Suchergebnisse

The ubiquitous presence of Galactic cirri in deep optical images represents a major obstacle to study the low surface brightness features of extragalactic sources. To address this issue, we have explored the optical properties of cirri using g, r, i, and z bands in the Sloan Digital Sky Survey (SDSS) Stripe82 region. Using state-of-the-art, custom made, image processing techniques, including the modeling and removal of the instrumental scattered light produced by the stars, we managed to isolate the optical diffuse emission by the cirri, allowing their photometric characterization. We find that their optical colors are driven by the dust column density: The cirri become redder as their 100 μm emission increases. Remarkably, the optical colors of the Galactic cirri differ significantly from those of extragalactic sources, with a characteristic bluer r-i color for a given g-r, allowing one to detect these by using a simple color relation. Our results show the high potential of deep multi-band optical photometry, on its own, identifying the presence of cirri at a higher spatial resolution than those provided by far-infrared observations. The combination of very deep data and multi-band photometry (as the one produced by LSST and Euclid) would make it possible to build dust maps of unprecedented quality. © 2020 ESO. ; The authors of this paper also acknowledge support from grant AYA2016-77 237-C3-1-P from the Spanish Ministry of Economy and Competitiveness (MINECO) and from IAC project P/300624, financed by the Ministry of Science, Innovation and Universities, through the State Budget and by the Canary Islands Department of Economy, Knowledge and Employment, through the Regional Budget of the Autonomous Community. We acknowledge support from the Fundación BBVA under its 2017 program of assistance to scientific research groups, for the project "Using machine-learning techniques to drag galaxies from the noise in deep imaging". JR acknowledge financial support from the grants AYA2015-65973-C3-1-R and RTI2018-096228-B-C31 (MINECO/FEDER, UE), as well as from the State Agency for Research of the Spanish MCIU through the "Center of Excellence Severo Ochoa" award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). I.T. acknowledges financial support from the European Union's Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement No 721463 to the SUNDIAL ITN network. We thank Timothy Brandt for sharing the spectrum of the diffuse galactic light with us. We thank Adolf Witt for interesting suggestions about our work. We thank Jorge Sánchez Almeida and David Valls-Gabaud for interesting discussions about the results. We thank Aaron Watkins for complementary analysis about the galactic dust colors and Juergen Fliri for his excellent work on the construction of the IAC Stripe82 Legacy Survey. We thank Lee Kelvin for sharing his code to compute beautiful color composed images. JR thanks Anastasia Khamatullina for interesting discussions. We thank the participants of the workshop "Exploring the Ultra-Low Surface Brightness Universe" hosted in the ISSI headquarters, Bern, Switzerland on January 2017, in which preliminary result were shown. We also thank the participants of the meeting "The low surface brightness Universe as seen by LSST" hosted in Sesto, Italy on January 2020 for interesting discussions ; Peer reviewed

A robust and extended characterization of the point spread function (PSF) is crucial to extract the photometric information produced by deep imaging surveys. Here, we present the extended PSFs of the Sloan Digital Sky Survey (SDSS), one of the most productive astronomical surveys of all time. By stacking similar to 1000 images of individual stars with different brightness, we obtain the bidimensional SDSS PSFs extending over 8 arcmin in radius for all the SDSS filters (u, g, r, i, z). This new characterization of the SDSS PSFs is near a factor of 10 larger in extension than previous PSFs characterizations of the same survey. We found asymmetries in the shape of the PSFs caused by the drift scanning observing mode. The flux of the PSFs is larger along the drift scanning direction. Finally, we illustrate with an example how the PSF models can be used to remove the scattered light field produced by the brightest stars in the central region of the Coma cluster field. This particular example shows the huge importance of PSFs in the study of the low-surface brightness Universe, especially with the upcoming of ultradeep surveys, such as the Large Synoptic Survey Telescope (LSST). Following a reproducible science philosophy, we make all the PSF models and the scripts used to do the analysis of this paper publicly available (snapshot v0.4-0-gd966ad0). ©2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society ; We thank the referee for a constructive report that helped to improve the presentation of the manuscript. This research has been supported by the Spanish Ministry of Economy and Competitiveness (MINECO) under grants AYA2016-77237-C3-1-P and AYA2016-76219-P. We also acknowledge support from the Fundacion BBVA under