Search Publications
Speckle Interferometry at SOAR in 2022
Tokovinin, Andrei; Mason, Brian D.; Mendez, Rene A. +1 more
Results of the speckle-interferometry observations at the 4.1 m SOuthern Astrophysical Research Telescope obtained during 2022 are presented: 2508 measurements of 1925 resolved pairs or subsystems and 785 nonresolutions of 611 targets; 26 pairs are resolved here for the first time. This work continues our long-term effort to monitor orbital motion…
ZZ Ceti stars of the southern ecliptic hemisphere re-observed by TESS
Sódor, Ádám; Kawaler, Steven D.; Bognár, Zsófia +1 more
Context. In 2020, a publication presented the first-light results for 18 known ZZ Ceti stars observed by the TESS Space Telescope during the first survey observations of the southern ecliptic hemisphere. However, in the meantime, new measurements have become available from this field, in many cases with the new, 20 s ultrashort cadence mode.
…
Wavelet spectral timing: X-ray reverberation from a dynamic black hole corona hidden beneath ultrafast outflows
Wilkins, D. R.
Spectral timing analyses based upon wavelet transforms provide a new means to study the variability of the X-ray emission from accreting systems, including AGN, stellar mass black holes, and neutron stars, and can be used to trace the time variability of X-ray reverberation from the inner accretion disc. The previously missing iron K reverberation…
Fast Reconstruction of 3D Density Distribution around the Sun Based on the MAS by Deep Learning
Moon, Yong-Jae; Rahman, Sumiaya; Park, Eunsu +5 more
This study is the first attempt to generate a three-dimensional (3D) coronal electron density distribution based on the pix2pixHD model, whose computing time is much shorter than that of the magnetohydrodynamic (MHD) simulation. For this, we consider photospheric solar magnetic fields as input, and electron density distribution simulated with the …
Detection of optical emission from the supernova remnant G7.7-3.7
Boumis, P.; Vink, J.; Chiotellis, A. +6 more
We present the first optical study of the supernova remnant (SNR) G7.7-3.7, with the aim of determining its evolutionary phase since it has been suggested to be the remnant of SN 386 AD. We obtained narrow-band images in the filters H α + [N II], H β, [O III], [S II] that revealed faint optical emission in the southern region of the SNR consisting…
Independent Validation of the Temperate Super-Earth HD 79211 b using HARPS-N
López-Morales, Mercedes; Bieryla, Allyson; Stassun, Keivan G. +28 more
We present high-precision radial velocities (RVs) from the HARPS-N spectrograph for HD 79210 and HD 79211, two M0V members of a gravitationally bound binary system. We detect a planet candidate with a period of ${24.421}_{-0.017}^{+0.016}$ days around HD 79211 in these HARPS-N RVs, validating the planet candidate originally identified in CARMENES …
Dense Molecular Environments of B[e] Supergiants and Yellow Hypergiants
Kraus, Michaela; Torres, Andrea F.; Kourniotis, Michalis +2 more
Massive stars expel large amounts of mass during their late evolutionary phases. We aim to unveil the physical conditions within the warm molecular environments of B[e] supergiants (B[e]SGs) and yellow hypergiants (YHGs), which are known to be embedded in circumstellar shells and disks. We present K-band spectra of two B[e]SGs from the Large Magel…
Electrostatic Solitary Waves in the Venusian Ionosphere Pervaded by the Solar Wind: A Theoretical Perspective
Lakhina, G. S.; Kamalam, T.; Singh, S. V. +3 more
Electrostatic solitary waves (ESWs) in the Venusian ionosphere that are impinged by the solar wind are investigated using a homogeneous, collisionless, and magnetized multicomponent plasma consisting of Venusian H+ and O+ ions, Maxwellian Venusian electrons and streaming solar wind protons, and suprathermal electrons followin…
Observed dust surface density across cosmic times
Howk, J. Christopher; Péroux, Céline; De Cia, Annalisa
Our ability to interpret observations of galaxies and trace their stellar, gas, and dust content over cosmic time critically relies on our understanding of how the dust abundance and properties vary with environment. Here, we compute the dust surface density across cosmic times to put novel constraints on simulations of the build-up of dust. We pr…
The ultraluminous X-ray source M 81 X-6: a weakly magnetised neutron star with a precessing accretion disc?
Godet, O.; Webb, N. A.; Middleton, M. J. +2 more
Context. Thanks to their proximity, ultraluminous X-ray sources (ULXs) represent a privileged astrophysical laboratory to study super-Eddington accretion. Current open questions concern the nature of the compact object, which is still hard to determine in those cases where pulsations are not directly detected, and the mechanisms responsible for th…