Universidade do Vale do Paraíba
Context. Spectroscopic surveys like APOGEE, GALAH, and LAMOST have significantly advanced our understanding of the Milky Way by providing extensive stellar parameters and chemical abundances. Complementing these, photometric surveys with narrow/medium-band filters, such as the Southern Photometric Local Universe Survey (S-PLUS), offer the potential to estimate stellar parameters and abundances for a much larger number of stars. Aims. This work develops methodologies to extract stellar atmospheric parameters and selected chemical abundances from S-PLUS photometric data, which spans ~3000 square degrees using seven narrowband and five broadband filters. Methods. Using 66 S-PLUS colors, we estimated parameters based on training samples from LAMOST, APOGEE, and GALAH, applying Cost-Sensitive Neural Networks (NN) and Random Forests (RF). We tested for spurious correlations by including abundances not covered by the S-PLUS filters and evaluated NN and RF performance, with NN consistently outperforming RF. Including Teff and log g as features improved accuracy by ~3%. We retained only parameters with a goodness-of-fit above 50%. Results. Our approach provides reliable estimates of fundamental parameters (Teff, log g, [Fe/H]) and abundance ratios such as [{\alpha}/Fe], [Al/Fe], [C/Fe], [Li/Fe], and [Mg/Fe] for ~5 million stars, with goodness-of-fit >60%. Additional ratios like [Cu/Fe], [O/Fe], and [Si/Fe] were derived but are less accurate. Validation using star clusters, TESS, and J-PLUS data confirmed the robustness of our methodology. Conclusions. By leveraging S-PLUS photometry and machine learning, we present a cost-effective alternative to high-resolution spectroscopy for deriving stellar parameters and abundances, enabling insights into Milky Way stellar populations and supporting future classification efforts.
Kelvin-Helmholtz instabilities are common in astrophysical systems, ranging from jet black holes up to protoplanetary accretion disk. An astrophysical object with strong characteristics of the Kelvin-Helmholtz instability is Caraguejo Nebula, in which the material expansion was caused by the explosion of a supernova about 1000 years ago. This instability occurs at the boundary between two fluids of different densities when one of the fluids accelerated with respect to the other. In order to study this instability, we performed a simulation with the code ATHENA Eulerian mesh. For this simulation, we consider a square domain with periodic boundaries on the sides, and reflecting on the boundary of the top and bottom. The upper box is filled with a gas density {\rho}=1.0, pressure P1 = 1.0, adiabatic index {\gamma}=5/3, and velocity u1=0.03 in the x direction (to the right). The lower portion has a density {\rho}=2.0, the same pressure, velocity, and adiabatic index, only in the opposite direction to the left. Speed is defined as a sinusoidal function, which creates the initial disturbance. As a result, we observe the principle of instability and the formation of vortices, with well-defined ridges. The distinctness of the boundary between the material of high and low density is well preserved due to the relatively low diffusion algorithm. We also note that the simulation evolving vortices formed from the turmoil merge.
The metal content of a galaxy's interstellar medium reflects the interplay between different evolutionary processes such as feedback from massive stars and the accretion of gas from the intergalactic medium. Despite the expected abundance of low-luminosity galaxies, the low-mass and low-metallicity regime remains relatively understudied. Since the properties of their interstellar medium resemble those of early galaxies, identifying such objects in the Local Universe is crucial to understand the early stages of galaxy evolution. We used the DR3 catalog of the Southern Photometric Local Universe Survey (S-PLUS) to select low-metallicity dwarf galaxy candidates based on color selection criteria typical of metal-poor, star-forming, low-mass systems. The final sample contains approximately 50 candidates. Spectral energy distribution fitting of the 12 S-PLUS bands reveals that \sim 60% of the candidates are best fit by models with low stellar metallicities. We obtained long-slit observations with the Gemini Multi-Object Spectrograph to follow-up a pilot sample and confirm whether these galaxies have low metallicities. We find oxygen abundances in the range 7.28< 12 + log(O/H) < 7.82 (4% to 13% of the solar value), confirming their metal-poor nature. Most targets are outliers in the mass-metallicity relation, i.e. they display a low metal content relative to their observed stellar masses. In some cases, perturbed optical morphologies might give evidence of dwarf-dwarf interactions or mergers. These results suggest that the low oxygen abundances may be associated with an external event causing the accretion of metal-poor gas, which dilutes the oxygen abundance in these systems.
