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Near- to mid-infrared spectroscopy of the heavily obscured AGN LEDA 1712304 with AKARI/IRC
Oyabu, S.; Toba, Y.; Kaneda, H. +5 more
Context. Although heavily obscured active galactic nuclei (AGNs) have been found by many observational studies, the properties of the surrounding dust are poorly understood. Using AKARI/IRC spectroscopy, we discovered a new heavily obscured AGN in LEDA 1712304 which shows a deep spectral absorption feature due to silicate dust.
Aims: We study…
A Photometric Study of the Contact Binary V384 Serpentis
Michaels, E. J.; Lanning, C. M.; Self, S. N.
In this paper we present the first photometric light curves in the Sloan g', r', and i' passbands for the contact binary V384 Ser. Photometric solutions were obtained using the Wilson-Devinney program which revealed the star to be a W-type system with a mass ratio of q = 2.65 and a f = 36% degree of contact. The less massive component was found to…
An XMM-Newton look at the strongly variable radio-weak BL Lac Fermi J1544-0639
Pian, E.; Masetti, N.; Ubertini, P. +6 more
Context. Fermi J1544-0639/ASASSN-17gs/AT2017egv was identified as a gamma-ray/optical transient on May 15, 2017. Subsequent multiwavelength observations suggest that this source may belong to the new class of radio-weak BL Lacs.
Aims: We studied the X-ray spectral properties and short-term variability of Fermi J1544-0639 to constrain the X-ra…
Generalized Additive Modeling Combined With Multiple Collinear for ICME Velocity Forecasting
Ji, H. S.; Wang, M.; Lu, J. Y. +5 more
One of the main issues of space weather is the timely prediction of disturbed solar wind parameters at L1, especially caused by Coronal Mass Ejection (CME). Using the data from 170 front halo, flare-associated CMEs, and in-site solar wind data, an analysis of the Interplanetary Coronal Mass Ejection (ICME) peak velocity at L1 related to associated…
Ultraviolet HST Spectroscopy of Planck Cold Clumps
Meyer, David M.; Dirks, Cody
We report results of the first study utilizing the ultraviolet capabilities of the Hubble Space Telescope to investigate a sample of Planck Galactic Cold Clump (PGCC) sources. We have selected high-resolution spectra toward 25 stars that contain a multitude of interstellar absorption lines associated with the interstellar medium (ISM) gas within t…
Kinematics of Hot Subdwarfs from the Gaia DR2 Catalogue
Bobylev, V. V.; Bajkova, A. T.
We have studied the kinematic properties of the candidates for hot subdwarfs (HSDs) selected by Geier et al. from theGaiaDR2 catalogue. We have used a total of 12 515 stars with relative trigonometric parallax errors less than 30%. The HSDs are shown to have different kinematics, depending on their positions on the celestial sphere. For example, t…
Active experiments beyond the Earth: Plasma effects of sounding radar operations in the ionospheres of Venus, Mars, and the Jovian system
Barabash, Stas; Holmstrom, Mats; Frahm, Rudy A. +1 more
Operation of powerful satellite- and rocket-born sounding radars is often accompanied by a heating/acceleration of the local electrons and ions. Intense fluxes of sounder accelerated particles were detected in Earth's ionosphere when the frequency of the radar transmitter was close to one of the fundamental plasma resonances: harmonic of the elect…
Seismological Determination of the Alfvén Speed and Plasma Beta in Solar Photospheric Bright Points
Moon, Yong-Jae; Cho, Kyung-Suk; Kim, Yeon-Han +7 more
The Alfvén speed and plasma beta in photospheric bright points (BPs) observed by the Broadband Filter Imager (BFI) of the Solar Optical Telescope on board the Hinode satellite are estimated seismologically. The diagnostics is based on the theory of slow magnetoacoustic waves in a non-isothermally stratified photosphere with a uniform vertical magn…
Formation of Central Pits in Impact Craters on Mars: A Statistical Investigation of Proposed Mechanisms
Burr, Devon M.; Peel, Samantha E.; Tran, Liem
Central pit craters (CPCs) are complex craters that exhibit depressions within their floors or central uplifts. Some proposed models for central pit formation can be grouped by similar mechanism: (A) explosive volatile release, (B) central peak collapse, and (C) drainage of subsurface melted volatiles. We test these groups of mechanisms for centra…
Isolated High-Density Structures in Magnetic Anomaly Regions of the Martian Lower Ionosphere
Venkateswara Rao, N.; Leelavathi, V.; Mohanamanasa, P. +1 more
The occurrence of density structures in magnetic anomaly regions is one of the prominent features of the Martian ionosphere. These structures, in general, occur at altitudes above the main peak. In the present study, we analyze four cases of unusually strong oblique echoes that occur in magnetic anomaly regions and are observed by the Mars Express…