63 citations · 89 across the 3 of their papers we have counts for
5 papers · 1 filter
A galaxy cluster in the innermost Zone of Avoidance, close to the radio phoenix VLSSJ2217.5+594
W. Kollatschny, H. Meusinger, M. Hoeft +5
The steep spectrum radio source VLSSJ2217.5+5943 shows a complex, filamentary morphology and a curved spectrum. Therefore, the source has previously been classified as a radio phoe…
Optical and X-ray discovery of the changing-look AGN IRAS23226-3843 showing extremely broad and double-peaked Balmer profiles
W. Kollatschny, D. Grupe, M. L. Parker +6
We detected a very strong X-ray decline in the galaxy IRAS23226-3843 within the XMM-Newton slew survey in 2017. Subsequently, we carried out multi-band follow-up studies to investi…
NGC6240: A triple nucleus system in the advanced or final state of merging
W. Kollatschny, P. M. Weilbacher, M. W. Ochmann +4
NGC6240 is a well-studied nearby galaxy system in the process of merging. Based on optical, X-ray, and radio observations, it is thought to harbor two active nuclei We carried out…
Broad-line region structure and line profile variations in the changing look AGN HE1136-2304
W. Kollatschny, M. W. Ochmann, M. Zetzl +5
A strong X-ray outburst was detected in HE1136-2304 in 2014. Accompanying optical spectra revealed that the spectral type has changed from a nearly Seyfert 2 type (1.95), classifie…
Long-term optical, UV, and X-ray continuum variations in the changing-look AGN HE 1136-2304
M. Zetzl, W. Kollatschny, M. W. Ochmann +6
A strong outburst in the X-ray continuum and a change of its Seyfert spectral type was detected in HE 1136-2304 in 2014. The spectral type changed from nearly Seyfert 2 type (1.95)…