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Orbital variability of the optical linear polarization of the γ-ray binary LS I +61° 303 and new constraints on the orbital parameters
Piirola, Vilppu; Tsygankov, Sergey S.; Poutanen, Juri +8 more
We studied the variability of the linear polarization and brightness of the γ-ray binary LS I +61° 303. High-precision BVR photopolarimetric observations were carried out with the Dipol-2 polarimeter on the 2.2 m remotely controlled UH88 telescope at Mauna Kea Observatory and the 60 cm Tohoku telescope at Haleakala bservatory (Hawaii) over 140 nig…
Estimating the Temperature and Density of a Spicule from 100 GHz Data Obtained with ALMA
Shibata, Kazunari; Shimojo, Masumi; Narukage, Noriyuki +6 more
We succeeded in observing two large spicules simultaneously with the Atacama Large Millimeter/submillimeter Array (ALMA), the Interface Region Imaging Spectrograph (IRIS), and the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamics Observatory. One is a spicule seen in the IRIS Mg II slit-jaw images and AIA 304 Å images (Mg II/304 Å spi…
Follow-up Studies of Five Cataclysmic Variable Candidates Discovered by LAMOST
Thorstensen, John R.
We report follow-up observations of five cataclysmic variable candidates from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) published by Hou et al. LAMOST J024048.51+195226.9 is the most unusual of the five; an early-M type secondary star contributes strongly to its spectrum, and its spectral and photometric behavior are s…
Plasma Diagnostics from Active Region and Quiet-Sun Spectra Observed by Hinode/EIS: Quantifying the Departures from a Maxwellian Distribution
Dudík, Jaroslav; Dzifčáková, Elena; Mason, Helen E. +2 more
We perform plasma diagnostics, including that of the non-Maxwellian κ-distributions, in several structures observed in the solar corona by the Extreme-Ultraviolet Imaging Spectrometer (EIS) on board the Hinode spacecraft. To prevent uncertainties due to the in-flight calibration of EIS, we selected spectral atlases observed shortly after the launc…
The Sloan Digital Sky Survey Reverberation Mapping Project: the XMM-Newton X-Ray Source Catalog and Multiband Counterparts
Green, Paul J.; Shen, Yue; Nandra, Kirpal +10 more
The XMM-RM project was designed to provide X-ray coverage of the Sloan Digital Sky Survey Reverberation Mapping (SDSS-RM) field. Forty-one XMM-Newton exposures, placed surrounding the Chandra AEGIS field, were taken, covering an area of 6.13 deg2 and reaching a nominal exposure depth of ∼15 ks. We present an X-ray catalog of 3553 source…
A White-light Flare Powered by Magnetic Reconnection in the Lower Solar Atmosphere
Chen, Yajie; Song, Yongliang; Tian, Hui +3 more
White-light flares (WLFs), first observed in 1859, refer to a type of solar flare showing an obvious enhancement of the visible continuum emission. This type of enhancement often occurs in most energetic flares, and is usually interpreted as a consequence of efficient heating in the lower solar atmosphere through nonthermal electrons propagating d…
Constraining Type Iax supernova progenitor systems with stellar population age dating
Foley, Ryan J.; Rest, Armin; Fong, Wen-fai +6 more
Type Iax supernovae (SNe Iax) are the most common class of peculiar SNe. While they are thought to be thermonuclear white-dwarf (WD) SNe, SNe Iax are observationally similar to, but distinct from SNe Ia. Unlike SNe Ia, where roughly 30 per cent occur in early-type galaxies, only one SN Iax has been discovered in an early-type galaxy, suggesting a …
Sudden and steady orbital period changes across six classical Nova Eruptions: the end of hibernation and two serious challenges for the magnetic braking model of cataclysmic variable evolution
Schaefer, Bradley E.
I report on two new measures of the sudden change in the orbital period (P) across the nova eruption (ΔP) and the steady period change in quiescence (\dot{P}) for classical novae (CNe) RR Pic and HR Del, bringing a total of six such measures for CNe, all in a final report of my large and long observing program. The fractional changes (ΔP/P) in par…
A disc reflection model for ultra-soft narrow-line Seyfert 1 galaxies
Fabian, Andrew C.; Reynolds, Christopher S.; Jiang, Jiachen +2 more
We present a detailed analysis of the XMM-Newton observations of five narrow-line Seyfert 1 galaxies (NLS1s). They all show very soft continuum emission in the X-ray band with a photon index of Γ ≳ 2.5. Therefore, they are referred to as 'ultra-soft' NLS1s in this paper. By modelling their optical/UV-X-ray spectral energy distribution (SED) with a…
An underlying clock in the extreme flip-flop state transitions of the black hole transient Swift J1658.2-4242
Nandra, K.; Ponti, G.; Miller-Jones, J. C. A. +8 more
Aims: Flip-flops are top-hat-like X-ray flux variations, which have been observed in some transient accreting black hole binary systems, and feature simultaneous changes in the spectral hardness and the power density spectrum (PDS). They occur at a crucial time in the evolution of these systems, when the accretion disc emission starts to domi…