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In this work, we investigated the nitrogen and oxygen abundances in a sample of galaxies with Low Ionization Nuclear Emission Regions (LINERs) in their nucleus. Optical spectroscopic data (3 600 - 10 000 {\AA}) of 40 LINERs from the Mapping Nearby Galaxies (MaNGA) survey were considered. Only objects classified as retired galaxies, i.e. whose main ionization sources are post-Asymptotic Giant Branch (pAGB) stars, were selected. The abundance estimates were obtained through detailed photoionization models built with the cloudy code to reproduce a set of observational emission line intensities ratios of the sample. Our results show that LINERs have oxygen and nitrogen abundances in the ranges of $ 8.0 \leq 12+\log(O/H) \leq 9.0$ (mean value $8.74\pm 0.27$) and $7.6 \leq 12+\log(N/H) \leq 8.5$ (mean value $8.05\pm 0.25$), respectively. About 70% of the sample have oversolar O/H and N/H abundances. Our abundance estimates are in consonance with those for Seyfert 2 nuclei and H ii regions with the highest metallicity, indicating that these distinct object classes show similar enrichment of the interstellar medium (ISM). The LINERs in our sample are located in the higher N/O region of the N/O versus O/H diagram, showing an expected negative correlation between these two parameters. These results suggest that these LINERs mainly exhibit a secondary nitrogen production and could be acting some other mechanisms that deviate them from the usual theoretical secondary nitrogen production curve and the H ii regions observations. However, we did not find any evidence in our data able to support the literature suggested mechanisms. On the other hand, our results show that LINERs do not present any correlation between the N/O abundances and the stellar masses of the hosting galaxies., Comment: Accepted for publication in MNRAS

The Fornax galaxy cluster is the richest nearby (D ~ 20 Mpc) galaxy association in the southern sky. As such, it provides a wealth of oportunities to elucidate on the processes where environment holds a key role in transforming galaxies. Although it has been the focus of many studies, Fornax has never been explored with contiguous homogeneous wide-field imaging in 12 photometric narrow- and broad-bands like those provided by the Southern Photometric Local Universe Survey (S-PLUS). In this paper we present the S-PLUS Fornax Project (S+FP) that aims to comprehensively analyse the galaxy content of the Fornax cluster using S-PLUS. Our data set consists of 106 S-PLUS wide-field frames (FoV ~ 1.4 x 1.4 deg$^2$) observed in five SDSS-like ugriz broad-bands and seven narrow-bands covering specific spectroscopic features like [OII], CaII H+K, H$\delta$, G-band, Mg b triplet, H$\alpha$, and the CaII triplet. Based on S-PLUS specific automated photometry, aimed at correctly detecting Fornax galaxies and globular clusters in S-PLUS images, our dataset provides the community with catalogues containing homogeneous 12-band photometry for ~ 3 x 10$^6$ resolved and unresolved objects within a region extending over ~ 208 deg$^2$ (~ 5 Rvir in RA) around Fornax' central galaxy, NGC 1399. We further explore the EAGLE and IllustrisTNG cosmological simulations to identify 45 Fornax-like clusters and generate mock images on all 12 S-PLUS bands of these structures down to galaxies with M$\star \geq 10^8$ M$\odot$. The S+FP dataset we put forward in this first paper of a series will enable a variety of studies some of which are briefly presented., Comment: 25 pages, 30 figures, accepted for publication in MNRAS

