Search Publications
XMM-Newton Observation of the Northwest Radio Relic Region in A3667
Sarazin, Craig L.; Nakazawa, Kazuhiro; Wik, Daniel R. +2 more
A3667 is the archetype of a merging cluster with radio relics. The northwest (NW) radio relic is the brightest cluster relic or halo known and is believed to be due to a strong merger shock. We have observed the NW relic for ~40 ks of net XMM-Newton time. We observe a global decline of temperature across the relic from 6 to 1 keV, similar to the S…
Reconstructing Coronal Mass Ejections with Coordinated Imaging and in Situ Observations: Global Structure, Kinematics, and Implications for Space Weather Forecasting
Vourlidas, Angelos; Thernisien, Arnaud; Bale, Stuart D. +4 more
We reconstruct the global structure and kinematics of coronal mass ejections (CMEs) using coordinated imaging and in situ observations from multiple vantage points. A forward modeling technique, which assumes a rope-like morphology for CMEs, is used to determine the global structure (including orientation and propagation direction) from coronagrap…
The Nature of Starbursts. II. The Duration of Starbursts in Dwarf Galaxies
McQuinn, Kristen B. W.; Cannon, John M.; Skillman, Evan D. +7 more
The starburst phenomenon can shape the evolution of the host galaxy and the surrounding intergalactic medium. The extent of the evolutionary impact is partly determined by the duration of the starburst, which has a direct correlation with both the amount of stellar feedback and the development of galactic winds, particularly for smaller mass dwarf…
On Sizes, Kinematics, M/L Gradients, and Light Profiles of Massive Compact Galaxies at z ~ 2
van Dokkum, Pieter G.; Franx, Marijn; Hernquist, Lars +5 more
We present a detailed analysis of the structure and resolved stellar populations of simulated merger remnants, and compare them to observations of compact quiescent galaxies at z ~ 2. We find that major merging is a viable mechanism to produce systems of ~1011 M sun and ~1 kpc size, provided the gas fraction at the time of fi…
A Multiwavelength Study of a Sample of 70 µm Selected Galaxies in the COSMOS Field. II. The Role of Mergers in Galaxy Evolution
Aussel, H.; Le Floc'h, E.; Kartaltepe, Jeyhan S. +26 more
We analyze the morphological properties of a large sample of 1503 70 µm selected galaxies in the COSMOS field spanning the redshift range 0.01 < z < 3.5 with a median redshift of 0.5 and an infrared luminosity range of 108 < L IR(8 - 1000 µm)< 1014 L sun with a median luminosity o…
LoCuSS: A Comparison of Cluster Mass Measurements from XMM-Newton and Subaru—Testing Deviation from Hydrostatic Equilibrium and Non-thermal Pressure Support
Smith, Graham P.; Babul, Arif; Marrone, Daniel P. +8 more
We compare X-ray hydrostatic and weak-lensing mass estimates for a sample of 12 clusters that have been observed with both XMM-Newton and Subaru. At an over-density of Δ = 500, we obtain 1 - M X/M WL = 0.01 ± 0.07 for the whole sample. We also divided the sample into undisturbed and disturbed sub-samples based on quantitative…
Driving Mechanism and Onset Condition of a Confined Eruption
Ding, M. D.; Schmieder, B.; Li, H. +3 more
We study a confined eruption accompanied by an M1.1 flare in solar active region (AR) NOAA 10767 on 2005 May 27, where a pre-eruptive magnetic flux rope was reported in a nonlinear force-free field (NLFFF) extrapolation. The observations show a strong writhing motion of the erupting structure, suggesting that a flux rope was indeed present and con…
Ultradeep Infrared Array Camera Observations of Sub-L* z ~ 7 and z ~ 8 Galaxies in the Hubble Ultra Deep Field: the Contribution of Low-Luminosity Galaxies to the Stellar Mass Density and Reionization
Trenti, M.; Oesch, P. A.; Carollo, C. M. +9 more
We study the Spitzer Infrared Array Camera (IRAC) mid-infrared (rest-frame optical) fluxes of 14 newly WFC3/IR-detected z ~ 7 z 850-dropout galaxies and 5z ~ 8 Y 105-dropout galaxies. The WFC3/IR depth and spatial resolution allow accurate removal of contaminating foreground light, enabling reliable flux measurements at 3.6 &…
Solar Meridional Circulation from Doppler Shifts of the Fe I Line at 5250 Å as Measured by the 150-foot Solar Tower Telescope at the Mt. Wilson Observatory
Ulrich, Roger K.
Doppler shifts of the Fe I spectral line at 5250 Å from the full solar disk obtained over the period 1986 to 2009 are analyzed to determine the circulation velocity of the solar surface along meridional planes. Simultaneous measurements of the Zeeman splitting of this line are used to obtain measurements of the solar magnetic field that are used t…
The Luminosity, Mass, and Age Distributions of Compact Star Clusters in M83 Based on Hubble Space Telescope/Wide Field Camera 3 Observations
Mutchler, Max; Calzetti, Daniela; Whitmore, Bradley C. +21 more
The newly installed Wide Field Camera 3 (WFC3) on the Hubble Space Telescope has been used to obtain multi-band images of the nearby spiral galaxy M83. These new observations are the deepest and highest resolution images ever taken of a grand-design spiral, particularly in the near-ultraviolet, and allow us to better differentiate compact star clu…