We have recently obtained simultaneous two-dimensional (2D) plasmaDoppler spectroscopic images of plasma brightness, temperature, and flow fields. Using compact polarization optical methods, quadrature images of the optical coherence of an isolated spectral line are multiplexed to four quadrants of a fast charge-coupled device camera. The simultaneously captured, but distinct, images can be simply processed to unfold the plasma brightness, temperature, and flow fields. This static system, which is a spatial-multiplex variant of previously reported electro-optically modulated, temporal-multiplex coherence imaging systems, is based on a high-throughput imagingpolarizationinterferometer that employs crossed Wollaston prisms and appropriate image plane masks. Because the images are captured simultaneously, it is well suited to high-spectral-resolution, high-throughput 2D imaging of transient or rapidly changing spectroscopic scenes. To illustrate instrument performance we present recent results using a static 4-quadrant Dopplercoherence imaging on the H-1 heliac at the ANU. ; This work has been, in part, supported by the Australian Government Department of Education, Science and Training under the International Science Linkages program, Grant No. CG050061.
We have recently obtained simultaneous two-dimensional (2D) plasmaDoppler spectroscopic images of plasma brightness, temperature, and flow fields. Using compact polarization optical methods, quadrature images of the optical coherence of an isolated spectral line are multiplexed to four quadrants of a fast charge-coupled device camera. The simultaneously captured, but distinct, images can be simply processed to unfold the plasma brightness, temperature, and flow fields. This static system, which is a spatial-multiplex variant of previously reported electro-optically modulated, temporal-multiplex coherence imaging systems, is based on a high-throughput imagingpolarizationinterferometer that employs crossed Wollaston prisms and appropriate image plane masks. Because the images are captured simultaneously, it is well suited to high-spectral-resolution, high-throughput 2D imaging of transient or rapidly changing spectroscopic scenes. To illustrate instrument performance we present recent results using a static 4-quadrant Dopplercoherence imaging on the H-1 heliac at the ANU. ; This work has been, in part, supported by the Australian Government Department of Education, Science and Training under the International Science Linkages program, Grant No. CG050061.
Context. Many massive stars have nearby companions whose presence hamper their characterization through spectroscopy. Aims. We want to obtain spatially resolved spectroscopy of close massive visual binaries to derive their spectral types. Methods. We obtained a large number of short long-slit spectroscopic exposures of five close binaries under good seeing conditions. We selected those with the best characteristics, extracted the spectra using multiple-profile fitting, and combined the results to derive spatially separated spectra. Results. We demonstrate the usefulness of Lucky Spectroscopy by presenting the spatially resolved spectra of the components of each system, in two cases with separations of only ~0.′′3. Those are δ Ori Aa+Ab (resolved in the optical for the first time) and σ Ori AaAb+B (first time ever resolved). We also spatially resolve 15 Mon AaAb+B, ζ Ori AaAb+B (both previously resolved with GOSSS, the Galactic O-Star Spectroscopic Survey), and η Ori AaAb+B, a system with two spectroscopic B+B binaries and a fifth visual component. The systems have in common that they are composed of an inner pair of slow rotators orbited by one or more fast rotators, a characteristic that could have consequences for the theories of massive star formation. ; We acknowledge support from the Spanish Government Ministerio de Economía y Competitividad (MINECO) through grants AYA2016-75 931-C2-1/2-P (J.M.A., A.S., E.T.P., and E.J.A), AYA2015-68 012-C2-1/2-P (S.S.-D. and E.T.P.) and AYA2016-79 425-C3-2-P (J.A.C.). R.H.B. acknowledges support from the ESAC Faculty Council Visitor Program.
