Search Publications
Dark Energy Survey Year 1 results: the impact of galaxy neighbours on weak lensing cosmology with IM3SHAPE
Benoit-Lévy, A.; Bechtol, K.; Smith, M. +69 more
We use a suite of simulated images based on Year 1 of the Dark Energy Survey to explore the impact of galaxy neighbours on shape measurement and shear cosmology. The HOOPOE image simulations include realistic blending, galaxy positions, and spatial variations in depth and point spread function properties. Using the IM3SHAPE maximum-likelihood shap…
Galaxies Probing Galaxies in PRIMUS. I. Sample, Spectroscopy, and Characteristics of the z\sim 0.5 Mg II-absorbing Circumgalactic Medium
Moustakas, John; Coil, Alison L.; Diamond-Stanic, Aleksandar M. +2 more
The spectroscopy of background QSO sightlines passing close to foreground galaxies is a potent technique for studying the circumgalactic medium (CGM). However, QSOs are effectively point sources, limiting their potential to constrain the size of circumgalactic gaseous structures. Here we present the first large Keck/Low-resolution Imaging Spectrom…
Formation of dipolarization fronts after current sheet thinning
Xu, Y.; Fu, H. S.; Liu, C. M. +2 more
Dipolarization front (DF)—a sharp boundary separating hot tenuous plasmas from cold dense plasmas—is a key structure responsible for particle acceleration and energy transport in the magnetotail. How such a structure is formed has been unclear so far. Two possible mechanisms suggested in previous studies are magnetic reconnection and spontaneous f…
Modelling high-resolution ALMA observations of strongly lensed highly star-forming galaxies detected by Herschel
Cooray, A.; Farrah, D.; Marchetti, L. +12 more
We have modelled ∼0.1 arcsec resolution Atacama Large Millimetre/submillimeter Array imaging of six strong gravitationally lensed galaxies detected by the Herschel Space Observatory. Our modelling recovers mass properties of the lensing galaxies and, by determining magnification factors, intrinsic properties of the lensed submillimetre sources. We…
The Araucaria Project: High-precision Cepheid Astrophysics from the Analysis of Variables in Double-lined Eclipsing Binaries
Udalski, Andrzej; Soszyński, Igor; Thompson, Ian B. +15 more
Based on new observations and improved modeling techniques, we have reanalyzed seven Cepheids in the Large Magellanic Cloud. Improved physical parameters have been determined for the exotic system OGLE LMC-CEP-1718 composed of two first-overtone Cepheids and a completely new model was obtained for the OGLE LMC-CEP-1812 classical Cepheid. This is n…
A tale of two periods: determination of the orbital ephemeris of the super-Eddington pulsar NGC 7793 P13
Harrison, F. A.; Fabian, A. C.; Pinto, C. +10 more
We present a timing analysis of multiple XMM-Newton and NuSTAR observations of the ultra-luminous pulsar NGC 7793 P13 spread over its 65 d variability period. We use the measured pulse periods to determine the orbital ephemeris, confirm a long orbital period with Porb = 63.9+0.5-0.6 d, and find an eccentricity of e…
Does Circumgalactic O VI Trace Low-pressure Gas Beyond the Accretion Shock? Clues from H I and Low-ion Absorption, Line Kinematics, and Dust Extinction
Stern, Jonathan; Faucher-Giguère, Claude-André; Hennawi, Joseph F. +3 more
Large O VI columns are observed around star-forming low-redshift ∼ {L}* galaxies, with a dependence on impact parameter indicating that most {{{O}}}5+ particles reside beyond half the halo virial radius (≳ 100 {kpc}). In order to constrain the nature of the gas traced by {{O}} {{vi}}, we analyze additional observables of the…
Predicting Stellar-mass Black Hole Populations in Globular Clusters
Rodriguez, Carl L.; Chatterjee, Sourav; Weatherford, Newlin C. +1 more
Recent discoveries of black hole (BH) candidates in Galactic and extragalactic globular clusters (GCs) have ignited interest in understanding how BHs dynamically evolve in a GC and the number of BHs ({N}BH}) that may still be retained by today’s GCs. Numerical models show that even if stellar-mass BHs are retained in today’s GCs, they a…
A 20-year record (1998-2017) of permafrost, active layer and meteorological conditions at a high Arctic permafrost research site (Bayelva, Spitsbergen)
Hauber, Ernst; Boike, Julia; Juszak, Inge +10 more
Most permafrost is located in the Arctic, where frozen organic carbon makes it an important component of the global climate system. Despite the fact that the Arctic climate changes more rapidly than the rest of the globe, observational data density in the region is low. Permafrost thaw and carbon release to the atmosphere are a positive feedback m…
On the accuracy of mass measurement for microlensing black holes as seen by Gaia and OGLE
Rybicki, Krzysztof A.; Wyrzykowski, Łukasz; Klencki, Jakub +3 more
We investigate the impact of combining Gaia astrometry from space with precise, high cadence OGLE photometry from the ground. For the archival event OGLE3-ULENS-PAR-02, which is likely a black hole, we simulate a realistic astrometric time series of Gaia measurements and combine it with the real photometric data collected by the OGLE project. We p…