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The study of planetary nebulae provides important constraints for many aspects of stellar and Galactic evolution. Hen 2-108 is a poorly known planetary nebula with a slight elliptical morphology and a peculiar central star (CS), which has defied classification. In this work, we present the first detailed integral field spectroscopic study of the planetary nebula Hen 2-108 and its CS. We provide spatially resolved flux maps for important emission lines, as well as diagnostic maps of extinction and electronic density and temperature. Physical conditions and chemical abundances were also calculated from the integrated spectrum. The analysis was also performed with the code satellite which uses a distinct strategy to evaluate physical and chemical properties. Both satellite and traditional procedure give consistent results, showing some variation in physical and chemical properties. We detect and measure a number of faint heavy element recombination lines from which we find a significant abundance discrepancy factor for O/H, and possibly for N/H. Pseudo 3D photoionization models were used to assist in the interpretation with results supporting the low-ionisation nature of this nebula, indicating a CS with Teff = 40 kK and a shell structure. The spectrum of the CS has been analysed with a detailed model for expanding atmospheres to infer stellar parameters, finding that it is a [Of/WN8] type with T* = 41.5 kK, making it a new addition to a small set (~20) of rare objects., Comment: 23 pages, 16 figures, 7 tables; published in MNRAS

We report the validation of a recently proposed infrared selection criterion for symbiotic stars (SySts). Spectroscopic data were obtained for seven candidates, selected from the SySt candidates of Akras et al. (2019, MNRAS, 483, 5077) by employing the new supplementary infrared selection criterion for SySts in the VST/OmegaCAM Photometric H-Alpha Survey (VPHAS+). Five of them turned out to be genuine SySts after the detection of H$\alpha$, He II and [O III] emission lines as well as TiO molecular bands. The characteristic O VI Raman-scattered line is also detected in one of these SySts. According to their infrared colours and optical spectra, all five newly discovered SySts are classified as S-type. The high rate of true SySts detections of this work demonstrates that the combination of the H$\alpha$-emission and the new infrared criterion improves the selection of target lists for follow-up observations by minimizing the number of contaminants and optimizing the observing time., Comment: 5 pages, 2 figures, one table, accepted for publication in MNRAS

A classical nova is an eruption on the surface of a white dwarf in an accreting binary system. The material ejected from the white dwarf surface generally forms an axisymmetric shell. The shaping mechanisms of nova shells are probes of the processes that take place at energy scales between planetary nebulae and supernova remnants. We report on the discovery of nova shells surrounding the post-nova systems V4362 Sagittarii (1994) and more limited observations of DO Aquilae (1925). Distance measurements of 0.5p/m1.4 kpc for V4362 Sgr and 6.7 p/m 3.5 kpc -0.2 for DO Aql are found based on the expansion parallax method. The growth rates are measured to be 0.07``/year for DO Aql and 0.32``/year for V4362 Sgr. A preliminary investigation into the ionisation structure of the nova shell associated with V4362 Sgr is presented. The observed ionisation structure of nova shells depends strongly on their morphology and the orientation of the central component towards the observer. X-ray, IR and UV observations as well as optical integral field unit spectroscopy are required to better understand these interesting objects., Comment: 18 pages, 14 Figures, 9 Tables, accepted MNRAS

