling phase possibly happened around 8 Gyr ago. All these results point towards bars being long-lasting even in the presence of gas.
Integral field spectroscopy (IFS) studies based on CALIFA survey data have recently revealed ongoing low-level star formation (SF) in the periphery of a small fraction (~10%) of local early-type ...galaxies (ETGs), witnessing a still ongoing inside-out galaxy growth process. A distinctive property of the nebular component in these ETGs, classified i+, is a structure with two radial zones, the inner of which displays LINER emission with a Hα equivalent width EW(Hα) ≃ 1 Å, the outer (3 Å <EW(Hα) ≲ 20 Å) Hii-region characteristics. Using CALIFA IFS data, we empirically demonstrate that the confinement of nebular emission to the galaxy periphery leads to a strong aperture (or, correspondingly, redshift) bias in spectroscopic single-fiber studies of type i+ ETGs: at low redshift (z ≲ 0.45), SDSS spectroscopy is restricted to the inner (SF-devoid LINER) zone, which causes the galaxies to be erroneously classified as “retired”, that is, systems entirely lacking SF, and whose faint nebular emissionis solely powered by the post-AGB stellar component. The SDSS aperture progressively encompasses the outer SF zone only at higher z, at which the galaxies are unambiguously classified as “composite SF/LINER”. We also empirically demonstrate that the principal effect of a decreasing spectroscopic aperture on the classification of i+ ETGs through standard Nii/Hα vs. Oiii/Hβ emission-line (BPT) ratios consists of a monotonic shift upward and to the right precisely along the upper right wing of the “seagull” distribution on the BPT plane, that is, along the pathway connecting composite SF/Hii galaxies with AGN/LINERs. Motivated by these observational insights, we also investigate theoretically observational biases in aperture-limited studies of inside-out growing galaxies as a function of z. To this end, we devise a simple 1D model that involves an outward-propagating exponentially decreasing SF process since z ~ 10 and reproduces the radial extent and two-zone EW(Hα) distribution of local i+ ETGs. By simulating the 3′′ spectroscopic SDSS aperture in this model, we find that SDSS studies at z ≲ 1 are progressively restricted to the inner (SF-devoid LINER) zone and miss an increasingly larger portion of the Hα-emitting periphery. This leads to the incorrect spectroscopic classification of these inside-out assembling galaxies as retired ETG/LINERs and also to a severe underestimation of their total star formation rate (SFR) in a manner inversely related to z. More specifically, the SFR inferred from the Hα luminosity registered within the SDSS fiber is reduced by 50% at z ~ 0.86, reaching only 0.1% of its integral value at z = 0.1. We argue that the aperture-driven biases described above pertain to any morphological analog of i+ ETGs (e.g., SF-quiescent bulges within star-forming disks), regardless of whether it is viewed from the perspective of inside-out growth or inside-out SF quenching, and might be of considerable relevance to galaxy taxonomy and studies of the cosmic SFR density as a function of z.
