TY - BOOK A1 - Bauer, Hartmut A1 - Hajasch, Lydia A1 - Lübking, Uwe A1 - Stein, Ursula A1 - Roth, Roland A1 - Sippel, Hanns-Jörg A1 - Bock, Stephanie A1 - Friesecke, Frank A1 - Kleger, Heinz A1 - Vowe, Gerhard A1 - Utz, Stephanie Sophia A1 - Buchmann, Madeleine A1 - Löffler, Roland A1 - Zielske, Johanna ED - Bauer, Hartmut ED - Büchner, Christiane ED - Hajasch, Lydia T1 - Partizipation in der Bürgerkommune T3 - KWI Schriften N2 - Konzepte, nach denen sich die demokratische Mitwirkung der Bürger vornehmlich in Wahlen erschöpft, gehören spätestens seit „Stuttgart 21“ der Vergangenheit an. Indes ist die Bürgerbeteiligung auch jenseits solcher Großprojekte längst zu einem beherrschenden Thema der Zeit herangewachsen. Das gilt zumal für die kommunale Ebene. Dort werden traditionsreiche Partizipationsformen nicht nur intensiv genutzt, sondern zunehmend um neue Beteiligungsvarianten ergänzt und in innovativen Modellprojekten fortentwickelt. Dabei treten zwei Antriebskräfte besonders hervor. Zum einen fordern die Bürger nach den Maximen „Mitmachen, Mitwirken, Mitentscheiden“ deutlich verbesserte Partizipationsmöglichkeiten ein. Zum anderen setzen die Kommunen verstärkt auf bürgerschaftliches Engagement zur Erschließung Ressourcen privater Akteure für die Bereitstellung öffentlicher Leistungen. Übergreifende Perspektive ist die Ausbildung einer Neuen Partizipationskultur in der Bürgerkommune zur Optimierung des Gemeinwohls. Für die kommunale Praxis ist das partizipationsgestützte Miteinander von Verwaltung. Politik und Bürgerschaft in Systementwürfen, Leitbildern, Organisations- und Verfahrensmodellen sowie lokalen Beteiligungsformaten konkretisiert. Doch verbinden sich mit den alten und neuen Ansätzen der Bürgerbeteiligung noch eine ganze Reihe offener Fragen – so etwa nach den rechtlichen Möglichkeiten und Grenzen der neuen kommunalen Beteiligungskultur, nach Erfolgsbedingungen und konkreten Erfahrungen mit der Umsetzung von Partizipationsmodellen. Auf der 21. Fachtagung des Kommunalwissenschaftlichen Instituts (KWI) der Universität Potsdam wurden Schlüsselthemen der Neuen Partizipationskultur in der Bürgerkommune, namentlich der normativen Rahmenbedingungen und politischen Direktiven, Modernisierungsimpulse und Aktivierungsstrategien, Erfolgsbedingungen und spezifische Problemlagen einschließlich der Fallstricke in der Praxis und nicht zuletzt ausgewählter Einsatzfelder mit den dazugehörigen Erfahrungen diskutiert. T3 - KWI-Schriften - 10 KW - kommunale Demokratie KW - kommunale Entscheidungsprozesse KW - Partizipation KW - Partizipationsprozesse KW - Bürgerkommune Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-101601 SN - 978-3-86956-371-8 SN - 1867-951X SN - 1867-9528 IS - 10 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Göttgens, Fabian A1 - Weilbacher, Peter Michael A1 - Roth, Martin M. A1 - Dreizler, Stefan A1 - Giesers, Benjamin A1 - Husser, Tim-Oliver A1 - Kamann, Sebastian A1 - Brinchmann, Jarle A1 - Kollatschny, Wolfram A1 - Monreal-Ibero, Ana A1 - Schmidt, Kasper Borello A1 - Wendt, Martin A1 - Wisotzki, Lutz A1 - Bacon, Roland T1 - Discovery of an old nova remnant in the Galactic globular cluster M 22 JF - Astronomy and astrophysics : an international weekly journal N2 - A nova is a cataclysmic event on the surface of a white dwarf in a binary system that increases the overall brightness by several orders of magnitude. Although binary systems with a white dwarf are expected to be overabundant in globular clusters compared with in the Galaxy, only two novae from Galactic globular clusters have been observed. We present the discovery of an emission nebula in the Galactic globular cluster M 22 (NGC 6656) in observations made with the integral-field spectrograph MUSE. We extracted the spectrum of the nebula and used the radial velocity determined from the emission lines to confirm that the nebula is part of NGC 6656. Emission-line ratios were used to determine the electron temperature and density. It is estimated to have a mass of 1-17 x 10(-5) M-circle dot. This mass and the emission-line ratios indicate that the nebula is a nova