Search Publications

LASCO White-Light Observations of Eruptive Current Sheets Trailing CMEs

Vourlidas, Angelos; Webb, David F.

Many models of eruptive flares or coronal mass ejections (CMEs) involve formation of a current sheet connecting the ejecting CME flux rope with a magnetic loop arcade. However, there is very limited observational information on the properties and evolution of these structures, hindering progress in understanding eruptive activity from the Sun. In …

Rhea gravity field and interior modeling from Cassini data analysis

Nimmo, Francis; Iess, Luciano; Jacobson, Robert A. +4 more

During its tour of the Saturn system, Cassini performed two close flybys of Rhea dedicated to gravity investigations, the first in November 2005 and the second in March 2013. This paper presents an estimation of Rhea's fully unconstrained quadrupole gravity field obtained from a joint multi-arc analysis of the two Cassini flybys.

Our best est…

The JCMT and Herschel Gould Belt Surveys: a comparison of SCUBA-2 and Herschel data of dense cores in the Taurus dark cloud L1495

Hill, T.; Könyves, V.; Palmeirim, P. +27 more

We present a comparison of Submillimetre Common User Bolometer Array-2 (SCUBA-2) 850-µm and Herschel 70-500-µm observations of the L1495 filament in the Taurus Molecular Cloud with the goal of characterizing the SCUBA-2 Gould Belt Survey (GBS) data set. We identify and characterize starless cores in three data sets: SCUBA-2 850-µ…

Early science with the Large Millimetre Telescope: Deep LMT/AzTEC millimetre observations of ɛ Eridani and its surroundings

Dent, W. R. F.; Eiroa, C.; Marshall, J. P. +21 more

ɛ Eridani is a nearby, young Sun-like star that hosts a ring of cool debris analogous to the Solar system's Edgeworth-Kuiper belt. Early observations at (sub-)mm wavelengths gave tentative evidence of the presence of inhomogeneities in the ring, which have been ascribed to the effect of a putative low eccentricity planet, orbiting close to the rin…

Ancient eruptions of η Carinae: a tale written in proper motions

Smith, Nathan; Reiter, Megan; Kiminki, Megan M.

We analyse eight epochs of Hubble Space Telescope Hα+[N II] imaging of η Carinae's outer ejecta. Proper motions of nearly 800 knots reveal that the detected ejecta are divided into three apparent age groups, dating to around 1250 A.D., to around 1550 A.D., and to during or shortly before the Great Eruption of the 1840s. Ejecta from these groups re…

First NuSTAR Observations of the BL Lac-type Blazar PKS 2155-304: Constraints on the Jet Content and Distribution of Radiating Particles

Harrison, F. A.; Hornstrup, A.; Hailey, C. +35 more

We report the first hard X-ray observations with NuSTAR of the BL Lac-type blazar PKS 2155-304, augmented with soft X-ray data from XMM-Newton and γ-ray data from the Fermi Large Area Telescope, obtained in 2013 April when the source was in a very low flux state. A joint NuSTAR and XMM spectrum, covering the energy range 0.5-60 keV, is best descri…

Statistical Study of Network Jets Observed in the Solar Transition Region: a Comparison Between Coronal Holes and Quiet-Sun Regions

Cranmer, Steven R.; Tian, Hui; Banerjee, Dipankar +4 more

Recent IRIS observations have revealed a prevalence of intermittent small-scale jets with apparent speeds of 80 -250 kms−¹, emanating from small-scale bright regions inside network boundaries of coronal holes. We find that these network jets appear not only in coronal holes but also in quiet-sun regions. Using IRIS 1330 Å (C II) slit-ja…

The presence of clathrates in comet 67P/Churyumov-Gerasimenko

Wurz, P.; Fuselier, S. A.; Rubin, M. +6 more

Cometary nuclei are considered to most closely reflect the composition of the building blocks of our solar system. As such, comets carry important information about the prevalent conditions in the solar nebula before and after planet formation. Recent measurements of the time variation of major and minor volatile species in the coma of the Jupiter…

Photogeologic mapping and the geologic history of the Hellas basin floor, Mars

Hiesinger, H.; Bernhardt, H.; Ivanov, M. A. +3 more

The Hellas basin on Mars is the second-largest topographically well-defined impact structure in the Solar System and has repeatedly been interpreted as a major sink of volcanic, glacio-fluvial and eolian materials. Based on established guidelines for planetary mapping, we compiled a comprehensive photogeological map of Hellas Planitia, i.e., the H…

Pathways to quiescence: SHARDS view on the star formation histories of massive quiescent galaxies at 1.0 < z < 1.5

Barro, Guillermo; Pérez-González, Pablo G.; Koekemoer, Anton M. +12 more

We present star formation histories (SFHs) for a sample of 104 massive (stellar mass M > 10¹⁰ M_⊙) quiescent galaxies (MQGs) at z = 1.0-1.5 from the analysis of spectrophotometric data from the Survey for High-z Absorption Red and Dead Sources (SHARDS) and HST/WFC3 G102 and G141 surveys of the GOODS-North field, jointly wit…