Search Publications
Gas and stellar dynamics in Stephan's Quintet. Mapping the kinematics in a closely interacting compact galaxy group
Eckart, A.; Sánchez-Monge, Á.; Yttergren, M. +4 more
In nearby compact galaxy groups we can study the complex processes of galaxy interactions at high resolution and obtain a window into a time in the history of the Universe when the galaxies were closely spaced and the intergalactic medium was awash with gas. Stephan's Quintet is a nearby compact galaxy group and a perfect laboratory for studying t…
NGC 6124: a young open cluster with anomalous- and fast-rotating giant stars
Pereira, C. B.; Holanda, N.; Drake, N. A. +5 more
We present the results of a chemical analysis of fast and anomalous rotator giants members of the young open cluster NGC 6124. For this purpose, we carried out abundances of the mixing sensitive species such as Li, C, N, Na, and 12C/13C isotopic ratio, as well as other chemical species for a sample of four giants among the se…
The Spatial Distributions of Blue Main-sequence Stars in Magellanic Cloud Star Clusters
Deng, Licai; de Grijs, Richard; Li, Chengyuan +1 more
The color-magnitude diagrams of young star clusters show that, particularly at ultraviolet wavelengths, their upper main sequences (MSs) bifurcate into a sequence comprising the bulk population and a blue periphery. The spatial distribution of stars is crucial to understanding the reasons for these distinct stellar populations. This study uses hig…
The Astrophysical Variance in Gaia-Radial Velocity Spectrometer Spectra
Rampalli, Rayna; Ness, Melissa; Wylie, Shola
Large surveys are providing a diversity of spectroscopic observations with Gaia alone set to deliver millions of Ca-triplet-region spectra across the Galaxy. We aim to understand the dimensionality of the chemical abundance information in the Gaia-Radial Velocity Spectrometer (RVS) data to inform galactic archeology pursuits. We fit a quadratic mo…
Electric field measurements at the plasma frequency around comet 67P by RPC-MIP on board Rosetta
Palmerio, E.; Nilsson, H.; Henri, P. +7 more
Context. The Mutual Impedance Probe (RPC-MIP) carried by the Rosetta spacecraft monitored both the plasma density and the electric field in the close environment of comet 67P/Churyumov-Gerasimenko (67P), as the instrument was operating alternatively in two main modes: active and passive. The active mode is used primarily to perform plasma density …
The Origins and Geological Histories of Deimos and Phobos: Hypotheses and Open Questions
Head, James W.; Ramsley, Kenneth R.
Quantitative measurements and photographic imaging of the moons of Mars set limits on several key geological conclusions-such as the orbits of the moons. Other examples include their estimated bulk densities where Phobos has a density of ∼1.876 g/cm3 and Deimos has a lower and less certain density of ∼1.48 g/cm3. Imaging data…
The near-UV transit of HD 189733b with the XMM-Newton optical monitor
Wheatley, Peter J.; Louden, Tom; Steinrueck, Maria E. +6 more
We present analysis of XMM-Newton optical monitor observations in the near-ultraviolet of HD 189733, covering 20 primary transits of its hot Jupiter planet. The transit is clearly detected with both the UVW2 and UVM2 filters, and our fits to the data reveal transit depths in agreement with that observed optically. The measured depths correspond to…
The New Ephemeris and Light Curve Analysis of V870 Ara by the Ground-Based and TESS Data
Davoudi, Fatemeh; Poro, Atila; Blackford, Mark G. +4 more
New CCD photometric observations and their investigation of the W UMa-type binary, V870 Ara, are presented. Light curves of the system were taken through BVIfilters from the Congarinni Observatory in Australia. The new ephemeris is calculated based on seven new determined minimum times, together with the TESS data and others compiled from the lite…
Dayside Magnetopause Processes
Fuselier, Stephen A.
A 2-d orbital period for a redback millisecond pulsar candidate in the globular cluster NGC 6397
Maccarone, Thomas J.; Heinke, Craig O.; Pichardo Marcano, Manuel +2 more
We report optical modulation of the companion to the X-ray source U18 in the globular cluster NGC 6397. U18, with combined evidence from radio and X-ray measurements, is a strong candidate as the second redback in this cluster, initially missed in pulsar searches. This object is a bright variable star with an anomalous red colour and optical varia…