Integral Field Spectroscopy (IFS) is well known for providing detailed insight of extended sources thanks to the possibility of handling space resolved spectroscopic information. Simple and straightforward analysis such as single line fitting yield interesting results, although it might miss a more complete picture in many cases. Violent star forming regions, such as starburst galaxies, display very complex emission line profiles due to multiple kinematic components superposed in the line of sight. We perform a spatially resolved kinematical study of a single Green Pea (GP) galaxy, SDSSJ083843.63+385350.5, using a new method for analyzing Integral Field Unit (IFU) observations of emission line spectra. The method considers the presence of multiple components in the emission-line profiles and makes use of a statistical indicator to determine the meaningful number of components to fit the observed profiles. We are able to identify three distinct kinematic features throughout the field and discuss their link with a rotating component, a strong outflow and a turbulent mixing layer. We also derive an updated star formation rate for \ourobj and discuss the link between the observed signatures of a large scale outflow and of the Lyman continuum (LyC) leakage detected in GP galaxies.
The influence of Active Galactic Nuclei (AGN) on star formation within their host galaxies remains a topic of intense debate. One of the primary challenges in quantifying the star formation rate (SFR) within AGN hosts arises from the prevalent assumption in most methodologies, which attribute gas excitation to young stars alone. However, this assumption does not consider the contribution of the AGN to the ionization of the gas in their environment. To address this issue, we evaluate the use of strong optical emission lines to obtain the SFR surface density (ΣSFRAGN\Sigma{{\rm SFR_{AGN}}}) in regions predominantly ionized by an AGN, using a sample of 293 AGN hosts from the MaNGA survey, with SFR measurements available through stellar population fitting. We propose calibrations involving the Hα\alpha and [O\,{\sc iii}]λ\lambda5007 emission lines, which can be used to determine ΣSFRAGN\Sigma{{\rm SFR_{AGN}}}, resulting in values consistent with those estimated through stellar population fitting.
We analyse the spectral energy distribution (SED) of the eclipsing supersoft X-ray source CAL 87 covering wavelengths from X-rays to the near-infrared. Our study incorporates 26 data points across ultraviolet to near-infrared, sourced from published literature, unpublished data, and new observations. In addition, archival XMM-Newton spectra were used to represent the X-ray emission. Care was taken to use out-of-eclipse flux measurements when the irradiated side of the companion faces the observer. The SED model includes contributions from a central source, a reprocessed accretion disk, and an irradiated companion star atmosphere, resulting in a good match to the observed fluxes. The revised and new parameters for the disk and the central source align with previous studies and match expectations for such systems. The temperature of the irradiated side of the companion star was estimated based on its B-V colour during the secondary eclipse. This work highlights the importance of broad wavelength coverage for understanding the properties of supersoft X-ray sources.
White dwarf symbiotic binaries are detected in X-rays with luminosities in the range of 1030^{30} to 1034^{34} lumcgs. Their X-ray emission arises either from the accretion disk boundary layer, from a region where the winds from both components collide or from nuclear burning on the white dwarf surface. In our continuous effort to identify X-ray emitting symbiotic stars, we studied four systems using observations from the Neil Gehrels Swift Observatory and XMM-Newton satellites in X-rays and from TESS in the optical. The X-ray spectra were fit with absorbed optically thin thermal plasma models, either single- or multitemperature with kT < 8 keV for all targets. Based on the characteristics of their X-ray spectra, we classified BD Cam as possible β\beta-type, V1261 Ori and CD -27 8661 as δ\delta-type, and confirmed NQ Gem as β\beta/δ\delta-type. The δ\delta-type X-ray emission most likely arise in the boundary layer of the accretion disk, while in the case of BD Cam, its mostly-soft emission originates from shocks, possibly between the red giant and WD/disk winds. In general, we have found that the observed X-ray emission is powered by accretion at a low accretion rate of about 1011^{-11} M_{\odot} yr1^{-1}. The low ratio of X-ray to optical luminosities, however indicates that the accretion-disk boundary layer is mostly optically thick and tends to emit in the far or extreme UV. The detection of flickering in optical data provides evidence of the existence of an accretion disk.