Authors: Molino, A.; Costa-Duarte, M. V.; Sampedro, L.; Herpich, F. R.; Sodré, L., Jr.; Mendes de Oliveira, C.; Schoenell, W.; Barbosa, C. E.; Queiroz, C.; Lima, E. V. R.; Azanha, L.; Muñoz-Elgueta, N.; Ribeiro, T.; Kanaan, A.; Hernandez-Jimenez, J. A.; Cortesi, A.; Akras, S.; Lopes de Oliveira, R.; Torres-Flores, S.; Lima-Dias, C.; Castellon, J. L. Nilo; Damke, G.; Alvarez-Candal, A.; Jiménez-Teja, Y.; Coelho, P.; Pereira, E.; Montero-Dorta, A. D.; Benítez, N.; Gonçalves, T. S.; Santana-Silva, L.; Werner, S. V.; Almeida, L. A.; Lopes, P. A. A.; Chies-Santos, A. L.; Telles, E.; de Souza, Thom; C, R.; Gonçalves, D. R.; de Souza, R. S.; Makler, M.; Buzzo, M. L.; Placco, V. M.; Nakazono, L. M. I.; Saito, R. K.; Overzier, R. A.; Abramo, L. R., 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 seven narrow +5 broad passband filter system, with a typical photometric-depth of r ∼ 21 AB. For this exercise, we utilize the Data Release 1 (DR1), corresponding to 336 deg2 from the Stripe-82 region. We rely on the 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 ∼100 k galaxies, we find a precision of σz, AM would like to acknowledge the financial support of the Brazilian funding agency FAPESP (Post-doc fellowship - process number 2014/11806-9), and his colleague Dr. Carlos Lopez-Sanjuan for all his valuable advices regarding PDF analysis. Likewise, AM acknowledges Ulisses Manzo and Carlos E. Paladini at IAG/USP for helping with software installation. In addition, AM would like to dedicate this work to his first son Tiago who was born in Brazil during the time this paper was written. MVCD thanks his scholarship from FAPESP (processes 2014/18632-6 and 2016/052549). This work has used the computing facilities of the Laboratory of Astroinformatics (IAG/USP, NAT/Unicsul), whose purchase was made possible by the Brazilian agency FAPESP (grant 2009/540064) and the INCT-A. LS acknowledges the financial support of the Brazilian funding agency FAPESP (Post-doc fellowship -process number 2016/21664-2). The S-PLUS project, including the T80S robotic telescope and the S-PLUS scientific survey, was founded as a partnership between the Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), the Observatorio Nacional (ON), the Universidade Federal de Sergipe (UFS), and the Universidade Federal de Santa Catarina (UFSC), with important financial and practical contributions from other collaborating institutes in Brazil, Chile (Universidad de La Serena), and Spain (Centro de Estudios de Fisica del Cosmos de Aragon, CEFCA). LSJ acknowledges support from FAPESP and CNPq. CMdO acknowledges support from FAPESP (grants 2009/54202-8, 2011/51680-6, 2014/07684-5, 2016/17119-9, 2017/50277-0, and 2019/11910-4) and CNPq (grant 312333/20145). JLNC is grateful for financial support received from the grant programs FA9550-15-1-0167 and FA9550-18-1-0018 of the Southern Office of Aerospace Research and Development (SOARD), a branch of theAir ForceOffice of the ScientificResearch International Office of the United States (AFOSR/IO). ADMD thanks FAPESP for financial support. SA acknowledges financial support from Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq, grant 454794/2015-0). AAC acknowledges support from FAPERJ (grant E26/203.186/2016) and CNPq (grants 304971/20162 and 401669/2016-5). LAA would like to acknowledge the financial support from FAPESP (N 2012/09716-6, 2013/18245-0). AC acknowledges funding from CNPq (403580/2016-1, 311153/20186) and FAPERGS (17/2551-0001). JAHJ thanks Brazilian institution CNPq for financial support through postdoctoral fellowship (project 150237/2017-0) and Chilean institution CONICYT, Programa de Astronomia, Fondo ALMA-CONICYT 2017, Codigo de proyecto 31170038. PAAL thanks the support of CNPq, grant 309398/20185. We are grateful for the contributions of CTIO staff in helping in the construction, comissioning, andmaintenance of the telescope and camera, and we are particularly thankful to the CTIO director, Steve Heathcote, for his support at every phase, without which this project would not have been completed. We thank Cesar Iniguez for making the 2D measurements of the filter transmissions at CEFCA. We warmly thank David Cristobal-Hornillos and his group for helping us to install and run the reduction package JYPE version 0.9.9 in the SPLUS computer system in Chile. We warmly thank Mariano Moles, Javier Cenarro, Tamara Civera, Sergio Chueca, Javier Hernandez Fuertes, AntonioMarin Franch, JesusVareta, Hector-VazquezRamio, and Alessandro Ederoclite - the success of the S-PLUS project relies on the dedication of these and other CEFCA staff members in building OAJ and running J-PLUS and J-PAS. We deeply thank Rene Laporte and INPE, as well as Keith Taylor, for their contributions to the T80S camera.