We present observations of the unusually luminous Type II supernova (SN) 2016gsd. With a peak absolute magnitude of V = -19.95 +/- 0.08, this object is one of the brightest Type II SNe, and lies in the gap of magnitudes between the majority of Type II SNe and the superluminous SNe. Its light curve shows little evidence of the expected drop from the optically thick phase to the radioactively powered tail. The velocities derived from the absorption in( )H alpha are also unusually high with the blue edge tracing the fastest moving gas initially at 20 000 km s(-1), and then declining approximately linearly to 15000 km s(-1) over similar to 100 d. The dwarf host galaxy of the SN indicates a low-metallicity progenitor which may also contribute to the weakness of the metal lines in its spectra. We examine SN 2016gsd with reference to similarly luminous, linear Type II SNe such as SNe 1979C and 1998S, and discuss the interpretation of its observational characteristics. We compare the observations with a model produced by the JEKYLL code and find that a massive star with a depleted and inflated hydrogen envelope struggles to reproduce the high luminosity and extreme linearity of SN 2016gsd. Instead, we suggest that the influence of interaction between the SN ejecta and circumstellar material can explain the majority of the observed properties of the SN. The high velocities and strong H alpha absorption present throughout the evolution of the SN may imply a circumstellar medium configured in an asymmetric geometry. ; Jenny and AnttiWihuri Foundation Vilho, Yrjo and Kalle Vaisala Fund of the Finnish academy of Science and Letters UCD seed funding scheme SF1518 Science Foundation Ireland Swedish Research Council Villum Fonden 13261 Independent Research Fund Denmark (IRFD) 802100170B Instrument Center for Danish Astronomy (IDA) European Organisation for Astronomical Research in the Southern Hemisphere, Chile as part of PESSTO (the Public ESO Spectroscopic Survey for Transient Objects) ESO program 188.D-3003 191.D-0935 National Aeronautics & Space Administration (NASA) NNX08AR22G National Science Foundation (NSF) AST-1238877 Chinese Academy of Sciences KJCX2-EW-T06 Chinese Astronomical Data Center (CAsDC) National Natural Science Foundation of China 11573003 National Astronomical Observatories of China Chinese Academy of Sciences Special Fund for Astronomy from the Ministry of Finance Science & Technology Facilities Council (STFC) ST/P000312/1 National Aeronautics & Space Administration (NASA) NN12AR55G 80NSSC18K0284 80NSSC18K1575 Iniciativa Cientifica Milenio del Ministerio de Economia, Fomento y Turismo de Chile IC120009 CONICYT PAI/INDUSTRIA 79090016 Finnish Cultural Foundation National Science Foundation (NSF) AST-1313484 LSSTC Data Science Fellowship Program - LSSTC NSF Cybertraining Grant 1829740 Brinson Foundation Gordon and Betty Moore Foundation European Union (EU) 839090 European Southern Observatory under ESO programme 0103.D0338(A) EU/FP7-ERC grant 615929
We present observations of the unusually luminous Type II supernova (SN) 2016gsd. With a peak absolute magnitude of V = -19.95 ± 0.08, this object is one of the brightest Type II SNe, and lies in the gap of magnitudes between the majority of Type II SNe and the superluminous SNe. Its light curve shows little evidence of the expected drop from the optically thick phase to the radioactively powered tail. The velocities derived from the absorption in H α are also unusually high with the blue edge tracing the fastest moving gas initially at 20 000 km s-1, and then declining approximately linearly to 15 000 km s-1 over ∼100 d. The dwarf host galaxy of the SN indicates a low-metallicity progenitor which may also contribute to the weakness of the metal lines in its spectra. We examine SN 2016gsd with reference to similarly luminous, linear Type II SNe such as SNe 1979C and 1998S, and discuss the interpretation of its observational characteristics. We compare the observations with a model produced by the jekyll code and find that a massive star with a depleted and inflated hydrogen envelope struggles to reproduce the high luminosity and extreme linearity of SN 2016gsd. Instead, we suggest that the influence of interaction between the SN ejecta and circumstellar material can explain the majority of the observed properties of the SN. The high velocities and strong H α absorption present throughout the evolution of the SN may imply a circumstellar medium configured in an asymmetric geometry. ; MF acknowledges the support of a Royal Society – Science Foundation Ireland University Research Fellowship. The JEKYLL simulations were performed on resources provided by the Swedish National Infrastructure for Computing (SNIC) at Parallelldatorcentrum (PDC). PL acknowledges support from the Swedish Research Council. MS is supported by a generous grant (13261) from Villum Fonden and a project grant (8021-00170B) from the Independent