Search Publications
The Pair Fraction of Massive Galaxies at 0 <= z <= 3
van der Wel, Arjen; Zirm, Andrew W.; Wuyts, Stijn +2 more
Using a mass-selected (M sstarf >= 1011 M ⊙) sample of 198 galaxies at 0 <= z <= 3.0 with Hubble Space Telescope/NICMOS H 160-band images from the COSMOS survey, we find evidence for the evolution of the pair fraction above z ~ 2, an epoch in which massive galaxies are believed to undergo signif…
The Contribution of TP-AGB and RHeB Stars to the Near-IR Luminosity of Local Galaxies: Implications for Stellar Mass Measurements of High-redshift Galaxies
Williams, Benjamin F.; Boyer, Martha L.; Girardi, Léo +9 more
Using high spatial resolution Hubble Space Telescope WFC3 and Advanced Camera for Surveys imaging of resolved stellar populations, we constrain the contribution of thermally pulsing asymptotic giant branch (TP-AGB) stars and red helium burning (RHeB) stars to the 1.6 µm near-infrared (NIR) luminosities of 23 nearby galaxies, including dwarfs…
A Study of the Dark Core in A520 with the Hubble Space Telescope: The Mystery Deepens
Dalcanton, J. J.; Capak, P.; Hoekstra, H. +4 more
We present a Hubble Space Telescope/Wide Field Planetary Camera 2 weak-lensing study of A520, where a previous analysis of ground-based data suggested the presence of a dark mass concentration. We map the complex mass structure in much greater detail, leveraging more than a factor of three increase in the number density of source galaxies availabl…
Dark gas in the solar neighborhood from extinction data
Bernard, J. -P.; Fukui, Y.; Onishi, T. +4 more
Context. When modeling infrared or γ-ray data as a linear combination of observed gas tracers, excess emission has been detected compared to expectations from known neutral and molecular gas traced by HI and CO measurements, respectively. This excess might correspond to additional gas component. This so-called “dark gas” (DG) has been observed in …
Hubble Space Telescope Measures of Mass Accretion Rates in the Orion Nebula Cluster
Lodato, G.; Robberto, M.; Da Rio, N. +4 more
The present observational understanding of the evolution of the mass accretion rates (\dot{M}_acc) in pre-main-sequence stars is limited by the lack of accurate measurements of \dot{M}_acc over homogeneous and large statistical samples of young stars. Such observational effort is needed to properly constrain the theory of star formation and disk e…
The origin and timing of fluvial activity at Eberswalde crater, Mars
Mangold, N.; Quantin, C.; Hauber, E. +6 more
The fan deposit in Eberswalde crater has been interpreted as strong evidence for sustained liquid water on early Mars with a paleolake formed during the Noachian period (>3.7 Gy). This location became a key region for understanding the Mars paleo-environment. Eberswalde crater is located 50 km north of the rim of the 150 km diameter crater Hold…
Heavily reddened quasars at z ∼ 2 in the UKIDSS Large Area Survey: a transitional phase in AGN evolution
McMahon, Richard G.; Venemans, Bram P.; Hewett, Paul C. +4 more
We present a new sample of purely near-infrared-selected KVega < 16.5 [KAB < 18.4] extremely red [(J - K)Vega > 2.5] quasar candidates at z ∼ 2 from ≃900 deg2 of data in the UKIDSS Large Area Survey (LAS). Five of these are spectroscopically confirmed to be heavily reddened type 1 active galacti…
Rapid Changes of Photospheric Magnetic Field after Tether-cutting Reconnection and Magnetic Implosion
Xu, Yan; Liu, Chang; Jing, Ju +6 more
The rapid, irreversible change of the photospheric magnetic field has been recognized as an important element of the solar flare process. This Letter reports such a rapid change of magnetic fields during the 2011 February 13 M6.6 flare in NOAA AR 11158 that we found from the vector magnetograms of the Helioseismic and Magnetic Imager (HMI) with 12…
Late-time Optical Emission from Core-collapse Supernovae
Chevalier, Roger A.; Kirshner, Robert P.; Challis, Peter +3 more
Ground-based optical spectra and Hubble Space Telescope images of 10 core-collapse supernovae (CCSNe) obtained several years to decades after outburst are analyzed with the aim of understanding the general properties of their late-time emissions. New observations of SN 1957D, 1970G, 1980K, and 1993J are included as part of the study. Blueshifted l…
Enceladus' extreme heat flux as revealed by its relaxed craters
Singer, Kelsi N.; Schenk, Paul M.; McKinnon, William B. +1 more
Enceladus' cratered terrains contain large numbers of unusually shallow craters consistent with deformation by viscous relaxation of water ice under conditions of elevated heat flow. Here we use high-resolution topography to measure the relaxation fraction of craters on Enceladus far from the active South Pole. We find that many craters are shallo…