Search Publications
The upper atmosphere of Venus: Model predictions for mass spectrometry measurements
Wurz, P.; Galli, A.; Vorburger, A. +1 more
Venus is the closest and most similar planet to Earth in the whole solar system, yet, basic measurements are missing. The atmospheric composition has been studied to some extent with the Pioneer Venus Orbiter mission and the more recent Venus Express, however, the concentration of many species and their isotopic ratios are not yet known with satis…
Astrometry and Occultation Predictions to Trans-Neptunian and Centaur Objects Observed within the Dark Energy Survey
Smith, M.; Abbott, T. M. C.; Abdalla, F. B. +60 more
Trans-Neptunian objects (TNOs) are a source of invaluable information to access the history and evolution of the outer solar system. However, observing these faint objects is a difficult task. As a consequence, important properties such as size and albedo are known for only a small fraction of them. Now, with the results from deep sky surveys and …
Early-type galaxies in low-density environments: NGC 6876 explored through its globular cluster system
Bassino, Lilia P.; Caso, Juan P.; Ennis, Ana I. +1 more
We present the results of a photometric study of the early-type galaxy NGC 6876 and the surrounding globular cluster (GC) system. The host galaxy is a massive elliptical, the brightest of this type in the Pavo Group. According to its intrinsic brightness (Mv ∼ -22.7), it is expected to belong to a galaxy cluster instead of a poor group.…
Proper Motions and Shock Wave Dynamics in the HH 7-11 Stellar Jet
Hartigan, P.; Frank, A.; Holcomb, R.
We have used the Hubble Space Telescope (HST) to acquire new broadband and narrowband images of the optical line emission and red continuum associated with the HH 7-11 stellar jet in the NGC 1333 star formation region. Combining the new narrowband images of Hα, [O I] λ6300, and [S II] λ6716 allows us to measure electron densities and excitations a…
Upper limits on the water vapour content of the β Pictoris debris disk
Olofsson, G.; Liseau, R.; Larsson, B. +3 more
Context. The debris disk surrounding β Pictoris has been observed with ALMA to contain a belt of CO gas with a distinct peak at 85 au. This CO clump is thought to be the result of a region of enhanced density of solids that collide and release CO through vaporisation. The parent bodies are thought to be comparable to solar system comets, in which …
Broadband X-ray observations of four gamma-ray narrow-line Seyfert 1 galaxies
Piconcelli, E.; Foschini, L.; Pogge, R. W. +4 more
Narrow-line Seyfert 1 galaxies (NLS1s) is one of the few classes of active galactic nuclei harboring powerful relativistic jets and detected in γ-rays. NLS1s are well-known X-ray sources. While in non-jetted sources the origin of this X-ray emission may be a hot corona surrounding the accretion disk, in jetted objects, especially beamed ones, the …
Annual parallax measurements of a semi-regular variable star SV Pegasus with VERA
Honma, Mareki; Nakagawa, Akiharu; Nagayama, Takahiro +6 more
Many studies have shown that there are clear sequences in the period-luminosity relationship (PLR) for Mira variables and semi-regular variables (SRVs) in the Large Magellanic Cloud (LMC). To investigate the PLR for SRVs in our galaxy, we examined the annual parallax measurement and conducted K'-band photometric monitoring of an SRV star SV Pegasu…
Galactic resonance rings: modelling of motions in the wide solar neighbourhood
Melnik, A. M.
Models of the Galaxy with analytical Ferrers bars can reproduce the residual velocities of OB associations in the Sagittarius, Perseus and Local System star-gas complexes located within 3 kpc of the solar neighbourhood. Ferrers ellipsoids with a density distribution defined by power indices n = 1 and 2 are considered. The successful reproduction o…
RR Lyrae Stars in the Field of Sagittarius II
Rey, Soo-Chang; Jerjen, Helmut; Cha, Sang-Mok +10 more
We present the detection of RR Lyrae variable stars in the field of the Sagittarius II (Sgr II) ultra-faint dwarf (UFD) galaxy. Using B, V time-series photometry obtained with the Korea Microlensing Telescope Network (KMTNet) 1.6 m telescope at CTIO and G-band data from Gaia Data Release 2 (DR2), we identified and characterized two ab-type and fou…
Galactic Rotation Based on OB Stars from the Gaia DR2 Catalogue
Bobylev, V. V.; Bajkova, A. T.
We have studied a sample containing 6000 OB stars with proper motions and trigonometric parallaxes from the Gaia DR2 catalogue. The following parameters of the angular velocity of Galactic rotation have been found: Ω0 = 29.70 ± 0.11 km s-1 kpc-1, Ω'0 = -4.035 ± 0.031 km s-1 kpc-2, a…