Search Publications
Toward Precision Photometry for the ELT Era: The Double Subgiant Branch of NGC 1851 Observed with the Gemini/GeMS MCAO System
Stetson, P. B.; Bono, G.; Fiorentino, G. +4 more
The Extremely Large Telescopes currently under construction have a collecting area that is an order of magnitude larger than the present largest optical telescopes. For seeing-limited observations the performance will scale as the collecting area, but with the successful use of adaptive optics (AO), for many applications it will scale as D4
A Measurement of Diffusion in 47 Tucanae
Richer, Harvey B.; Heyl, Jeremy; Kalirai, Jason +4 more
Using images from the Hubble Space Telescope Wide-Field Camera 3, we measure the rate of diffusion of stars through the core of the globular cluster 47 Tucanae (47 Tuc) using a sample of young white dwarfs that were identified in these observations. This is the first direct measurement of diffusion due to gravitational relaxation. We find that the…
On the Enhanced Coronal Mass Ejection Detection Rate since the Solar Cycle 23 Polar Field Reversal
Petrie, G. J. D.
Compared to cycle 23, coronal mass ejections (CMEs) with angular widths >30° have been observed to occur at a higher rate during solar cycle 24, per sunspot number. This result is supported by data from three independent databases constructed using Large Angle and Spectrometric Coronagraph Experiment coronagraph images, two employing automated …
Spectrum of Relativistic and Subrelativistic Cosmic Rays in the 100 pc Central Region
Cheng, K. S.; Hui, C. Y.; Nobukawa, M. +6 more
From the rate of hydrogen ionization and the gamma-ray flux, we derived the spectrum of relativistic and subrelativistic cosmic rays (CRs) nearby and inside the molecular cloud Sgr B2 near the Galactic Center. We studied two cases of CR propagation in molecular clouds: free propagation and scattering of particles by magnetic fluctuations excited b…
Panchromatic Hubble Andromeda Treasury. XIV. The Period-Age Relationship of Cepheid Variables in M31 Star Clusters
Williams, Benjamin F.; Johnson, L. Clifton; Dolphin, Andrew +6 more
We present a sample of 11 M31 Cepheids in stellar clusters, derived from the overlap of the Panchromatic Hubble Andromeda Treasury cluster catalog and the Pan-STARRS1 (PS1) disk Cepheid catalog. After identifying the PS1 Cepheids in the Hubble Space Telescope (HST) catalog, we calibrate the PS1 mean magnitudes using the higher resolution HST photo…
Dispersal of G-band Bright Points at Different Longitudinal Magnetic Field Strengths
Yang, Yunfei; Feng, Song; Wang, Feng +3 more
G-band bright points (GBPs) are thought to be the foot-points of magnetic flux tubes. The aim of this paper is to investigate the relation between the diffusion regimes of GBPs and the associated longitudinal magnetic field strengths. Two high resolution observations of different magnetized environments were acquired with the Hinode/Solar Optical …
Evolution of Intermittency in the Slow and Fast Solar Wind beyond the Ecliptic Plane
Bruno, R.; Wawrzaszek, A.; Macek, W. M. +1 more
We study intermittency as a departure from self-similarity of the solar wind magnetic turbulence and investigate the evolution with the heliocentric distance and latitude. We use data from the Ulysses spacecraft measured during two solar minima (1997-1998 and 2007-2008) and one solar maximum (1999-2001). In particular, by modeling a multifractal s…
Brightest X-Ray Clusters of Galaxies in the CFHTLS Wide Fields: Catalog and Optical Mass Estimator
Finoguenov, A.; Tanaka, M.; Egami, E. +13 more
The Canada-France-Hawaii Telescope Legacy Survey (CFHTLS) presents a unique data set for weak-lensing studies, having high-quality imaging and deep multiband photometry. We have initiated an XMM-CFHTLS project to provide X-ray observations of the brightest X-ray-selected clusters within the wide CFHTLS area. Performance of these observations and t…
The Slim-disk State of the Ultraluminous X-Ray Source in M83
Soria, Roberto; Blair, William P.; Kuntz, K. D. +3 more
The transient ULX in M83 that went into outburst in, or shortly before, 2010 is still active. Our new XMM-Newton spectra show that it has a curved spectrum typical of the upper end of the high/soft state or slim-disk state. It appears to be spanning the gap between Galactic stellar-mass black holes (BHs) and the ultraluminous state, at X-ray lumin…
Triangulation of the Interstellar Magnetic Field
McComas, D. J.; Schwadron, N. A.; Richardson, J. D. +2 more
Determining the direction of the local interstellar magnetic field (LISMF) is important for understanding the heliosphere’s global structure, the properties of the interstellar medium, and the propagation of cosmic rays in the local galactic medium. Measurements of interstellar neutral atoms by Ulysses for He and by SOHO/SWAN for H provided some o…