Search Publications
Planck Lensing and Cosmic Infrared Background Cross-correlation with Fermi-LAT: Tracing Dark Matter Signals in the Gamma-ray Background
Cooray, Asantha; Feng, Chang; Keating, Brian
The extragalactic γ-ray background and its spatial anisotropy could potentially contain a signature of dark matter (DM) annihilation or particle decay. Astrophysical foregrounds, such as blazars and star-forming galaxies (SFGs), however, dominate the γ-ray background, precluding an easy detection of the signal associated with the DM annihilation o…
Planck limits on non-canonical generalizations of large-field inflation models
Stein, Nina K.; Kinney, William H.
In this paper, we consider two case examples of Dirac-Born-Infeld (DBI) generalizations of canonical large-field inflation models, characterized by a reduced sound speed, cS < 1. The reduced speed of sound lowers the tensor-scalar ratio, improving the fit of the models to the data, but increases the equilateral-mode non-Gaussianity, …
Towards the origin of the radio emission in AR Scorpii, the first radio-pulsing white dwarf binary
Marsh, T. R.; Marcote, B.; Stanway, E. R. +2 more
Context. The binary system AR Sco contains an M star and the only known radio-pulsing white dwarf. The system shows emission from radio to X-rays, likely dominated by synchrotron radiation. The mechanism that produces most of this emission remains unclear. Two competing scenarios have been proposed: collimated outflows, and direct interaction betw…
A systematic analysis of the XMM-Newton background: IV. Origin of the unfocused and focused components
Tiengo, A.; Rossetti, M.; Moretti, A. +6 more
We show the results obtained in the FP7 European program EXTraS and in the ESA R&D ATHENA activity AREMBES aimed at a deeper understanding of the XMM-Newton background to better design the ATHENA mission. Thanks to an analysis of the full EPIC archive coupled to the information obtained by the Radiation Monitor we show the cosmic ray origin of…
Limits to the presence of transiting circumbinary planets in CoRoT Data
Csizmadia, Sz.; Cabrera, J.; Klagyivik, P. +2 more
Aims: During its flight phase, from 2007-2012, the CoRoT mission delivered light curves for over 2000 eclipsing binaries. Data from the Kepler mission have proven the existence of several transiting circumbinary planets. While light curves from CoRoT typically have lower precision and shorter coverage, the number of CoRoT targets is similar t…
Swift J164449.3+573451 and Swift J2058.4+0516: Black hole mass estimates for tidal disruption event sources
Titarchuk, Lev; Seifina, Elena; Virgilli, Enrico
A tidal disruption event (TDE) is an astronomical phenomenon in which a previously dormant black hole (BH) destroys a star passing too close to its central part. We analyzed the flaring episode detected from the TDE sources, Swift J164449.3+573451 and Swift J2058.4+0516 (hereafter Swift J1644+57 and Swift J2058+05, respectively) using RXTE, Swift …
Development of an ensemble Kalman filter data assimilation system for the Venusian atmosphere
Sugimoto, Norihiko; Takagi, Masahiro; Kouyama, Toru +3 more
The size and mass of Venus is similar to those of the Earth; however, its atmospheric dynamics are considerably different and they are poorly understood due to limited observations and computational difficulties. Here, we developed a data assimilation system based on the local ensemble transform Kalman filter (LETKF) for a Venusian Atmospheric GCM…
Discovery of Galactic O iv and O v X-ray absorption due to transition temperature gas in the PKS 2155-304 spectrum
Kaastra, J.; Bonamente, M.; Paerels, F. +4 more
Far-ultraviolet (FUV) observations have revealed transition temperature gas (TTG; log T(K) 5), located in the lower Galactic halo and in high-velocity clouds. However, the corresponding X-ray absorption has so far remained mostly undetected. In order to make an improvement in this respect in Galactic X-ray absorption studies, we accumulated very d…
New observational limits on dark radiation in braneworld cosmology
Mathews, Grant J.; Kusakabe, Motohiko; Gangopadhyay, Mayukh Raj +1 more
A dark radiation term arises as a correction to the energy-momentum tensor in the simplest five-dimensional RS-II brane-world cosmology. In this paper we revisit the constraints on dark radiation based upon the newest results for light element nuclear reaction rates, observed light element abundances, and the power spectrum of the cosmic microwave…
Physical properties of seven binary and higher-order multiple OB systems
Mayer, Pavel; Harmanec, Petr; Chini, Rolf +7 more
Analyses of multi-epoch, high-resolution (R 50 000) optical spectra of seven early-type systems provided various important new insights with respect to their multiplicity. First determinations of orbital periods were made for HD 92206 C (2.^d022), HD 112244 (27.^d665), HD 164438 (10.^d25), HD 123056 A ( 1314 d) and HD 123056 B (<2 d); the orbit…