Search Publications
New Constraints on Cosmic Polarization Rotation from the ACTPol Cosmic Microwave Background B-mode Polarization Observation and the BICEP2 Constraint Update
di Serego Alighieri, Sperello; Xu, Lixin; Mei, Hsien-Hao +2 more
Recently, ACTPol measured the cosmic microwave background (CMB) B-mode and E-mode polarizations and obtained TE, EE, BB, TB, and EB power spectra in the multipole range 225-8725. In our previous paper (Paper I), we jointly analyzed the results of three experiments on the CMB B-mode polarization—SPTpol, POLARBEAR, and BICEP2—to include in the model…
Proton intensity spectra during the solar energetic particle events of May 17, 2012 and January 6, 2014
Dresing, N.; Heber, B.; Kühl, P. +4 more
Context. Ground-level enhancements (GLEs) are solar energetic particle events that show a significant intensity increase at energies that can be measured by neutron monitors. The most recent GLE-like events were recorded on May 17, 2012 and January 6, 2014. They were also measured by sophisticated instrumentation in space such as PAMELA and the El…
Transient Sulfate Aerosols as a Signature of Exoplanet Volcanism
Krissansen-Totton, Joshua; Sholes, Steven; Misra, Amit +1 more
Geological activity is thought to be important for the origin of life and for maintaining planetary habitability. We show that transient sulfate aerosols could be a signature of exoplanet volcanism, and therefore a geologically active world. A detection of transient aerosols, if linked to volcanism, could thus aid in habitability evaluations of th…
A Full Study on the Sun-Earth Connection of an Earth-directed CME Magnetic Flux Rope
Vemareddy, Panditi; Mishra, Wageesh
We present an investigation of an eruption event of a coronal mass ejection (CME) magnetic flux rope (MFR) from the source active region (AR) NOAA 11719 on 2013 April 11 utilizing observations from the Solar Dynamic Observatory, the Solar Terrestrial Relations Observatory, the Solar and Heliospheric Observatory, and the WIND spacecraft. The source…
Unveiling the nature of the γ-ray emitting active galactic nucleus PKS 0521-36
Ghisellini, G.; Pian, E.; Tosti, G. +11 more
PKS 0521-36 is an active galactic nucleus (AGN) with uncertain classification. We investigate the properties of this source from radio to γ-rays. The broad emission lines in the optical and ultraviolet bands and steep radio spectrum indicate a possible classification as an intermediate object between broad-line radio galaxies (BLRG) and steep spec…
Observational consistency and future predictions for a 3.5 keV ALP to photon line
Conlon, Joseph P.; Rummel, Markus; Alvarez, Pedro D. +2 more
Motivated by the possibility of explaining the 3.5 keV line through dark matter decaying to axion-like particles that subsequently convert to photons, we study ALP-photon conversion for sightlines passing within 50 pc of the galactic centre. Conversion depends on the galactic centre magnetic field which is highly uncertain. For fields at low or mi…
Distribution of sulphuric acid aerosols in the clouds and upper haze of Venus using Venus Express VAST and VeRa temperature profiles
Vandaele, Ann Carine; Tellmann, Silvia; Pätzold, Martin +8 more
Observations from Pioneer Venus and from SPICAV/SOIR aboard Venus Express (VEx) have shown the upper haze (UH) of Venus to be highly spatially and temporally variable, and populated by multiple particle size modes. Previous models of this system (e.g., Gao et al., 2014. Icarus 231, 83-98), using a typical temperature profile representative of the …
The high energy spectrum of 3C 273
Lähteenmäki, A.; Tramacere, A.; Walter, R. +4 more
Aims: The high energy spectrum of 3C 273 is usually understood in terms of inverse-Compton emission in a relativistic leptonic jet. This model predicts variability patterns and delays that could be tested with simultaneous observations from the radio to the GeV range.
Methods: The instruments IBIS, SPI, JEM-X on board INTEGRAL, PCA on bo…
HST/COS detection of a Ne VIII absorber towards PG 1407+265: an unambiguous tracer of collisionally ionized hot gas?
Narayanan, A.; Wakker, B. P.; Muzahid, S. +4 more
We report the detection of Ne VIII in a zabs = 0.599 61 absorber towards the QSO PG1407+265 (zem= 0.94). Besides Ne VIII, absorption from H I Lyman series lines (H I λ1025-λ915), several other low (C II, N II, O II and S II), intermediate (C III, N III, N IV, O III, S IV and S V) and high (S VI, O VI and Ne VIII) ionization m…
Shapley Supercluster Survey: Galaxy evolution from filaments to cluster cores
Okabe, N.; Bourdin, H.; Mazzotta, P. +11 more
We present an overview of a multiwavelength survey of the Shapley Supercluster (SSC; z ∼ 0.05) covering a contiguous area of 260 h^{-2}_{70} Mpc2 including the supercluster core. The project main aim is to quantify the influence of cluster-scale mass assembly on galaxy evolution in one of the most massive structures in the local Univers…