This paper presents a method for finding ram-pressure stripped (RPS) galaxy candidates by performing a morphological analysis of galaxy images obtained from the Legacy survey. We consider a sample of about 600 galaxies located in different environments such as groups and clusters, tidally interacting pairs and the field. The sample includes 160 RPS previously classified in the literature into classes from J1 to J5, based on the increasing level of disturbances. Our morphological analysis was done using the {\sc astromorphlib} software followed by the inspection of diagnostic diagrams involving combinations of different parameters like the asymmetry ($A$), concentration ($C$), S\'ersic index ($n$), and bulge strength parameters $F(G,\,M_{20})$. We found that some of those diagrams display a distinct region in which galaxies classified as J3, J4 and J5 decouples from isolated galaxies. We call this region as the morphological transition zone and we also found that tidally interacting galaxies in pairs are predominant within this zone. Nevertheless, after visually inspecting the objects in the morphological transition zone to discard obvious contaminants, we ended up with 33 bonafide new RPS candidates in the studied nearby groups and clusters (Hydra, Fornax, and CLoGS sample), of which one-third show clear evidence of unwinding arms. Future works may potentially further increase significantly the samples of known RPS using such method., Comment: 17 pages, 9 figures

The ionizing source of Low Ionization Nuclear Emission Regions (LINERs) is uncertain. Because of this, an empirical relation to determine the chemical abundances of these objects has not been proposed. In this work, for the first time, we derived two semi-empirical calibrations based on photoionization models to estimate the oxygen abundance of LINERS as a function of the $N2$ and $O3N2$ emission-line intensity ratios. These relations were calibrated using oxygen abundance estimations obtained by comparing the observational emission-line ratios of 43 LINER galaxies (taken from the MaNGA survey) and grids of photoionization models built with the {\sc Cloudy} code assuming post-Asymptotic Giant Branch (post-AGB) stars with different temperatures. We found that the oxygen abundance of LINERs in our sample is in the $\rm 8.48 <~ 12+log(O/H) <~ 8.84$ range, with a mean value of $\rm 12+\log(O/H)=8.65$. We recommend the use of the $N2$ index to estimate the oxygen abundances of LINERs, since the calibration with this index presented a much smaller dispersion than the $O3N2$ index. In addition, the estimated metallicities are in good agreement with those derived by extrapolating the disk oxygen abundance gradients to the centre of the galaxies showing that the assumptions of the models are suitable for LINERs. We also obtained a calibration between the logarithm of the ionization parameter and the [OIII]/[OII] emission-line ratio., Comment: 16 pages, 14 figures, 3 tables, accepted for publication in MNRAS

The structure of the Small Magellanic Cloud (SMC) is very complex, in particular in the periphery that suffers more from the interactions with the Large Magellanic Cloud (LMC). A wealth of observational evidence has been accumulated revealing tidal tails and bridges made up of gas, stars and star clusters. Nevertheless, a full picture of the SMC outskirts is only recently starting to emerge with a 6D phase-space map plus age and metallicity using star clusters as tracers. In this work, we continue our analysis of another outer region of the SMC, the so-called West Halo, and combined it with the previously analysed Northern Bridge. We use both structures to define the Bridge and Counter-bridge trailing and leading tidal tails. These two structures are moving away from each other, roughly in the SMC-LMC direction. The West Halo form a ring around the SMC inner regions that goes up to the background of the Northern Bridge shaping an extended layer of the Counter-bridge. Four old Bridge clusters were identified at distances larger than 8 kpc from the SMC centre moving towards the LMC, which is consistent with the SMC-LMC closest distance of 7.5 kpc when the Magellanic Bridge was formed about 150Myr ago; this shows that the Magellanic Bridge was not formed only by pulled gas, but it also removed older stars from the SMC during its formation. We also found age and metallicity radial gradients using projected distances on sky, which are vanished when we use the real 3D distances., Comment: 14 pages, 8 figures + appendix. Accepted for publication in MNRAS

