Search Publications
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…
A Magellan MIKE and Spitzer MIPS Study of 1.5-1.0 M sun Stars in Scorpius-Centaurus
Weinberger, Alycia J.; Chen, Christine H.; Mamajek, Eric E. +3 more
We obtained Spitzer Space Telescope Multiband Imaging Photometer for Spitzer (MIPS) 24 µm and 70 µm observations of 182 nearby, Hipparcos F- and G-type common proper motion single and binary systems in the nearest OB association, Scorpius-Centaurus. We also obtained Magellan/MIKE R ~ 50,000 visual spectra at 3500-10500 Å for 181 candid…
An Accounting of the Dust-obscured Star Formation and Accretion Histories Over the Last ~11 Billion Years
Frayer, D. T.; Chary, R. -R.; Dickinson, M. +3 more
We report on an accounting of the star-formation- and accretion-driven energetics of 24 µm-detected sources in the Great Observatories Origins Deep Survey-North field. For sources having infrared (IR; 8-1000 µm) luminosities gsim3 × 1012 L sun when derived by fitting local spectral energy distributions (SEDs) to 2…
The ACS LCID Project. V. The Star Formation History of the Dwarf Galaxy LGS-3: Clues to Cosmic Reionization and Feedback
Ferguson, Henry; Dolphin, Andrew; Tolstoy, Eline +11 more
We present an analysis of the star formation history (SFH) of the transition-type (dIrr/dSph) Local Group galaxy LGS-3 (Pisces) based on deep photometry obtained with the Advanced Camera for Surveys onboard the Hubble Space Telescope. Our observations reach the oldest main-sequence turnoffs at high signal to noise, allowing a time resolution at th…
The HST/ACS Coma Cluster Survey. IV. Intergalactic Globular Clusters and the Massive Globular Cluster System at the Core of the Coma Galaxy Cluster
Ferguson, Henry C.; Miller, Bryan W.; Hudson, Michael J. +21 more
Intracluster stellar populations are a natural result of tidal interactions in galaxy clusters. Measuring these populations is difficult, but important for understanding the assembly of the most massive galaxies. The Coma cluster of galaxies is one of the nearest truly massive galaxy clusters and is host to a correspondingly large system of globul…
The Assembly History of Disk Galaxies. I. The Tully-Fisher Relation to z ~= 1.3 from Deep Exposures with DEIMOS
Treu, Tommaso; Ellis, Richard S.; Miller, Sarah H. +2 more
We present new measures of the evolving scaling relations between stellar mass, luminosity and rotational velocity for a morphologically inclusive sample of 129 disk-like galaxies with z AB < 22.5 in the redshift range 0.2 <z < 1.3, based on spectra from DEep Imaging Multi-Object Spectrograph on the Keck II telescope, multi-col…