ABSTRACT This paper aims to provide aperture corrections for emission lines in a sample of spiral galaxies from the Calar Alto Legacy Integral Field Area Survey (CALIFA) database. In particular, we ...explore the behavior of the log(O iii λ5007/Hβ)/(N ii λ6583/H ) (O3N2) and logN ii λ6583/H (N2) flux ratios since they are closely connected to different empirical calibrations of the oxygen abundances in star-forming galaxies. We compute the median growth curves of H , H /Hβ, O3N2, and N2 up to 2.5R50 and 1.5 disk . These distances cover most of the optical spatial extent of the CALIFA galaxies. The growth curves simulate the effect of observing galaxies through apertures of varying radii. We split these growth curves by morphological types and stellar masses to check if there is any dependence on these properties. The median growth curve of the H flux shows a monotonous increase with radius with no strong dependence on galaxy inclination, morphological type, and stellar mass. The median growth curve of the H /Hβ ratio monotonically decreases from the center toward larger radii, showing for small apertures a maximum value of 10% larger than the integrated one. It does not show any dependence on inclination, morphological type, and stellar mass. The median growth curve of N2 shows a similar behavior, decreasing from the center toward larger radii. No strong dependence is seen on the inclination, morphological type, and stellar mass. Finally, the median growth curve of O3N2 increases monotonically with radius, and it does not show dependence on the inclination. However, at small radii it shows systematically higher values for galaxies of earlier morphological types and for high stellar mass galaxies. Applying our aperture corrections to a sample of galaxies from the SDSS survey at 0.02 ≤ z ≤ 0.3 shows that the average difference between fiber-based and aperture-corrected oxygen abundances, for different galaxy stellar mass and redshift ranges, reaches typically to 11%, depending on the abundance calibration used. This average difference is found to be systematically biased, though still within the typical uncertainties of oxygen abundances derived from empirical calibrations. Caution must be exercised when using observations of galaxies for small radii (e.g., below 0.5 ) given the high dispersion shown around the median growth curves. Thus, the application of these median aperture corrections to derive abundances for individual galaxies is not recommended when their fluxes come from radii much smaller than either R50 or .
The miniJPAS survey Rodríguez-Martín, J. E.; González Delgado, R. M.; Martínez-Solaeche, G. ...
Astronomy and astrophysics (Berlin),
10/2022, Letnik:
666
Journal Article
Recenzirano
Odprti dostop
The Javalambre-Physics of the Accelerating Universe Astrophysical Survey (J-PAS) is a photometric survey that is poised to scan several thousands of square degrees of the sky. It will use 54 ...narrow-band filters, combining the benefits of low-resolution spectra and photometry. Its offshoot, miniJPAS, is a 1 deg
2
survey that uses J-PAS filter system with the Pathfinder camera. In this work, we study mJPC2470-1771, the most massive cluster detected in miniJPAS. We survey the stellar population properties of the members, their star formation rates (SFR), star formation histories (SFH), the emission line galaxy (ELG) population, spatial distribution of these properties, and the ensuing effects of the environment. This work shows the power of J-PAS to study the role of environment in galaxy evolution. We used a spectral energy distribution (SED) fitting code to derive the stellar population properties of the galaxy members: stellar mass, extinction, metallicity, (
u
−
r
)
res
and (
u
−
r
)
int
colours, mass-weighted age, the SFH that is parametrised by a delayed-
τ
model (
τ
,
t
0
), and SFRs. We used artificial neural networks for the identification of the ELG population via the detection of the H
α
, NII, H
β
, and OIII nebular emission. We used the Ew(H
α
)-NII (WHAN) and OIII/H
α
-NII/H
α
(BPT) diagrams to separate them into individual star-forming galaxies and AGNs. We find that the fraction of red galaxies increases with the cluster-centric radius; and at 0.5
R
200
the red and blue fractions are both equal. The redder, more metallic, and more massive galaxies tend to be inside the central part of the cluster, whereas blue, less metallic, and less massive galaxies are mainly located outside of the inner 0.5
R
200
. We selected 49 ELG, with 65.3% of them likely to be star-forming galaxies, dominated by blue galaxies, and 24% likely to have an AGN (Seyfert or LINER galaxies). The rest are difficult to classify and are most likely composite galaxies. These latter galaxies are red, and their abundance decreases with the cluster-centric radius; in contrast, the fraction of star-forming galaxies increases outwards up to
R
200
. Our results are compatible with an scenario in which galaxy members were formed roughly at the same epoch, but blue galaxies have had more recent star formation episodes, and they are quenching out from within the cluster centre. The spatial distribution of red galaxies and their properties suggest that they were quenched prior to the cluster accretion or an earlier cluster accretion epoch. AGN feedback or mass might also stand as an obstacle in the quenching of these galaxies.