We present a study for a sample of galaxies with active nuclei to characterize the main type of PAH molecules present in these objects and the local physical conditions of their irradiating sources, as well as the characteristics of the residing ionized gas, by combining optical and infrared data. Photoionization models were built with the {\sc CLOUDY} code to reproduce optical emission line ratios in combination with PAH intensity ratios. We find that the species containing 10 $-$ 82 carbon atoms are the most abundant in the sample. We suggest that family of species with only two or three fused rings of and a nitrogen hanging, such as small aromatic amides are important targets worthy of consideration in future experimental/theoretical as well as observational studies. We find that the AGN photoionization models reproduce most of the observational data in the log (6.2/11.3) versus log ([\ion{N}{ii}]$\lambda$6584/H$\alpha$) diagram with the optical to X-ray spectral index of $\alpha_{\rm ox}=-1.4$. The flux of small PAH, as well as the flux of ionized PAHs and PANH, decrease as the logarithm of the ionization parameter (log $U$) increases. The 6.2/11.3 PAH intensity ratio presents anti correlation between the oxygen abundance and log $U$, in the sense that the 6.2/11.3 ratio decreases as the oxygen abundance and log $U$ increases. Finally, we found that the ionization degree of PAH species increases with the decreasing of the 11.3/7.7 ratio and the log U, in agreement with the models proposed by Draine \& Li., Comment: 21 pages, 13 figures, accepted for publication in MNRAS

Chemical abundance determinations in Low-Ionization Nuclear Line Regions (LINERs) are especially complex and uncertain because the nature of the ionizing source of this kind of object is unknown. In this work, we study the oxygen abundance in relation to the hydrogen abundance (O/H) of the gas phase of the UGC4805 LINER nucleus. Optical spectroscopic data from the Mapping Nearby Galaxies (MaNGA) survey was employed to derive the O/H abundance of the UGC4805 nucleus based on the extrapolation of the disk abundance gradient, on calibrations between O/H abundance and strong emission-lines for Active Galactic Nuclei (AGNs) as well as on photoionization models built with the Cloudy code, assuming gas accretion into a black hole (AGN) and post-Asymptotic Giant Branch (p-AGB) stars with different effective temperatures. We found that abundance gradient extrapolations, AGN calibrations, AGN and p-AGB photoionization models produce similar O/H values for the UGC4805 nucleus and similar ionization parameter values. The study demonstrated that the methods used to estimate the O/H abundance using nuclear emission-line ratios produce reliable results, which are in agreement with the O/H values obtained from the independent method of galactic metallicity gradient extrapolation. Finally, the results from the WHAN diagram combined with the fact that the high excitation level of the gas has to be maintained at kpc scales, we suggest that the main ionizing source of the UGC4805 nucleus probably has a stellar origin rather than an AGN., Comment: 17 pages, 13 figures

We present the first systematic study of the stellar populations of ultra-diffuse galaxies (UDGs) in the field, integrating the large area search and characterization of UDGs by the SMUDGes survey with the twelve-band optical photometry of the S-PLUS survey. Based on Bayesian modeling of the optical colors of UDGs, we determine the ages, metallicities and stellar masses of 100 UDGs distributed in an area of $\sim 330$ deg$^2$ in the Stripe 82 region. We find that the stellar masses and metallicities of field UDGs are similar to those observed in clusters and follow the trends previously defined in studies of dwarf and giant galaxies. However, field UDGs have younger luminosity-weighted ages than do UDGs in clusters. We interpret this result to mean that field UDGs have more extended star formation histories, including some that continue to form stars at low levels to the present time. Finally, we examine stellar population scaling relations that show that UDGs are, as a population, similar to other low-surface brightness galaxies., Comment: 24 pages, 10 figures, accepted for Publication in ApJS

