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The interplay between active galactic nuclei and star formation activities of type 1 active galactic nuclei probed by polycyclic aromatic hydrocarbon 3.3 µm emission feature with AKARI
Nakagawa, Takao; Oyabu, Shinki; Ohyama, Youichi +11 more
We investigate the connection between active galactic nucleus (AGN) and star formation activities of AGN host galaxies by studying the 3.3 µm polycyclic aromatic hydrocarbon (PAH) emission feature of 79 type 1 AGNs using the AKARI space telescope. Utilizing the slitless spectroscopic capability of the AKARI Infrared Camera, we obtained the s…
X-ray activity from different types of stars
Zhang, Yong; Soria, Roberto; Bai, Yu +10 more
X-ray emission is an important indicator of stellar activity. In this paper, we study stellar X-ray activity using the XMM-Newton and LAMOST data for different types of stars. We provide a sample including 1259 X-ray-emitting stars, of which 1090 have accurate stellar parameter estimations. Our sample size is much larger than those used in previou…
Warm CO in evolved stars from the THROES catalogue. II. Herschel/PACS spectroscopy of C-rich envelopes
García-Lario, P.; Sánchez Contreras, C.; da Silva Santos, J. M. +1 more
Context. This is the second paper of a series making use of Herschel/PACS spectroscopy of evolved stars in the THROES catalogue to study the inner warm regions of their circumstellar envelopes (CSEs).
Aims: We analyse the CO emission spectra, including a large number of high-J CO lines (from J = 14-13 to J = 45-44, ν = 0), as a proxy for the …
The loud and the quiet: searching for radio counterparts of two radio-weak BL Lac candidates with VLBI
Frey, Sándor; Yang, Jun; An, Tao +4 more
BL Lac objects are known to have compact jets inclined to our line of sight at a small angle, showing prominent radio emission. Two radio-weak BL Lac candidates with no counterparts in current radio surveys were recently reported by Massaro et al. Both sources were selected as candidate low-energy counterparts of unassociated Fermi γ-ray sources. …
Signal enhancement for planetary radar sounders
Seu, R.; Mastrogiuseppe, M.; Piazzo, L. +1 more
Geomorphological Evidence of Localized Stagnant Ice Deposits in Terra Cimmeria, Mars
Hauber, Ernst; Jaumann, Ralf; Fawdon, Peter +3 more
The presence of snow and ice at midlatitudes of Mars cannot be explained by current climatic conditions, as surface ice is unstable. However, a large variety of debris-covered glaciers have been observed at both midlatitudes. Here, we report the presence of local, small-scale, and debris-covered stagnant ice deposits on the floor of a valley syste…
Variation of coronal holes latitudinal distribution: Correction of limb brightening of EUV coronal images
Chargeishvili, B. B.; Maghradze, D. A.; Japaridze, D. R. +4 more
We studied the limb brightening of SOHO EIT daily images of the solar corona taken in 195 Å wavelength line from 1996 to 2018. Using special software, we studied the distribution of the background intensity of the entire disk in the direction of rotation (horizontally) and perpendicular to the direction of rotation (vertical). The study shows that…
2FHL J0826.1-4500: Discovery of a Possible Shock-Cloud Interaction on the Western Edge of the Vela Supernova Remnant
Ajello, M.; Tibaldo, L.; Marchesi, S. +3 more
We report on the investigation of a very high-energy, Galactic γ-ray source recently discovered at >50 GeV using the Large Area Telescope on board Fermi. This object, 2FHL J0826.1-4500, displays one of the hardest >50 GeV spectra (photon index Γ γ ∼ 1.6) in the 2FHL catalog, and a follow-up observation with XMM-Newton has uncover…
HD 42659: the only known roAp star in a spectroscopic binary observed with B photometry, TESS, and SALT
Holdsworth, Daniel L.; Saio, Hideyuki; Kurtz, Donald W.
We present a multi-instrument analysis of the rapidly oscillating Ap (roAp) star HD 42659. We have obtained B photometric data for this star and use these data, in conjunction with the Transiting Exoplanet Survey Satellite (TESS) observations, to analyse the high-frequency pulsation in detail. We find a triplet that is split by the rotation freque…
Post-rendezvous radar properties of comet 67P/CG from the Rosetta Mission: understanding future Earth-based radar observations and the dynamical evolution of comets
Kofman, Wlodek; Heggy, Essam; Palmer, Elizabeth M. +2 more
Radar observations provide crucial insights into the formation and dynamical evolution of comets. This ability is constrained by our knowledge of the dielectric and textural properties of these small-bodies. Using several observations by Rosetta as well as results from the Earth-based Arecibo radio telescope, we provide an updated and comprehensiv…