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A New Reconstruction of the Sun's Magnetic Field and Total Irradiance since 1700
Wang, Y. -M.; Lean, J. L.
We model the Sun's large-scale magnetic field and total solar irradiance (TSI) since 1700 by combining flux transport simulations with empirical relationships between facular brightening, sunspot darkening, and the total photospheric flux. The photospheric field is evolved subject to the constraints that (1) the flux emergence rate scales as the y…
Discovery of the 5 keV Cyclotron Line Followed by Three Harmonics in Swift J1626.6-5156
Tsygankov, S.; Santangelo, A.; Lutovinov, A. +4 more
We report on observations of the Be/X-ray binary system Swift J1626.6-5156 performed with the Nuclear Spectroscopic Telescope ARray (NuSTAR) during a short outburst in 2021 March, following its detection by the MAXI monitor and Spektrum-Roentgen-Gamma (SRG) observatory. Our analysis of the broadband X-ray spectrum of the source confirms the presen…
The New Magnetar SGR J1830-0645 in Outburst
Tiengo, A.; Rea, N.; Esposito, P. +13 more
The detection of a short hard X-ray burst and an associated bright soft X-ray source by the Swift satellite in 2020 October heralded a new magnetar in outburst, SGR J1830-0645. Pulsations at a period of ∼10.4 s were detected in prompt follow-up X-ray observations. We present here the analysis of the Swift/Burst Alert Telescope burst, of XMM-Newton…
The Epoch of Giant Planet Migration Planet Search Program. I. Near-infrared Radial Velocity Jitter of Young Sun-like Stars
Cochran, William D.; Endl, Michael; Mahadevan, Suvrath +8 more
We present early results from the Epoch of Giant Planet Migration program, a precise radial velocity (RV) survey of more than 100 intermediate-age (∼20-200 Myr) G and K dwarfs with the Habitable Zone Planet Finder spectrograph (HPF) at McDonald Observatory's Hobby-Eberly Telescope. The goals of this program are to determine the timescale and domin…
Coronal Heating and Solar Wind Formation in Quiet Sun and Coronal Holes: A Unified Scenario
Solanki, Sami K.; Tripathi, Durgesh; Nived, V. N.
Coronal holes (CHs) are darker than the quiet Sun (QS) when observed in coronal channels. This study aims to understand the similarities and differences between CHs and QS in the transition region using the Si IV 1394 Å line, recorded by the Interface Region Imaging Spectrograph, by considering the distribution of magnetic field measured by the He…
Mass-loss law for red giant stars in simple population globular clusters
Milone, A. P.; Cordoni, G.; Marino, A. F. +12 more
The amount of mass lost by stars during the red-giant branch (RGB) phase is one of the main parameters to understand and correctly model the late stages of stellar evolution. Nevertheless, a fully comprehensive knowledge of the RGB mass-loss is still missing. Galactic Globular Clusters (GCs) are ideal targets to derive empirical formulations of ma…
Ultra-compact dwarfs beyond the centre of the Fornax galaxy cluster: hints of UCD formation in low-density environments
Janz, Joachim; Mieske, Steffen; Peletier, Reynier F. +6 more
Ultra-compact dwarf galaxies (UCDs) were serendipitously discovered by spectroscopic surveys in the Fornax cluster 20 yr ago. Nowadays, it is commonly accepted that many bright UCDs are the nuclei of galaxies that have been stripped. However, this conclusion might be driven by biased samples of UCDs in high-density environments, on which most sear…
The Chameleon on the branches: spectral state transition and dips in NGC 247 ULX-1
Fabian, A. C.; Pinto, C.; D'Aì, A. +14 more
Soft Ultra-Luminous X-ray (ULXs) sources are a subclass of the ULXs that can switch from a supersoft spectral state, where most of the luminosity is emitted below 1 keV, to a soft spectral state with significant emission above 1 keV. In a few systems, dips have been observed. The mechanism behind this state transition and the dips nature are still…
High precision meteor observations with the Canadian automated meteor observatory: Data reduction pipeline and application to meteoroid mechanical strength measurements
Weryk, Robert J.; Stober, Gunter; Vida, Denis +3 more
Context. The mirror tracking system of the Canadian Automated Meteor Observatory (CAMO) can track meteors in real time, providing an effective angular resolution of 1 arc second and a temporal resolution of 100 frames per second. Aims. We describe the upgraded hardware and give details of the data calibration and reduction pipeline. We investigate…
Galactic bulge millisecond pulsars shining in x rays: A γ -ray perspective
Calore, Francesca; Petrucci, Pierre-Olivier; Clavel, Maïca +3 more
If the mysterious Fermi-LAT GeV γ -ray excess is due to an unresolved population of millisecond pulsars (MSP) in the Galactic bulge, one expects this very same population to shine in x rays. For the first time, we address the question of what is the sensitivity of current x-ray telescopes to an MSP population in the Galactic bulge. To this end, we…