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Deciphering the 3D Orion Nebula. III. Structure on the NE Boundary of the Orion-S Embedded Molecular Cloud
Abel, N. P.; O'Dell, C. R.; Ferland, G. J.
We have extended the work of Papers I and II of this series to determine at a higher spatial resolution the properties of the embedded Orion-S Molecular Cloud that lies within the ionized cavity of the Orion Nebula and of the thin ionized layer that lies between the Cloud and the observer. This was done using existing and new [N II] (658.3 nm) and…
Morphological study of the nested planetary nebula Hubble 12
Zhang, Yong; Sadjadi, SeyedAbdolreza; Hsia, Chih-Hao +3 more
We present a visible-infrared imaging study of young planetary nebula (PN) Hubble 12 (Hb 12; PN G111.8-02.8) obtained with Hubble Space Telescope (HST) archival data and our own Canada-France-Hawaii Telescope (CFHT) measurements. Deep HST and CFHT observations of this nebula reveal three pairs of bipolar structures and an arc-shaped filament near …
MEGARA-GTC stellar spectral library - II. MEGASTAR first release
Mollá, M.; Cardiel, N.; Gil de Paz, A. +4 more
MEGARA is an optical integral field and multi-object fibre-based spectrograph for the 10.4 m Gran Telescopio CANARIAS that offers medium-to-high spectral resolutions (FWHM) of R ≃ 6000, 12 000, 20 000. Commissioned at the telescope in 2017, it started operation as a common-user instrument in 2018. We are creating an instrument-oriented empirical s…
An investigation of the causal relationship between sunspot groups and coronal mass ejections by determining source active regions
Wang, Haimin; Wang, Jason T. L.; Cavus, Huseyin +3 more
Although the source active regions of some coronal mass ejections (CMEs) were identified in CME catalogues, vast majority of CMEs do not have an identified source active region. We propose a method that uses a filtration process and machine learning to identify the sunspot groups associated with a large fraction of CMEs and compare the physical pa…
The Gaia-ASAS-SN Classical Cepheid Sample. I. Sample Selection
Rix, Hans-Walter; Drimmel, R.; Poggio, E. +4 more
We present a well-defined and characterized all-sky sample of classical Cepheids in the Milky Way, obtained by combining two time-domain all-sky surveys: Gaia DR2 (Gaia Collaboration et al. 2018) and All-Sky Automated Survey for Supernovae (ASAS-SN; Shappee et al. 2014). We first use parallax and variability information from Gaia to select ~30,000…
High-resolution imaging follow-up of doubly imaged quasars
Treu, Tommaso; Wisotzki, Lutz; Fassnacht, Christopher D. +8 more
We report upon 3 years of follow-up and confirmation of doubly imaged quasar lenses through imaging campaigns from 2016 to 2018 with the Near-Infrared Camera2 (NIRC2) on the W. M. Keck Observatory. A sample of 57 quasar lens candidates are imaged in adaptive-optics-assisted or seeing-limited K'-band observations. Out of these 57 candida…
Red Be stars in the Magellanic Clouds?
Vieira, Katherine; Hernández, Jesús; García-Varela, Alejandro +2 more
We revisit the subject of Be candidate stars towards the Magellanic Clouds, previously studied by the authors using SPM4 proper motions. We obtain Gaia DR2 parallaxes and proper motions for 2357 and 994 LMC and SMC Be candidates, respectively. Parallaxes and proper motions versus colour V - I easily reveal the presence of the redder galactic conta…
A possible nonthermal X-ray emission from γ Cas analogues stars
Ryspaeva, Elizaveta B.; Kholtygin, Alexander F.
We analyze the archival XMM-Newton X-ray observations of 15 γ Cas analogue stars and two candidates for such objects. The EPIC spectra of the considered stars in the range of 0.2-8 keV were extracted and fitted by different models. Our estimates show that assuming the X-ray emission from γ Cas analogues to be totally thermal, their model plasma te…
Optical observations of near isotropic comet C/2006 OF2 (Broughton) at two different heliocentric distances
Lara, L.; Afanasiev, V.; Kulyk, I. +3 more
Spectra and images of comet C/2006 OF2 (Broughton) were obtained with the 4.2-m William Herschel Telescope (La Palma, Spain) and with the 6-m Big Telescope Alt-azimuth (SAO RAN, Russia) at two observing epochs on October 15, 2007 and December 05, 2008.The comet was at heliocentric distances of 4.24 au and 2.59 au before and after the perihelion, r…
Curiouser and curiouser: the peculiar chemical composition of the Li- and Na-rich star in ω Centauri
Salaris, M.; Bonifacio, P.; Momany, Y. +5 more
We present a multi-instrument spectroscopic analysis of the unique Li- and Na-rich giant star #25664 in ω Centauri, using spectra acquired with FLAMES-GIRAFFE, X-shooter, UVES, and HARPS. Li and Na abundances have been derived from the UVES spectrum using transitions weakly sensitive to non-local thermodynamic equilibrium and assumed isotopic rati…