Search Publications
Investigating Pre-eruptive Magnetic Properties at the Footprints of Erupting Magnetic Flux Ropes
Qiu, Jiong; Wang, Yuming; Liu, Rui +4 more
It is well established that solar eruptions are powered by free magnetic energy stored in the current-carrying magnetic field in the corona. It has also been generally accepted that magnetic flux ropes (MFRs) are a critical component of many coronal mass ejections. What remains controversial is whether MFRs are present well before the eruption. Ou…
Stars, Gas, and Star Formation of Distant Post-starburst Galaxies
Maseda, Michael V.; D'Eugenio, Francesco; van der Wel, Arjen +5 more
We present a comprehensive multiwavelength study of five post-starburst galaxies with M * > 1011 M ⊙ at z ~ 0.7, examining their stars, gas, and current and past star formation activities. Using optical images from the Subaru Telescope and Hubble Space Telescope, we observe a high incidence of companion galaxies…
ALMA ACA study of the H2S/OCS ratio in low-mass protostars
Tabone, Benoît; Drozdovskaya, Maria N.; Tychoniec, Łukasz +1 more
Context. The identification of the main sulfur reservoir on its way from the diffuse interstellar medium to the cold dense star-forming cores and, ultimately, to protostars is a long-standing problem. Despite sulfur's astrochemical relevance, the abundance of S-bearing molecules in dense cores and regions around protostars is still insufficiently …
Intensification of magnetic field in merging magnetic flux tubes driven by supergranular vortical flows
Chian, Abraham C. -L.; Silva, Suzana S. A.; Rempel, Erico L. +2 more
The spatiotemporal dynamics of vorticity and magnetic field in the region of a photospheric vortex at a supergranular junction of the quiet Sun is studied, using Hinode's continuum intensity images and longitudinal magnetograms. We show that in a 30-min interval during the vortex lifetime, the magnetic field is intensified at the centres of two me…
M67 Blue Stragglers with High-resolution Infrared Spectroscopy
Sneden, C.; Brady, K. E.; Pilachowski, C. A. +5 more
We report on the first detailed infrared chemical analysis of five binary members (S277, S997, S975, S1031, and S1195) in the open cluster M67 (NGC 2682). These stars are located outside (bluer and/or brighter than) the main-sequence turnoff region in M67. High-resolution (R ~ 45,000) near-infrared spectra were obtained with the Immersion GRating …
Detached eclipsing binaries in compact hierarchical triples: triple-lined systems BD+442258 and KIC 06525196
Kambe, E.; Maehara, H.; Hełminiak, K. G. +5 more
Compact hierarchical triples (CHTs) are systems with the tertiary star orbiting the inner binary in an orbit shorter than 1000 d. CHT with an eclipsing binary as its inner binary can help us extract a multitude of information about all three stars in the system. In this study, we use independent observational techniques to estimate the orbital, st…
Chromospheric Heating from Local Magnetic Growth and Ambipolar Diffusion under Nonequilibrium Conditions
Martínez-Sykora, Juan; De Pontieu, Bart; Hansteen, Viggo H. +3 more
The heating of the chromosphere in internetwork regions remains one of the foremost open questions in solar physics. In the present study, we tackle this old problem by using a very-high-spatial-resolution simulation of quiet-Sun conditions performed with radiative MHD numerical models and interface region imaging spectrograph (IRIS) observations.…
Interpreting the Si II and C II Line Spectra from the COS Legacy Archive Spectroscopic SurveY Using a Virtual Galaxy from a High-resolution Radiation-hydrodynamic Simulation
Wilkins, Stephen M.; Martin, Crystal L.; Garel, Thibault +19 more
Observations of low-ionization state metal lines provide crucial insights into the interstellar medium (ISM) of galaxies, yet, disentangling the physical processes responsible for the emerging line profiles is difficult. This work investigates how mock spectra generated using a single galaxy in a radiation-hydrodynamical simulation can help us int…
Investigating Gaia EDR3 parallax systematics using asteroseismology of cool giant stars observed by Kepler, K2, and TESS. II. Deciphering Gaia parallax systematics using red clump stars
Khan, S.; Anderson, R. I.; Miglio, A. +2 more
We analyse Gaia EDR3 parallax systematics as a function of magnitude and sky location using a recently published catalogue of 12 500 asteroseismic red-giant star distances. We selected ∼3500 red clump (RC) stars of similar chemical composition as the optimal subsample for this purpose because (1) their similar luminosity allows for straightforward…
Two new white dwarfs with variable magnetic Balmer emission lines
Hermes, J. J.; Clemens, J. C.; Reding, Joshua S. +2 more
We report the discovery of two apparently isolated stellar remnants that exhibit rotationally modulated magnetic Balmer emission, adding to the emerging DAHe class of white dwarf stars. While the previously discovered members of this class show Zeeman-split triplet emission features corresponding to single magnetic field strengths, these two new o…