Search Publications
A Characteristic Magnetic Field Pattern Associated with All Major Solar Flares and Its Use in Flare Forecasting
Schrijver, Carolus J.
Solar flares result from some electromagnetic instability that occurs within regions of relatively strong magnetic field in the Sun's atmosphere. The processes that enable and trigger these flares remain topics of intense study and debate. I analyze observations of 289 X- and M-class flares and over 2500 active region magnetograms to discover (1) …
Combining Strong and Weak Gravitational Lensing in Abell 1689
Richard, Johan; Smith, Graham P.; Smail, Ian +14 more
We present a reconstruction of the mass distribution of galaxy cluster Abell 1689 at z=0.18 using detected strong lensing features from deep ACS observations and extensive ground based spectroscopy. Earlier analyses have reported up to 32 multiply imaged systems in this cluster, of which only 3 were spectroscopically confirmed. In this work, we pr…
On the Progenitor of SN 2005gl and the Nature of Type IIn Supernovae
Cenko, S. B.; Filippenko, Alexei V.; Aldering, G. +9 more
We present a study of the Type IIn supernova (SN) 2005gl, in the relatively nearby (d~66 Mpc) galaxy NGC 266. Photometry and spectroscopy of the SN indicate that it is a typical member of its class. Pre-explosion Hubble Space Telescope (HST) imaging of the location of the SN, along with a precise localization of this event using the laser guide st…
A Complete Sample of 12 Very X-Ray Luminous Galaxy Clusters at z > 0.5
Edge, A. C.; Ebeling, H.; Ma, C. -J. +3 more
We present the statistically complete and cosmologically most relevant subset of the 12 most distant galaxy clusters detected at z>0.5 by the Massive Cluster Survey (MACS). Ten of these systems are new discoveries; only two (MACS J0018.5+1626, aka Cl 0016+1609, and MACS J0454.1-0300, aka MS 0451.6-0305) were previously known. We provide fundame…
On the Magnetic Flux Budget in Low-Corona Magnetic Reconnection and Interplanetary Coronal Mass Ejections
Qiu, Jiong; Hu, Qiang; Howard, Timothy A. +1 more
We present the first quantitative comparison between the total magnetic reconnection flux in the low corona in the wake of coronal mass ejections (CMEs) and the magnetic flux in magnetic clouds (MCs) that reach 1 AU 2-3 days after CME onset. The total reconnection flux is measured from flare ribbons, and the MC flux is computed using in situ obser…
Using Stellar Limb-Darkening to Refine the Properties of HD 209458b
Knutson, Heather A.; Gilliland, Ronald L.; Charbonneau, David +2 more
We use multiband photometry to refine estimates for the planetary radius and orbital inclination of the transiting planet system HD 209458. We gathered 1066 spectra over four distinct transits with the STIS spectrometer on the Hubble Space Telescope using two gratings with a resolution R=1500 and a combined wavelength range of 290-1030 nm. We divi…
Hubble Space Telescope and Spitzer Imaging of Red and Blue Galaxies at z ~ 2.5: A Correlation between Size and Star Formation Activity from Compact Quiescent Galaxies to Extended Star-forming Galaxies
Wuyts, S.; Förster Schreiber, N. M.; Papovich, C. +13 more
We present HST NICMOS+ACS and Spitzer IRAC+MIPS observations of 41 galaxies at 2<z<3.5 in the FIRES MS 1054 field with red and blue rest-frame optical colors. About half of the galaxies are very compact (effective radii re<1 kpc) at rest-frame optical wavelengths; the others are extended (1 kpc<re<10 kpc). For …
Characterization of Dusty Debris Disks: The IRAS and Hipparcos Catalogs
Zuckerman, B.; Song, Inseok; McElwain, Michael +1 more
Dusty debris disks around main-sequence stars are signposts for the existence of planetesimals and exoplanets. From cross-correlating Hipparcos stars with the IRAS catalogs, we identify 146 stars within 120 pc of Earth that show excess emission at 60 µm. This search took special precautions to avoid false positives. Our sample is reasonably …
C IV λ1549 as an Eigenvector 1 Parameter for Active Galactic Nuclei
Sulentic, Jack W.; Marziani, Paola; Negrete, C. Alenka +2 more
We are exploring a spectroscopic unification for all types of broad-line emitting AGNs. The four-dimensional Eigenvector 1 (4DE1) parameter space organizes quasar diversity in a sequence primarily governed by Eddington ratio. This paper considers the role of C IV λ1549 measures as 4DE1 diagnostics. We use HST archival spectra for 130 sources with …
Coronal ``Wave'': Magnetic Footprint of a Coronal Mass Ejection?
Harra, Louise K.; Attrill, Gemma D. R.; van Driel-Gesztelyi, Lidia +1 more
We investigate the properties of two ``classical'' EUV Imaging Telescope (EIT) coronal waves. The two source regions of the associated coronal mass ejections (CMEs) possess opposite helicities, and the coronal waves display rotations in opposite senses. We observe deep core dimmings near the flare site and also widespread diffuse dimming, accompan…