Search Publications
NGC 1266: Characterization of the Nuclear Molecular Gas in an Unusual SB0 Galaxy
Glenn, J.; Maloney, P. R.; Rangwala, N. +1 more
With a substantial nuclear molecular gas reservoir and broad, high-velocity CO molecular line wings previously interpreted as an outflow, NGC 1266 is a rare SB0 galaxy. Previous analyses of interferometry, spectrally resolved low-J CO emission lines, and unresolved high-J emission lines have established basic properties of the molecular gas and th…
HST+COS spectra of the double white dwarf CSS 41177 place the secondary inside the pulsational instability strip
Gänsicke, B. T.; Marsh, T. R.; Parsons, S. G. +1 more
We present Hubble Space Telescope + Cosmic Origins Spectrograph (HST+COS) data of the eclipsing double white dwarf binary CSS 41177. Due to the temperature difference between the two white dwarfs, the HST+COS far-ultraviolet data are dominated by the hot, primary white dwarf and allow us to precisely measure its temperature (T1). Using …
The role of ion-neutral collisions in Titan's magnetospheric interaction
Sillanpää, Ilkka; Johnson, Robert E.
We have studied the effects of ion-neutral collisions on Titan's interaction with the magnetospheric plasma flow and also on the Alfvén wings formed in this super-Alfvénic interaction. We have used the HYB-Titan hybrid simulation model to study the role of charge exchange processes and elastic ion collisions in the interaction region. The simulati…
Constraining the intracluster pressure profile from the thermal SZ power spectrum
Bertoldi, F.; Pacaud, F.; Ramos-Ceja, M. E. +1 more
The angular power spectrum of the thermal Sunyaev-Zel'dovich (tSZ) effect is highly sensitive to cosmological parameters such as σ8 and Ωm, but its use as a precision cosmological probe is hindered by the astrophysical uncertainties in modeling the gas pressure profile in galaxy groups and clusters. In this paper we assume th…
Acceleration of ions and nano dust at a comet in the solar wind
Kallio, E.; Gunell, H.; Nilsson, H. +6 more
A quasi-neutral hybrid simulation of the interaction of the solar wind with the atmosphere of a comet is used together with a test particle simulation of cometary ions and dust to compute trajectories and velocity distribution functions of charged particles, starting outside the diamagnetic cavity at 150 km cometocentric distance. The simulations …
Relative Abundance Measurements in Plumes and Interplumes
Hahn, M.; Savin, D. W.; Guennou, C.
We present measurements of relative elemental abundances in plumes and interplumes. Plumes are bright, narrow structures in coronal holes that extend along open magnetic field lines far out into the corona. Previous work has found that in some coronal structures the abundances of elements with a low first ionization potential (FIP) <10 eV are e…
Intrinsic colour indices of Be stars obtained from 2MASS photometry
Wegner, W.
This paper is based on 2MASS photometry (JHK_s magnitudes) of 1172 Be stars. The observed mean intrinsic colours have been derived with aid of two-colour diagrams for Be stars of luminosity classes Ie-IIe, IIIe and IVe-Ve. The obtained results are the first determinations of their intrinsic colours in the astronomical literature. The smoothed infr…
An introduction to the data and tools of planetary geomorphology
Beyer, Ross A.
This manuscript presents a review of data used by planetary geomorphologists and the software tools needed to prepare, process, and analyze those data, along with an example of doing so. Visible image capture and the photometric and geometric processing of those images are reviewed, as are laser altimetry data, and terrain data derived from images…
The double-gradient magnetic instability: Stabilizing effect of the guide field
Korovinskiy, D. B.; Semenov, V. S.; Erkaev, N. V. +7 more
The role of the dawn-dusk magnetic field component in stabilizing of the magnetotail flapping oscillations is investigated in the double-gradient model framework (Erkaev et al., Phys. Rev. Lett. 99, 235003 (2007)), extended for the magnetotail-like configurations with non-zero guide field By. Contribution of the guide field is examined …
Disentangling Overlapping Astronomical Sources Using Spatial and Spectral Information
van Dyk, David A.; Kashyap, Vinay L.; Jones, David E.
We present a powerful new algorithm that combines both spatial information (event locations and the point-spread function) and spectral information (photon energies) to separate photons from overlapping sources. We use Bayesian statistical methods to simultaneously infer the number of overlapping sources, to probabilistically separate the photons …