We present a catalogue of 348 galaxy clusters and groups with 0.2 < z < 1.2 selected in the 2.78 deg2 Advanced Large, Homogeneous Area Medium Band Redshift Astronomical (ALHAMBRA) survey. The high ...precision of our photometric redshifts, close to 1 per cent, and the wide spread of the seven ALHAMBRA pointings ensure that this catalogue has better mass sensitivity and is less affected by cosmic variance than comparable samples. The detection has been carried out with the Bayesian Cluster Finder, whose performance has been checked in ALHAMBRA-like light-cone mock catalogues. Great care has been taken to ensure that the observable properties of the mocks photometry accurately correspond to those of real catalogues. From our simulations, we expect to detect galaxy clusters and groups with both 70 per cent completeness and purity down to dark matter halo masses of M
h ∼ 3 × 1013 M⊙ for z < 0.85. Cluster redshifts are expected to be recovered with ∼0.6 per cent precision for z < 1. We also expect to measure cluster masses with
$\sigma _{M_{\rm h}|M^*_{{\rm CL}}}\sim 0.25\hbox{-} 0.35\,\mathrm{dex}$
precision down to ∼ 3 × 1013 M⊙, masses which are 50 per cent smaller than those reached by similar work. We have compared these detections with previous optical, spectroscopic and X-rays work, finding an excellent agreement with the rates reported from the simulations. We have also explored the overall properties of these detections such as the presence of a colour–magnitude relation, the evolution of the photometric blue fraction and the clustering of these sources in the different ALHAMBRA fields. Despite the small numbers, we observe tentative evidence that, for a fixed stellar mass, the environment is playing a crucial role at lower redshifts (z < 0.5).
In recent years, there has been an increase of studies dedicated to cognitive rehabilitation in patients with multiple sclerosis (MS); however, few of these analyze the impact on such variables as ...cognitive reserve. The study aims to explore the effects of a cognitive rehabilitation program comprising a combination of cognitive and physical exercises, as well as group sessions to improve cognitive performance, emotional state, and cognitive reserve index.
Fifty patients with MS were subdivided into 2 groups: the control group, which performed aerobic exercise (n=25), and the experimental group (n=25), which participated in the integrated cognitive rehabilitation program (ICRP). All participants were evaluated 3 times (baseline, post-treatment, and long-term) with the Brief Repeatable Battery of Neuropsychological Tests, Cognitive Reserve Scale, Beck Depression Inventory, and a scale evaluating trait and state anxiety.
Compared with the control group, patients in the experimental group showed improvements in cognitive function, with significant changes in measures of information processing speed, attention, memory, cognitive reserve index, and long-term mood.
The ICRP was effective in improving cognitive and emotional function in MS, and increased the cognitive reserve index.
En los últimos años se ha observado un interés creciente por la rehabilitación cognitiva en pacientes con esclerosis múltiple. Sin embargo, pocos estudios han analizado su impacto en variables como la reserva cognitiva. Analizamos el efecto de un programa de rehabilitación cognitiva que incluye ejercicios físicos y cognitivos, así como sesiones en grupo enfocadas a mejorar el rendimiento cognitivo, el estado emocional y el índice de reserva cognitiva.
Nuestro estudio incluyó a 50 pacientes con esclerosis múltiple, divididos en 2 grupos: un grupo control (n = 25), en el que los pacientes realizaban ejercicio aeróbico, y un grupo experimental (n = 25), al que se administró un programa integral de rehabilitación cognitiva. Evaluamos a todos los pacientes en 3 momentos diferentes (al inicio, tras el tratamiento, y a largo plazo) con la Batería Neuropsicológica Breve, la Escala de Reserva Cognitiva, el Inventario de Depresión de Beck y una escala para medir la ansiedad rasgo y la ansiedad estado.
Los pacientes del grupo experimental mostraron un mejor rendimiento cognitivo que los controles, con cambios significativos en medidas de velocidad de procesamiento de la información, atención, memoria, índice de reserva cognitiva y estado de ánimo a largo plazo.
