Search Publications
AutoTAB: Automatic Tracking Algorithm for Bipolar Magnetic Regions
Banerjee, Dipankar; Sreedevi, Anu; Jha, Bibhuti Kumar +1 more
Bipolar magnetic regions (BMRs) provide crucial information about solar magnetism. They exhibit varying morphology and magnetic properties throughout their lifetime, and studying these properties can provide valuable insights into the workings of the solar dynamo. The majority of previous studies have counted every detected BMR as a new one and ha…
eRASSt J074426.3 + 291606: prompt accretion disc formation in a 'faint and slow' tidal disruption event
Salvato, M.; Liu, Z.; Buchner, J. +10 more
We report on multiwavelength observations of the tidal disruption event (TDE) candidate eRASSt J074426.3 + 291606 (J0744), located in the nucleus of a previously quiescent galaxy at z = 0.0396. J0744 was first detected as a new, ultra-soft X-ray source (photon index ~4) during the second SRG/eROSITA All-Sky Survey (eRASS2), where it had brightened…
Constraining the X-ray reflection in low accretion-rate active galactic nuclei using XMM-Newton, NuSTAR, and Swift
Malizia, A.; Arévalo, P.; Diaz, Y. +8 more
Context. An interesting feature of active galactic nuclei (AGN) accreting at low rates is the weakness of the reflection features in their X-ray spectra, which may result from the gradual disappearance of the torus with decreasing accretion rates. It has been suggested that low-luminosity AGN (LLAGN) would exhibit a different reflector configurati…
Ultra-high-resolution observations of plasmoid-mediated magnetic reconnection in the deep solar atmosphere
de la Cruz Rodríguez, Jaime; van Noort, Michiel; Rouppe van der Voort, Luc H. M.
Context. Magnetic reconnection in the deep solar atmosphere can give rise to enhanced emission in the Balmer hydrogen lines, a phenomenon referred to as Ellerman bombs.
Aims: To effectively trace magnetic reconnection below the canopy of chromospheric fibrils, we analyzed unique spectroscopic observations of Ellerman bombs in the Hα line.
Elemental Abundances of the Super-Neptune WASP-107b's Host Star Using High-resolution, Near-infrared Spectroscopy
Souto, Diogo; Crossfield, Ian J. M.; Nordlander, Thomas +8 more
We present the first elemental abundance measurements of the K dwarf (K7V) exoplanet-host star WASP-107 using high-resolution (R ≃45,000), near-infrared (H- and K-band) spectra taken from Gemini-S/IGRINS. We use the previously determined physical parameters of the star from the literature and infer the abundances of 15 elements—C, N, O, Na, Mg, Al…
Updated characterization of long-period single companion by combining radial velocity, relative astrometry, and absolute astrometry
Kiefer, F.; Lagrange, A. -M.; Rubini, P. +2 more
Context. Thanks to more than 20 yr of monitoring, the radial velocity (RV) method has detected long-period companions (P > 10 yr) around several dozens of stars. Yet, the true nature of these companions remains unclear because of the uncertainty as to the inclination of the companion orbital plane.
Aims: We wish to constrain the orbital in…
The first two-dimensional stellar structure and evolution models of rotating stars. Calibration to β Cephei pulsator HD 192575
Rieutord, M.; Espinosa Lara, F.; Mombarg, J. S. G.
Contact. Rotation is a key ingredient in the theory of stellar structure and evolution. Until now, stellar evolution codes operate in a one-dimensional framework for which the validity domain in regards to the rotation rate is not well understood.
Aims: In this Letter, we present the first results of self-consistent stellar models in two spat…
An X-Ray-dim "Isolated" Neutron Star in a Binary?
Shi, Jianrong; Ramsay, Gavin; Esamdin, Ali +13 more
We report the discovery of a dark companion to 2MASS J15274848+3536572 with an orbital period of 6.14 hr. Combining the radial velocity from LAMOST observations and modeling of the multiband light curve, one obtains a mass function of ≃0.131 M ⊙, an inclination of $45\buildrel{\circ}\over{.} {20}_{-0\buildrel{\circ}\over{.} \,20}^{+0\bu…
Accurate oxygen abundance of interstellar gas in Mrk 71 from optical and infrared spectra
Weiner, Benjamin; Spilker, Justin; Fadda, Dario +9 more
The heavy element content (`metallicity') of the Universe is a record of the total star formation history. Gas-phase metallicity in galaxies, as well as its evolution with time, is of particular interest as a tracer of accretion and outflow processes. However, metallicities from the widely used electron temperature (Te) method are typic…
The Near Infrared Imager and Slitless Spectrograph for JWST. V. Kernel Phase Imaging and Data Analysis
Willott, Chris J.; Noirot, Gaël; Mérand, Antoine +26 more
Kernel phase imaging (KPI) enables the direct detection of substellar companions and circumstellar dust close to and below the classical (Rayleigh) diffraction limit. The high-Strehl full pupil images provided by the James Webb Space Telescope (JWST) are ideal for application of the KPI technique. We present a kernel phase analysis of JWST NIRISS …