150 citations · 1.3k across the 36 of their papers we have counts for
36 papers
Six decades of TIGRE and Mount Wilson chromospheric monitoring in the H and K lines: The quest for an understanding of solar-type activity
J. H. M. M. Schmitt, K. -P. Schröder, M. Mittag +3
The combined time series of the consistently calibrated chromospheric activity indicator, the S-index -- derived from Mount Wilson and TIGRE data -- now spans more than five decade…
Outstanding X-ray emission from the stellar radio pulsar CU Virginis
J. Robrade, L. M. Oskinova, J. H. M. M. Schmitt +2
We present X-ray observations of CU Vir performed with XMM-Newton and Chandra. With Lx = 3 x 10^28 erg/s the source is moderately X-ray bright, but its spectrum is extremely hard c…
The relation between stellar magnetic field geometry and chromospheric activity cycles II: The rapid 120 day magnetic cycle of Tau Bootis
S. V. Jeffers, M. Mengel, C. Moutou +7
One of the aims of the BCool programme is to search for cycles in other stars and to understand how similar they are to the Sun. In this paper we aim to monitor the evolution of $τ…
Structure and variability in the corona of the ultrafast rotator LO Peg
S. Lalitha, J. H. M. M. Schmitt, K. P. Singh
Low-mass ultrafast rotators show the typical signatures of magnetic activity and are known to produce flares, probably as a result of magnetic reconnection. As a consequence, the c…
Coronal activity cycles in action - X-rays from alpha Centauri A/B
J. Robrade, J. H. M. M. Schmitt
We report on the coronal activity cycles of our stellar neighbors alpha Centauri A/B. The binary has been monitored with XMM-Newton since 2002 to study the long-term evolution of c…
A sensitive search for unknown spectral emission lines in the diffuse X-ray background with XMM-Newton
A. Gewering-Peine, D. Horns, J. H. M. M. Schmitt
The Standard Model of particle physics can be extended to include sterile (right-handed) neutrinos or axions to solve the dark matter problem. Depending upon the mixing angle betwe…