Search Publications
Magnetic field fluctuations in the shocked umbral chromosphere
Asensio Ramos, A.; González Manrique, S. J.; Felipe, T. +1 more
Context. Umbral chromospheric observations show the presence of magnetoacoustic shocks. Several recent studies have reported magnetic field fluctuations associated with these shock waves. The mechanism behind these periodic magnetic field changes is still an unresolved question.
Aims: We aim to study the properties and origin of magnetic fiel…
TOI-733 b: A planet in the small-planet radius valley orbiting a Sun-like star
Vanderburg, Andrew; Latham, David W.; Cochran, William D. +40 more
We report the discovery of a hot (Teq ≈ 1055 K) planet in the small-planet radius valley that transits the Sun-like star TOI-733. It was discovered as part of the KESPRINT follow-up program of TESS planets carried out with the HARPS spectrograph. TESS photometry from sectors 9 and 36 yields an orbital period of {P{{orb}}} = 4…
Signatures of feedback in the spectacular extended emission region of NGC 5972
Koss, Michael; Sartori, Lia F.; Maksym, W. Peter +10 more
We present Chandra X-ray Observatory observations and Space Telescope Imaging Spectrograph spectra of NGC 5972, one of the 19 'Voorwerpjes' galaxies. This galaxy contains an extended emission-line region (EELR) and an arcsecond scale nuclear bubble. NGC 5972 is a faded active galactic nucleus (AGN), with EELR luminosity suggesting a 2.1 dex decrea…
3D Spectroscopy with GTC-MEGARA of the Triple AGN Candidate in SDSS J102700.40+174900.8
Shen, Yue; Liu, Xin; Rodríguez-Espinosa, José Miguel +4 more
Triple-active galactic nucleus (AGN) systems are expected to be the result of the hierarchical model of galaxy formation. Since there are very few of them confirmed as such, we present the results of a new study of the triple AGN candidate SDSS J102700.40+174900.8 (center nucleus) through observations with the GTC-MEGARA Integral Field Unit. 1D an…
Discovery of the lensed quasar eRASS1 J050129.5−073309 with SRG/eROSITA and Gaia
Schramm, Malte; Schwope, Axel; Bulbul, Esra +9 more
We report the discovery and spectroscopic identification of the bright doubly lensed quasar eRASS1 J050129.5−073309 at redshift z = 2.47, selected from the first all-sky survey of the Spectrum Roentgen Gamma (SRG) eROSITA telescope and the Gaia EDR3 catalog. We systematically searched for extragalactic sources with eROSITA X-ray positions that hav…
How much large dust could be present in hot exozodiacal dust systems?
Krivov, A. V.; Ertel, S.; Wolf, S. +3 more
Context. An infrared excess over the stellar photospheric emission of main-sequence stars has been found in interferometric surveys, commonly attributed to the presence of hot exozodiacal dust (HEZD). While submicrometer-sized grains in close vicinity to their host star have been inferred to be responsible for the found near-infrared excesses, the…
The Missing Link: Testing Galactic Chemical Evolution Models with the First Multi-isotopic Abundances in Solar Twin Stars
Crossfield, Ian J. M.; Freedman, Richard; Lothringer, Joshua +3 more
We present the first isotopic abundances of both 13CO and C18O in solar twin stars and test the results against several galactic chemical evolution (GCE) models with different nucleosynthesis prescriptions. First, we compare M-band spectra from IRTF/iSHELL to synthetic spectra generated from custom solar atmosphere models usi…
Comparative Solar Minima Using the McIntosh Archive
Gibson, Sarah E.; Webb, David F.; Hewins, Ian M. +3 more
The McIntosh Archive consists of four solar cycles (SC20-23) of synoptic maps of solar features (magnetic polarities, coronal holes, filaments, sunspots, plage) that were produced by Patrick McIntosh and his cartographers. In this paper we present the full Archive for the first time and find a hemispheric pattern of coronal hole polarity reflectin…
White dwarf mass-radius relation in theories beyond general relativity
Alam, Khursid; Islam, Tousif
We explore the internal structures of the white dwarfs in two different modified theories of gravity: (i) scalar-tensor-vector gravity and (ii) beyond Horndeski theories of G 3 type. The modification of the gravitational force inside the white dwarf results in the modification of the mass and radius of the white dwarf. We use observatio…
Possible Detection of a Flare-associated Coronal Mass Ejection on an M-dwarf
Wang, J.
We here report a probable detection of a stellar coronal mass ejection (CME) in active M dwarf KIC 8093473 by performing an analysis on its time resolved X-ray spectra observed by the XMM-Newton satellite. Compared to the value at the quiescent state and the interstellar one, our spectral modeling returns a marginal (and probably evolving) excess …