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A Herschel/HIFI Legacy Survey of HF and H2O in the Galaxy: Probing Diffuse Molecular Cloud Chemistry
Gerin, M.; Neufeld, D. A.; Sonnentrucker, P. +5 more
We combine Herschel observations for a total of 12 sources to construct the most uniform survey of HF and H2O in our Galactic disk. Both molecules are detected in absorption along all sight lines. The high spectral resolution of the Heterodyne Instrument for the Far-infrared (HIFI) allows us to compare the HF and H2O distribu…
Redshifted Fe Kα line from the unusual γ-ray source PMN J1603-4904
Stawarz, Ł.; Dauser, T.; Wilms, J. +13 more
Context. Multiwavelength observations have revealed the highly unusual properties of the γ-ray source PMN J1603-4904, which are difficult to reconcile with any other well-established γ-ray source class. The object is either a very atypical blazar or a compact jet source seen at a larger angle to the line of sight.
Aims: To determine the physi…
The Relation between Dynamical Mass-to-light Ratio and Color for Massive Quiescent Galaxies out to z ~ 2 and Comparison with Stellar Population Synthesis Models
van Dokkum, Pieter G.; Franx, Marijn; Bezanson, Rachel +2 more
We explore the relation between the dynamical mass-to-light ratio (M/L) and rest-frame color of massive quiescent galaxies out to z ~ 2. We use a galaxy sample with measured stellar velocity dispersions in combination with Hubble Space Telescope and ground-based multi-band photometry. Our sample spans a large range in log M dyn/L g…
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…