Search Publications
Metallicity Gradient of a Lensed Face-on Spiral Galaxy at Redshift 1.49
Swinbank, A. M.; Richard, J.; Yuan, T. -T. +2 more
We present the first metallicity gradient measurement for a grand-design face-on spiral galaxy at z ~ 1.5. This galaxy has been magnified by a factor of 22× by a massive, X-ray luminous galaxy cluster MACS J1149.5+2223 at z = 0.544. Using the Laser Guide Star Adaptive Optics aided integral field spectrograph OSIRIS on KECK II, we target the Hα emi…
The SL2S Galaxy-scale Lens Sample. II. Cosmic Evolution of Dark and Luminous Mass in Early-type Galaxies
Treu, Tommaso; Gavazzi, Raphaël; Marshall, Philip J. +3 more
We present a joint gravitational lensing and stellar-dynamical analysis of 11 early-type galaxies (median deflector redshift z d = 0.5) from Strong Lenses in the Legacy Survey (SL2S). Using newly measured redshifts and stellar velocity dispersions from Keck spectroscopy with lens models from Paper I, we derive the total mass-density slo…
Heating the Hot Atmospheres of Galaxy Groups and Clusters with Cavities: The Relationship between Jet Power and Low-frequency Radio Emission
Giacintucci, S.; O'Sullivan, E.; Ponman, T. J. +4 more
We present scaling relations between jet power and radio power measured using the Giant Metrewave Radio Telescope (GMRT), Chandra, and XMM-Newton, for a sample of nine galaxy groups combined with the Bîrzan et al. sample of clusters. Cavity power is used as a proxy for mechanical jet power. Radio power is measured at 235 MHz and 1.4 GHz, and the i…
First Evidence of Coexisting EIT Wave and Coronal Moreton Wave from SDO/AIA Observations
Chen, P. F.; Wu, Y.
"EIT waves" are a globally propagating wavelike phenomenon. They were often interpreted as fast-mode magnetoacoustic waves in the corona, despite various discrepancies between the fast-mode wave model and observations. To reconcile these discrepancies, we suggested that "EIT waves" are the apparent propagation of the plasma compression due to succ…
The First Observation of a Rapidly Rotating Coronal Mass Ejection in the Middle Corona
Nieves-Chinchilla, T.; Stenborg, G.; Vourlidas, A. +1 more
In this Letter, we present the first direct detection of a rotating coronal mass ejection (CME) in the middle corona (5-15 R sun). The CME rotation rate is 60° day-1, which is the highest rate reported yet. The Earth-directed event was observed by the STEREO/SECCHI and SOHO/LASCO instruments. We are able to derive the three-d…
Observations and Magnetic Field Modeling of the Flare/coronal Mass Ejection Event on 2010 April 8
Golub, Leon; van Ballegooijen, Adriaan; DeLuca, Edward +2 more
We present a study of the flare/coronal mass ejection event that occurred in Active Region 11060 on 2010 April 8. This event also involves a filament eruption, EIT wave, and coronal dimming. Prior to the flare onset and filament eruption, both SDO/AIA and STEREO/EUVI observe a nearly horizontal filament ejection along the internal polarity inversi…
Narrowband Imaging of Escaping Lyman-continuum Emission in the SSA22 Field
Siana, Brian; Shapley, Alice E.; Steidel, Charles C. +1 more
We present the results of an ultradeep, narrowband imaging survey for Lyman-continuum (LyC) emission at z ~ 3 in the SSA22a field. We employ a custom narrowband filter centered at λ = 3640 Å (NB3640), which probes the LyC region for galaxies at z >= 3.06. We also analyze new and archival NB4980 imaging tuned to the wavelength of the Lyα emissio…
High-resolution Imaging of Solar Flare Ribbons and Its Implication on the Thick-target Beam Model
Krucker, Säm; Lin, R. P.; Hudson, H. S. +5 more
We report on high-resolution optical and hard X-ray observations of solar flare ribbons seen during the GOES X6.5 class white-light flare of 2006 December 6. The data consist of imaging observations at 430 nm (the Fraunhofer G band) taken by the Hinode Solar Optical Telescope with the hard X-rays observed by the Reuven Ramaty High Energy Solar Spe…
When a Standard Candle Flickers
Kouveliotou, Chryssa; Krimm, Hans A.; Kuulkers, Erik +28 more
The Crab Nebula is the only hard X-ray source in the sky that is both bright enough and steady enough to be easily used as a standard candle. As a result, it has been used as a normalization standard by most X-ray/gamma-ray telescopes. Although small-scale variations in the nebula are well known, since the start of science operations of the Fermi …
X-Ray Variability and Hardness of ESO 243-49 HLX-1: Clear Evidence for Spectral State Transitions
Lin, Dacheng; Godet, Olivier; Webb, Natalie A. +3 more
The ultraluminous X-ray (ULX) source ESO 243-49 HLX-1, which reaches a maximum luminosity of 1042 erg s-1 (0.2-10 keV), currently provides the strongest evidence for the existence of intermediate-mass black holes (IMBHs). To study the spectral variability of the source, we conduct an ongoing monitoring campaign with the Swift…