its 2017 programme of assistance to scientific research groups, for the project 'Using machine-learning techniques to drag galaxies from the noise in deep imaging'. This work was partly done using the reproducible template project (Akhlaghi et al. in preparation). The reproducible template was also supported by European Union's Horizon 2020 (H2020) research and innovation programme via the RDA EU 4.0 project (ref. GA no. 777388). We thank Mohammad Akhlaghi for all his time spent in explaining how to make the core part of this project reproducible. We thank Roelof de Jong for kindly providing us the PSF profiles obtained in his work. We thank Alejandro Borlaff, Nushkia Chamba, and Simon Diaz-Garcia for their comments. This work was partly done using GNU Astronomy Utilities (Gnuastro, ascl.net/1801.009) version 0.10. Work on Gnuastro has been funded by the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT) scholarship and its Grant-in-Aid for Scientific Research (21244012, 24253003), the European Research Council (ERC) advanced grant 339659-MUSICOS, European Unions Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement No 721463 to the SUNDIAL ITN. Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the U.S. Department of Energy Office of Science, and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS web site is www.sdss.org.SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrofisica de Canarias, The Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU) / University of Tokyo, the Korean Participation Group, Lawrence Berkeley National Laboratory, Leibniz Institut fur Astrophysik Potsdam (AIP), Max-Planck-Institut fur Astronomie (MPIA Heidelberg), Max-Planck-Institut fur Astrophysik (MPA Garching), Max-Planck-Institut fur Extraterrestrische Physik (MPE), National Astronomical Observatories of China, New Mexico State University, New York University, University of Notre Dame, Observatario Nacional/MCTI, The Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Autonoma de Mexico, University of Arizona, University of Colorado Boulder, University of Oxford, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University, and Yale University. ; Peer reviewed

We present the first results of the LBT Imaging of Galaxy Haloes and Tidal Structures (LIGHTS) survey. LIGHTS is an ongoing observational campaign with the 2 × 8.4 m Large Binocular Telescope (LBT) aiming to explore the stellar haloes and the low surface brightness population of satellites down to a depth of μV ∼31 mag arcsec-2 (3σ in 10″ × 10″ boxes) of nearby galaxies. We simultaneously collected deep imaging in the g and r Sloan filters using the Large Binocular Cameras. The resulting images are 60 times (i.e. ∼4.5 mag) deeper than those from the Sloan Digital Sky Survey, and they have characteristics comparable (in depth and spatial resolution) to the ones expected from the future Legacy Survey of Space and Time (LSST). Here we show the first results of our pilot programme targeting NGC 1042 (an M 33 analogue at a distance of 13.5 Mpc) and its surroundings. The depth of the images allowed us to detect an asymmetric stellar halo in the outskirts of this galaxy whose mass (1.4 ± 0.4 × 108 M) is in agreement with the ΛCDM expectations. Additionally, we show that deep imaging from the LBT reveals low mass satellites (a few times 105 M) with very faint central surface brightness μV(0) ∼27 mag arcsec-2 (i.e. similar to Local Group dwarf spheroidals, such as Andromeda XIV or Sextans, but at distances well beyond the local volume). The depth and spatial resolution provided by the LIGHTS survey open up a unique opportunity to explore the 'missing satellites' problem in a large variety of galaxies beyond our Local Group down to masses where the difference between the theory and observation (if any) should be significant. © 2021 ESO. ; We acknowledge support from grant PID2019-107427GB-C32 from The Spanish Ministry of Science and Innovation. We acknowledge financial support from the European Union's Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement No 721463 to the SUNDIAL ITN network, and the European Regional Development Fund (FEDER), from IAC project P/300624, financed by the Ministry of Science, Innovation and Universities, through the State Budget and by the Canary Islands Department of Economy, Knowledge and Employment, through the Regional Budget of the Autonomous Community. DZ acknowledges financial support from NSF AST-2006785. NC acknowledges support from the research project grant "Understanding the Dynamic Universe" funded by the Knut and Alice Wallenberg Foundation under Dnr KAW 2018.0067 and Chris Usher for interesting comments. DJS acknowledges support from NSF grants AST-1821967 and 1813708. JR acknowledges funding from the State Agency for Research of the Spanish MCIU through the `Center of Excellence Severo Ochoa' award to the Instituto de Astrofisica de Andalucia (SEV-2017-0709), financial support from the grants AYA2015-65973-C3-1-R and RTI2018-096228B-C31 (MINECO/FEDER, UE) as well as support from the State Research Agency (AEI-MCINN) of the Spanish Ministry