TY  - JOUR
A1  - Merz, Bruno
A1  - Aerts, Jeroen C. J. H.
A1  - Arnbjerg-Nielsen, Karsten
A1  - Baldi, M.
A1  - Becker, Andrew C.
A1  - Bichet, A.
A1  - Bloeschl, G.
A1  - Bouwer, Laurens M.
A1  - Brauer, Achim
A1  - Cioffi, F.
A1  - Delgado, Jose Miguel Martins
A1  - Gocht, M.
A1  - Guzzetti, F.
A1  - Harrigan, S.
A1  - Hirschboeck, K.
A1  - Kilsby, C.
A1  - Kron, W.
A1  - Kwon, H. -H.
A1  - Lall, U.
A1  - Merz, R.
A1  - Nissen, K.
A1  - Salvatti, P.
A1  - Swierczynski, Tina
A1  - Ulbrich, U.
A1  - Viglione, A.
A1  - Ward, P. J.
A1  - Weiler, M.
A1  - Wilhelm, B.
A1  - Nied, Manuela
T1  - Floods and climate: emerging perspectives for flood risk assessment and management
JF  - Natural hazards and earth system sciences
N2  - Flood estimation and flood management have traditionally been the domain of hydrologists, water resources engineers and statisticians, and disciplinary approaches abound. Dominant views have been shaped; one example is the catchment perspective: floods are formed and influenced by the interaction of local, catchment-specific characteristics, such as meteorology, topography and geology. These traditional views have been beneficial, but they have a narrow framing. In this paper we contrast traditional views with broader perspectives that are emerging from an improved understanding of the climatic context of floods. We come to the following conclusions: (1) extending the traditional system boundaries (local catchment, recent decades, hydrological/hydraulic processes) opens up exciting possibilities for better understanding and improved tools for flood risk assessment and management. (2) Statistical approaches in flood estimation need to be complemented by the search for the causal mechanisms and dominant processes in the atmosphere, catchment and river system that leave their fingerprints on flood characteristics. (3) Natural climate variability leads to time-varying flood characteristics, and this variation may be partially quantifiable and predictable, with the perspective of dynamic, climate-informed flood risk management. (4) Efforts are needed to fully account for factors that contribute to changes in all three risk components (hazard, exposure, vulnerability) and to better understand the interactions between society and floods. (5) Given the global scale and societal importance, we call for the organization of an international multidisciplinary collaboration and data-sharing initiative to further understand the links between climate and flooding and to advance flood research.
Y1  - 2014
U6  - https://doi.org/10.5194/nhess-14-1921-2014
SN  - 1561-8633
VL  - 14
IS  - 7
SP  - 1921
EP  - 1942
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Bomans, Dominik J.
A1  - Becker, Andrew C.
A1  - Kleemann, B.
A1  - Weis, K.
A1  - Pasquali, A.
T1  - Luminous Wolf-Rayet stars at low metallicity
JF  - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015
N2  - The evolution of massive stars in very low metallicity galaxies is less well observationally
constrained than in environments more similar to the Milky Way, M33, or the LMC. We discuss
in this contribution the current state of our program to search for and characterize Wolf-Rayet stars (and other massive emission line stars) in low metallicity galaxies in the Local Volume.
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87635
SP  - 51
EP  - 54
ER  - 
TY  - JOUR
A1  - Bersier, David
A1  - Fruchter, Andrew S.
A1  - Strolger, Louis-Gregory
A1  - Gorosabel, Javier
A1  - Levan, Andrew
A1  - Burud, Ingunn
A1  - Rhoads, James E.
A1  - Becker, Andrew C.
A1  - Cassan, Andrew C.
A1  - Chornock, Ryan
A1  - Covino, Stefano
A1  - De Jong, Roelof S.
A1  - Dominis, Dijana
A1  - Filippenko, Alexei V.
A1  - Hjorth, Jens
A1  - Holmberg, Johan
A1  - Malesani, Daniele
A1  - Mobasher, Bahram
A1  - Olsen, Kurt A. G.
A1  - Stefanon, Mauro
A1  - Castro Cerón, José María C.
A1  - Fynbo, Johan P. U.
A1  - Holland, Stephen T.
A1  - Kouveliotou, Chryssa
A1  - Pedersen, Hans-Georg
A1  - Tanvir, Nieal R.
A1  - Woosley, S. E.
T1  - Evidence for a supernova associated with the X-ray flash 020903
N2  - We present ground-based and Hubble Space Telescope optical observations of the X-ray flash ( XRF) 020903, covering 300 days. The afterglow showed a very rapid rise in the first day, followed by a relatively slow decay in the next few days. There was a clear bump in the light curve after similar to 25 days, accompanied by a drastic change in the spectral energy distribution. The light curve and the spectral energy distribution are naturally interpreted as describing the emergence and subsequent decay of a supernova ( SN), similar to SN 1998bw. At peak luminosity, the SN is estimated to be 0.8 +/- 0.1 mag fainter than SN 1998bw. This argues in favor of the existence of a SN associated with this XRF. A spectrum obtained 35 days after the burst shows emission lines from the host galaxy. We use this spectrum to put an upper limit on the oxygen abundance of the host at [O/H] <= 0.6 dex. We also discuss a possible trend between the softness of several bursts and the early behavior of the optical afterglow, in the sense that XRFs and X-ray-rich gamma- ray bursts ( GRBs) seem to have a plateau phase or even a rising light curve. This can be naturally explained in models in which XRFs are similar to GRBs but are seen off the jet axis.
Y1  - 2006
UR  - http://iopscience.iop.org/0004-637X/
U6  - https://doi.org/10.1086/502640
SN  - 0004-637X
ER  - 
TY  - JOUR
A1  - Becker, Andrew C.
A1  - Bomans, Dominik J.
A1  - Weis, K.
T1  - Finding new Wolf-Rayet stars in the Magellanic Clouds
JF  - Wolf-Rayet Stars : Proceedings of an International Workshop held in Potsdam, Germany, 1.–5. June 2015
N2  - Obtaining a complete census of massive, evolved stars in a galaxy would be a key ingredient for testing stellar evolution models. However, as the evolution of stars is also strongly dependent on their metallicity, it is inevitable to have this kind of data for a variety of galaxies with different metallicities. Between 2009 and 2011, we conducted the Magellanic Clouds Massive Stars and Feedback Survey (MSCF); a spatially complete, multi-epoch, broad- and narrow-band optical imaging survey of the Large and Small Magellanic Clouds. With the inclusion of shallow images, we are able to give a complete photometric catalog of stars between B ≈ 18 and B ≈ 19 mag.
These observations were augmented with additional photometric data of similar spatial res-
olution from UV to IR (e.g. from GALEX, 2MASS and Spitzer) in order to sample a large portion of the spectral energy distribution of the brightest stars (B < 16 mag) in the Magel- lanic Clouds. Using these data, were are able to train a machine learning algorithm that gives us a good estimate of the spectral type of tens of thousands of stars.
This method can be applied to the search for Wolf-Rayet-Stars to obtain a sample of candi- dates for follow-up observations. As this approach can, in principle, be adopted for any resolved galaxy as long as sufficient photometric data is available, it can form an effective alternative method to the classical strategies (e.g. He II filter imaging).
Y1  - 2015
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-87618
SP  - 47
EP  - 50
ER  -