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Gaia-GOSA: A Collaborative Service for Asteroid Observers
Santana-Ros, Toni; Marciniak, Anna; Bartczak, Prezemyslaw
We describe the Gaia-Ground-based Observational Service for Asteroids (Gaia-GOSA), which is a website aiming to facilitate asteroid observers in contributing to the Gaia mission by gathering lightcurves of selected targets. GOSA users can plan their observing runs by selecting the visible targets for a given date, collaborate with other observers …
Photoionization Modeling of the Low-luminosity Seyfert 1 Nucleus in NGC 3516
Devereux, Nick
Spectroscopic observations of the low-luminosity Seyfert 1 nucleus in NGC 3516 obtained with the Hubble Space Telescope show that the visible spectrum is dominated by Balmer emission lines of hydrogen (H) and a continuum luminosity that rises into the UV. The anomalous {{H}}α /Hβ emission line ratio, the Balmer emission line luminosity, and the di…
Spin State Estimation of Tumbling Small Bodies
Bhaskaran, Shyam; Olson, Corwin; Russell, Ryan P.
It is expected that a non-trivial percentage of small bodies that future missions may visit are in non-principal axis rotation (i.e. "tumbling"). The primary contribution of this paper is the application of the Extended Kalman Filter (EKF) Simultaneous Localization and Mapping (SLAM) method to estimate the small body spin state, mass, and moments …
Star formation in a diffuse high-altitude cloud?
Kerp, J.; Lenz, D.; Röhser, T.
Context. A recent discovery of two stellar clusters associated with the diffuse high-latitude cloud HRK 81.4-77.8 has important implications for star formation in the Galactic halo.
Aims: We derive a plausible distance estimate to HRK 81.4-77.8 primarily from its gaseous properties.
Methods: We spatially correlate state-of-the-art HI, fa…
V421 Pegasi: a detached eclipsing binary with a possible γ Doradus component
Akan, C.; Çakırlı, Ö.; Özdarcan, O.
We present spectroscopic and photometric study of V421 Peg. This eclipsing binary displays lines from both components that are well separated. This allowed us to classify the primary and secondary component as F(1 ± 0.5) V and F(2 ± 0.5) V, respectively. We use our radial velocity measurements together with Hipparcos and ASAS photometry and apply …
Averaged universe confronted with cosmological observations: A fully covariant approach
Ishak, Mustapha; Lin, Weikang; Wijenayake, Tharake
One of the outstanding problems in general relativistic cosmology is that of the averaging, that is, how the lumpy universe that we observe at small scales averages out to a smooth Friedmann-Lemaître-Robertson-Walker (FLRW) model. The root of the problem is that averaging does not commute with the Einstein equations that govern the dynamics of the…
Resolving Gas Flows in the Ultraluminous Starburst IRAS 23365+3604 with Keck LGSAO/OSIRIS
Martin, Crystal L.; Soto, Kurt T.
Keck OSIRIS/LGSAO observations of the ultraluminous galaxy IRAS 23365+3604 resolve a circumnuclear bar (or irregular disk) of semimajor axis 0.″42 (520 pc) in Paα emission. The line-of-sight velocity of the ionized gas increases from the northeast toward the southwest; this gradient is perpendicular to the photometric major axis of the infrared em…
Spectral behavior of Nova GQ Mus in the ultraviolet
Sanad, M. R.; Abdel-Sabour, M. A.
We present ultraviolet spectroscopic study of nova GQ Mus observed with the International Ultraviolet Explorer (IUE) during the period 1983–1985. Different spectra showing the changes in line fluxes at different times are presented. The outflow velocity of the ionized ejecta was calculated to be 1010–2900
Origin of the X-ray broad iron spectral feature in GRS 1915+105
Tsujimoto, Masahiro; Ebisawa, Ken; Mizumoto, Misaki +1 more
The X-ray spectrum of GRS 1915+105 is known to have a "broad iron spectral feature" in the spectral hard state. Similar spectral features are often observed in active galactic nuclei (AGNs) and other black-hole binaries (BHBs), and several models have been proposed for explaining it. In order to distinguish spectral models, time variation provides…
Time-of-flight mass spectrographs—From ions to neutral atoms
Galvin, A. B.; Kistler, L. M.; Kucharek, H. +2 more
After their introduction to space physics in the mid 1980s time-of-flight (TOF) spectrographs have become a main staple in spaceborne mass spectrometry. They have largely replaced magnetic spectrometers, except when extremely high mass resolution is required to identify complex molecules, for example, in the vicinity of comets or in planetary atmo…