Research Fund Denmark (IRFD). NUTS2 is funded in part by the Instrument Center for Danish Astronomy (IDA). This work is based (in part) on observations collected at the European Organisation for Astronomical Research in the Southern Hemisphere, Chile as part of PESSTO (the Public ESO Spectroscopic Survey for Transient Objects) ESO program 188.D−3003, 191.D−0935, more ESO acknowledgements. The Pan-STARRS1 Surveys (PS1) and the PS1 public science archive have been made possible through contributions by the Institute for Astronomy, the University of Hawaii, the Pan-STARRS Project Office, the Max-Planck Society and its participating institutes, the Max Planck Institute for Astronomy, Heidelberg and the Max Planck Institute for Extraterrestrial Physics, Garching, The Johns Hopkins University, Durham University, the University of Edinburgh, the Queen's University Belfast, the Harvard-Smithsonian Center for Astrophysics, the Las Cumbres Observatory Global Telescope Network Incorporated, the National Central University of Taiwan, the Space Telescope Science Institute, the National Aeronautics and Space Administration under Grant No. NNX08AR22G issued through the Planetary Science Division of the NASA Science Mission Directorate, the National Science Foundation Grant No. AST−1238877, the University of Maryland, Eotvos Lorand University (ELTE), the Los Alamos National Laboratory, and the Gordon and Betty Moore Foundation. The SCUSS is funded by the Main Direction Program of Knowledge Innovation of Chinese Academy of Sciences (No. KJCX2−EW−T06). It is also an international cooperative project between National Astronomical Observatories, Chinese Academy of Sciences, and Steward Observatory, University of Arizona, USA. Technical support and observational assistance from the Bok telescope are provided by Steward Observatory. The project is managed by the National Astronomical Observatory of China and Shanghai Astronomical Observatory. Data resources are supported by Chinese Astronomical Data Center (CAsDC). SD and PC acknowledge Project 11573003 supported by NSFC. This research uses data obtained through the Telescope Access Program (TAP), which has been funded by the National Astronomical Observatories of China, the Chinese Academy of Sciences, and the Special Fund for Astronomy from the Ministry of Finance. SJS acknowledges STFC grant ST/P000312/1. This work has made use of data from the Asteroid Terrestial-impact Last Alert System (ATLAS) Project. ATLAS is primarily funded to search for near earth asteroids through NASA grants NN12AR55G, 80NSSC18K0284, and 80NSSC18K1575; byproducts of the NEO search include images and catalogues from the survey area. The ATLAS science products have been made possible through the contributions of the University of Hawaii Institute for Astronomy, the Queen's Univeristy Belfast, the Space Telescope Science Institute, and the South African Astronomical Observatory. OR acknowledges support by projects IC120009 'Millennium Institute of Astrophysics (MAS)' of the Iniciativa Científica Milenio del Ministerio de Economía, Fomento y Turismo de Chile and CONICYT PAI/INDUSTRIA 79090016. JH acknowledges financial support from the Finnish Cultural Foundation. Some data were taken with the Las Cumbres Observatory Network. GH and DAH are supported by NSF grant AST-1313484. GH thanks the LSSTC Data Science Fellowship Program, which is funded by LSSTC, NSF Cybertraining Grant #1829740, the Brinson Foundation, and the Moore Foundation; his participation in the program has benefited this work. LG was funded by the European Union's Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 839090. This work also makes use of observations collected at the European Southern Observatory under ESO programme 0103.D-0338(A). CPG acknowledges support from EU/FP7-ERC grant no. [615929].
Context. Many massive stars have nearby companions. These hamper a characterization of massive stars through spectroscopy. Aims. We continue to obtain spatially resolved spectroscopy of close massive visual binaries to derive their spectral types. Methods. We used the lucky spectroscopy technique to obtain a large number of short long-slit spectroscopic exposures of 19 close visual binaries under good seeing conditions. We selected those with the best characteristics, extracted the spectra using multiple-profile fitting, and combined the results to derive spatially separated spectra. The results were analyzed in combination with data from lucky imaging, regular intermediate-resolution single-order spectroscopy, and échelle high-resolution spectroscopy. Results. The new application of lucky spectroscopy has allowed us (among other results) to [a] spatially disentangle two O stars (FN CMa B and 6 Cas B) with brighter BA supergiant companions for the first time; [b] determine that two B stars (α Sco B and HD 164 492 B) with close and more massive companions are fast rotators (in the