In this paper, we present a semi-empirical calibration between the oxygen abundance and the N2N2 emission-line ratio for Low Ionization Nuclear Emission Regions (LINERs). This relation was derived by comparing the optical spectroscopic data of 118 nuclear spaxels classified as LINERs using three different BPT diagrams from the Mapping Nearby Galaxies survey (MaNGA) and sub-classified as weak (wAGN, 84 objects) and strong (sAGN, 34 objects) AGN (active galactic nucleus) from the WHAN diagnostic diagram and photoionization model results obtained with the {\sc cloudy} code assuming gas accretion into a black hole (representing an AGN). We found that our wAGN LINERs exhibit an oxygen abundance in the range of $8.50 \lesssim \mathrm{12+\log(O/H)} \lesssim 8.90 ,withanaveragevalueof, with an average value of \mathrm{12+\log(O/H)}=8.68$, while our sAGN LINERs exhibit an oxygen abundance in the range of $8.51 \lesssim \: \mathrm{12+\log(O/H)} \: \lesssim \: 8.81 $, with an average value of 12+log(O/H)=8.65\mathrm{12+\log(O/H)}=8.65. Our abundance estimations are in good agreement with those derived for another two different samples one of them with 463 Seyfert 2 objects and the other with 43 LINERs galaxies ionized by post-AGB stars, showing that the assumptions of our models are likely suitable for wAGN and sAGN LINERs. A relation between the equivalent width of the observed Hα\alpha emission-line and the estimated ionization parameter provided by models was obtained. Our results also suggest that LINERs does not show a clear correlation between oxygen abundances and the stellar mass of the hosting galaxies.
WZ Sge stars are highly evolved accreting white dwarf systems (AWDs) exhibiting remarkably large amplitude outbursts (a.k.a. super-outbursts), typically followed by short rebrightenings/echo outbursts. These systems have some of the lowest mass transfer rates among AWDs, making even low magnetic fields dynamically important. Such magnetic fields are often invoked to explain the phenomenology observed in these systems, such as their X-ray luminosity and long periods of quiescence (30+ years). However, the detection of these is very elusive given the quenching of the accretion columns during outburst and the low luminosity of these systems during quiescence. Here we present high-cadence multi-band observations with {\it OPTICAM} of the recent outburst of the recently discovered WZ Sge star GOTO065054.49+593624.51, during the end of the main outburst and the dip in-between rebrightenings, covering 2 orders of magnitude in brightness. Our observations reveal the presence of a statistically significant signal with Pω148P_{\omega}\simeq148 seconds in the bluer (gg) band which is detected only during the dip between the main outburst and the rebrigthenings. We interpret this signal as the spin period of the AWD. If confirmed, GOTO 0650 would bridge the gap between intermediate- and fast-rotating intermediate polars (IPs) below the period gap.