Nuestros resultados demuestran la eficacia del programa de rehabilitación cognitiva para mejorar las funciones cognitiva y emocional de los pacientes con esclerosis múltiple y aumentar el índice de reserva cognitiva.
The Low Redshift survey at Calar Alto (LoRCA) Comparat, J; Chuang, C.-H; Rodríguez-Torres, S ...
Monthly notices of the Royal Astronomical Society,
05/2016, Letnik:
458, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The Baryon Acoustic Oscillation (BAO) feature in the power spectrum of galaxies provides a standard ruler to measure the accelerated expansion of the Universe. To extract all available information ...about dark energy, it is necessary to measure a standard ruler in the local, z < 0.2, universe where dark energy dominates most the energy density of the Universe. Though the volume available in the local universe is limited, it is just big enough to measure accurately the long 100 h
−1 Mpc wave-mode of the BAO. Using cosmological N-body simulations and approximate methods based on Lagrangian perturbation theory, we construct a suite of a thousand light-cones to evaluate the precision at which one can measure the BAO standard ruler in the local universe. We find that using the most massive galaxies on the full sky (34 000 deg2), i.e. a K
2MASS < 14 magnitude-limited sample, one can measure the BAO scale up to a precision of 4 per cent (∼1.2 per cent using reconstruction). We also find that such a survey would help to detect the dynamics of dark energy. Therefore, we propose a 3-year long observational project, named the Low Redshift survey at Calar Alto, to observe spectroscopically about 200 000 galaxies in the northern sky to contribute to the construction of aforementioned galaxy sample. The suite of light-cones is made available to the public.
Context. The study of the integrated properties of star-forming galaxies is central to understand their formation and evolution. Some of these properties are extensive and therefore their analysis ...require totally covering and spatially resolved observations. Among these properties, metallicity can be defined in spiral discs by means of integral field spectroscopy (IFS) of individual H ii regions. The simultaneous analysis of the abundances of primary elements, as oxygen, and secondary, as nitrogen, also provides clues about the star formation history and the processes that shape the build-up of spiral discs. Aims. Our main aim is to analyse simultaneously O/H and N/O abundance ratios in H ii regions in different radial positions of the discs in a large sample of spiral galaxies to obtain the slopes and the characteristic abundance ratios that can be related to their integrated properties. Methods. We analysed the optical spectra of individual selected H ii regions extracted from a sample of 350 spiral galaxies of the CALIFA survey. We calculated total O/H abundances and, for the first time, N/O ratios using the semi-empirical routine Hii-Chi-mistry, which, according to Pérez-Montero (2014, MNRAS, 441, 2663), is consistent with the direct method and reduces the uncertainty in the O/H derivation using N ii lines owing to the dispersion in the O/H-N/O relation. Then we performed linear fittings to the abundances as a function of the de-projected galactocentric distances. Results. The analysis of the radial distribution both for O/H and N/O in the non-interacting galaxies reveals that both average slopes are negative, but a non-negligible fraction of objects have a flat or even a positive gradient (at least 10% for O/H and 4% for N/O). The slopes normalised to the effective radius appear to have a slight dependence on the total stellar mass and the morphological type, as late low-mass objects tend to have flatter slopes. No clear relation is found, however, to explain the presence of inverted gradients in this sample, and there is no dependence between the average slopes and the presence of a bar. The relation between the resulting O/H and N/O linear fittings at the effective radius is much tighter (correlation coefficient ρs = 0.80) than between O/H and N/O slopes (ρs = 0.39) or for O/H and N/O in the individual H ii regions (ρs = 0.37). These O/H and N/O values at the effective radius also correlate very tightly (less than 0.03 dex of dispersion) with total luminosity and stellar mass. The relation with other integrated properties, such as star formation rate, colour, or morphology, can be understood only in light of the found relation with mass.
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