Search Publications
Enhancement of the 6.4 keV Line in the Inner Galactic Ridge: Proton-induced Fluorescence?
Koyama, K.; Tanaka, T.; Fukui, Y. +7 more
A common idea for the origin of the Galactic diffuse X-ray emission, particularly that of the iron lines from neutral and highly ionized atoms, is a superposition of many cataclysmic variables and coronally active binaries. In this scenario, the flux should symmetrically distribute between the east and west on the plane with respect to Sagittarius…
Modeled Interaction of Comet 67P/Churyumov-Gerasimenko with the Solar Wind Inside 2 AU
Ip, W. -H.; Gombosi, T. I.; Rubin, M. +4 more
Periodic comets move around the Sun on elliptical orbits. As such comet 67P/Churyumov-Gerasimenko (hereafter 67P) spends a portion of time in the inner solar system where it is exposed to increased solar insolation. Therefore given the change in heliocentric distance, in case of 67P from aphelion at 5.68 AU to perihelion at ~1.24 AU, the comet's a…
Relating the inhomogeneous power spectrum to the CMB hemispherical anisotropy
Jain, Pankaj; Rath, Pranati K.; Aluri, Pavan K.
We relate the observed hemispherical anisotropy in the cosmic microwave radiation data to an inhomogeneous power spectrum model. The hemispherical anisotropy can be parametrized in terms of the dipole modulation model. This model leads to correlations between spherical harmonic coefficients corresponding to multipoles, l and l +1 . We extract the …
The Three-dimensional Evolution of Ion-scale Current Sheets: Tearing and Drift-kink Instabilities in the Presence of Proton Temperature Anisotropy
Matteini, L.; Burgess, D.; Gingell, P. W.
We present the first three-dimensional (3D) hybrid simulations of the evolution of ion-scale current sheets, with an investigation of the role of temperature anisotropy and associated kinetic instabilities on the growth of the tearing instability and particle heating. We confirm the ability of the ion cyclotron and firehose instabilities to enhanc…
Photometric properties of Ceres from telescopic observations using Dawn Framing Camera color filters
Nathues, Andreas; Li, Jian-Yang; Reddy, Vishnu +7 more
The dwarf planet Ceres is likely differentiated similar to the terrestrial planets but with a water/ice dominated mantle and an aqueously altered crust. Detailed modeling of Ceres' phase function has never been performed to understand its surface properties. The Dawn spacecraft began orbital science operations at the dwarf planet in April 2015. We…
X-Ray Spectral Residuals in NGC 5408 X-1: Diffuse Emission from Star Formation, or the Signature of a Super-Eddington Wind?
Middleton, Matthew J.; Sutton, Andrew D.; Roberts, Timothy P.
If ultraluminous X-ray sources (ULXs) are powered by accretion onto stellar remnant black holes, then many must be accreting at super-Eddington rates. It is predicted that such high accretion rates should give rise to massive, radiatively driven winds. However, observational evidence of a wind, in the form of absorption or emission features, has r…
Observations of Near-Simultaneous Split-Band Solar Type-II Radio Bursts at Low Frequencies
Ramesh, R.; Kathiravan, C.; Hariharan, K.
We report ground-based radio spectral and polarimeter observations of two successive split-band Type-II bursts that occurred on 20 February 2014 at low frequencies (<100 MHz) in association with a solar coronal mass ejection (CME). The temporal interval between the onset of the two bursts was very small, ≈ one minute. Both of the bursts exhibit…
Evidence for (and Against) Progenitor Bias in the Size Growth of Compact Red Galaxies
Newman, Jeffrey; Graves, Genevieve; Abraham, Roberto G. +5 more
Most massive, passive galaxies are compact at high redshifts, but similarly compact massive galaxies are rare in the local universe. The most common interpretation of this phenomenon is that massive galaxies have grown in size by a factor of about five since redshift z = 2. An alternative explanation is that recently quenched massive galaxies are …
Instantaneous three-dimensional thermal structure of the South Polar Vortex of Venus
Hueso, R.; Sánchez-Lavega, A.; García Muñoz, A. +1 more
The Venus thermal radiation spectrum exhibits the signature of CO2 absorption bands. By means of inversion techniques, those bands enable the retrieval of atmospheric temperature profiles. We have analyzed VIRTIS-M-IR night-side data obtaining high-resolution thermal maps of the Venus south polar region between 55 and 85 km altitudes. T…
3C 57 as an atypical radio-loud quasar: implications for the radio-loud/radio-quiet dichotomy
Marziani, P.; Stirpe, G. M.; del Olmo, A. +4 more
Lobe-dominated radio-loud (LD RL) quasars occupy a restricted domain in the 4D Eigenvector 1 (4DE1) parameter space which implies restricted geometry/physics/kinematics for this subclass compared to the radio-quiet (RQ) majority of quasars. We discuss how this restricted domain for the LD RL parent population supports the notion for a RQ-RL dichot…