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Non-thermal Electron Energization During the Impulsive Phase of an X9.3 Flare Revealed by Insight-HXMT
Wang, W.; Tian, H.; Zhang, S. +8 more
The X9.3 flare SOL20170906T11:55 was observed by the CsI detector aboard the first Chinese X-ray observatory Hard X-ray Modulation telescope (Insight-HXMT). Using the wavelets method, we report 22 s quasiperiodic pulsations during the impulsive phase. The spectra from 100 keV to 800 keV show the evolution with the gamma-ray flux of a power-law pho…
Hard X-Ray Emission Associated with White Dwarfs. IV. Signs of Accretion from Substellar Companions
Toalá, Jesús A.; Guerrero, Martín A.; Chu, You-Hua +3 more
With an effective temperature of ≃200,000 K, KPD 0005+5106 is one of the hottest white dwarfs (WDs). ROSAT unexpectedly detected "hard" (∼1 keV) X-rays from this apparently single WD. We have obtained Chandra observations that confirm the spatial coincidence of this hard X-ray source with KPD 0005+5106. We have also obtained XMM-Newton observation…
Purveyors of fine halos. III. Chemical abundance analysis of a potential ωCen associate
Hanke, Michael; Hansen, Camilla Juul; Bonifacio, Piercarlo +3 more
Globular clusters (GCs) are important donors to the build-up of the Milky Way (MW) stellar halo, having contributed at the ten percent level over the Galactic history. Stars that originated from the second generation of dissolved or dissolving clusters can be readily identified via distinct light-element signatures such as enhanced N and Na and si…
Five New Hot Jupiter Transits Investigated with Swift-UVOT
Rauscher, Emily; King, George W.; Reynolds, Mark +3 more
Short-wavelength exoplanet transit measurements have been used to probe mass loss in exoplanet atmospheres. We present the Swift-UVOT transit light curves for five hot Jupiters orbiting UV-bright F-type stars: XO-3, KELT-3, WASP-3, WASP-62, and HAT-P-6. We report one positive transit detection of XO-3b and one marginal detection of KELT-3b. We pla…
Hunting for Planetary Nebulae toward the Galactic Center
Hong, Jihye; An, Deokkeun; Ramírez, Solange V. +2 more
We present near-infrared (IR) spectra of two planetary nebula (PN) candidates in close lines of sight toward the Galactic center (GC) using the Gemini Near-Infrared Spectrograph at Gemini North. High-resolution images from radio continuum and narrowband IR observations reveal ringlike or barrel-shaped morphologies of these objects, and their mid-I…
X-ray reverberation models of the disc wind in ultraluminous X-ray source NGC 5408 X-1
Chainakun, P.; Luangtip, W.; Loekkesee, S. +3 more
Majority of ultraluminous X-ray sources (ULXs) are believed to be super-Eddington objects, providing a nearby prototype for studying an accretion in supercritical regime. In this work, we present the study of time-lag spectra of the ULX NGC 5408 X-1 using a reverberation mapping technique. The time-lag data were binned using two different methods:…
On the Origin of Hard X-Ray Emissions from the Behind-the-limb Flare on 2014 September 1
Kouloumvakos, Athanasios; Rouillard, Alexis P.; Warmuth, Alexander +6 more
The origin of hard X-rays and γ-rays emitted from the solar atmosphere during occulted solar flares is still debated. The hard X-ray emissions could come from flaring loop tops rising above the limb or coronal mass ejection shock waves, two by-products of energetic solar storms. For the shock scenario to work, accelerated particles must be release…
Restoration of the K and F Components of the Solar Corona from LASCO-C2 Images over 24 Years [1996 - 2019]
Lamy, Philippe; Gilardy, Hugo; Llebaria, Antoine +2 more
We present a photometrically accurate restoration of the K- and F-coronae from white-light images obtained over 24 years [1996 - 2019] by the Large-Angle Spectrometric COronagraph (LASCO-C2) onboard the Solar and Heliospheric Observatory (SOHO). The procedure starts with the data set of unpolarized images of 512 × 512 pixels produced by the polari…
Potential and sky coverage for off-axis fringe tracking in optical long baseline interferometry
Hadjara, Massinissa; Benkhaldoun, Zouhair; Boskri, Abdelkarim +6 more
The spectacular results provided by the second-generationVLTI instruments GRAVITY and MATISSE on active galactic nuclei (AGN) trigger and justify a strong increase in the sensitivity limit of optical interferometers. A key component of such an upgrade is off-axis fringe tracking. To evaluate its potential and limitations, we describe and analyse i…
Optical Variability of ICRF3 Quasars in the Pan-STARRS 3Pi Survey with Functional Principal Component Analysis
Makarov, V. V.; Goldman, B.; Berghea, C. T. +1 more
We make use of individual (epoch) detection data from the Pan-STARRS 3 survey for 2863 optical ICRF3 counterparts in the five wavelength bands g, r, i, z, and y, published as part of the Data Release 2. A dedicated method based on the Functional Principal Component Analysis is developed for these sparse and irregularly sampled data. With certain r…