Search Publications
What drives the dust activity of comet 67P/Churyumov-Gerasimenko?
Blum, J.; Gundlach, B.; Keller, H. U. +1 more
Context. The gas-driven dust activity of comets is still an unsolved question in cometary physics. Homogeneous dust layers composed of micrometer-sized grains possess tensile strengths of ~1 kPa, which is far higher than typical gas pressures caused by the sublimation of the ices beneath the covering dust layer. This implies that the dust grains c…
The Panchromatic Hubble Andromeda Treasury. VIII. A Wide-area, High-resolution Map of Dust Extinction in M31
Bell, Eric F.; Gouliermis, Dimitrios A.; Skillman, Evan D. +15 more
We map the distribution of dust in M31 at 25 pc resolution using stellar photometry from the Panchromatic Hubble Andromeda Treasury survey. The map is derived with a new technique that models the near-infrared color-magnitude diagram (CMD) of red giant branch (RGB) stars. The model CMDs combine an unreddened foreground of RGB stars with a reddened…
Comparison of 3D kinetic and hydrodynamic models to ROSINA-COPS measurements of the neutral coma of 67P/Churyumov-Gerasimenko
De Keyser, Johan; Berthelier, Jean-Jacques; Fiethe, Björn +22 more
67P/Churyumov-Gerasimenko (67P) is a Jupiter-family comet and the object of investigation of the European Space Agency mission Rosetta. This report presents the first full 3D simulation results of 67P's neutral gas coma. In this study we include results from a direct simulation Monte Carlo method, a hydrodynamic code, and a purely geometric calcul…
redMaPPer - III. A detailed comparison of the Planck 2013 and SDSS DR8 redMaPPer cluster catalogues
Rykoff, E. S.; Rozo, E.; Melin, Jean-Baptiste +1 more
We compare the Planck Sunyaev-Zeldovich (SZ) cluster sample (PSZ1) to the Sloan Digital Sky Survey (SDSS) redMaPPer catalogue, finding that all Planck clusters within the redMaPPer mask and within the redshift range probed by redMaPPer are contained in the redMaPPer cluster catalogue. These common clusters define a tight scaling relation in the ri…
The Extended GMRT Radio Halo Survey. II. Further results and analysis of the full sample
Brunetti, G.; Kale, R.; Giacintucci, S. +6 more
The intra-cluster medium contains cosmic rays and magnetic fields that are manifested through the large scale synchrotron sources, termed radio haloes, relics, and mini-haloes. The Extended Giant Metrewave Radio Telescope (GMRT) Radio Halo Survey (EGRHS) is an extension of the GMRT Radio Halo Survey (GRHS) designed to search for radio haloes using…
GIADA: shining a light on the monitoring of the comet dust production from the nucleus of 67P/Churyumov-Gerasimenko
Lamy, P. L.; Fulle, M.; Rodrigo, R. +37 more
Context. During the period between 15 September 2014 and 4 February 2015, the Rosetta spacecraft accomplished the circular orbit phase around the nucleus of comet 67P/Churyumov-Gerasimenko (67P). The Grain Impact Analyzer and Dust Accumulator (GIADA) onboard Rosetta monitored the 67P coma dust environment for the entire period.
Aims: We aim t…
Revised Filter Profiles and Zero Points for Broadband Photometry
Mann, Andrew W.; von Braun, Kaspar
Estimating accurate bolometric fluxes for stars requires reliable photometry to absolutely flux calibrate the spectra. This is a significant problem for studies of very bright stars, which are generally saturated in modern photometric surveys. Instead we must rely on photometry with less precise calibration. We utilize precisely flux-calibrated sp…
The Cause of the Weak Solar Cycle 24
Schüssler, M.; Jiang, J.; Cameron, R. H.
The ongoing 11 year cycle of solar activity is considerably less vigorous than the three cycles before. It was preceded by a very deep activity minimum with a low polar magnetic flux, the source of the toroidal field responsible for solar magnetic activity in the subsequent cycle. Simulation of the evolution of the solar surface field shows that t…
Compton thick AGN in the XMM-COSMOS survey
Berta, S.; Pozzi, F.; Georgakakis, A. +27 more
Heavily obscured, Compton thick (CT, NH> 1024 cm-2) active galactic nuclei (AGN) may represent an important phase in AGN/galaxy co-evolution and are expected to provide a significant contribution to the cosmic X-ray background at its peak. However, unambiguously identifying CT AGN beyond the local Universe is a …
Relation between fine structure of energy spectra for pulsating aurora electrons and frequency spectra of whistler mode chorus waves
Asamura, K.; Santolik, O.; Ebihara, Y. +10 more
We investigate the origin of the fine structure of the energy spectrum of precipitating electrons for the pulsating aurora (PsA) observed by the low-altitude Reimei satellite. The Reimei satellite achieved simultaneous observations of the optical images and precipitating electrons of the PsA from satellite altitude (~620 km) with resolution of 40 …