We present a star/galaxy classification for the Southern Photometric Local Universe Survey (S-PLUS), based on a Machine Learning approach: the Random Forest algorithm. We train the algorithm using the S-PLUS optical photometry up to $r$=21, matched to SDSS/DR13, and morphological parameters. The metric of importance is defined as the relative decrease of the initial accuracy when all correlations related to a certain feature is vanished. In general, the broad photometric bands presented higher importance when compared to narrow ones. The influence of the morphological parameters has been evaluated training the RF with and without the inclusion of morphological parameters, presenting accuracy values of 95.0\% and 88.1\%, respectively. Particularly, the morphological parameter {\rm FWHM/PSF} performed the highest importance over all features to distinguish between stars and galaxies, indicating that it is crucial to classify objects into stars and galaxies. We investigate the misclassification of stars and galaxies in the broad-band colour-colour diagram $(g-r)$ versus $(r-i)$. The morphology can notably improve the classification of objects at regions in the diagram where the misclassification was relatively high. Consequently, it provides cleaner samples for statistical studies. The expected contamination rate of red galaxies as a function of the redshift is estimated, providing corrections for red galaxy samples. The classification of QSOs as extragalactic objects is slightly better using photometric-only case. An extragalactic point-source catalogue is provided using the classification without any morphology feature (only the SED information) with additional constraints on photometric redshifts and {\rm FWHM/PSF} values., Comment: 11 pages and 6 figures, submitted to MNRAS

In a framework where galaxies mostly migrate on the colour-magnitude diagram from star-forming to quiescent, the green valley is considered a transitional galaxy stage. The details of the processes that drive galaxies from star-forming to passive systems still remain unknown. We developed a method that estimates empirically the star formation quenching times-scales of green valley galaxies, assuming an exponential decay model of the SFH and through a combination of narrow and broad bands from J-PLUS and GALEX. We correlate these quenching time-scales with the presence of bars. We find that the J-PLUS colours F0395-g and F0415-g are sensitive to different SFH, showing, a clear correlation with the Dn(4000) and H-delta,A spectral indices. We find that quenching time-scales obtained with our new approach are in agreement with those determined using spectral indices. We also find that galaxies with high bar probability tend to quench their star formation slowly. We conclude that: 1) J-PLUS filters can be used to measure quenching timescales in nearby green valley galaxies; and 2) the resulting star formation quenching time-scales are longer for barred green valley galaxies. Considering that the presence of a bar indicates that more violent processes (e.g., major mergers) are absent in host galaxies, we conclude that the presence of a bar can be used as a morphological signature for slow star formation quenching., Comment: 14 pages, 17 figures, accepted by Astronomy and Astrophysics

In this paper we present a thorough discussion about the photometric redshift (photo-z) performance of the Southern Photometric Local Universe Survey (S-PLUS). This survey combines a 7 narrow + 5 broad passband filter system, with a typical photometric-depth of r$\sim$21 AB. For this exercise, we utilize the Data Release 1 (DR1), corresponding to 336 deg$^{2}$ from the Stripe-82 region. We rely on the \texttt{BPZ2} code to compute our estimates, using a new library of SED models, which includes additional templates for quiescent galaxies. When compared to a spectroscopic redshift control sample of $\sim$100k galaxies, we find a precision of $\sigma_{z}<$0.8\%, $<$2.0\% or $<$3.0\% for galaxies with magnitudes r$<$17, $<$19 and $<$21, respectively. A precision of 0.6\% is attained for galaxies with the highest \texttt{Odds} values. These estimates have a negligible bias and a fraction of catastrophic outliers inferior to 1\%. We identify a redshift window (i.e., 0.26$

