Search Publications
Identification of Kinetic Alfvén Wave Turbulence in the Solar Wind
Bale, S. D.; Chen, C. H. K.; Mozer, F. S. +4 more
The nature of small-scale turbulent fluctuations in the solar wind is investigated using a comparison of Cluster magnetic and electric field measurements to predictions arising from models consisting of either kinetic Alfvén waves or whistler waves. The electric and magnetic field properties of these waves from linear theory are used to construct …
Multiple Stellar Populations in 47 Tucanae
Di Criscienzo, M.; Anderson, J.; Milone, A. P. +16 more
We use Hubble Space Telescope (HST) and ground-based imaging to study the multiple populations of 47 Tucanae (47 Tuc), combining high-precision photometry with calculations of synthetic spectra. Using filters covering a wide range of wavelengths, our HST photometry splits the main sequence into two branches, and we find that this duality is repeat…
The M31 Velocity Vector. II. Radial Orbit toward the Milky Way and Implied Local Group Mass
Anderson, Jay; van der Marel, Roeland P.; Beaton, Rachael L. +5 more
We determine the velocity vector of M31 with respect to the Milky Way and use this to constrain the mass of the Local Group, based on Hubble Space Telescope proper-motion measurements of three fields presented in Paper I. We construct N-body models for M31 to correct the measurements for the contributions from stellar motions internal to M31. This…
On the Cluster Physics of Sunyaev-Zel'dovich and X-Ray Surveys. I. The Influence of Feedback, Non-thermal Pressure, and Cluster Shapes on Y-M Scaling Relations
Bond, J. R.; Battaglia, N.; Sievers, J. L. +1 more
The utility of large Sunyaev-Zel'dovich (SZ) surveys for determining cosmological parameters from cluster abundances is limited by the theoretical uncertainties in the integrated SZ-flux-to-mass relation, Y-M. We explore how non-thermal pressure and the anisotropic shape of the gas distribution of the intracluster medium (ICM) impacts Y-M scaling …
The Dependence of Quenching upon the Inner Structure of Galaxies at 0.5 <= z < 0.8 in the DEEP2/AEGIS Survey
Bell, Eric F.; Kocevski, Dale D.; Koekemoer, Anton M. +25 more
The shutdown of star formation in galaxies is generally termed "quenching." Quenching may occur through a variety of processes, e.g., active galactic nucleus (AGN) feedback, stellar feedback, or the shock heating of gas in the dark matter halo. However, which mechanism(s) is, in fact, responsible for quenching is still in question. This paper addr…
Understanding Dual Active Galactic Nucleus Activation in the nearby Universe
Koss, Michael; Veilleux, Sylvain; Mushotzky, Richard +3 more
We study the fraction of dual active galactic nuclei (AGNs) in a sample of 167 nearby (z < 0.05), moderate-luminosity, ultra-hard X-ray-selected AGNs from the all-sky Swift Burst Alert Telescope (BAT) survey. Combining new Chandra and Gemini observations together with optical and X-ray observations, we find that the dual AGN frequency at scales…
Large-amplitude Variations of an L/T Transition Brown Dwarf: Multi-wavelength Observations of Patchy, High-contrast Cloud Features
Marley, Mark; Radigan, Jacqueline; Saumon, Didier +3 more
We present multiple-epoch photometric monitoring in the J, H, and Ks bands of the T1.5 dwarf 2MASS J21392676+0220226 (2M2139), revealing persistent, periodic (P = 7.721 ± 0.005 hr) variability with a peak-to-peak amplitude as high as 26% in the J band. The light curve shape varies on a timescale of days, suggesting that evolving atmosph…
Herschel Far-infrared and Submillimeter Photometry for the KINGFISH Sample of nearby Galaxies
Helou, G.; Roussel, H.; Murphy, E. J. +39 more
New far-infrared and submillimeter photometry from the Herschel Space Observatory is presented for 61 nearby galaxies from the Key Insights on Nearby Galaxies: A Far-Infrared Survey with Herschel (KINGFISH) sample. The spatially integrated fluxes are largely consistent with expectations based on Spitzer far-infrared photometry and extrapolations t…
A Radio-selected Sample of Gamma-Ray Burst Afterglows
Chandra, Poonam; Frail, Dale A.
We present a catalog of radio afterglow observations of gamma-ray bursts (GRBs) over a 14 year period from 1997 to 2011. Our sample of 304 afterglows consists of 2995 flux density measurements (including upper limits) at frequencies between 0.6 GHz and 660 GHz, with the majority of data taken at 8.5 GHz frequency band (1539 measurements). We use t…
GOODS-Herschel Measurements of the Dust Attenuation of Typical Star-forming Galaxies at High Redshift: Observations of Ultraviolet-selected Galaxies at z ~ 2
Magnelli, B.; Altieri, B.; Aussel, H. +20 more
We take advantage of the sensitivity and resolution of the Herschel Space Observatory at 100 and 160 µm to directly image the thermal dust emission and investigate the infrared luminosities (L IR) and dust obscuration of typical star-forming (L*) galaxies at high redshift. Our sample consists of 146 UV-selected galaxies with spect…