We present a new approach to study planetary nebulae using integral field spectroscopy. VLT@VIMOS datacube of the planetary nebula Abell 14 is analysed in three different ways by extracting: (i) the integrated spectrum, (ii) 1-dimensional simulated long slit spectra for different position angles and (iii) spaxel-by-spaxel spectra. These data are used to built emission-line diagnostic diagrams and explore the ionization structure and excitation mechanisms combining data from 1- and 3- dimensional photoionization models. The integrated and 1D simulated spectra are suitable for developing diagnostic diagrams, while the spaxel spectra can lead to misinterpretation of the observations. We find that the emission-line ratios of Abell 14 are consistent with UV photo-ionized emission, however there are some pieces of evidence of an additional thermal mechanism. The chemical abundances confirm its previous classification as a Type I planetary nebula, without spatial variation. We find, though, variation in the ionization correction factors (ICFs) as a function of the slit position angle. The star at the geometric centre of Abell 14 has an A5 spectral type with an effective temperature of Teff = 7909$\pm$135 K and surface gravity log(g) = 1.4$\pm$0.1 cm s$^{-2}$. Hence, this star cannot be responsible for the ionization state of the nebula. Gaia parallaxes of this star yield distances between 3.6 and 4.5 kpc in good agreement with the distance derived from a 3-dimensional photoionization modelling of Abell 14, indicating the presence of a binary system at the centre of the planetary nebula., 16 pages, 11 figures, 3 tables. Accepted for publication in MNRAS

Accurate distance estimates of astrophysical objects such as planetary nebulae (PNe), and nova and supernova remnants, among others, allow us to constrain their physical characteristics, such as size, mass, luminosity, and age. An innovative technique based on the expansion parallax method, the so-called distance mapping technique (DMT), provides distance maps of expanding nebulae as well as an estimation of their distances. The DMT combines the tangential velocity vectors obtained from 3D morpho-kinematic models and the observed proper motion vectors to estimate the distance. We applied the DMT to four PNe (NGC 6702, NGC 6543, NGC 6302, and BD+30 3639) and one nova remnant (GK Persei) and derived new distances in good agreement with previous studies. New simple morpho-kinematic shape models were generated for NGC 6543, NGC 6302, and NGC 6702, whereas for BD+30 3639 and GK Persei published models were used. We demonstrate that the DMT is a useful tool to obtain distance values of PNe, in addition to revealing kinematically peculiar regions within the nebulae. Distances are also derived from the trigonometric Gaia parallaxes. The effect of the non-negligible parallax offset in the second Gaia data release is also discussed., Comment: 16 pages, 9 figures, 5 tables. Accepted for publication in MNRAS

In this study we define a new sample of distant powerful radio galaxies in order to study their host-galaxy properties and provide targets for future observations of HI absorption with new radio telescopes and to understand the fuelling and feedback from such sources. We have cross-matched the Sydney University Molonglo Sky Survey (SUMSS) radio catalogue at 843 MHz with the VISTA Hemisphere Survey (VHS) near-infrared catalogue using the Likelihood Ratio technique. Photometric redshifts from the Dark Energy Survey are then used to assign redshifts to the radio source counterparts. We found a total of 249 radio sources with photometric redshifts over a 148 deg^2 region. By fitting the optical and near-infrared photometry with spectral synthesis models we determine the stellar mass and star-formation rates of the radio sources, finding typical stellar masses of 10^{11} - 10^{12}M$_{\odot}$ for the powerful high-redshift radio galaxies. We also find a population of low-mass blue galaxies. However, by comparing the derived star-formation rates to the radio luminosity, we suggest that these sources are false positives in our likelihood ratio analysis. Follow up, higher-resolution (, 11 pages, 9 figures. Accepted for publication in MNRAS

We present a detailed analysis of deep VLT/X-Shooter observations of the planetary nebula Tc 1. We calculate gas temperature, density, extinction, and abundances for several species from the empirical analysis of the total line fluxes. In addition, a spatially resolved analysis of the most intense lines provides the distribution of such quantities across the nebula. The new data reveal that several lines exhibit a double peak spectral profile consistent with the blue- and red-shifted components of an expanding spherical shell. The study of such components allowed us to construct for the first time a three-dimensional morphological model, which reveals that Tc 1 is a slightly elongated spheroid with an equatorial density enhancement seen almost pole on. A few bright lines present extended wings (with velocities up to a few hundred km/s), but the mechanism producing them is not clear. We constructed photoionization models for the main shell of Tc 1. The models predict the central star temperature and luminosity, as well as the nebular density and abundances similar to previous studies. Our models indicate that Tc 1 is located at a distance of approximately 2 kpc. We report the first detection of the [Kr III] 6825 A emission line, from which we determine the Krypton abundance. Our model indicates that the main shell of Tc 1 is matter bounded; leaking H ionizing photons may explain the ionization of its faint AGB-remnant halo., Comment: Accepted for publication in MNRAS. 27 pages, 20 figures