The Southern Photometric Local Universe Survey (S-PLUS) is imaging ~9300 deg^2 of the celestial sphere in twelve optical bands using a dedicated 0.8 m robotic telescope, the T80-South, at the Cerro Tololo Inter-American Observatory, Chile. The telescope is equipped with a 9.2k by 9.2k e2v detector with 10 um pixels, resulting in a field-of-view of 2 deg^2 with a plate scale of 0.55"/pixel. The survey consists of four main subfields, which include two non-contiguous fields at high Galactic latitudes (8000 deg^2 at |b| > 30 deg) and two areas of the Galactic plane and bulge (for an additional 1300 deg^2). S-PLUS uses the Javalambre 12-band magnitude system, which includes the 5 u, g, r, i, z broad-band filters and 7 narrow-band filters centered on prominent stellar spectral features: the Balmer jump/[OII], Ca H+K, H-delta, G-band, Mg b triplet, H-alpha, and the Ca triplet. S-PLUS delivers accurate photometric redshifts (delta_z/(1+z) = 0.02 or better) for galaxies with r < 20 AB mag and redshift < 0.5, thus producing a 3D map of the local Universe over a volume of more than 1 (Gpc/h)^3. The final S-PLUS catalogue will also enable the study of star formation and stellar populations in and around the Milky Way and nearby galaxies, as well as searches for quasars, variable sources, and low-metallicity stars. In this paper we introduce the main characteristics of the survey, illustrated with science verification data highlighting the unique capabilities of S-PLUS. We also present the first public data release of ~336 deg^2 of the Stripe-82 area, which is available at http://datalab.noao.edu/splus., Comment: Updated to reflect the published version (MNRAS, 489, 241). For a short introductory video of the S-PLUS project, see https://youtu.be/yc5kHrHU9Jk - The S-PLUS Data Release 1 is available at http://datalab.noao.edu/splus

Ultracool dwarfs (UCDs) are objects with spectral types equal or later than M7. Most of them have been discovered using wide-field imaging surveys. The Virtual Observatory (VO) has proven to be of great utility to efficiently exploit these astronomical resources. We aim to validate a VO methodology designed to discover and characterize UCDs in the J-PLUS photometric survey. J-PLUS is a multiband survey carried out with the wide angle T80Cam optical camera mounted on the 0.83-m telescope JAST/T80 in the Observatorio Astrof\'isico de Javalambre. In this work we make use of the Internal Data Release (IDR) covering 528 deg$^2$. We complement J-PLUS photometry with other catalogues in the optical and IR using VOSA, a VO tool that estimates physical parameters from the spectral energy distribution fitting to collections of theoretical models. Objects identified as UCDs are distinguished from background M giants and highly reddened stars using parallaxes and proper motions from Gaia DR2. We identify 559 UCDs, ranging from i=16.2 to 22.4 mag, of which 187 are candidate UCDs not previously reported in the literature. This represents an increase in the number of known UCDs of about 50% in the studied region of the sky, particularly at the faint end of our sensitivity, which is interesting as reference for future wide and deep surveys such as Euclid. Three candidates constitute interesting targets for exoplanet surveys because of their proximity (<40 pc). We also analyze the kinematics of UCDs in our catalogue and find evidence that it is consistent with a Galactic thin-disk population, except for 6 objects that might be members of the thick disk. The results obtained validate the proposed methodology, which will be used in future J-PLUS and J-PAS releases. Considering the region of the sky covered by the IDR used, we foresee to discover 3,000-3,500 new UCDs at the end of the J-PLUS project., Comment: Accepted in A&A

The intracluster light (ICL) is a luminous component of galaxy clusters composed of stars that are gravitationally bound to the cluster potential but do not belong to the individual galaxies. Previous studies of the ICL have shown that its formation and evolution are intimately linked to the evolutionary stage of the cluster. Thus, the analysis of the ICL in the Coma cluster will give insights into the main processes driving the dynamics in this highly complex system. Using a recently developed technique, we measure the ICL fraction in Coma at several wavelengths, using the J-PLUS unique filter system. The combination of narrow- and broadband filters provides valuable information on the dynamical state of the cluster, the ICL stellar types, and the morphology of the diffuse light. We use the Chebyshev-Fourier Intracluster Light Estimator (CICLE) to disentangle the ICL from the light of the galaxies, and to robustly measure the ICL fraction in seven J-PLUS filters. We obtain the ICL fraction distribution of the Coma cluster at different optical wavelengths, which varies from $\sim 7\%-21\%$, showing the highest values in the narrowband filters J0395, J0410, and J0430. This ICL fraction excess is distinctive pattern recently observed in dynamically active clusters (mergers), indicating a higher amount of bluer stars in the ICL compared to the cluster galaxies. Both the high ICL fractions and the excess in the bluer filters are indicative of a merging state. The presence of younger/lower-metallicity stars the ICL suggests that the main mechanism of ICL formation for the Coma cluster is the stripping of the stars in the outskirts of infalling galaxies and, possibly, the disruption of dwarf galaxies during past/ongoing mergers., Comment: 10 pages, 3 figures, 1 table. Accepted for publication in A&A

