Search Publications
An Intriguing Chromospheric Jet Observed by Hinode: Fine Structure Kinematics and Evidence of Unwinding Twists
Liu, Wei; Berger, Thomas E.; Tarbell, Theodore D. +1 more
We report a chromospheric jet lasting for more than 1 hr observed by the Hinode Solar Optical Telescope in unprecedented detail. The ejection occurred in three episodes separated by 12-14 minutes, with the amount and velocity of material decreasing with time. The upward velocities range from 438 to 33 km\nolimits s\nolimits ^{-1}, while the downwa…
High-Redshift Starbursting Dwarf Galaxies Revealed by γ-Ray Burst Afterglows
Pettini, Max; Chen, Hsiao-Wen; Perley, Daniel A. +7 more
We present a study of 15 long-duration γ-ray burst (GRB) host galaxies at z > 2. The GRBs are selected with available early-time afterglow spectra in order to compare interstellar medium (ISM) absorption-line properties with stellar properties of the host galaxies. In addition to five previously studied hosts, we consider new detections for the…
Evidence for an Intermediate-mass Black Hole in NGC 5408 X-1
Mushotzky, Richard F.; Strohmayer, Tod E.
We report the discovery with XMM-Newton of correlated spectral and timing behavior in the ultraluminous X-ray source (ULX) NGC 5408 X-1. An ≈100 ks pointing with XMM/Newton obtained in 2008 January reveals a strong 10 mHz quasi-periodic oscillation (QPO) in the >1 keV flux, as well as flat-topped, band-limited noise breaking to a power law. The…
Discovery of the Largest Known Lensed Images Formed by a Critically Convergent Lensing Cluster
Broadhurst, Tom; Zitrin, Adi
We identify the largest known lensed images of a single spiral galaxy, lying close to the center of the distant cluster MACS J1149.5+2223 (z = 0.544). These images cover a total area of ≃ 150'' and are magnified ≃200 times. Unusually, there is very little image distortion, implying that the central mass distribution is almost uniform over a wide a…
Propagating Slow Magnetoacoustic Waves in Coronal Loops Observed by Hinode/EIS
Wang, T. J.; Davila, J. M.; Ofman, L.
We present the first Hinode/EUV Imaging Spectrometer observations of 5 minute quasi-periodic oscillations detected in a transition-region line (He II) and five coronal lines (Fe X, Fe XII, Fe XIII, Fe XIV, and Fe XV) at the footpoint of a coronal loop. The oscillations exist throughout the whole observation, characterized by a series of wave packe…
The Extension of the Transition Temperature Plasma into the Lower Galactic Halo
Savage, Blair D.; Wakker, Bart P.
Column densities for H I, Al III, Si IV, C IV, and O VI toward 109 stars and 30 extragalactic objects have been assembled to study the extensions of these species away from the Galactic plane into the Galactic halo. H I and Al III mostly trace the warm neutral and warm ionized medium, respectively, while Si IV, C IV, and O VI trace a combination o…
Discovery of a 112 ms X-Ray Pulsar in Puppis A: Further Evidence of Neutron Stars Weakly Magnetized at Birth
Gotthelf, E. V.; Halpern, J. P.
We report the discovery of 112 ms X-ray pulsations from RX J0822-4300, the compact central object (CCO) in the supernova remnant (SNR) Puppis A, in two archival Newton X-Ray Multi-Mirror Mission observations taken in 2001. The sinusoidal light curve has a pulsed fraction of 11% with an abrupt 180° change in phase at 1.2 keV. The observed phase shi…
Deep 2MASS Photometry of M67 and Calibration of the Main-Sequence J - KS Color Difference as an Age Indicator
Kirkpatrick, Allison; Dotter, Aaron; Sarajedini, Ata
We present an analysis of Two Micron All Sky Survey (2MASS) calibration photometry of the old open cluster M67 (NGC 2682). The proper-motion-cleaned color-magnitude diagram (CMD) resulting from these data extends ~3 mag deeper than one based on data from the point source catalog. The CMD extends from above the helium-burning red clump to a faint l…
Density and Kinematic Cusps in M54 at the Heart of the Sagittarius Dwarf Galaxy: Evidence for A 104 M sun Black Hole?
Dalessandro, E.; Bellazzini, M.; Mackey, A. D. +8 more
We report the detection of a stellar density cusp and a velocity dispersion increase in the center of the globular cluster M54, located at the center of the Sagittarius dwarf galaxy (Sgr). The central line-of-sight velocity dispersion is 20.2 ± 0.7 km s-1, decreasing to 16.4 ± 0.4 km s-1 at 2farcs5 (0.3 pc). Modeling the kine…
A Note on the Torsional Oscillation at Solar Minimum
Thompson, M. J.; Howe, R.; Komm, R. +3 more
We examine the evolution of the zonal flow pattern in the upper solar convection zone during the current extended solar minimum, and compare it with that during the previous minimum. The results suggest that a configuration matching that at the previous minimum was reached during 2008, but that the flow band corresponding to the new cycle has been…