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Lifting the dust veil from the globular cluster Palomar 2
Chies-Santos, Ana L.; Bonatto, Charles
This work employs high-quality Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) F606W and F814W photometry to correct for the differential reddening affecting the colour-magnitude diagram (CMD) of the poorly studied globular cluster (GC) Palomar 2. Differential reddening is taken into account by assuming that morphological difference…
Extended X-ray emission from the z = 4.26 radio galaxy 4C 63.20
Haardt, Francesco; Ciardi, Benedetta; Ghisellini, Gabriele +5 more
We report on deep Chandra X-ray Telescope imaging observations of 4C 63.20, one of the few known radio galaxies at z > 3.5. The X-ray counterpart is resolved into a core plus two off-nuclear sources that (combined) account for close to 30 per cent of the total X-ray flux. Their morphology and orientation are consistent with a diffuse, lobe-like…
Surprising Variability of the Planetary Nebula IC 4997 = QV Sge
Arkhipova, V. P.; Esipov, V. F.; Ikonnikova, N. P. +3 more
We present the results of a new epoch (2009-2019) of a long-term (50 years) photometric monitoring of the variable planetary nebula IC 4997 (QV Sge). The integral (star + nebula) $UBV$ light curves display a continuing brightening of $0\overset{m}{.}15$ in $V$, a slight rise (${<}0\overset{m}{.}1$) in $B$, and constancy in $U$. The $B-V$ color …
Discrete element modeling of boulder and cliff morphologies on comet 67P/Churyumov-Gerasimenko
Otto, K. A.; Sachse, M.; Kappel, D. +1 more
Context. Even after the Rosetta mission, some of the mechanical parameters of comet 67P/Churyumov-Gerasimenko's surface material are not yet well constrained. These parameters are needed to improve our understanding of cometary activity or for planning sample return missions.
Aims: We study some of the physical processes involved in the forma…
Fast Magnetosonic Waves and Flows in a Solar Prominence Foot: Observations and Modeling
Ofman, Leon; Kucera, Therese A.
We study recent observations of propagating fluctuations in a prominence foot with Hinode Solar Optical Telescope (SOT) high-resolution observations in Ca II and Hα emission, which we identify as nonlinear fast magnetosonic waves. Here we analyze further the observations of propagating waves and flows with Interface Region Imaging Spectrograph Mg …
Formation and dynamics of transequatorial loops
Tripathi, Durgesh; Ghosh, Avyarthana
Aims: We aim to study the dynamical evolution of transequatorial loops (TELs) using imaging techniques and spectroscopy.
Methods: We used the images recorded by the Atmospheric Imaging Assembly and the Helioseismic Magnetic Imager on board the Solar Dynamics Observatory together with spectroscopic observations taken from the Extreme-Ultr…
Gaia DR2 Distances to Planetary Nebulae
Manteiga, Minia; Dafonte, Carlos; Manchado, Arturo +2 more
The aim of this work is to examine distances to planetary nebulae (PNe) together with other properties that were derived from them, using the astrometry of Gaia Data Release 2 (DR2). We were able to identify 1571 objects classified as PNe, for which we assumed distances calculated following a Bayesian statistical approach. From those objects, we s…
UV and NIR size of the low-mass field galaxies: the UV compact galaxies
Cheng, Cheng; Huang, Jia-Sheng; Pan, Zhizheng +10 more
Context. Most of the massive star-forming galaxies are found to have "inside-out" stellar mass growth modes, which means the inner parts of the galaxies mainly consist of the older stellar population, while the star forming in the outskirt of the galaxy is still ongoing.
Aims: The high-resolution HST images from Hubble Deep UV Legacy Survey a…
Global maps of Venus nightside mean infrared thermal emissions obtained by VIRTIS on Venus Express
Drossart, P.; Piccioni, G.; Grassi, D. +6 more
One of the striking features about Venus atmosphere is its temporal variability and dynamics, with a chaotic polar vortex, large-scale atmospheric waves, sheared features and variable winds that depend on local time and possibly orographic features. The aim of this research is to combine data accumulated over several years and obtain a global mean…
The absolute magnitudes MJ, the binary fraction, and the binary mass ratios of M7-M9.5 dwarfs
Warren, S. J.; Laithwaite, R. C.
We use the large homogeneous sample of late M dwarfs, M7-M9.5, of Ahmed & Warren (2019) matched to Gaia DR2, to measure the relation between absolute magnitude and spectral type, and to infer the multiplicity fraction of the population, and the distribution of mass ratios in the binary systems. Binaries are identified photometrically as overlu…