Interacting galaxies provide us with an excellent laboratory for studying a number of physical phenomena associated with these processes. In this paper, we present a spectroscopic and kinematic analysis of the interacting galaxy NGC 4656 and its companion Tidal Dwarf Galaxy (TDG) candidate, NGC 4656UV. Using Fabry-Perot and GMOS multi-slit data, we investigated the possible origin of NGC 4656UV. We found that NGC 4656UV has a low metallicity (12+log(O/H)$\sim$8.2) and it follows the mass-metallicity relation (MZR) for normal dwarf galaxies. For NGC 4656, we estimated a flat oxygen abundance gradient of $\beta$ = -0.027$\pm$0.029 dex kpc$^{-1}$, which suggests the presence of gas flows induced by gravitational interactions. By analysing radial velocity profiles and by fitting a kinematic model of the observed velocity field, we confirm the literature result that NGC 4656 consists of one single body instead of two objects. We estimated a dynamical mass of $6.8^{1.8}_{-0.6}\times10^{9}$ M$_{\odot}$ and R of 12.1 kpc from the kinematic model of NGC 4656. Although the observed velocity field is dominated by rotation at large scales (V$_{max}$/$\sigma\gtrsim$2.8), important non-rotational motions are present at small scales. Based on these new results, and on previously published information, we propose that NGC 4656 and 4656UV are a pair of interacting galaxies. NGC 4656UV is a companion of NGC 4656 and it does not have a tidal origin. The interaction between the two could have triggered the star formation in NGC 4656UV and increased the star formation in the northeast side of NGC 4656., Comment: 23 pages, 18 figures. Accepted for publication in MNRAS

In the present paper we aim to validate a methodology designed to extract the Halpha emission line flux from J-PLUS photometric data. J-PLUS is a multi narrow-band filter survey carried out with the 2 deg2 field of view T80Cam camera, mounted on the JAST/T80 telescope in the OAJ, Teruel, Spain. The information of the twelve J-PLUS bands, including the J0660 narrow-band filter located at rest-frame Halpha, is used over 42 deg2 to extract de-reddened and [NII] decontaminated Halpha emission line fluxes of 46 star-forming regions with previous SDSS and/or CALIFA spectroscopic information. The agreement of the inferred J-PLUS photometric Halpha fluxes and those obtained with spectroscopic data is remarkable, with a median comparison ratio R = 1.05 +- 0.25. This demonstrates that it is possible to retrieve reliable Halpha emission line fluxes from J-PLUS photometric data. With an expected area of thousands of square degrees upon completion, the J-PLUS dataset will allow the study of several star formation science cases in the nearby universe, as the spatially resolved star formation rate of nearby galaxies at z < 0.015, and how it is influenced by the environment, morphology or nuclear activity. As an illustrative example, the close pair of interacting galaxies NGC3994 and NGC3995 is analyzed, finding an enhancement of the star formation rate not only in the center, but also in outer parts of the disk of NGC3994., Comment: 13 pages, 8 figures, 3 tables. Submitted to Astronomy and Astrophysics. Comments are welcome

