Search Publications
Constraint on the primordial gravitational waves from the joint analysis of BICEP2 and Planck HFI 353 GHz dust polarization data
Cheng, Cheng; Huang, Qing-Guo; Wang, Sai
We make a joint analysis of BICEP2 and recently released Planck HFI 353 GHz dust polarization data, and find that there is no evidence for the primordial gravitational waves and the bound on the tensor-to-scalar ratio becomes r < 0.083 at 95% confidence level in the base ΛCDM + tensor model. Extending to the model with running of scalar spectra…
The SLUGGS Survey: HST/ACS Mosaic Imaging of the NGC 3115 Globular Cluster System
Romanowsky, Aaron J.; Brodie, Jean P.; Strader, Jay +6 more
We present Hubble Space Telescope/Advanced Camera for Surveys (HST/ACS) g and z photometry and half-light radii R h measurements of 360 globular cluster (GC) candidates around the nearby S0 galaxy NGC 3115. We also include Subaru/Suprime-Cam g, r, and i photometry of 421 additional candidates. The well-established color bimodality of th…
Feedback, scatter and structure in the core of the PKS 0745-191 galaxy cluster
Fabian, A. C.; Hlavacek-Larrondo, J.; Russell, H. R. +5 more
We present Chandra X-ray Observatory observations of the core of the galaxy cluster PKS 0745-191. Its centre shows X-ray cavities caused by AGN feedback and cold fronts with an associated spiral structure. The cavity energetics imply they are powerful enough to compensate for cooling. Despite the evidence for AGN feedback, the Chandra and XMM-RGS …
Alleviating the tension at low ℓ through axion monodromy
Meerburg, P. Daniel
There exists some tension on large scales between the Planck data and the ΛCDM concordance model of the Universe, which has been amplified by the recently claimed discovery of nonzero tensor-to-scalar ratio r. At the same time, the current best-fit value of r suggests large field inflation Δϕinf>Mp, which requires a U…
Fomalhaut b as A Cloud of Dust: Testing Aspects of Planet Formation Theory
Currie, Thayne; Kenyon, Scott J.; Bromley, Benjamin C.
We consider the ability of three models—impacts, captures, and collisional cascades—to account for a bright cloud of dust in Fomalhaut b. Our analysis is based on a novel approach to the power-law size distribution of solid particles central to each model. When impacts produce debris with (1) little material in the largest remnant and (2) a steep …
X-ray reflection in oxygen-rich accretion discs of ultracompact X-ray binaries
Fabian, A. C.; García, J.; Parker, M. L. +4 more
We present spectroscopic X-ray data of two candidate ultracompact X-ray binaries (UCXBs): 4U 0614+091 and 4U 1543-624. We confirm the presence of a broad O VIII Lyα reflection line (at ≈18 Å) using XMM-Newton and Chandra observations obtained in 2012 and 2013. The donor star in these sources is a carbon-oxygen or oxygen-neon-magnesium white dwarf.…
Multispacecraft Cluster observations of quasiperiodic emissions close to the geomagnetic equator
Pickett, J. S.; Santolík, O.; Němec, F.
We present a detailed analysis of three electromagnetic wave events observed by the Cluster Wide-Band Data instruments at frequencies of a few kilohertz, which exhibit a periodic time modulation of the wave intensity (quasiperiodic emissions). The events were measured when crossing the geomagnetic equator at radial distances of about 3-4 RE
Anomalous dynamics of the extremely compressed magnetosphere during 21 January 2005 magnetic storm
Veselovsky, I. S.; Myagkova, I. N.; Dmitriev, A. V. +7 more
The dayside magnetosphere and proton radiation belt were analyzed during unusual magnetic storm on 21 January 2005. We have found that from 1712 to 2400 UT, the subsolar magnetopause was continuously located inside geosynchronous orbit due to strong compression. The compression was extremely strong from 1846 to 2035 UT when the dense plasma of fas…
Extra-nuclear Starbursts: Young Luminous Hinge Clumps in Interacting Galaxies
Soria, Roberto; Swartz, Douglas A.; Struck, Curtis +3 more
Hinge clumps are luminous knots of star formation near the base of tidal features in some interacting galaxies. We use archival Hubble Space Telescope (HST) UV/optical/IR images and Chandra X-ray maps along with Galaxy Evolution Explorer UV, Spitzer IR, and ground-based optical/near-IR images to investigate the star forming properties in a sample …
Floor-Fractured Craters on Mars - Observations and Origin
Jaumann, R.; Michael, G. G.; Kneissl, T. +2 more
Floor-Fractured Craters (FFCs) represent an impact crater type, where the infilling is separated by cracks into knobs of different sizes and shapes. This work focuses on the possible processes which form FFCs to understand the relationship between location and geological environment. We generated a global distribution map using new High Resolution…