remnant. Its position coincides with the reported location of a "guest star", an ancient Chinese term for transients, observed in May 48 BCE. With this discovery, this nova may be one of the oldest confirmed extra-solar events recorded in human history. KW - globular clusters: individual: NGC 6656 KW - novae, cataclysmic variables KW - techniques: imaging spectroscopy Y1 - 2019 U6 - https://doi.org/10.1051/0004-6361/201935221 SN - 1432-0746 VL - 626 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Roth, Roland T1 - Bürgerpartizipation BT - Stärkung oder Aushöhlung kommunaler Demokratie? JF - Partizipation in der Bürgerkommune (KWI Schriften) KW - Bürgerkommune KW - Partizipation KW - Partizipationsprozesse KW - kommunale Demokratie KW - kommunale Entscheidungsprozesse Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-104743 SN - 978-3-86956-371-8 SN - 1867-951X SN - 1867-9528 IS - 10 SP - 57 EP - 79 PB - Universitätsverlag Potsdam CY - Potsdam ER - TY - JOUR A1 - Weilbacher, Peter Michael A1 - Monreal-Ibero, Ana A1 - Verhamme, Anne A1 - Sandin, Christer A1 - Steinmetz, Matthias A1 - Kollatschny, Wolfram A1 - Krajnovic, Davor A1 - Kamann, Sebastian A1 - Roth, Martin M. A1 - Erroz-Ferrer, Santiago A1 - Marino, Raffaella Anna A1 - Maseda, Michael V. A1 - Wendt, Martin A1 - Bacon, Roland A1 - Dreizler, Stefan A1 - Richard, Johan A1 - Wisotzki, Lutz T1 - Lyman-continuum leakage as dominant source of diffuse ionized gas in the Antennae galaxy JF - Astronomy and astrophysics : an international weekly journal N2 - The Antennae galaxy (NGC 4038/39) is the closest major interacting galaxy system and is therefore often studied as a merger prototype. We present the first comprehensive integral field spectroscopic dataset of this system, observed with the MUSE instrument at the ESO VLT. We cover the two regions in this system which exhibit recent star formation: the central galaxy interaction and a region near the tip of the southern tidal tail. In these fields, we detect H II regions and diffuse ionized gas to unprecedented depth. About 15% of the ionized gas was undetected by previous observing campaigns. This newly detected faint ionized gas is visible everywhere around the central merger, and shows filamentary structure. We estimate diffuse gas fractions of about 60% in the central field and 10% in the southern region. We are able to show that the southern region contains a significantly different population of H II regions, showing fainter luminosities. By comparing H II region luminosities with the HST catalog of young star clusters in the central field, we estimate that there is enough Lyman-continuum leakage in the merger to explain the amount of diffuse ionized gas that we detect. We compare the Lyman-continuum escape fraction of each H II region against emission line ratios that are sensitive to the ionization parameter. While we find no systematic trend between these properties, the most extreme line ratios seem to be strong indicators of density bounded ionization. Extrapolating the Lyman-continuum escape fractions to the southern region, we conclude that simply from the comparison of the young stellar populations to the ionized gas there is no need to invoke other ionization mechanisms than Lyman-continuum leaking H II regions for the diffuse ionized gas in the Antennae. KW - galaxies: interactions KW - galaxies: individual: NGC 4038, NGC 4039 KW - galaxies: ISM KW - ISM: structure KW - H II regions Y1 - 2018 U6 - https://doi.org/10.1051/0004-6361/201731669 SN - 1432-0746 VL - 611 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Husser, Tim-Oliver A1 - Kamann, Sebastian A1 - Dreizler, Stefan A1 - Wendt, Martin A1 - Wulff, Nina A1 - Bacon, Roland A1 - Wisotzki, Lutz A1 - Brinchmann, Jarle A1 - Weilbacher, Peter Michael A1 - Roth, Martin M. A1 - Monreal-Ibero, Ana T1 - MUSE crowded field 3D spectroscopy of over 12 000 stars in the globular cluster NGC 6397 I. The first comprehensive HRD of a globular cluster JF - Nucleic acids research N2 - Aims. We demonstrate the high multiplex advantage of crowded field 3D spectroscopy with the new integral