of Science and Innovation under the grant `The structure and evolution of galaxies and their central regions' with reference PID2019-105602GB-I00/10.13039/501100011033. The LBT is an international collaboration among institutions in the United States, Italy and Germany. LBT Corporation partners are: The University of Arizona on behalf of the Arizona Board of Regents; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max-Planck Society, The Leibniz Institute for Astrophysics Potsdam, and Heidelberg University; The Ohio State University, representing OSU, University of Notre Dame, University of Minnesota and University of Virginia. This research has made use of the NASA/IPAC Extragalactic Database (NED), which is funded by the National Aeronautics and Space Administration and operated by the California Institute of Technology. This work was partly done using GNU Astronomy Utilities (Gnuastro, ascl.net/1801.009) version 0.13.12-f50c. Work on Gnuastro has been funded by the Japanese Ministry of Education, Culture, Sports, Science, and Technology (MEXT) scholarship and its Grant-in-Aid for Scientific Research (21244012, 24253003), the European Research Council (ERC) advanced grant 339659-MUSICOS, and the Spanish Ministry of Economy and Competitiveness (MINECO) under grant number AYA2016-76219-P. ; Peer reviewed

Free access at publisher's website https://www.aanda.org/articles/aa/pdf/2019/01/aa34312-18.pdf. ; he Hubble Ultra Deep field (HUDF) is the deepest region ever observed with the Hubble Space Telescope. With the main objective of unveiling the nature of galaxies up to z ∼ 7 - 8, the observing and reduction strategy have focused on the properties of small and unresolved objects, rather than the outskirts of the largest objects, which are usually over-subtracted. Aims. We aim to create a new set of WFC3 IR mosaics of the HUDF using novel techniques to preserve the properties of the low surface brightness regions. Methods. We created ABYSS: A pipeline that optimises the estimate and modelling of low-level systematic effects to obtain a robust background subtraction. We have improved four key points in the reduction: 1) creation of new absolute sky flat fields, 2) extended persistence models, 3) dedicated sky background subtraction and 4) robust co-adding. Results. The new mosaics successfully recover the low surface brightness structure removed on the previous HUDF published reductions. The amount of light recovered with a mean surface brightness dimmer than μ = 26 mag arcsec -2 is equivalent to a m = 19 mag source when compared to the XDF and a m = 20 mag compared to the HUDF12. Conclusions. We present a set of techniques to reduce ultra-deep images (μ > 32.5 mag arcsec -2 , 3σ in 10 × 10 arcsec boxes), that successfully allow us to detect the low surface brightness structure of extended sources on ultra deep surveys. The developed procedures are applicable to HST, JWST, Euclid and many other space and ground-based observatories. © ESO 2019. ; The authors would like to thank the XDF and HUDF12 teams for their extraordinary work in which this contribution is based on, truly standing on the shoulders of giants. This work would not have been possible without the kind assistance of all the members of the STScI Help Desk. We specially thank Knox Long by its work on persistence effects and its extraordinary support during this work. A.B. acknowledges support from the International Space Science Institute (ISSI) as part of the Exploring the Ultra-Low Surface Brightness Universe International team. Some/all of the data presented in this paper were obtained from the Mikulski Archive for Space Telescopes (MAST). STScI is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555. I.T. and C.M.L acknowledges the support from the SUNDIAL EU Network and from the European Union's Horizon 2020 research and innovation programme under Marie Sklodowska-Curie grant agreement No 721463 and the SUNDIAL ITN network. C.M.L. acknowledges financial support from the Spanish Ministry of Economy and Competitiveness (MINECO) under grant number AYA2016-76219-P. N.C acknowledged support from the Spanish Programa Nacional de Astronimía y Astrofísica under grant AYA2016-75808-R. C.G.G. acknowledges support from the European Research Council (ERC) Consolidator Grant funding scheme (project ConTExt, grant number 648179). Support for MAST for non-HST data is provided by the NASA Office of Space Science via grant NNX09AF08G and by other grants and contracts. This work was partly done using GNU Astronomy Utilities Gnuastro version 0.5. Gnuastro is a generic package for astronomical data manipulation and analysis which was primarily created and developed for research funded by the Monbukagakusho (Japanese government) scholarship and ERC advanced grant 339659-MUSICOS. Support for this work was provided by the Spanish Ministe-rio de Economía y Competitividad (MINECO; grant AYA 2016-77237-C3-I-P). This research made use of Astropy (http://www.astropy.org) a community-developed core Python package for Astronomy (Astropy Collaboration 2013; Price-Whelan et al. 2018). ; Peer reviewed