We aim to use multi-band imaging from the Phase-3 Verification Data of the J-PLUS survey to derive accurate photometric redshifts (photo-z) and look for potential new members in the surroundings of the nearby galaxy clusters A2589 (z=0.0414) & A2593 (z=0.0440), using redshift probability distribution functions. The ultimate goal is to demonstrate the usefulness of a 12-band filter system in the study of large-scale structure in the local universe. We present an optimized pipeline for the estimation of photo-z in clusters of galaxies. We tested our photo-z with a sample of 296 spectroscopically confirmed cluster members with a magnitude of = 16.6 and redshift =0.041. The combination of seven narrow and five broadband filters with a typical photometric-depth of r<21.5 provides dz/(1+z)=0.01 photo-z estimates. A precision of dz/(1+z)=0.005 is obtained for the 177 galaxies brighter than magnitude r<17. To foresee the precision beyond the spectroscopic sample, we designed a set of simulations in which real cluster galaxies are modeled and reinjected inside the images at different signal-to-noise. A precision of dz/(1+z)=0.02 and dz/(1+z)=0.03 is expected at = 18-22, respectively. Complementarily, we used SDSS/DR12 data to derive photo-z estimates for the same galaxy sample, demonstrating that the wavelength-resolution of the J-PLUS can double the precision achieved by SDSS for galaxies with a high S/N. We find as much as 170 new candidates across the entire field. The spatial distribution of these galaxies may suggest an overlap between the systems with no evidence of a clear filamentary structure connecting the clusters. These preliminary results show the potential of J-PLUS data to revisit membership of groups and clusters from nearby galaxies, important for the determination of luminosity and mass functions and environmental studies at the intermediate and low-mass regime., Comment: 16 pages, 9 figures & 3 tables

J-PLUS is an ongoing 12-band photometric optical survey, observing thousands of square degrees of the Northern hemisphere from the dedicated JAST/T80 telescope at the Observatorio Astrof\'isico de Javalambre. T80Cam is a 2 sq.deg field-of-view camera mounted on this 83cm-diameter telescope, and is equipped with a unique system of filters spanning the entire optical range. This filter system is a combination of broad, medium and narrow-band filters, optimally designed to extract the rest-frame spectral features (the 3700-4000\AA\ Balmer break region, H$\delta$, Ca H+K, the G-band, the Mgb and Ca triplets) that are key to both characterize stellar types and to deliver a low-resolution photo-spectrum for each pixel of the sky observed. With a typical depth of AB $\sim 21.25$ mag per band, this filter set thus allows for an indiscriminate and accurate characterization of the stellar population in our Galaxy, it provides an unprecedented 2D photo-spectral information for all resolved galaxies in the local universe, as well as accurate photo-z estimates ($\Delta\,z\sim 0.01-0.03$) for moderately bright (up to $r\sim 20$ mag) extragalactic sources. While some narrow band filters are designed for the study of particular emission features ([OII]/$\lambda$3727, H$\alpha$/$\lambda$6563) up to $z < 0.015$, they also provide well-defined windows for the analysis of other emission lines at higher redshifts. As a result, J-PLUS has the potential to contribute to a wide range of fields in Astrophysics, both in the nearby universe (Milky Way, 2D IFU-like studies, stellar populations of nearby and moderate redshift galaxies, clusters of galaxies) and at high redshifts (ELGs at $z\approx 0.77, 2.2$ and $4.4$, QSOs, etc). With this paper, we release $\sim 36$ sq.deg of J-PLUS data, containing about $1.5\times 10^5$ stars and $10^5$ galaxies at $r<21$ mag., Comment: Submitted to A&A

