Search Publications
Chemical Complexity in the Eu-enhanced Monometallic Globular NGC 5986
Caldwell, Nelson; Rich, R. Michael; Johnson, Christian I. +4 more
NGC 5986 is a poorly studied but relatively massive Galactic globular cluster that shares several physical and morphological characteristics with “iron-complex” clusters known to exhibit significant metallicity and heavy-element dispersions. In order to determine whether NGC 5986 joins the iron-complex cluster class, we investigated the chemical c…
The Role of Pebble Fragmentation in Planetesimal Formation. II. Numerical Simulations
Blum, Jürgen; Johansen, Anders; Wahlberg Jansson, Karl +1 more
Some scenarios for planetesimal formation go through a phase of collapse of gravitationally bound clouds of millimeter- to centimeter-size pebbles. Such clouds can form, for example, through the streaming instability in protoplanetary disks. We model the collapse process with a statistical model to obtain the internal structure of planetesimals wi…
Cliffs versus plains: Can ROSINA/COPS and OSIRIS data of comet 67P/Churyumov-Gerasimenko in autumn 2014 constrain inhomogeneous outgassing?
Jorda, L.; Altwegg, K.; Sierks, H. +18 more
Context. This paper describes the modelling of gas and dust data acquired in the period August to October 2014 from the European Space Agency's Rosetta spacecraft when it was in close proximity to the nucleus of comet 67P/Churyumov-Gerasimenko.
Aims: With our 3D gas and dust comae models this work attempts to test the hypothesis that cliff ac…
Detection of Mg-spinel bearing central peaks using M3 images: Implications for the petrogenesis of Mg-spinel
Li, Lin; Sun, Ying; Zhang, Yuanzhi
Mg-spinel bearing lithologies, lacking abundant mafic materials, have been discovered with images acquired by the Moon Mineralogy Mapper (M3) aboard Chandrayaan-1. We conducted a systematic screening of lunar crater central peaks for the presence of Mg-spinel to address its distribution and petrogenesis. 38 Mg-spinel bearing crater cent…
The First ALMA Observation of a Solar Plasmoid Ejection from an X-Ray Bright Point
Shimojo, Masumi; White, Stephen M.; Hudson, Hugh S. +2 more
Eruptive phenomena such as plasmoid ejections or jets are important features of solar activity and have the potential to improve our understanding of the dynamics of the solar atmosphere. Such ejections are often thought to be signatures of the outflows expected in regions of fast magnetic reconnection. The 304 Å EUV line of helium, formed at arou…
A Solar cycle correlation of coronal element abundances in Sun-as-a-star observations
Warren, Harry P.; Brooks, David H.; Baker, Deborah +1 more
The elemental composition in the coronae of low-activity solar-like stars appears to be related to fundamental stellar properties such as rotation, surface gravity, and spectral type. Here we use full-Sun observations from the Solar Dynamics Observatory, to show that when the Sun is observed as a star, the variation of coronal composition is highl…
KiDS-450: tomographic cross-correlation of galaxy shear with Planck lensing
Hoekstra, Henk; Heymans, Catherine; Merten, Julian +15 more
We present the tomographic cross-correlation between galaxy lensing measured in the Kilo Degree Survey (KiDS-450) with overlapping lensing measurements of the cosmic microwave background (CMB), as detected by Planck 2015. We compare our joint probe measurement to the theoretical expectation for a flat Λ cold dark matter cosmology, assuming the bes…
Evolution of the magnetic field at comet 67P/Churyumov-Gerasimenko
Goetz, Charlotte; Richter, Ingo; Volwerk, Martin +1 more
The magnetic field at a comet is significantly influenced by the solar wind on one side and the outgassing rate on the other. There are no simple spatial models for the magnetic field direction, neither at a comet with low outgassing rates (∼1025 s-1) where ion gyroradius effects are non-negligible, nor at high outgassing rat…
Are we seeing accretion flows in a 250 kpc Lyα halo at z = 3?
Boulanger, F.; Humphrey, A.; Villar-Martín, M. +8 more
Using MUSE on the ESO-VLT, we obtained a four-hour exposure of the z = 3.12 radio galaxy MRC 0316-257. We detect features down to 10-19 erg s-1 cm-2 arcsec-2, with the highest surface brightness regions reaching more than a factor of 100 higher. We find Lyα emission out to 250 kpc in projection from the …
Dynamic molecular oxygen production in cometary comae
Yao, Yunxi; Giapis, Konstantinos P.
Abundant molecular oxygen was discovered in the coma of comet 67P/Churyumov-Gerasimenko. Its origin was ascribed to primordial gaseous O2 incorporated into the nucleus during the comet's formation. This thesis was put forward after discounting several O2 production mechanisms in comets, including photolysis and radiolysis of …