Search Publications

The origin and timing of fluvial activity at Eberswalde crater, Mars
DOI: 10.1016/j.icarus.2012.05.026 Bibcode: 2012Icar..220..530M

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…

2012 Icarus
MEx 89
Heavily reddened quasars at z ∼ 2 in the UKIDSS Large Area Survey: a transitional phase in AGN evolution
DOI: 10.1111/j.1365-2966.2012.22099.x Bibcode: 2012MNRAS.427.2275B

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…

2012 Monthly Notices of the Royal Astronomical Society
XMM-Newton 89
Rapid Changes of Photospheric Magnetic Field after Tether-cutting Reconnection and Magnetic Implosion
DOI: 10.1088/2041-8205/745/1/L4 Bibcode: 2012ApJ...745L...4L

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…

2012 The Astrophysical Journal
Hinode 89
Late-time Optical Emission from Core-collapse Supernovae
DOI: 10.1088/0004-637X/751/1/25 Bibcode: 2012ApJ...751...25M

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…

2012 The Astrophysical Journal
eHST 89
Enceladus' extreme heat flux as revealed by its relaxed craters
DOI: 10.1029/2012GL052736 Bibcode: 2012GeoRL..3917204B

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…

2012 Geophysical Research Letters
Cassini 89
The Taiwan ECDFS Near-Infrared Survey: Ultra-deep J and KS Imaging in the Extended Chandra Deep Field-South
DOI: 10.1088/0067-0049/203/2/23 Bibcode: 2012ApJS..203...23H

Yan, Haojing; Ho, Paul T. P.; Hsieh, Bau-Ching +4 more

We present ultra-deep J and KS imaging observations covering a 30' × 30' area of the Extended Chandra Deep Field-South (ECDFS) carried out by our Taiwan ECDFS Near-Infrared Survey (TENIS). The median 5σ limiting magnitudes for all detected objects in the ECDFS reach 24.5 and 23.9 mag (AB) for J and KS , respectively. In the i…

2012 The Astrophysical Journal Supplement Series
eHST 89
On the Migration of Jupiter and Saturn: Constraints from Linear Models of Secular Resonant Coupling with the Terrestrial Planets
DOI: 10.1088/0004-637X/745/2/143 Bibcode: 2012ApJ...745..143A

Lin, D. N. C.; Agnor, Craig B.

We examine how the late divergent migration of Jupiter and Saturn may have perturbed the terrestrial planets. Using a modified secular model we have identified six secular resonances between the ν5 frequency of Jupiter and Saturn and the four apsidal eigenfrequencies of the terrestrial planets (g 1-4). We derive analytic uppe…

2012 The Astrophysical Journal
Cassini 88
Galaxy-scale Star Formation on the Red Sequence: The Continued Growth of S0s and the Quiescence of Ellipticals
DOI: 10.1088/0004-637X/755/2/105 Bibcode: 2012ApJ...755..105S

Faber, S. M.; Salim, Samir; Rich, R. Michael +2 more

This paper examines star formation (SF) in relatively massive, primarily early-type galaxies (ETGs) at z ~ 0.1. A sample is drawn from bulge-dominated Galaxy Evolution Explorer/Sloan Digital Sky Survey (GALEX/SDSS) galaxies on the optical red sequence with strong UV excess and yet quiescent SDSS spectra. High-resolution far-UV imaging of 27 such E…

2012 The Astrophysical Journal
eHST 88
Water in star-forming regions with Herschel: highly excited molecular emission from the NGC 1333 IRAS 4B outflow
DOI: 10.1051/0004-6361/201117914 Bibcode: 2012A&A...540A..84H

van Dishoeck, E. F.; Pontoppidan, K. M.; Bergin, E. A. +9 more

During the embedded phase of pre-main sequence stellar evolution, a disk forms from the dense envelope while an accretion-driven outflow carves out a cavity within the envelope. Highly excited (E' = 1000 - 3000 K) H2O emission in spatially unresolved Spitzer/IRS spectra of a low-mass Class 0 object, NGC 1333 IRAS 4B, has previously been…

2012 Astronomy and Astrophysics
Herschel 88
Photospheric Flux Cancellation and the Build-up of Sigmoidal Flux Ropes on the Sun
DOI: 10.1088/0004-637X/759/2/105 Bibcode: 2012ApJ...759..105S

van Ballegooijen, A. A.; Green, L. M.; DeLuca, E. E. +1 more

In this study we explore the scenario of photospheric flux cancellation being the primary formation mechanism of sigmoidal flux ropes in decaying active regions. We analyze magnetogram and X-ray observations together with data-driven non-linear force-free field (NLFFF) models of observed sigmoidal regions to test this idea. We measure the total an…

2012 The Astrophysical Journal
Hinode SOHO 88