5 papers
Center-to-limb variations of solar active regions: Observations of spots, faculae, and network in the 6173 Ã continuum
A. G. M. Pietrow, S. Sumra, D. J. M. Petit dit de la Roche +3
Accurate modeling of stellar active regions (ARs) remains a major bottleneck for radial-velocity and transmission-spectroscopy studies aimed at finding Earth-like planets. While mu…
The calm before the storm: High spatial resolution mosaic of active region NOAA 14274 at the onset of an X1.2 flare
Carsten Denker, Robert Kamlah, Meetu Verma +1
Active region NOAA 14274 produced some of the strongest flares of Solar Cycle 25, including the X1.2 and X5.1 flares on 10 and 11 November 2025, respectively. We present the first…
Differential rotation of solar α sunspots and implications for stellar light curves
Emily Joe LöÃnitz, Alexander G. M. Pietrow, Hritam Chakraborty +5
Differential rotation is a key driver of magnetic activity and dynamo processes in the Sun and other stars, especially as the rate differs across the solar layers, but also in acti…
High-spectral Resolution, Multi-wavelength Center-to-limb Observations of the Sun
Meetu Verma, Carsten Denker, Alexander G. M. Pietrow +2
The center-to-limb variations (CLVs) of photospheric and chromospheric spectral lines were obtained in 2025 July and August using drift scans from the echelle spectrograph of the 0…
Automatic detection of Ellerman bombs in the H line
A. Faryad, A. G. M. Pietrow, M. Verma +1
Ellerman bombs (EBs) are small and short-lived magnetic reconnection events in the lower solar atmosphere, most commonly reported in the line wings of the H line. These events…