PNe are known to be photoionized objects. However they also have low-ionization structures (LIS) with different excitation behavior. We are only now starting to answer why most LIS have lower electron densities than the PN shells hosting them, and whether or not their intense emission in low-ionization lines is the key to their main excitation mechanism. Can LIS line ratios, chemical abundances and kinematics enlight the interplay between the different excitation and formation processes in PNe? Based on the spectra of five PNe with LIS and using new diagnostic diagrams from shock models, we demonstrate that LIS’s main excitation is due to shocks, whereas the other components are mainly photoionized. We propose new diagnostic diagrams involving a few emission lines ([N II], [O III], [S II]) and fshocks/f*, where fshocks and f* are the ionization photon fluxes due to the shocks and to the central star ionizing continuum, respectively.

BD +30° 3639 is a member of a group of uncommon planetary nebulae with Wolf–Rayet central star and higher expansion velocities in [O iii] than in [N ii] lines. Images and high-resolution spectra from the literature are used in order to construct a 3D model of the nebula using the morpho-kinematic code shape. We find that two homologous expansion laws are needed for the [N ii] and [O iii] shells. We conclude that the internal velocity field of BD +30° 3639 decreases with the distance from the central star at least between the [O iii] and [N ii] shells. A cylindrical velocity component is used to replicate the high-speed bipolar collimated outflows. We also present a new kinematic analysis technique called ‘distance mapping’. It uses the observed proper motion vectors and the 3D velocity field to generate maps that can be used as a constraint to the morpho-kinematic modelling with shape as well as improve the accuracy for distance determination. It is applied to BD +30° 3639 using 178 internal proper motion vectors from Li, Harrington & Borkowski and our 3D velocity field to determine a distance of 1.52 ± 0.21 kpc. Finally, we find evidence for an interaction between the eastern part of the nebula and the ambient H2 molecular gas.

We present optical broad-band ( UBVRI ) aperture polarimetry of 52 post-AGB stars, selected from De Ruyter et al. (2006) and the Torun Catalog, based on the shape of their SED and near-infrared excess. We find 10 (19%) of the stars in our sample to have high polarization ( P > 5%), 30 (56%) intermediate/low polarization (1% P P P > 3%), show systematically [12] − [25] > 1.5, J − H > 0.5 and J − K > 0.5, clearly separated from the group of RV Tauri stars, which are found to have very low polarization ( P < 3%).

Images and high–resolution spectra from the literature are used in order to construct a 3–D model of BD +30 3639 using the morpho–kinematic code SHAPE. We find that two homologous expansion laws are needed for the [N II] and [O III] shell. A cylindrical velocity component is used to replicate the high–speed bipolar collimated outflows. We also present a new kinematic analysis technique called “distance mapping”. It uses the observed proper motion vectors and the 3–D velocity field to generate maps that can be used as a constraint to the morpho–kinematic modeling with SHAPE as well as improve the accuracy for distance determination. It is applied to BD+30 3639 using 178 internal proper motion vectors from Li et al. ([?]) and our 3–D velocity field to determine a distance of 1.52 ± 0.21 kpc. Finally, we find evidence for an interaction between the eastern part of nebula and the ambient H2 molecular gas.

We present high resolution long-slit spectra from the San Pedro Martir kinematic catalogue (López et al. 2012) of plantetary nebulae M1-32 and M2-42 and their modeled PV diagrams using the 3-D morpho-kinematic code SHAPE. We find high-speed collimated outflows, surrounded by a equatorial thick torus/ring. The same SHAPE model is able to fit both planetary nebulae assuming one cylindrical velocity field for the outflows and one Hubble-law for the torus/ring concluding that they may be akin objects which just appear at different projections.