activity
20202026
most citedInference of the chromospheric magnetic field configuration of solar plage using the Ca II 8542 Å line

35 citations · 55 across the 14 of their papers we have counts for

collaborators

14 papers

astro-ph.SR2026

Forward modeling solar spectra onto Doppler images of λ And

Ö. Adebali, A. G. M. Pietrow

By using the Doppler images of λ And, we aim to investigate whether surface temperature information can be reversed to create its activity parameters, by feeding a toy model with s…

astro-ph.IM2026

Thermal background reduction for mid-infrared imaging by low-rank background and sparse point-source modelling

R. A. R. Moens, A. G. M. Pietrow, B. Brandl +1

Mid-infrared astronomy from the ground faces critical challenges in accurately detecting and quantifying sources due to the dominant spatially and time-variable background noise. M…

astro-ph.SR2026

Prominence signatures in the Fraunhofer G-band; Testing ionization memory with multi-line prominence diagnostics

A. G. M. Pietrow, H. Balthasar, P. Váradi Nagy +4

The Fraunhofer G-band around 4304 Å is widely used as a photospheric diagnostic and is generally not expected to show signatures of chromospheric or coronal structures. However, re…

astro-ph.SR2026★ 2 cited

Chromospheric and photospheric properties of sunspots as inferred from Stokes inversions under magneto-hydrostatic and non-local-thermodynamic equilibrium

A. Vicente Arevalo, J. M. Borrero, I. Milic +3

Sunspots are crucial for exploring how magnetic fields and plasma flows interact in the solar atmosphere, spanning from the stable photosphere to the shock-dominated chromosphere.…

astro-ph.SR2026

Does the solar oxygen abundance change over the solar cycle? An investigation into activity-induced variations of the O I infrared triplet

A. G. M. Pietrow, M. Baratella, I. V. Ilyin +2

The determination of the solar oxygen abundance remains a central problem in astrophysics, as its accuracy is limited not only by models but also by systematics. While many of thes…

astro-ph.IM2025

Understanding Solar Flares and Energetic Events: Open questions, observational requirements, and instrumental needs over the coming decade

Malcolm K. Druett, Graham S. Kerr, Joel C. Allred +15

Solar flares are the largest energy-release events in the Solar System, allowing us to study fundamental physical phenomena under extreme conditions. Those include magnetic reconne…

astro-ph.IM2025

Why every solar eclipse viewing event needs a disco ball

Valerie A. Rapson, Alex Pietrow, Robert J. Cumming +12

Solar eclipses offer unparalleled opportunities for public engagement in astronomy. Large groups of people often gather to view eclipses, and these events require affordable and ea…

astro-ph.EP2025★ 9 cited

ATREIDES I. Embarking on a trek across the exo-Neptunian landscape with the TOI-421 system

V. Bourrier, M. Steiner, A. Castro-González +75

The distribution of close-in exoplanets is shaped by the interplay between atmospheric and dynamical processes. The Neptunian Desert, Ridge, and Savanna illustrate the sensitivity…

astro-ph.SR2025★ 2 cited

Solar Flux Atlases: The new HARPS-N Quiet Sun Benchmark and Ca II H & K Lines Continuum Normalisation

F. Hanassi-Savari, A. G. M. Pietrow, M. K. Druett +2

Context. Solar flux atlases observe the spatially integrated light from the Sun, treating it as a star. They are fundamental tools for gaining insight into the composition of the S…

astro-ph.SR2025★ 1 cited

An Atlas of Spectroheliograms from 3641 to 6600 Å

P. Váradi Nagy, A. G. M. Pietrow

We present a spectral atlas of solar spectroheliograms covering the wavelength range from 3641 to 6600 Å, with continuous coverage between 3711 and 5300 Å, and sparser coverage bey…

astro-ph.SR2024

Stellar surface information from the Ca II H&K lines -- II. Defining better activity proxies

M. Cretignier, N. C. Hara, A. G. M. Pietrow +6

In our former paper I, we showed on the Sun that different active regions possess unique intensity profiles on the Ca II H & K lines. We now extend the analysis by showing how thos…

astro-ph.SR2024★ 3 cited

Spectral Characteristics of a Rotating Solar Prominence in Multiple Wavelengths

A. G. M. Pietrow, V. Liakh, C. M. J. Osborne +2

We present synthetic spectra corresponding to a 2.5D magnetohydrodynamical simulation of a rotating prominence in the Ca II 8542 Å, H, Ca II K, Mg II k, Ly , and Ly lines…

astro-ph.IM2020★ 3 cited

Towards a physical understanding of the thermal background in large ground-based telescopes

Leonard Burtscher, Ioannis Politopoulos, Sergio Fernández-Acosta +11

Ground-based thermal-infrared observations have a unique scientific potential, but are also extremely challenging due to the need to accurately subtract the high thermal background…

astro-ph.SR2020★ 35 cited

Inference of the chromospheric magnetic field configuration of solar plage using the Ca II 8542 Å line

A. G. M. Pietrow, D. Kiselman, J. de la Cruz Rodríguez +3

It has so far proven impossible to reproduce all aspects of the solar plage chromosphere in quasi-realistic numerical models. The magnetic field configuration in the lower atmosphe…