second case, solving a case of mistaken identity); [c] extend the technique to cases with extreme magnitude differences (the previous two cases plus CS Cam A,B), shorter separations (HD 193 443 A,B), and fainter primary magnitudes down to B = 11 (HD 219 460 A,B); [d] spatially disentangle the spectra of stars with companions as diverse as an A supergiant (6 Cas A), a Wolf-Rayet star (HD 219 460 B = WR 157), and an M supergiant (α Sco A); [e] discover the unexpected identity of some targets such as two previously unknown bright O stars (HD 51 756 B and BD +60 544) and a new member of the rare OC category (HD 8768 A); and [f] identify and classify (in some cases for the first time) which of the components of four visual binaries (σ Ori, HD 219 460, HD 194 649, and HD 191 201) is a double-lined spectroscopic binary. For another seven systems (FN CMa, σ Sco, HD 51 756, HD 218 195, HD 17 520, HD 24 431, and HD 164 492), we detect signs of spectroscopic binarity using high-spectral-resolution spectroscopy. We also determine the limits of the technique. ; J.M.A., C.F., A.S., M.P.G., and G.H. acknowledge support from the Spanish Government Ministerio de Ciencia through grant PGC2018-095049-B-C22. R.H.B. acknowledges support from the ESAC Faculty Visitor Program. I.N. and S.S.-D. acknowledge support from the Spanish Government Ministerio de Ciencia through grant PGC2018-093741-B-C21/22 (MICIU/AEI/FEDER, UE). S.S.-D. also acknowledges funding from the Spanish Government Ministerio de Ciencia through grants SEV 2015-0548 and CEX2019-000920-S, and from the Canarian Agency for Research, Innovation and Information Society (ACIISI), of the Canary Islands Government, and the European Regional Development Fund (ERDF), under grant with reference ProID2017010115.
We measured the gas abundance profiles in a sample of 122 face-on spiral galaxies observed by the CALIFA survey and included all spaxels whose line emission was consistent with star formation. This type of analysis allowed us to improve the statistics with respect to previous studies, and to properly estimate the oxygen distribution across the entire disc to a distance of up to 3-4 disc effective radii (r). We confirm the results obtained from classical H ii region analysis. In addition to the general negative gradient, an outer flattening can be observed in the oxygen abundance radial profile. An inner drop is also found in some cases. There is a common abundance gradient between 0.5 and 2.0 r of α =-0.075 dex/r with a scatter of σ = 0.016 dex/r when normalising the distances to the disc effective radius. By performing a set of Kolmogorov-Smirnov tests, we determined that this slope is independent of other galaxy properties, such as morphology, absolute magnitude, and the presence or absence of bars. In particular, barred galaxies do not seem to display shallower gradients, as predicted by numerical simulations. Interestingly, we find that most of thegalaxies in the sample with reliable oxygen abundance values beyond ~2 effective radii (57 galaxies) present a flattening of the abundance gradient in these outer regions. This flattening is not associated with any morphological feature, which suggests that it is a common property of disc galaxies. Finally, we detect a drop or truncation of the abundance in the inner regions of 27 galaxies in the sample; this is only visible for the most massive galaxies. ; We acknowledge financial support from the Spanish Ministerio de Economia y Competitividad (MINECO) via grant AYA2012-31935, and from the >Junta de Andalucia> local government through the FQM-108 project. We also acknowledge support to the ConaCyt funding program 180125. Y.A. acknowledges finantial support from the Ramon y Cajal programme (RyC-2011-09461). Y.A. and A.I.D. acknowledge support from the project AYA2013-47742-C4-3-P from the Spanish MINECO, as well as the >Study of Emission-Line Galaxies with Integral-Field Spectroscopy> (SELGIFS) programme, funded by the EU (FP7-PEOPLE-2013-IRSES-612701). Support for L.G. is provided by the Ministry of Economy, Development, and Tourism's Millennium Science Initiative through grant IC120009, awarded to The Millennium Institute of Astrophysics, MAS. LG acknowledges support by CONICYT through FONDECYT grant 3140566. R.M.G.D. acknowledges support from the Spanish grant AYA2014-57490-P, and from the >Junta de Andalucia> P12-FQM2828 project. RAM thanks the Spanish program of International Campus of Excellence Moncloa (CEI). IM and A.d.O. acknowledge support from the Spanish MINECO grant AYA2013-42227P. JMA acknowledges support from the European Research Council Starting Grant (SEDmorph, P.I. V. Wild). Support for MM has been provided by DGICYT grant AYA2013-47742-C4-4-P. PSB acknowledges support from the Ramon y Cajal programme, grant ATA2010-21322-C03-02 from the Spanish MINECO. CJW acknowledges support through the Marie Curie Career Grant Integration 303912. ; Peer Reviewed
