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Geomorphological mapping of comet 67P/Churyumov-Gerasimenko's Southern hemisphere
Bertaux, Jean-Loup; Da Deppo, Vania; Naletto, Giampiero +49 more
In 2015 May, the Southern hemisphere of comet 67P/Churyumov-Gerasimenko became visible by the OSIRIS cameras on-board the Rosetta spacecraft. The resolution was high enough to carry out a detailed analysis of the surface morphology, which is quite different from the Northern hemisphere. Previous works show that fine particle deposits are the most …
The perihelion activity of comet 67P/Churyumov-Gerasimenko as seen by robotic telescopes
Meech, Karen J.; Snodgrass, Colin; Lister, Tim +13 more
Around the time of its perihelion passage, the observability of 67P/Churyumov-Gerasimenko from Earth was limited to very short windows each morning from any given site, due to the low solar elongation of the comet. The peak in the comet's activity was therefore difficult to observe with conventionally scheduled telescopes, but was possible where s…
Properties of the cluster population of NGC 1566 and their implications
Bastian, N.; Ryon, J. E.; Adamo, A. +2 more
We present results of a photometric study into the cluster population of NGC 1566, a nearby grand design spiral galaxy, sampled out to a Galactocentric radius of ≈5.5 kpc. The shape of the mass-limited age distribution shows negligible variation with radial distance from the centre of the galaxy, and demonstrates three separate sections, with a st…
Searching in the dark: the dark mass content of the Milky Way globular clusters NGC288 and NGC6218
Dalessandro, E.; Mucciarelli, A.; Origlia, L. +8 more
We present an observational estimate of the fraction and distribution of dark mass in the innermost region of the two Galactic globular clusters NGC 6218 (M12) and NGC 288. Such an assessment has been made by comparing the dynamical and luminous mass profiles derived from an accurate analysis of the most extensive spectroscopic and photometric sur…
Distance and extinction determination for APOGEE stars with Bayesian method
Shi, Jianrong; Pan, Kaike; Chen, Bingqiu +3 more
Using a Bayesian technology, we derived distances and extinctions for over 100 000 red giant stars observed by the Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey by taking into account spectroscopic constraints from the APOGEE stellar parameters and photometric constraints from Two Micron All-Sky Survey, as well as a prior …
Rings and arcs around evolved stars - I. Fingerprints of the last gasps in the formation process of planetary nebulae
Guerrero, M. A.; Toalá, J. A.; Santamaría, E. +3 more
Evolved stars such as asymptotic giant branch stars (AGB), post-AGB stars, proto-planetary nebulae (proto-PNe), and planetary nebulae (PNe) show rings and arcs around them and their nebular shells. We have searched for these morphological features in optical Hubble Space Telescope and mid-infrared Spitzer Space Telescope images of ∼650 proto-PNe a…
Simulation tests of galaxy cluster constraints on chameleon gravity
Zhao, Gong-Bo; Bacon, David; Romer, A. Kathy +3 more
We use two new hydrodynamical simulations of Λ cold dark matter (ΛCDM) and f(R) gravity to test the methodology used by Wilcox et al. (W15) in constraining the effects of a fifth force on the profiles of clusters of galaxies. We construct realistic simulated stacked weak lensing and X-ray surface brightness cluster profiles from these cosmological…
Geologic mapping of the Comet 67P/Churyumov-Gerasimenko's Northern hemisphere
Jorda, L.; Lamy, P. L.; Lara, L. M. +52 more
The Optical, Spectroscopic, and Infrared Remote Imaging System (OSIRIS), the scientific imaging system onboard the Rosetta mission, has been acquiring images of the nucleus of the comet 67P/Churyumov-Gerasimenko since 2014 August with a resolution which allows a detailed analysis of its surface. Indeed, data reveal a complex surface morphology whi…
Spectrophotometry of the Khonsu region on the comet 67P/Churyumov-Gerasimenko using OSIRIS instrument images
Jorda, L.; Lamy, P. L.; Bertaux, J. -L. +47 more
Our work focuses on the spectrophotometric analysis of selected terrain and bright patches in the Khonsu region on the comet 67P/Churyumov-Gerasimenko. Despite the variety of geological features, their spectrophotometric properties appear to indicate a similar composition. It is noticeable that the smooth areas in Khonsu possess similar spectropho…
Probing dark matter crests with white dwarfs and IMBHs
Schödel, R.; Amaro-Seoane, P.; Casanellas, J. +2 more
White dwarfs (WDs) are the most promising captors of dark matter (DM) particles in the crests that are expected to build up in the cores of dense stellar clusters. The DM particles could reach sufficient densities in WD cores to liberate energy through self-annihilation. The extinction associated with our Galactic Centre makes it impossible to det…