Search Publications
The Evolution of the Mass-Size Relation to z = 3.5 for UV-bright Galaxies and Submillimeter Galaxies in the GOODS-North Field
Franx, Marijn; Kriek, Mariska; Williams, Rik J. +1 more
We study the evolution of the size-stellar mass relation for a large spectroscopic sample of galaxies in the GOODS-North field up to z ~ 3.5. The sizes of the galaxies are measured from Ks -band images (corresponding to rest-frame optical/NIR) from the Subaru 8 m telescope. We reproduce earlier results based on photometric redshifts tha…
Photometric Determination of the Mass Accretion Rates of Pre-main-sequence Stars. II. NGC 346 in the Small Magellanic Cloud
Panagia, Nino; Sabbi, Elena; De Marchi, Guido +4 more
We have studied the properties of the stellar populations in the field of the NGC 346 cluster in the Small Magellanic Cloud, using a novel self-consistent method that allows us to reliably identify pre-main-sequence (PMS) objects actively undergoing mass accretion, regardless of their age. The method does not require spectroscopy and combines broa…
Scale Dependence of Magnetic Helicity in the Solar Wind
Brandenburg, Axel; Balogh, André; Subramanian, Kandaswamy +1 more
We determine the magnetic helicity, along with the magnetic energy, at high latitudes using data from the Ulysses mission. The data set spans the time period from 1993 to 1996. The basic assumption of the analysis is that the solar wind is homogeneous. Because the solar wind speed is high, we follow the approach first pioneered by Matthaeus et al.…
Physical Properties of the Circumnuclear Starburst Ring in the Barred Galaxy NGC 1097
Ho, Paul T. P.; Matsushita, Satoki; Oi, Nagisa +3 more
We report high-resolution 12CO(J = 2-1), 13CO(J = 2-1), and 12CO(J = 3-2) imaging of the Seyfert 1/starburst ring galaxy NGC 1097 with the Submillimeter Array for the purpose of studying the physical and kinematic properties of the 1 kpc circumnuclear starburst ring. Individual star clusters as detected in the Hubb…
The Dissipation of Solar Wind Turbulent Fluctuations at Electron Scales
Burgess, David; Camporeale, Enrico
We present two-dimensional fully kinetic particle-in-cell simulations of decaying electromagnetic fluctuations. The computational box is such that wavelengths ranging from electron to ion gyroradii are resolved. The parameters used are realistic for the solar wind, and the ion-to-electron mass ratio is physical. The dissipation of turbulent fluctu…
On the Origin of Ultraviolet Emission and the Accretion Model of Low-luminosity Active Galactic Nuclei
Ho, Luis C.; Yuan, Feng; Yu, Zhaolong
Low-luminosity active galactic nuclei (LLAGNs) are generally believed to be powered by an inner radiatively inefficient, advection-dominated accretion flow (ADAF), an outer truncated thin disk, and a jet. Maoz recently challenged this picture based on the observation that the strength of ultraviolet emission relative to the X-ray and radio bands d…
The Resolved Stellar Halo of NGC 253
Bell, Eric F.; Radburn-Smith, David J.; Bailin, Jeremy +2 more
We have obtained Magellan/IMACS and Hubble Space Telescope (HST)/Advanced Camera for Surveys imaging data that resolve red giant branch stars in the stellar halo of the starburst galaxy NGC 253. The HST data cover a small area, and allow us to accurately interpret the ground-based data, which cover 30% of the halo to a distance of 30 kpc, allowing…
The ACS Fornax Cluster Survey. X. Color Gradients of Globular Cluster Systems in Early-type Galaxies
Jordán, Andrés; Liu, Chengze; Côté, Patrick +4 more
We use the largest homogeneous sample of globular clusters (GCs), drawn from the ACS Virgo Cluster Survey (ACSVCS) and ACS Fornax Cluster Survey (ACSFCS), to investigate the color gradients of GC systems in 76 early-type galaxies. We find that most GC systems possess an obvious negative gradient in (g-z) color with radius (bluer outward), which is…
Discovery of Cold, Pristine Gas Possibly Accreting onto an Overdensity of Star-forming Galaxies at Redshift z ~ 1.6
Dickinson, Mark; Ferguson, Henry C.; Giavalisco, Mauro +11 more
We report the discovery of large amounts of cold (T ~ 104 K), chemically young gas in an overdensity of galaxies at redshift z ≈ 1.6 located in the Great Observatories Origins Deep Survey southern field. The gas is identified thanks to the ultra-strong Mg II λ2800 absorption features it imprints onto the rest-frame UV spectra of galaxie…
The Megaparsec-scale X-ray Jet of The BL Lac Object OJ287
Jorstad, Svetlana G.; Marscher, Alan P.
We present an X-ray image of the BL Lacertae (BL Lac) object OJ287 revealing a long jet, curved by 55° and extending 20'' or 90 kpc from the nucleus. This de-projects to >1 Mpc based on the viewing angle on parsec scales. Radio emission follows the general X-ray morphology but extends even farther from the nucleus. The upper limit to the isotro…