Search Publications
LBT/ARGOS adaptive optics observations of z ∼ 2 lensed galaxies
Lutz, D.; Grillo, C.; Contursi, A. +24 more
Aims: Gravitationally lensed systems allow a detailed view of galaxies at high redshift. High spatial- and spectral-resolution measurements of arc-like structures can offer unique constraints on the physical and dynamical properties of high-z systems.
Methods: We present near-infrared spectra centred on the gravitational arcs of six know…
HST/WFPC2 imaging analysis and cloudy modelling of the multiple-shell planetary nebulae NGC 3242, NGC 6826, and NGC 7662
Kimeswenger, S.; Barría, D.
We performed a detailed photometric analysis and photoionization modelling on three high-excitation multiple-shell planetary nebulae: NGC 3242, NGC 6826, and NGC 7662. Archival Hubble Space Telescope/Wide Field Planetary Camera 2 (HST/WFPC2) narrow band filter images were used to investigate shocked regions by two independent methods: using low-ex…
Using GALEX-SDSS-PanSTARRS-HST-Gaia to understand post-AGB evolution
Bianchi, Luciana; Casewell, Sarah; Bohlin, Ralph +2 more
Hot WDs in binary systems with a less evolved star are particularly invaluable astrophysical probes, the unevolved companion enabling better derivation of distance and age than is usually possible for post-AGB objects, and therefore also of their radius and luminosity. But hot white dwarfs (WD) are elusive at all wavelengths except the UV (Bianchi…
Long-term variations in the X-ray activity of HR 1099
Schmitt, J. H. M. M.; Robrade, J.; Schneider, P. C. +6 more
Context. Although timing variations in close binary systems have been studied for a long time, their underlying causes are still unclear. A possible explanation is the so-called Applegate mechanism, where a strong, variable magnetic field can periodically change the gravitational quadrupole moment of a stellar component, thus causing observable pe…
A compact circumstellar shell as the source of high-velocity features in SN 2011fe
Wheeler, J. Craig; Mulligan, Brian W.
High-velocity features (HVFs), especially of Ca II, are frequently seen in Type Ia supernova observed prior to B-band maximum (Bmax). These HVFs evolve in velocity from more than 25 000 km s-1, in the days after first light, to about 18 000 km s-1 near Bmax. To recreate the evolution of the Ca II near-infrared triplet (CaNIR)…
What can the SEDs of first hydrostatic core candidates reveal about their nature?
Hatchell, Jennifer; Harries, Tim J.; Young, Alison K. +2 more
The first hydrostatic core (FHSC) is the first stable object to form in simulations of star formation. This stage has yet to be observed definitively, although several candidate FHSCs have been reported. We have produced synthetic spectral energy distributions (SEDs) from 3D hydrodynamical simulations of pre-stellar cores undergoing gravitational …
Star formation history of Canis Major OB1. II. A bimodal X-ray population revealed by XMM-Newton
Montmerle, T.; Stelzer, B.; Gregorio-Hetem, J. +2 more
Aims: The Canis Major OB1 Association has an intriguing scenario of star formation, especially in the region called Canis Major R1 (CMa R1) traditionally assigned to a reflection nebula, but in reality an ionized region. This work is focussed on the young stellar population associated with CMa R1, for which our previous results from ROSAT, op…
The Quasi-monochromatic ULF Wave Boundary in the Venusian Foreshock: Venus Express Observations
Zhang, Tielong; Mazelle, Christian; Lu, Quanming +5 more
The location of ultralow-frequency (ULF) quasi-monochromatic wave onset upstream of Venus bow shock is explored using Venus Express magnetic field data. We report the existence of a spatial foreshock boundary behind which ULF waves are present. We have found that the ULF wave boundary at Venus is sensitive to the interplanetary magnetic field (IMF…
Energetic Neutral and Charged Particle Measurements in the Inner Saturnian Magnetosphere During the Grand Finale Orbits of Cassini 2016/2017
Krupp, N.; Dougherty, M. K.; Roussos, E. +6 more
We give an overview of the charged and neutral particle measurements during the Grand Finale of Cassini performed by the Magnetosphere Imaging Instrument, MIMI, on board. The first in situ measurements of MeV particles between the D-ring and the atmosphere of the planet showed protons with energies above 300 MeV with higher count rates when magnet…
X-Ray Observations of Magnetar SGR 0501+4516 from Outburst to Quiescence
Ng, C. -Y.; Mong, Y. -L.
Magnetars are neutron stars having extreme magnetic field strengths. Study of their emission properties in quiescent state can help understand effects of a strong magnetic field on neutron stars. SGR 0501+4516 is a magnetar that was discovered in 2008 during an outburst, which has recently returned to quiescence. We report its spectral and timing …