Search Publications
Hunting for Orphaned Central Compact Objects among Radio Pulsars
Ng, C. -Y.; Ho, W. C. G.; Bogdanov, S. +3 more
Central compact objects (CCOs) are a handful of young neutron stars found at the center of supernova remnants (SNRs). They show high thermal X-ray luminosities but no radio emission. Spin-down rate measurements of three CCOs with X-ray pulsations indicate surface dipole fields much weaker than those of typical young pulsars. To investigate if CCOs…
Craters on comets
Vincent, Jean-Baptiste; Oklay, Nilda; Sierks, Holger +2 more
This paper reviews the observations of crater-like features on cometary nuclei. We compare potential crater sizes and morphologies, and we discuss the probability of impacts between small asteroids in the Main Belt and a comet crossing this region of the Solar System. Finally, we investigate the fate of the impactor and its chances of survival on …
The First "Water Fountain" Collimated Outflow in a Planetary Nebula
Bendjoya, Philippe; Guerrero, Martín A.; Ramos-Larios, Gerardo +8 more
"Water fountains" (WFs) are evolved objects showing high-velocity, collimated jets traced by water maser emission. Most of them are in the post-asymptotic giant branch (post-AGB) and they may represent one of the first manifestations of collimated mass loss in evolved stars. We present water maser, carbon monoxide, and mid-infrared spectroscopic d…
Evidence for a [WR] or WEL-type binary nucleus in the bipolar planetary nebula Vy 1-2
Boumis, P.; López, J. A.; Akras, S. +3 more
We present high-dispersion spectroscopic data of the compact planetary nebula Vy 1-2, where high expansion velocities up to 100 km s-1 are found in the Hα, [N II] and [O III] emission lines. Hubble Space Telescope images reveal a bipolar structure. Vy 1-2 displays a bright ring-like structure with a size of 2.4 arcsec × 3.2 arcsec and t…
The warm molecular gas and dust of Seyfert galaxies: two different phases of accretion?
Prieto, M. A.; Fernández-Ontiveros, J. A.; Neumayer, N. +3 more
The distribution of warm molecular gas (1000-3000 K), traced by the near-IR H2 2.12 µm line, has been imaged with a resolution <0.5 arcsec in the central 1 kpc of seven nearby Seyfert galaxies. We find that this gas is highly concentrated towards the central 100 pc and that its morphology is often symmetrical. Lanes of warm H
Modeling the Chromosphere of a Sunspot and the Quiet Sun
Curdt, W.; Tian, H.; Landi, E. +2 more
Semiempirical atmospheric modeling attempts to match an observed spectrum by finding the temperature distribution and other physical parameters along the line of sight through the emitting region such that the calculated spectrum agrees with the observed one. In this paper we take the observed spectrum of a sunspot and the quiet Sun in the EUV wav…
A Determination of the North-South Heliospheric Magnetic Field Component from Inner Corona Closed-loop Propagation
Jackson, B. V.; Buffington, A.; Hick, P. P. +4 more
A component of the magnetic field measured in situ near the Earth in the solar wind is present from north-south fields from the low solar corona. Using the Current-sheet Source Surface model, these fields can be extrapolated upward from near the solar surface to 1 AU. Global velocities inferred from a combination of interplanetary scintillation ob…
The impact from survey depth and resolution on the morphological classification of galaxies
Cepa, J.; Infante, L.; Molino, A. +28 more
We consistently analyse for the first time the impact of survey depth and spatial resolution on the most used morphological parameters for classifying galaxies through non-parametric methods: Abraham and Conselice-Bershady concentration indices, Gini, M20 moment of light, asymmetry, and smoothness. Three different non-local data sets are used, Adv…
SWAP Observations of Post-flare Giant Arches in the Long-Duration 14 October 2014 Solar Eruption
West, Matthew J.; Seaton, Daniel B.
On 2014 October 14 the Sun Watcher with Active Pixels and Image Processing EUV solar telescope on board the Project for On Board Autonomy 2 spacecraft observed an eruption that led to the formation of perhaps the largest post-eruptive loop system seen in the solar corona in solar cycle 24. The initial eruption occurred at about 18:30 UT on October…
Calibration and in-orbit performance of the reflection grating spectrometer onboard XMM-Newton
Kaastra, J. S.; Raassen, A. J. J.; de Vries, C. P. +6 more
Context. XMM-Newton was launched on 10 December 1999 and has been operational since early 2000. One of the instruments onboard XMM-Newton is the reflection grating spectrometer (RGS). Two identical RGS instruments are available, with each RGS combining a reflection grating assembly and a camera with charge-coupled devices to record the spectra.