field spectrograph MUSE by means of a spectroscopic analysis of more than 12 000 individual stars in the globular cluster NGC 6397. Methods. The stars are deblended with a point spread function fitting technique, using a photometric reference catalogue from HST as prior, including relative positions and brightnesses. This catalogue is also used for a first analysis of the extracted spectra, followed by an automatic in-depth analysis via a full-spectrum fitting method based on a large grid of PHOENIX spectra. Results. We analysed the largest sample so far available for a single globular cluster of 18 932 spectra from 12 307 stars in NGC 6397. We derived a mean radial velocity of v(rad) = 17.84 +/- 0.07 km s(-1) and a mean metallicity of [Fe/H] = -2.120 +/- 0.002, with the latter seemingly varying with temperature for stars on the red giant branch (RGB). We determine Teff and [Fe/H] from the spectra, and log g from HST photometry. This is the first very comprehensive Hertzsprung-Russell diagram (HRD) for a globular cluster based on the analysis of several thousands of stellar spectra, ranging from the main sequence to the tip of the RGB. Furthermore, two interesting objects were identified; one is a post-AGB star and the other is a possible millisecond-pulsar companion. KW - methods: data analysis KW - techniques: imaging spectroscopy KW - planets and satellites: fundamental parameters KW - stars: atmospheres KW - pulsars: general KW - globular clusters: individual: NGC 6397 Y1 - 2016 U6 - https://doi.org/10.1051/0004-6361/201526949 SN - 1432-0746 VL - 588 PB - EDP Sciences CY - Les Ulis ER - TY - JOUR A1 - Kamann, S. A1 - Husser, T. -O. A1 - Brinchmann, Jarle A1 - Emsellem, E. A1 - Weilbacher, Peter Michael A1 - Wisotzki, Lutz A1 - Wendt, Martin A1 - Krajnovic, D. A1 - Roth, M. M. A1 - Bacon, Roland A1 - Dreizler, S. T1 - MUSE crowded field 3D spectroscopy of over 12 000 stars in the globular cluster NGC 6397 JF - Tectonophysics : international journal of geotectonics and the geology and physics of the interior of the earth N2 - We present a detailed analysis of the kinematics of the Galactic globular cluster NGC 6397 based on more than similar to 18 000 spectra obtained with the novel integral field spectrograph MUSE. While NGC 6397 is often considered a core collapse cluster, our analysis suggests a flattening of the surface brightness profile at the smallest radii. Although it is among the nearest globular clusters, the low velocity dispersion of NGC 6397 of < 5 km s(-1) imposes heavy demands on the quality of the kinematical data. We show that despite its limited spectral resolution, MUSE reaches an accuracy of 1 km s(-1) in the analysis of stellar spectra. We find slight evidence for a rotational component in the cluster and the velocity dispersion profile that we obtain shows a mild central cusp. To investigate the nature of this feature, we calculate spherical Jeans models and compare these models to our kinematical data. This comparison shows that if a constant mass-to-light ratio is assumed, the addition of an intermediate-mass black hole with a mass of 600 M-circle dot brings the model predictions into agreement with our data, and therefore could be at the origin of the velocity dispersion profile. We further investigate cases with varying mass-to-light ratios and find that a compact dark stellar component can also explain our observations. However, such a component would closely resemble the black hole from the constant mass-to-light ratio models as this component must be confined to the central similar to 5 ' of the cluster and must have a similar mass. Independent constraints on the distribution of stellar remnants in the cluster or kinematic measurements at the highest possible spatial resolution should be able to distinguish the two alternatives. KW - globular clusters: individual: NGC 6397 KW - stars: kinematics and dynamics KW - techniques: radial velocities KW - techniques: imaging spectroscopy KW - black hole physics Y1 - 2016 U6 - https://doi.org/10.1051/0004-6361/201527065 SN - 1432-0746 VL - 588 PB - EDP Sciences CY - Les Ulis ER -