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The UV Spectrum of the Ultracool Dwarf LSR J1835+3259 Observed with the Hubble Space Telescope
Saur, Joachim; Roth, Lorenz; Feldman, Paul D. +4 more
An interesting question about ultracool dwarfs recently raised in the literature is whether their emission is purely internally driven or partially powered by external processes similar to planetary aurora known from the solar system. In this work, we present Hubble Space Telescope observations of the energy fluxes of the M8.5 ultracool dwarf LSR …
Untwisting Jets Related to Magnetic Flux Cancellation
Wang, Yuming; Liu, Rui; Liu, Jiajia +1 more
The rotational motion of solar jets is believed to be a signature of the untwisting process resulting from magnetic reconnection, which takes place between twisted closed magnetic loops (i.e., magnetic flux ropes) and open magnetic field lines. The identification of the pre-existing flux rope, and the relationship between the twist contained in th…
Simultaneous VLBI Astrometry of H2O and SiO Masers toward the Semiregular Variable R Crateris
Kim, Dong-Jin; Rioja, María J.; Dodson, Richard +7 more
We obtained, for the first time, astrometrically registered maps of the 22.2 GHz H2O and 42.8, 43.1, and 86.2 GHz SiO maser emission toward the semiregular b-type variable (SRb) R Crateris, at three epochs (2015 May 21, and 2016 January 7 and 26) using the Korean Very-long-baseline Interferometry Network. The SiO masers show a ring-like…
Flux Relaxation after Two Outbursts of the Magnetar SGR 1627-41 and Possible Hard X-Ray Emission
An, Hongjun; Kaspi, Victoria M.; Cumming, Andrew
We report on the long-term flux relaxation of the magnetar SGR 1627-41 after its 2008 outburst, and evidence for hard X-ray excess measured with NuSTAR. We use new observations made with Chandra and XMM-Newton, and an archival NuSTAR observation, which add flux measurements at ∼2000 days into quiescence after the 2008 outburst. We find that the so…
Hard X-Ray View of HCG 16 (Arp 318)
Tanimoto, Atsushi; Ueda, Yoshihiro; Ricci, Claudio +1 more
We report the hard X-ray (3-50 keV) view of the compact group HCG 16 (Arp 318) observed with the Nuclear Spectroscopic Telescope Array (NuSTAR). NGC 838 and NGC 839 are undetected at energies above 8 keV, showing no evidence of heavily obscured active galactic nuclei (AGNs). This confirms that these are starburst-dominant galaxies as previously su…
Tracking Filament Evolution in the Low Solar Corona Using Remote Sensing and In Situ Observations
Kocher, Manan; Landi, Enrico; Lepri, Susan. T.
In the present work, we analyze a filament eruption associated with an interplanetary coronal mass ejection that arrived at L1 on 2011 August 5. In multiwavelength Solar Dynamic Observatory/Advanced Imaging Assembly (AIA) images, three plasma parcels within the filament were tracked at high cadence along the solar corona. A novel absorption diagno…
Deconvolving the HD 81809 Binary: Rotational and Activity Evidence for a Subgiant with a Sun-like Cycle
Egeland, Ricky
HD 81809 has one of the highest quality activity cycles from the sample of stars synoptically observed in the Mount Wilson Observatory HK Project. However, this object is in fact a binary system, raising the question as to which of the components is responsible for the observed cyclic activity and what are the properties of that active component. …
Stormy Weather in 3C 196.1: Nuclear Outbursts and Merger Events Shape the Environment of the Hybrid Radio Galaxy 3C 196.1
Lovisari, L.; Forman, W. R.; Liuzzo, E. +8 more
We present a multiwavelength analysis based on archival radio, optical, and X-ray data of the complex radio source 3C 196.1, whose host is the brightest cluster galaxy of a z = 0.198 cluster. HST data show Hα+[N II] emission aligned with the jet 8.4 GHz radio emission. An Hα+[N II] filament coincides with the brightest X-ray emission, the northern…
The Identification of Hydrogen-deficient Cataclysmic Variable Donor Stars
Harrison, Thomas E.
We have used ATLAS12 to generate hydrogen-deficient stellar atmospheres to allow us to construct synthetic spectra to explore the possibility that the donor stars in some cataclysmic variables (CVs) are hydrogen deficient. We find that four systems, AE Aqr, DX And, EY Cyg, and QZ Ser, have significant hydrogen deficits. We confirm that carbon and …
Deep Chandra Observations of X-Ray Point Sources in M87
Goulding, Andy D.; Andrade-Santos, Felipe; Jones, Christine +6 more
We present a study of X-ray source populations in M87, the cD galaxy of the Virgo cluster, using 12 archival Chandra observations with a total exposure of ∼680 ks spanning about a decade. A total of 346 point-like sources are detected down to a limiting 0.5-8 keV luminosity of 4 × 1037 erg s-1 and out to a galactocentric radi…