Metallicity (ZZ) estimates based on ultraviolet (UV) emission lines from the narrow-line regions (NLRs) of active galactic nuclei (AGNs) have been found to differ from those derived from optical lines. However, the origin of this discrepancy (ZRZR) remains poorly understood. To investigate the source of ZRZR, we compiled from the literature the fluxes of narrow near-UV (1000 < \lambda(\angstrom) < 2000) and optical (3000 < \lambda(\angstrom) < 7000) emission line measurements for a sample of 11 AGNs (9 at z<0.4 and 2 at z2.4z\sim2.4). Metallicity values for our sample were derived using a semi-empirical calibration based on the C43C43=log[(\ion{C{iv}λ\lambda1549+\ion{C{iii}]λ\lambda1909)/\ion{He}{ii}λ\lambda1640] emission-line ratio and compared with those obtained via direct measurement of the electron temperature (TeT_{\rm e}-method) and via calibrations based on optical emission-lines. The source of the discrepancy was investigated in terms of the ionization parameter (UU), electron density (NeN_{\rm e}), and carbon abundance (C/H). We found a weak correlation between ZRZR, UU and NeN_{\rm e}. However, a moderate correlation was observed between ZRZR and direct estimates of C/H, suggesting that the previously assumed (C/O)-ZZ relations in photoionization models used to derive UV carbon-line calibrations may not be valid for AGNs. By combining a large set of abundance estimates for local star-forming regions with those of our AGN sample, we derived a new (C/O)-ZZ relation. Comparisons between the results of photoionization models that assume this new abundance relation and the UV observational data of our sample produce ZZ values derived from the C43C43 index that are consistent with those obtained using the TeT_{\rm e}-method.
Metallicity (ZZ) estimates based on ultraviolet (UV) emission lines from the narrow-line regions (NLRs) of active galactic nuclei (AGNs) have been found to differ from those derived from optical lines. However, the origin of this discrepancy (ZRZR) remains poorly understood. To investigate the source of ZRZR, we compiled from the literature the fluxes of narrow near-UV ($1000 < \lambda(\angstrom) < 2000)andoptical( and optical (3000 < \lambda(\angstrom) < 7000)$ emission line measurements for a sample of 11 AGNs (9 at z&lt;0.4 and 2 at z2.4z\sim2.4). Metallicity values for our sample were derived using a semi-empirical calibration based on the C43C43=log[(\ion{C{iv}λ\lambda1549+\ion{C{iii}]λ\lambda1909)/\ion{He}{ii}λ\lambda1640] emission-line ratio and compared with those obtained via direct measurement of the electron temperature (TeT_{\rm e}-method) and via calibrations based on optical emission-lines. The source of the discrepancy was investigated in terms of the ionization parameter (UU), electron density (NeN_{\rm e}), and carbon abundance (C/H). We found a weak correlation between ZRZR, UU and NeN_{\rm e}. However, a moderate correlation was observed between ZRZR and direct estimates of C/H, suggesting that the previously assumed (C/O)-ZZ relations in photoionization models used to derive UV carbon-line calibrations may not be valid for AGNs. By combining a large set of abundance estimates for local star-forming regions with those of our AGN sample, we derived a new (C/O)-ZZ relation. Comparisons between the results of photoionization models that assume this new abundance relation and the UV observational data of our sample produce ZZ values derived from the C43C43 index that are consistent with those obtained using the TeT_{\rm e}-method.
In this study, a new semi-empirical calibration is proposed between ultraviolet emission lines (\ion{C}{iii}]λ1909\lambda1909, \ion{C}{iv}λ1549\lambda1549, \ion{He}{ii}]λ1640\lambda1640) of type~2 AGNs and their metallicity (ZZ). This calibration is derived by comparing a large sample of 106 objects (data taken from the literature) located over a wide range of redshifts (0z4.00 \: \lesssim \: z \: \lesssim \: 4.0) with predictions from photoionization models that adopt a recent C/O-O/H relation derived via estimates using the TeT_{\rm e} method, which is considered the most reliable method. We found that the new calibration produces ZZ values in agreement (within an uncertainty of ±0.1\pm 0.1 dex) with those from other calibrations and from estimates via the TeT_{\rm e}-method. We find also that AGN metallicities are already high at early epochs, with no evidence for monotonic evolution across the redshift range 0z120 \: \lesssim \: z \: \lesssim \: 12. Notably, the highest metallicities in our sample, reaching up to 4Z\rm 4\: Z_{\odot}, are found in objects at 2z32 \lesssim z \lesssim 3. This redshift range coincides with the peak of the cosmic star formation rate history, suggesting a strong connection between the major epoch of star formation, black hole growth, and rapid metal enrichment in the host galaxies of AGNs. Furthermore, our analysis reveals no significant correlation between AGN metallicity and radio properties (radio spectral index or radio luminosity) or host galaxy stellar mass. The lack of a clear mass-metallicity relation, consistent with findings for local AGNs, suggests that the chemical evolution of the nuclear gas is decoupled from the global properties of the host galaxy.
