Search Publications
Origins of the UV/X-ray relation in Arakelian 120
Done, C.; Porquet, D.; Lobban, A. +1 more
We explore the accretion geometry in Arakelian 120 using intensive UV and X-ray monitoring from Swift. The hard X-rays (1-10 keV) show large amplitude, fast (few-day) variability, so we expect reverberation from the disc to produce UV variability from the varying hard X-ray illumination. We model the spectral energy distribution (SED) including an…
Exploring source region of 3-min slow magnetoacoustic waves observed in coronal fan loops rooted in sunspot umbra
Gupta, Girjesh R.; Rawat, Ananya
Sunspots host various oscillations and wave phenomena like umbral flashes, umbral oscillations, running penumbral waves, and coronal waves. All fan loops rooted in sunspot umbra constantly show a 3-min period propagating slow magnetoacoustic waves in the corona. However, their origin in the lower atmosphere is still unclear. In this work, we studi…
Observational signatures of carbon-oxygen white dwarf merger remnants
Goulding, Andy; Quataert, Eliot; Yao, Philippe Z.
Many double white dwarf (WD) mergers likely do not lead to a prompt thermonuclear explosion. We investigate the prospects for observationally detecting the surviving remnants of such mergers, focusing on the case of mergers of double Carbon-Oxygen WDs. For ~104 yr, the merger remnant is observationally similar to an extreme AGB star evo…
Multi-spacecraft Observations of the 2022 March 25 CME and EUV Wave: An Analysis of Their Propagation and Interrelation
Telloni, Daniele; Liberatore, Alessandro; Vourlidas, Angelos +5 more
This paper reports on a well-defined EUV wave associated with a coronal mass ejection (CME) observed on 2022 March 25. The CME was observed by Solar Orbiter (SolO) during its first close perihelion (0.32 au) and by several other spacecraft from different viewpoints. The EUV wave was visible by the Extreme Ultraviolet Imager on board the Solar Terr…
Revealing the intrinsic X-ray reverberation lags in IRAS 13224-3809 through the Granger causality test
Chainakun, P.; Young, A. J.; Nakhonthong, N. +1 more
The Granger causality is an econometric test for determining whether one time series is useful for forecasting another one with a certain Granger lag. Here, the light curves in the 0.3-1 keV (reflection dominated, soft) and 1.2-5 keV (continuum dominated, hard) bands of active galactic nuclei are produced, and the Granger lags are estimated and co…
Capturing the lowest luminosity state of the supergiant fast X-ray transient XTE J1739−302
Ponti, G.; Sidoli, L.; Esposito, P. +1 more
Here, we report the results of our analysis of recent Chandra, XMM-Newton, and NuSTAR observations of the supergiant fast X-ray transient XTE J1739−302. The source was caught in a low X-ray luminosity state, from a few 1031-1034 erg s−1 (0.5-10 keV). A very low X-ray luminosity was captured during an XMM-Newton obs…
Modeling the Mg I from the NUV to MIR. II. Testing stellar models
Peralta, J. I.; Vieytes, M. C.; Mendez, A. M. P. +1 more
Context. Reliable atomic data are mandatory ingredients to obtain a realistic semiempirical model of any stellar atmosphere. Due to their importance, we further improved our recently published Mg I atomic model.
Aims: We tested the new atomic model using atmospheric models of stars of different spectral types: the Sun (dG2), HD 22049 (dK2, Ep…
A Low-mass, Pre-main-sequence Eclipsing Binary in the 40 Myr Columba Association-Fundamental Stellar Parameters and Modeling the Effect of Star Spots
Vanderburg, Andrew; Law, Nicholas M.; Ziegler, Carl +12 more
Young eclipsing binaries (EBs) are powerful probes of early stellar evolution. Current models are unable to simultaneously reproduce the measured and derived properties that are accessible for EB systems (e.g., mass, radius, temperature, and luminosity). In this study we add a benchmark EB to the pre-main-sequence population with our characterizat…
Time-dependent boundary conditions for data-driven coronal global and spherical wedge-shaped models
Feng, Xueshang; Jiang, Chaowei; Xiang, Changqing +1 more
The development of an efficient and accurate method for boundary condition treatments is of fundamental importance to data-driven magnetohydrodynamic (MHD) modelling of the global solar corona and solar active region. Particularly, in a 3D spherical wedge-shaped volume, suitable to the numerical study of solar active region, the transverse terms c…
Thermal Tides on Mars Before and During the 2018 Global Dust Event as Observed by TIRVIM-ACS Onboard ExoMars Trace Gas Orbiter
Grigoriev, A.; Forget, F.; Montmessin, F. +8 more
Migrating tides dominate the tropical climate on Mars and are known to reach high amplitudes during global dust events (GDE). In this study, we characterize the amplitude, phase and vertical wavelength of the diurnal and semidiurnal migrating tides in Mars' lower atmosphere (up to 50 km) by exploiting temperature vertical profiles retrieved from T…