Search Publications
Globular cluster clustering and tidal features around ultra-compact dwarf galaxies in the halo of NGC 1399
Hilker, Michael; Voggel, Karina; Richtler, Tom
We present a novel approach to constrain the formation channels of ultra-compact dwarf galaxies (UCDs). They most probably are an inhomogeneous class of objects, composed of remnants of tidally stripped dwarf elliptical galaxies and star clusters that occupy the high mass end of the globular cluster luminosity function. We use three methods to unr…
Disentangling the ICL with the CHEFs: Abell 2744 as a Case Study
Jiménez-Teja, Y.; Dupke, R.
Measurements of the intracluster light (ICL) are still prone to methodological ambiguities, and there are multiple techniques in the literature to address them, mostly based on the binding energy, the local density distribution, or the surface brightness. A common issue with these methods is the a priori assumption of a number of hypotheses on eit…
MC2: Mapping the Dark Matter Distribution of the "Toothbrush" Cluster RX J0603.3+4214 with Hubble Space Telescope and Subaru Weak Lensing
Bradač, Maruša; Dawson, William A.; Jee, M. James +5 more
The galaxy cluster RX J0603.3+4214 at z = 0.225 is one of the rarest clusters boasting an extremely large (∼2 Mpc) radio relic. Because of the remarkable morphology of the relic, the cluster is nicknamed the “Toothbrush Cluster.” Although the cluster's underlying mass distribution is one of the critical pieces of information needed to reconstruct …
An HST Survey for 100-1000 au Companions around Young Stellar Objects in the Orion Molecular Clouds: Evidence for Environmentally Dependent Multiplicity
Megeath, S. T.; Hartmann, L.; Fischer, W. J. +2 more
We present a near-infrared survey for the visual multiples in the Orion molecular clouds region at separations between 100 and 1000 au. These data were acquired at 1.6 µm with the NICMOS and WFC3 cameras on the Hubble Space Telescope. Additional photometry was obtained for some of the sources at 2.05 µm with NICMOS and in the L‧ band w…
Shock Connectivity in the August 2010 and July 2012 Solar Energetic Particle Events Inferred from Observations and ENLIL Modeling
Luhmann, J. G.; Jian, L. K.; Odstrcil, D. +3 more
During periods of increased solar activity, coronal mass ejections (CMEs) can occur in close succession and proximity to one another. This can lead to the interaction and merger of CME ejecta as they propagate in the heliosphere. The particles accelerated in these shocks can result in complex solar energetic particle (SEP) events, as observing spa…
Super- and sub-Eddington accreting massive black holes: a comparison of slim and thin accretion discs through study of the spectral energy distribution
Netzer, H.; Castelló-Mor, N.; Kaspi, S.
We employ optical and ultraviolet (UV) observations to present spectral energy distributions (SEDs) for two reverberation-mapped samples of super-Eddington and sub-Eddington active galactic nuclei (AGN) with similar luminosity distributions. The samples are fitted with accretion disc (AD) models in order to look for SED differences that depend on …
Cosmic troublemakers: the Cold Spot, the Eridanus supervoid, and the Great Walls
García-Bellido, Juan; Kovács, András
The alignment of the CMB Cold Spot and the Eridanus supervoid suggests a physical connection between these two relatively rare objects. We use galaxy catalogues with photometric (2MPZ) and spectroscopic (6dF) redshift measurements, supplemented by low-redshift compilations of cosmic voids, in order to improve the 3D mapping of the matter density i…
Planck intermediate results. XXXVI. Optical identification and redshifts of Planck SZ sources with telescopes at the Canary Islands observatories
Böhringer, H.; Kneissl, R.; Dahle, H. +188 more
We present the results of approximately three years of observations of Planck Sunyaev-Zeldovich (SZ) sources with telescopes at the Canary Islands observatories as part of the general optical follow-up programme undertaken by the Planck Collaboration. In total, 78 SZ sources are discussed. Deep-imaging observations were obtained for most of these …
Information gain on reheating: The one bit milestone
Ringeval, Christophe; Martin, Jérôme; Vennin, Vincent
We show that the Planck 2015 and BICEP2/KECK measurements of the cosmic microwave background (CMB) anisotropies provide together an information gain of 0.82 ±0.13 bits on the reheating history over all slow-roll single-field models of inflation. This corresponds to a 40% improvement compared to the Planck 2013 constraints on the reheating. Our met…
Titan's "Magic Islands": Transient features in a hydrocarbon sea
Soderblom, Jason M.; Lorenz, Ralph D.; Malaska, Michael J. +6 more
The region of Titan's hydrocarbon sea, Ligeia Mare, where transient bright features were previously discovered, was anomalously bright in the first of two more recent Cassini RADAR observations but not the second. Another transient bright feature in a different region of Ligeia Mare was also discovered in the first of the new observations. Here we…