We investigate the interplanetary conditions during 135 less strict high-intensity, long-duration, continuous AE activity (HILDCAA*) events between the years 1998-2007. The HILDCAA* events were chosen by following the three "traditional" criteria which describe the high-intensity, long-duration, continuous AE activity (HILDCAA). However, we include a small modification in the criteria that considers: "the AE values do not drop below 200 nT for more than 2 h at a time". This criteria is modified by changing 2 to 4 hours period in which the AE values should not drop below 200 nT. Once the events are selected, we perform a statistical analysis of the interplanetary parameters during their occurrences. The distribution of HILDCAA* events along the solar cycle shows a pattern of double peak, with a peak around the maximum of the sunspot cycle, and an other in the descending phase. This kind of distribution is similar to the distribution of low-latitude coronal holes. For each of the HILDCAA* events, we have found its related Interplanetary Magnetic Field (IMF) and plasma parameter signatures. The average values of AE, AU, AL, and Dst indices, the density and temperature of the solar wind protons, the solar wind speed, the Bz component of the IMF, the IMF intensity, dynamic pressure, and plasma beta, among all the 135 HILDCAA* events, found here are: AE (348.1 ±\pm 67.1 nT), AU (123.9 ±\pm 34.2 nT), AL (-224.2 ±\pm 47.3 nT), Dst (-22.1 ±\pm 9.1 nT), Density (4.3 ±\pm 1.3 cm-3), Temperature (170976.3 ±\pm 58049.9 K), Flow speed (547.1 ±\pm 83.9 km/s), Bz (-0.70 ±\pm 0.88 nT), IMF magnitude average (6.6 ±\pm 1.2 nT), pressure (2.4 ±\pm 0.6 nPa), and plasma Beta (0.66 ±\pm 0.27).
We derive the metallicity (traced by the O/H abundance) of the Narrow Line Region ( NLR) of 108 Seyfert galaxies as well as radial metallicity gradients along their galaxy disks and of these of a matched control sample of no active galaxies. In view of that, observational data from the SDSS-IV MaNGA survey and strong emission-line calibrations taken from the literature were considered. The metallicity obtained for the NLRs %each Active Galactic Nucleus (AGN) was compared to the value derived from the extrapolation of the radial oxygen abundance gradient, obtained from \ion{H}{ii} region estimates along the galaxy disk, to the central part of the host galaxies. We find that, for most of the objects (80%\sim 80\,\%), the NLR metallicity is lower than the extrapolated value, with the average difference ()betweentheseestimatesrangingfrom0.16to0.30dex.Wesuggestthat) between these estimates ranging from 0.16 to 0.30 dex. We suggest that is due to the accretion of metal-poor gas to the AGN that feeds the nuclear supermassive black hole (SMBH), which is drawn from a reservoir molecular and/or neutral hydrogen around the SMBH. Additionally, we look for correlations between DD and the electron density (NeN_{\rm e}), [\ion{O}{iii}]λ\lambda5007 and Hα\alpha luminosities, extinction coefficient (AV)A_{V}) of the NLRs, as well as the stellar mass (MM_{*}) of the host galaxies. Evidences of an inverse correlation between the DD and the parameters NeN_{\rm e}, MM_{*} and AvA_{\rm v} were found.
