Search Publications
How Do Star-forming Galaxies at z > 3 Assemble Their Masses?
Papovich, Casey; Ferguson, Henry C.; Giavalisco, Mauro +8 more
We investigate how star-forming galaxies typically assemble their masses at high redshift. Taking advantage of the deep multi-wavelength coverage of the GOODS data set, we select two of the largest samples of high-redshift star-forming galaxies based on their UV colors and measure stellar mass of individual galaxies. We use template-fitting photom…
CLASH: Precise New Constraints on the Mass Profile of the Galaxy Cluster A2261
Donahue, Megan; Broadhurst, Tom; Maoz, Dan +43 more
We precisely constrain the inner mass profile of A2261 (z = 0.225) for the first time and determine that this cluster is not "overconcentrated" as found previously, implying a formation time in agreement with ΛCDM expectations. These results are based on multiple strong-lensing analyses of new 16-band Hubble Space Telescope imaging obtained as par…
Solar Magnetic Field Reversals and the Role of Dynamo Families
Hoeksema, J. T.; Brun, A. S.; DeRosa, M. L.
The variable magnetic field of the solar photosphere exhibits periodic reversals as a result of dynamo activity occurring within the solar interior. We decompose the surface field as observed by both the Wilcox Solar Observatory and the Michelson Doppler Imager into its harmonic constituents, and present the time evolution of the mode coefficients…
Heavily obscured quasar host galaxies at z ∼ 2 are discs, not major mergers
Schawinski, Kevin; Urry, C. Megan; Simmons, Brooke D. +2 more
We explore the nature of heavily obscured quasar host galaxies at z∼ 2 using deep Hubble Space Telescope Wide Field Camera 3/infrared imaging of 28 dust-obscured galaxies (DOGs) to investigate the role of major mergers in driving black hole growth. The high levels of obscuration of the quasars selected for this study act as a natural coronagraph, …
An overfilled lacustrine system and progradational delta in Jezero crater, Mars: Implications for Noachian climate
Head, James W.; Fassett, Caleb I.; Schon, Samuel C.
The presence of valley networks and open-basin lakes in the late Noachian is cited as evidence for overland flow of liquid water and thus a climate on early Mars that might have supported precipitation and runoff. Outstanding questions center on the nature of such a climate, its duration and variability, and its cause. Open basin lakes, their inte…
Recent advances in understanding substorm dynamics
Nakamura, R.; Sergeev, V. A.; Angelopoulos, V.
Magnetospheric substorms are elemental processes of solar wind energy storage and explosive release in Earth's magnetosphere. They encompass fundamental plasma physics questions, are ubiquitous during all types of geomagnetic conditions, contribute significantly to magnetic storms, and are a key element of Space Weather applications. This paper re…
A New Low Magnetic Field Magnetar: The 2011 Outburst of Swift J1822.3-1606
Campana, S.; Tiengo, A.; Götz, D. +20 more
We report on the long-term X-ray monitoring with Swift, RXTE, Suzaku, Chandra, and XMM-Newton of the outburst of the newly discovered magnetar Swift J1822.3-1606 (SGR 1822-1606), from the first observations soon after the detection of the short X-ray bursts which led to its discovery, through the first stages of its outburst decay (covering the ti…
The ACS Fornax Cluster Survey. VI. The Nuclei of Early-type Galaxies in the Fornax Cluster
Jordán, Andrés; Côté, Patrick; Peng, Eric W. +5 more
The Advanced Camera for Surveys (ACS) Fornax Cluster Survey is a Hubble Space Telescope program to image 43 early-type galaxies in the Fornax cluster, using the F475W and F850LP bandpasses of the ACS. We employ both one-dimensional and two-dimensional techniques to characterize the properties of the stellar nuclei in these galaxies, defined as the…
The Canadian Cluster Comparison Project: weak lensing masses and SZ scaling relations
Hoekstra, Henk; Babul, Arif; Mahdavi, Andisheh +1 more
The Canadian Cluster Comparison Project is a comprehensive multi-wavelength survey targeting 50 massive X-ray selected clusters of galaxies to examine baryonic tracers of cluster mass and to probe the cluster-to-cluster variation in the thermal properties of the hot intra-cluster medium. In this paper we present the weak lensing masses, based on t…
Discovery of a Dissociative Galaxy Cluster Merger with Large Physical Separation
Bradač, Maruša; Hughes, John P.; Dawson, William A. +10 more
We present DLSCL J0916.2+2951 (z = 0.53), a newly discovered major cluster merger in which the collisional cluster gas has become dissociated from the collisionless galaxies and dark matter (DM). We identified the cluster using optical and weak-lensing observations as part of the Deep Lens Survey. Our follow-up observations with Keck, Subaru, Hubb…