Search Publications
A Chandra X-ray Observatory Study of PSR J1740-5340 and Candidate Millisecond Pulsars in the Globular Cluster NGC 6397
Bogdanov, Slavko; Heinke, Craig O.; Cohn, Haldan N. +3 more
We present a deep Chandra X-ray Observatory study of the peculiar binary radio millisecond pulsar (MSP) PSR J1740-5340 and candidate millisecond pulsars in the globular cluster NGC 6397. The X-rays from PSR J1740-5340 appear to be non-thermal and exhibit variability at the binary period. These properties suggest the presence of a relativistic intr…
Magnetic Bright Points in the Quiet Sun
Sánchez Almeida, J.; Del Moro, D.; Bonet, J. A. +1 more
We present a visual determination of the number of bright points (BPs) existing in the quiet Sun, which are structures though to trace intense kG magnetic concentrations. The measurement is based on a 0farcs1 angular resolution G-band movie obtained with the Swedish Solar Telescope at the solar disk center. We find 0.97 BPs Mm-2, which …
Evolution of the Solar Activity Over Time and Effects on Planetary Atmospheres. II. κ1 Ceti, an Analog of the Sun when Life Arose on Earth
Ribas, I.; de Medeiros, J. R.; Porto de Mello, G. F. +6 more
The early evolution of Earth's atmosphere and the origin of life took place at a time when physical conditions at the Earth were radically different from its present state. The radiative input from the Sun was much enhanced in the high-energy spectral domain, and in order to model early planetary atmospheres in detail, a knowledge of the solar rad…
Spitzer View of Young Massive Stars in the Large Magellanic Cloud H II Complexes. II. N 159
Meixner, Margaret; Chu, You-Hua; Sewilo, Marta +6 more
The H II complex N 159 in the Large Magellanic Cloud is used to study massive star formation in different environments, as it contains three giant molecular clouds (GMCs) that have similar sizes and masses but exhibit different intensities of star formation. We identify candidate massive young stellar objects (YSOs) using infrared photometry, and …
AKARI and BLAST Observations of the Cassiopeia A Supernova Remnant and Surrounding Interstellar Medium
Ade, P. A. R.; Bock, J. J.; Martin, P. G. +30 more
We use new large area far infrared maps ranging from 65 to 500 µm obtained with the AKARI and the Balloon-borne Large Aperture Submillimeter Telescope missions to characterize the dust emission toward the Cassiopeia A supernova remnant (SNR). Using the AKARI high-resolution data we find a new "tepid" dust grain population at a temperature of…
Unveiling the Three-dimensional Structure of Galaxy Clusters: Resolving the Discrepancy Between X-ray and Lensing Masses
Limousin, Marceau; Morandi, Andrea; Pedersen, Kristian
We present the first determination of the intrinsic three-dimensional (3D) shapes and the physical parameters of both dark matter (DM) and intracluster medium (ICM) in a triaxial galaxy cluster. While most previous studies rely on the standard spherical modeling, our approach allows us to infer the properties of the non-spherical intracluster gas …
A Detailed Spectropolarimetric Analysis of the Planet-hosting Star WASP-12
Fossati, L.; Hebb, L.; Kochukhov, O. +9 more
The knowledge of accurate stellar parameters is paramount in several fields of stellar astrophysics, particularly in the study of extrasolar planets, where often the star is the only visible component and therefore used to infer the planet's fundamental parameters. Another important aspect of the analysis of planetary systems is the stellar activi…
Three-Dimensional View of Transient Horizontal Magnetic Fields in the Photosphere
Tsuneta, Saku; Jurčák, Jan; Ishikawa, Ryohko
We infer the three-dimensional magnetic structure of a transient horizontal magnetic field (THMF) during its evolution through the photosphere using SIRGAUS inversion code. The SIRGAUS code is a modified version of SIR (Stokes Inversion based on Response function), and allows for retrieval of information on the magnetic and thermodynamic parameter…
The Sparsest Clusters with O Stars
Oey, M. S.; Werk, J. K.; Lamb, J. B. +1 more
There is much debate on how high-mass star formation varies with environment, and whether the sparsest star-forming environments are capable of forming massive stars. To address this issue, we have observed eight apparently isolated OB stars in the Small Magellanic Cloud (SMC) using Hubble Space Telescope's Advanced Camera for Surveys. Five of the…
The Stellar Kinematic Center and the True Galactic Nucleus of NGC 253
Prieto, M. A.; Acosta-Pulido, J. A.; González-Martín, O. +2 more
We present the first sub-arcsecond resolution two-dimensional stellar kinematics and X-ray observations of the prototypical starburst galaxy NGC 253 which define the position and nature of the galactic nucleus. These observations comprise some of the best probes of the central 300 pc of NGC 253, the nearest massive galaxy undergoing a powerful sta…