We explore the relations between the gas-phase metallicity radial profiles (few hundred inner parsec) and multiple galaxy properties for 15 Seyfert galaxies from the AGNIFS (Active Galactic Nuclei Integral Field Spectroscopy) sample using optical Integral Field Unit (IFU) observations from Gemini Multi-Object Spectrographs (GMOS) and Multi Unit Spectroscopic Explorer (MUSE) processed archival data. The data were selected at z0.013z \lesssim 0.013 within black hole mass range \left[6&lt;\log \left(M_{\rm BH}/{\rm M_\odot} \right)&lt;9\right] with moderate 14--150\,keV X-ray luminosities [42logLX(ergs1)44]\left[42\,\lesssim\,\log L_X (\rm erg\,s^{-1})\,\lesssim\,44\right]. We estimated the gas-phase metallicity using the strong-line methods and found mean values for the oxygen dependent (Z0.75ZZ \sim 0.75Z_\odot) and nitrogen dependent (Z1.14ZZ \sim 1.14Z_\odot) calibrations. These estimates show excellent agreement with ΔZ0.19\Delta Z \approx 0.19 dex and ΔZ0.18\Delta Z \approx 0.18 dex between the mean values from the two strong-line calibrations for GMOS and MUSE respectively, consistent with the order of metallicity uncertainty via the strong-line methods. We contend that our findings align with a scenario wherein local Seyferts have undergone seamless gas accretion histories, resulting in positive metallicity profile over an extended period of time, thereby providing insights into galaxy evolution and the chemical enrichment or depletion of the universe. Additionally, we argue that metal-poor gas inflow from the local interstellar medium (ISM) and accreted through the circumgalactic medium (CGM) onto the galaxy systems regulates the star formation processes by diluting their central metallicity and inverting their metallicity gradients, producing a more prominent anti-correlation between gas-phase metallicity and Eddington ratio.
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 deg2^2) observed in five SDSS-like ugriz broad-bands and seven narrow-bands covering specific spectroscopic features like [OII], CaII H+K, Hδ\delta, G-band, Mg b triplet, Hα\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 106^6 resolved and unresolved objects within a region extending over ~ 208 deg2^2 (~ 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 M108\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.
In this work, we present the development of the Tonalli code: a simplified multi-species (HI, HII, H-, and e) magnetohydrodynamics (MHD) model in Non-local Thermodynamic Equilibrium (NLTE) focused on solar chromospheric conditions. This new model integrates two well established models, Newtonian CAFE (MHD) and PakalMPI (NLTE), through a self-convergence system that links the state equations used by both codes to calculate density, pressure and temperature, with the mean molecular weight (μ\mu) serving as a proxy. Newtonian CAFE computes the plasma variables using the ideal MHD while PakalMPI calculates the species densities of neutral Hydrogen (HI), protons (HII), negative Hydrogen (H-), and electrons (ne) under the NLTE approximation. We used Tonalli to test the stability of the hydrostatic C7 model, covering 3000 km of the solar chromosphere with a vertical constant field of 30 Gauss and a vertical constant gravity field of 274.0 ms-2. As a result, Tonalli generates 3D cubes of densities, temperature, pressure, mean molecular weight, and the departure coefficient of Hydrogen in its first energy level b1, providing a detailed representation of the ionization states of the plasma at chromosphere altitudes. Despite the fact that MHD conditions can lead to numerical diffusion of the plasma, we demonstrate robustness and consistency, and self-convergence of the model with the relative error of electron density reaching values of 3.7x1073.7x10^{-7}.
