Search Publications
Combining Lens Distortion and Depletion to Map the Mass Distribution of A1689
Broadhurst, Tom; Umetsu, Keiichi
We derive a projected 2D mass map of the well-studied galaxy cluster A1689 based on an entropy-regularized maximum likelihood combination of the lens magnification and distortion of red background galaxies registered in deep Subaru images. The method is not restricted to the weak regime but applies to the whole area outside the tangential critical…
The Relation between Star Formation, Morphology, and Local Density in High-Redshift Clusters and Groups
Aragón-Salamanca, Alfonso; Milvang-Jensen, Bo; Zaritsky, Dennis +17 more
We investigate how the [O II] properties and the morphologies of galaxies in clusters and groups at z = 0.4-0.8 depend on projected local galaxy density, and compare with the field at similar redshifts and clusters at low z. In both nearby and distant clusters, higher density regions contain proportionally fewer star-forming galaxies, and the aver…
Observations and Modeling of the Early Acceleration Phase of Erupting Filaments Involved in Coronal Mass Ejections
Title, Alan M.; Török, Tibor; Kliem, Bernhard +2 more
We examine the early phases of two near-limb filament destabilizations involved in coronal mass ejections (CMEs) on 2005 June 16 and July 27, using high-resolution, high-cadence observations made with the Transition Region and Coronal Explorer (TRACE), complemented by coronagraphic observations by the Mauna Loa Solar Observatory (MLSO) and the Sol…
Modeling Nonpotential Magnetic Fields in Solar Active Regions
van Ballegooijen, A. A.; DeLuca, E. E.; Bobra, M. G.
Electric currents are present in the coronae above solar active regions, producing nonpotential magnetic fields that can be approximated as nonlinear force-free fields (NLFFFs). In this paper NLFFF models for two active regions observed in 2002 June are presented. The models are based on magnetograms from SOHO MDI and are constrained by nonpotenti…
Submillimeter Array Imaging of the CO(3-2) Line and 860 µm Continuum of Arp 220: Tracing the Spatial Distribution of Luminosity
Wilner, David J.; Zhang, Qizhou; Wang, Junzhi +6 more
We used the Submillimeter Array (SMA) to image 860 µm continuum and CO(3-2) line emission in the ultraluminous merging galaxy Arp 220, achieving a resolution of 0.23'' (80 pc) for the continuum and 0.33'' (120 pc) for the line. The CO emission peaks around the two merger nuclei with a velocity signature of gas rotation …
Separating Baryons and Dark Matter in Cluster Cores: A Full Two-dimensional Lensing and Dynamic Analysis of Abell 383 and MS 2137-23
Smith, Graham P.; Treu, Tommaso; Ellis, Richard S. +2 more
We utilize existing data for the galaxy clusters MS 2137-23 and Abell 383 to present improved measures of the distribution of dark and baryonic material in the clusters' central regions. Our method, based on the combination of gravitational lensing and dynamical data, is uniquely capable of separating the distribution of dark and baryonic componen…
Spatially Resolved Properties of the GRB 060505 Host: Implications for the Nature of the Progenitor
Fruchter, Andrew S.; Östlin, Göran; Hjorth, Jens +12 more
GRB 060505 was the first well-observed nearby possible long-duration gamma-ray burst (GRB) that had no associated supernova. Here we present spatially resolved spectra of the host galaxy of GRB 060505, an Sbc spiral, at redshift z = 0.0889. The GRB occurred inside a star-forming region in the northern spiral arm at 6.5 kpc from the center. From th…
Resonant Cyclotron Scattering in Magnetars' Emission
Götz, D.; Rea, N.; Lyutikov, M. +2 more
We present a systematic fit of a model of resonant cyclotron scattering (RCS) to the X-ray data of 10 magnetars, including canonical and transient anomalous X-ray pulsars (AXPs) and soft gamma repeaters (SGRs). In this scenario, nonthermal magnetar spectra in the soft X-rays (i.e., below ~10 keV) result from resonant cyclotron scattering of the th…
Modeling Fe II Emission and Revised Fe II (UV) Empirical Templates for the Seyfert 1 Galaxy I Zw 1
Bruhweiler, F.; Verner, E.
We use the narrow-lined broad-line region (BLR) of the Seyfert 1 galaxy, I Zw 1, as a laboratory for modeling the ultraviolet (UV) Fe II 2100-3050 Å emission complex. We calculate a grid of Fe II emission spectra representative of BLR clouds and compare them with the observed I Zw 1 spectrum. Our predicted spectrum for log [nH/(cm …
The Detailed Evolution of E+A Galaxies into Early Types
Zabludoff, Ann I.; Zaritsky, Dennis; Yang, Yujin +1 more
Poststarburst, or E+A, galaxies are the best candidates for galaxies in transition from being gas-rich and star-forming to gas-poor and passively evolving as a result of galaxy-galaxy interactions. To focus on what E+A galaxies become after their young stellar populations fade away, we present the detailed morphologies of 21 E+A galaxies using hig…