We investigate interaction effects on the dynamics and morphology of the galaxy pairs AM\,2058-381 and AM\,1228-260. This work is based on $r'$ images and long-slit spectra obtained with the Gemini Multi-Object Spectrograph at the Gemini South Telescope. The luminosity ratio between the main (AM\,2058A) and secondary (AM\,2058B) components of the first pair is a factor of $\sim$ 5, while for the other pair, the main (AM\,1228A) component is 20 times more luminous than the secondary (AM\,1228B). The four galaxies have pseudo-bulges, with a S\'ersic index $n<2$. Their observed radial velocities profiles (RVPs) present several irregularities. The receding side of the RVP of AM\,2058A is displaced with respect to the velocity field model, while there is a strong evidence that AM\,2058B is a tumbling body, rotating along its major axis. The RVPs for AM\,1228A indicate a misalignment between the kinematic and photometric major axes. The RVP for AM\,1228B is quite perturbed, very likely due to the interaction with AM\,1228A. NFW halo parameters for AM\,2058A are similar to those of the Milky Way and M\,31. The halo mass of AM\,1228A is roughly 10\% that of AM\,2058A. The mass-to-light (M/L) of AM\,2058 agrees with the mean value derived for late-type spirals, while the low M/L for AM\,1228A may be due to the intense star formation ongoing in this galaxy., Comment: 20 pages, 10 figures, accepted for publication in MNRAS

We employ the NASA Infrared Telescope Facility's near-infrared spectrograph SpeX at 0.8-2.4$\mu$m to investigate the spatial distribution of the stellar populations (SPs) in four well known Starburst galaxies: NGC34, NGC1614, NGC3310 and NGC7714. We use the STARLIGHT code updated with the synthetic simple stellar populations models computed by Maraston (2005, M05). Our main results are that the NIR light in the nuclear surroundings of the galaxies is dominated by young/intermediate age SPs ($t \leq 2\times10^9$yr), summing from $\sim$40\% up to 100\% of the light contribution. In the nuclear aperture of two sources (NGC1614 and NGC3310) we detected a predominant old SP component ($t > 2\times10^9$yr), while for NGC34 and NGC7714 the younger component prevails. Furthermore, we found evidence of a circumnuclear star formation ring-like structure and a secondary nucleus in NGC1614, in agreement with previous studies. We also suggest that the merger/interaction experienced by three of the galaxies studied, NGC1614, NGC3310 and NGC7714 can explain the lower metallicity values derived for the young SP component of these sources. In this scenario the fresh unprocessed metal poorer gas from the destroyed/interacting companion galaxy is driven to the centre of the galaxies and mixed with the central region gas, before star formation takes place. In order to deepen our analysis, we performed the same procedure of SP synthesis using Maraston (2011, M11) EPS models. Our results show that the newer and higher resolution M11 models tend to enhance the old/intermediate age SP contribution over the younger ages.

We present an observational study of the interaction effect on the dynamics and morphology of the minor merger AM1219-430. This work is based on r' and g' images and long-slit spectra obtained with the Gemini Multi-Object Spectrograph at the Gemini South Telescope. We detected a tidal tail in the main galaxy (AM1219A) and a bridge of material connecting the galaxies. In luminosity, AM1219A is about 3.8 times brighter than the secondary (AM1219B). The surface brightness profile of AM1219A was decomposed into bulge and disc components. The profile shows a light excess of ~ 53 % due to the contribution of star-forming regions, which is typical of starburst galaxies. On the other hand, the surface brightness profile of AM1219B shows a lens structure in addition to the bulge and disc. The scale lengths and central magnitudes of the disc structure of both galaxies agree with the average values derived for galaxies with no sign of ongoing interaction or disturbed morphology. The S\'ersic index (n<2), the effective and scale radii of the bulge of both galaxies are typical of pseudo-bulges. The rotation curve of AM1219A derived from the emission line of ionized gas is quite asymmetric, suggesting a gas perturbed by interaction. We explore all possible values of stellar and dark matter masses. The overall best-fitting solution for the mass distribution of AM1219A was found with M/L for bulge and disc of M/L_b=2.8_-0.4^+0.4 and M/L_d=2.4_-0.2^+0.3, respectively, and a Navarro, Frenk and White profile of M_200=2.0_-0.4^+0.5 x10^12 M_sun and c=16.0_-1.1^+1.2. The estimated dynamical mass is 1.6x10^11 M_sun, within a radius of ~ 10.6 kpc., Comment: 13 pages, 11 figures