Glycolaldehyde (HOCH2CHO) is the most straightforward sugar detected in the Interstellar Medium (ISM) and participates in the formation pathways of molecules fundamental to life, red such as ribose and derivatives. Although detected in several regions of the ISM, its formation route is still debated and its abundance cannot be explained only by reactions in the gas phase. This work explores a new gas-phase formation mechanism for glycolaldehyde and compares the energy barrier reduction when the same route happens on the surface of amorphous ices. The first step of the mechanism involves the formation of a carbon-carbon bond between formaldehyde (H2CO) and the formyl radical (HCO), with an energy barrier of 27 kJ mol-1 (gas-phase). The second step consists of barrierless hydrogen addition. Density functional calculations under periodic boundary conditions were applied to study this reaction path on 10 different amorphous ice surfaces through an Eley-Rideal type mechanism. It was found that the energy barrier is reduced on average by 49 per cent, leading in some cases to a 100 per cent reduction. The calculated adsorption energy of glycolaldehyde suggests that it can be promptly desorbed to the gas phase after its formation. This work, thus contributes to explaining the detected relative abundances of glycolaldehyde and opens a new methodological framework for studying the formation routes for Complex Organic Molecules (COMs) in interstellar icy grains.
We use SDSS data to investigate the scaling relations of 127 NoSOCS and 56 CIRS galaxy clusters at low redshift (z0.10z \le 0.10). We show that richness and both optical and X-ray luminosities are reliable mass proxies. The scatter in mass at fixed observable is \sim 40%, depending on the aperture, sample and observable considered. For example, for the massive CIRS systems σlnM500N500\sigma_{lnM500|N500} = 0.33 ±\pm 0.05 and σlnM500Lx\sigma_{lnM500|Lx} = 0.48 ±\pm 0.06. For the full sample σlnM500N500\sigma_{lnM500|N500} = 0.43 ±\pm 0.03 and σlnM500Lx\sigma_{lnM500|Lx} = 0.56 ±\pm 0.06. We estimate substructure using two and three dimensional optical data, verifying that substructure has no significant effect on the cluster scaling relations (intercepts and slopes), independent of which substructure test we use. For a subset of twenty-one clusters, we estimate masses from the M-TX_X relation using temperature measures from BAX. The scaling relations derived from the optical and X-ray masses are indeed very similar, indicating that our method consistently estimates the cluster mass and yields equivalent results regardless of the wavelength from which we measure mass. For massive systems, we represent the mass-richness relation by a function with the form ln(M200)=A+B×ln(N200/60){\rm ln (M_{200}) = A + B \times ln(N_{200}/60)}, with M200_{200} being expressed in units of 1014^{14} M_{\odot}. Using the virial mass, for CIRS clusters, we find A = (1.39 ±\pm 0.07) and B = (1.00 ±\pm 0.11). The relations based on the virial mass have a scatter of σlnM200N200\sigma_{lnM200|N200} = 0.37 ±\pm 0.05, while σlnM200N200\sigma_{lnM200|N200} = 0.77 ±\pm 0.22 for the caustic mass and σlnM200N200\sigma_{lnM200|N200} = 0.34 ±\pm 0.08 for the temperature based mass (abridged).
Compact groups of galaxies (CGs) show members with morphological disturbances, mainly products of galaxy-galaxy interactions, thus making them ideal systems to study galaxy evolution, in high-density environment. To understand how this environment affects the properties of galaxies, we select a sample of 340 CGs in the Stripe 82 region, for a total of 1083 galaxies, and a sample of 2281 field galaxies as a control sample. By performing a multi-wavelength morphological fitting process using S-PLUS data, we divide our sample into early-type (ETG), late-type (LTG), and transition galaxies using the r-band S\'ersic index and the colour (u-r). We find a bimodal distribution in the plane of the effective radius-S\'ersic index, where a secondary "peculiar" galaxy population of smaller and more compact galaxies is found in CGs, which is not observed in the control sample. This indicates that galaxies are undergoing a morphological transformation in CGs. In addition, we find significant statistical differences in the distribution of specific Star Formation Rate (sSFR) when we compare both environments for LTGs and ETGs. We also find a higher fraction of quenched galaxies and a lower median sSFR in CGs than in the control sample, suggesting the existence of environmental effects favoring the cessation of star formation, regardless of galaxy type. Our results support the notion that CGs promote morphological and physical transformations, highlighting their potential as ideal systems for galaxy pre-processing.
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