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Gaia 20eae: A Newly Discovered Episodically Accreting Young Star
Mahadevan, Suvrath; Wisniewski, John P.; Pandey, Rakesh +18 more
The Gaia Alert System issued an alert on 2020 August 28, on Gaia 20eae when its light curve showed a ~4.25 magnitude outburst. We present multiwavelength photometric and spectroscopic follow-up observations of this source since 2020 August and identify it as the newest member of the FUor/EXor family of sources. We find that the present brightening…
Probing red supergiant dynamics through photo-center displacements measured by Gaia
Chiavassa, A.; de Mink, S. E.; Davies, B. +2 more
Context. Red supergiant (RSGs) are cool massive stars in a late phase of their evolution when the stellar envelope becomes fully convective. They are the brightest stars in the universe at infrared light and can be detected in galaxies far beyond the Local Group, allowing for accurate determination of chemical composition of galaxies. The study of…
A fast radio burst progenitor born in a galaxy merger
Prochaska, J. Xavier; Kanekar, Nissim; Kaur, Balpreet
We report a Giant Metrewave Radio Telescope HI 21cm mapping study of the neutral atomic hydrogen (HI) in the host galaxy of the fast radio burst (FRB) FRB20180916B at z ≈ 0.03399. We find that the FRB host has an HI mass of MHI = (2.74 ± 0.33) × 109 M⊙ and a high HI-to-stellar mass ratio, ≈ 1.3. The FRB host is thu…
MICROSCOPE: systematic errors
Bergé, Joel; Chhun, Ratana; Métris, Gilles +19 more
The MICROSCOPE mission aims to test the weak equivalence principle (WEP) in orbit with an unprecedented precision of 10-15 on the Eötvös parameter thanks to electrostatic accelerometers on board a drag-free micro-satellite. The precision of the test is determined by statistical errors, due to the environment and instrument noises, and b…
4FGL J1120.0-2204: A Unique Gamma-Ray-bright Neutron Star Binary with an Extremely Low-mass Proto-white Dwarf
Strader, Jay; Dage, Kristen C.; Chomiuk, Laura +5 more
We have discovered a new X-ray-emitting compact binary that is the likely counterpart to the unassociated Fermi-LAT GeV γ-ray source 4FGL J1120.0-2204, the second brightest Fermi source that still remains formally unidentified. Using optical spectroscopy with the SOAR telescope, we have identified a warm (T eff ~ 8500 K) companion in a …
A highly dynamic small-scale jet in a polar coronal hole
Teriaca, Luca; Solanki, Sami K.; Schühle, Udo +6 more
We present an observational study of the plasma dynamics at the base of a solar coronal jet, using high resolution extreme ultraviolet imaging data taken by the Extreme Ultraviolet Imager on board Solar Orbiter, and by the Atmospheric Imaging Assembly on board Solar Dynamics Observatory. We observed multiple plasma ejection events over a period of…
High-energy Emission Component, Population, and Contribution to the Extragalactic Gamma-Ray Background of Gamma-Ray-emitting Radio Galaxies
Fukazawa, Yasushi; Inoue, Yoshiyuki; Matake, Hiroto +2 more
In this study, we systematically studied the X-ray to GeV gamma-ray spectra of 61 Fermi Large Area Telescope detected radio galaxies. We found an anticorrelation between peak frequency and peak luminosity in the high-energy spectral component of radio galaxies, similar to blazars. With this sample, we also constructed a gamma-ray luminosity functi…
Spinning up the Surface: Evidence for Planetary Engulfment or Unexpected Angular Momentum Transport?
Reffert, Sabine; García, Rafael A.; Breton, Sylvain N. +15 more
In this paper, we report the potential detection of a nonmonotonic radial rotation profile in a low-mass lower-luminosity giant star. For most low- and intermediate-mass stars, the rotation on the main sequence seems to be close to rigid. As these stars evolve into giants, the core contracts and the envelope expands, which should suggest a radial …
Bending waves excited by irregular gas inflow along warps
Debattista, Victor P.; Beraldo e Silva, Leandro; Khachaturyants, Tigran +1 more
Gaia has revealed clear evidence of bending waves in the vertical kinematics of stars in the solar neighbourhood. We study bending waves in two simulations, one warped, with the warp due to misaligned gas inflow, and the other unwarped. We find slow, retrograde bending waves in both models, with the ones in the warped model having larger amplitude…
The morphology of CS Cha circumbinary disk suggesting the existence of a Saturn-mass planet
Bayo, A.; Ginski, C.; Pinilla, P. +8 more
Context. Planets have been detected in circumbinary orbits in several different systems, despite the additional challenges faced during their formation in such an environment.
Aims: We investigate the possibility of planetary formation in the spectroscopic binary CS Cha by analyzing its circumbinary disk.
Methods: The system was studied …