258 citations · 1.3k across the 32 of their papers we have counts for
4 papers · 1 filter
Impact of sub-solar metallicities on photometric redshifts
Ralf Kotulla, Uta Fritze
With the advent of deep photometric surveys the use of photometric redshifts, obtained with a variety of techniques, has become more and more widespread. Giving access to galaxies…
Rescuing the Initial Mass Function for Arp 78
Ralf Kotulla, Uta Fritze, John S Gallagher
We present deep R and narrow-band Halpha images of Arp 78 obtained with the WIYN 3.5-m telescope on Kitt Peak. GALEX observations had shown a very extended UV structure for this sy…
New active galactic nuclei detected in ROSAT All Sky Survey galaxies - The complete dataset
W. Kollatschny, R. Kotulla, W. Pietsch +2
The ROSAT ALL Sky Survey Bright Source Catalogue (RASS-BSC) has been correlated with the Catalogue of Principal Galaxies (PGC) to identify new extragalactic counterparts. 550 relia…
Young Globular Clusters in an old S0: Clues to the Formation History of NGC 4570
Ralf Kotulla, Uta Fritze, Peter Anders
We here present our first attempt to use Globular Clusters as tracers of their parent galaxy's formation history. Globular Cluster Systems of most early-type galaxies feature two p…