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Investigation of the subsurface structure of a sunspot based on the spatial distribution of oscillation centers inferred from umbral flashes
Chae, Jongchul; Cho, Kyuhyoun; Madjarska, Maria S.
The subsurface structure of a solar sunspot is important for the stability of the sunspot and the energy transport therein. Two subsurface structure models have been proposed, the monolithic and cluster models, but no clear observational evidence supporting a particular model has been found to date. To obtain clues about the subsurface structure o…
Pairing function of visual binary stars
Chulkov, Dmitry
An all-sky sample of 1227 visual binaries based on Washington Double Star catalogue is constructed to infer the initial mass function (IMF), mass ratio, and projected distance distribution with a dedicated population synthesis model. Parallaxes from Gaia DR2 and Hipparcos are used to verify the distance distribution. The model is validated on the …
Chemodynamics of metal-poor wide binaries in the Galactic halo: Association with the Sequoia event
Hansen, Camilla Juul; Peñarrubia, Jorge; Lépine, Sebastien +4 more
Recently, an increasing number of wide binaries has been discovered. Their chemical and dynamical properties are studied through extensive surveys and pointed observations. However, the formation of these wide binaries is far from clear, although several scenarios have been suggested. In order to investigate the chemical compositions of these syst…
The origin of X-ray emission in 3CRR sources: Hints from mid-infrared Spitzer observations
Li, Shuang-Liang; Gu, Minfeng
Aims: Whether X-ray emission in radio-loud (RL) active galactic nuclei (AGNs) originates from disk coronae or jets is still under debate. For example, the positive relationships in radio-quiet AGNs (such as the optical to X-ray spectral index αOX and Eddington ration λO as well as the X-ray photon index Γ and λO
Nonthermal Velocity in the Transition Region of Active Regions and Its Center-to-limb Variation
Tripathi, Durgesh; Ghosh, Avyarthana; Klimchuk, James A.
We derive the nonthermal velocities (NTVs) in the transition region of an active region using the Si IV 1393.78 Å line observed by the Interface Region Imaging Spectrograph and compare them with the line-of-sight photospheric magnetic fields obtained by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory. The active region…
Optical Properties of Interstellar Dust around the Orion A Molecular Cloud
Dobashi, Kazuhito; Shimoikura, Tomomi; Naoi, Takahiro +2 more
We have studied optical properties of interstellar dust around the Orion A molecular cloud to investigate the size distribution and the composition of dust grains. Orion A is one of the most studied molecular clouds in the solar vicinity (d ≃ 400 pc). In this paper, we used optical and near-infrared photometric data. The optical data were obtained…
Deep Observations of CO and Free-Free Emission in Ultraluminous Infrared QSO IRAS F07599+6508
Kohno, Kotaro; Daddi, Emanuele; Gao, Yu +4 more
Infrared quasi-stellar objects (IR QSOs) are a rare subpopulation selected from ultraluminous infrared galaxies (ULIRGs) and have been regarded as promising candidates of ULIRG-to-optical QSO transition objects. Here we present NOEMA observations of the CO (1-0) line and 3 mm continuum emission in IR QSO IRAS F07599+6508 at z = 0.1486, which has m…
Searching for Surviving Companion in the Young SMC Supernova Remnant 1E 0102.2-7219
Ruiter, Ashley J.; Chu, You-Hua; Li, Chuan-Jui +3 more
1E 0102.2-7219 (hereafter E0102) is a young supernova remnant (SNR) in the Small Magellanic Cloud. It contains oxygen-rich SN ejecta, a possible neutron star (NS), and a small amount of fast-moving H-rich ejecta material. These properties are also seen in Cas A; it has thus been suggested that E0102 is also a Type IIb SNR, whose SN progenitor's hy…
A Long-Term Study of Ultraluminous X-ray Sources in NGC 891
Earley, Nicholas M.; Dwarkadas, Vikram V.; Cirillo, Victoria
We perform empirical fits to the Chandra and XMM-Newton spectra of three ultraluminous X-ray sources (ULXs) in the edge-on spiral galaxy NGC 891, monitoring the region over a 17-year time window. One of these sources was visible since the early 1990s with ROSAT and was observed multiple times with Chandra and XMM-Newton. Another was visible since …
Identification of a new spectral signature at 3 µm over Martian northern high latitudes: Implications for surface composition
Montmessin, Franck; Vincendon, Mathieu; Beck, Pierre +1 more
Mars northern polar latitudes are known to harbor an enhanced 3 µm spectral signature when observed from orbit. This may indicate a greater amount of surface adsorbed or bound water, although it has not yet been possible to easily reconcile orbital observations with ground measurements by Phoenix. Here we re-analyzed OMEGA/Mars Express obser…