Search Publications
Testing linear theory of EMIC waves in the inner magnetosphere: Cluster observations
Sauvaud, J. -A.; Klecker, B.; Kistler, L. M. +8 more
In this paper, we test whether time periods with hot proton temperature anisotropy are associated with electromagnetic ion cyclotron (EMIC) waves and whether the plasma conditions during the observed waves satisfy the linear theory threshold condition. We identify 865 events observed by the Composition Distribution Function instrument onboard Clus…
Hubble Space Telescope Pre-perihelion ACS/WFC Imaging Polarimetry of Comet Ison (c/2012 s1) at 3.81 AU
Mutchler, Max; Muinonen, Karri; Hines, Dean C. +9 more
We present polarization images of Comet ISON (C/2012 S1) taken with the Hubble Space Telescope (HST) on UTC 2013 May 8 (r h = 3.81 AU, Δ = 4.34 AU), when the phase angle was α ≈ 12.°16. This phase angle is approximately centered in the negative polarization branch for cometary dust. The region beyond 1000 km (~0.32 arcsec ≈ 6 pixels) fr…
The behaviour of quasar C IV emission-line properties with orientation
Shang, Zhaohui; Brotherton, M. S.; Runnoe, Jessie C. +1 more
With a quasar sample designed for studying orientation effects, we investigate the orientation dependence characteristics of the C IV λ1549 broad emission line in approximately 50 Type 1 quasars with z = 0.1-1.4. Understanding the role that orientation plays in determining the observed ultraviolet spectra in quasars is of interest both for the ins…
ALMA and Herschel observations of the prototype dusty and polluted white dwarf G29-38
Wyatt, M. C.; Bonsor, A.; Sibthorpe, B. +3 more
ALMA Cycle 0 and Herschel1 PACS observations are reported for the prototype, nearest, and brightest example of a dusty and polluted white dwarf, G29-38. These long-wavelength programmes attempted to detect an outlying, parent population of bodies at 1-100 au, from which originates the disrupted planetesimal debris that is observed withi…
Strong Chromatic Microlensing in HE0047-1756 and SDSS1155+6346
Muñoz, J. A.; Mediavilla, E.; Rojas, K. +3 more
We use spectra of the double-lensed quasars HE0047-1756 and SDSS1155+6346 to study their unresolved structure through the impact of microlensing. There is no significant evidence of microlensing in the emission line profiles except for the Lyα line of SDSS1155+6346, which shows strong differences in the shapes for images A and B. However, the cont…
Neutral Interstellar Helium Parameters Based on Ulysses/GAS and IBEX-Lo Observations: What are the Reasons for the Differences?
Wood, B. E.; Katushkina, O. A.; Izmodenov, V. V. +1 more
Recent analysis of the interstellar helium fluxes measured in 2009-2010 at Earth's orbit by the Interstellar Boundary Explorer (IBEX) has suggested that the interstellar velocity (both direction and magnitude) is inconsistent with that derived previously from Ulysses/GAS observations made in the period from 1990 to 2002 at 1.5-5.5 AU from the Sun.…
Suppressing CMB low multipoles with ISW effect
Das, Santanu; Souradeep, Tarun
Recent results of Planck data reveal that the power [1,2] in the low multipoles of the CMB angular power spectrum, approximately up to l = 30, is significantly lower than the theoretically predicted in the best fit ΛCDM model. There are different known physical effects that can affect the power at low multipoles, such as features in the primordial…
Axion cold dark matter: Status after Planck and BICEP2
Di Valentino, Eleonora; Melchiorri, Alessandro; Mena, Olga +2 more
We investigate the axion dark matter scenario (ADM), in which axions account for all of the dark matter in the Universe, in light of the most recent cosmological data. In particular, we use the Planck temperature data, complemented by WMAP E-polarization measurements, as well as the recent BICEP2 observations of B-modes. Baryon acoustic oscillatio…
Plasma and energetic particle behaviors during asymmetric magnetic reconnection at the magnetopause
Glassmeier, K. -H.; Zhang, H.; Zong, Q. -G. +6 more
The factors controlling asymmetric reconnection and the role of the cold plasma population in the reconnection process are two outstanding questions. We present a case study of multipoint Cluster observations demonstrating that the separatrix and flow boundary angles are greater on the magnetosheath than on the magnetospheric side of the magnetopa…
Extreme Blazars Studied with Fermi-LAT and Suzaku: 1ES 0347-121 and Blazar Candidate HESS J1943+213
Cheung, C. C.; Fukazawa, Y.; Kataoka, J. +9 more
We report on our study of high-energy properties of two peculiar TeV emitters: the "extreme blazar" 1ES 0347-121 and the "extreme blazar candidate" HESS J1943+213 located near the Galactic plane. Both objects are characterized by quiescent synchrotron emission with flat spectra extending up to the hard X-ray range, and both were reported to be mis…