Two weeks after the announcement of the discovery of and , astronomer Francesco Pepe of the Geneva Observatory reported that in a new analysis of 179 measurements taken by the HARPS spectrograph over 6.5 years, neither planet "g" nor planet "f" was detectable, and the relevant measurements were included in a paper uploaded to the arXiv preprint server, though still unpublished in a refereed journal. The non-existence of Gliese 581f was accepted relatively quickly: it was shown that the radial velocity variations that led to the claimed discovery of Gliese 581f were instead associated with the stellar activity cycle rather than an orbiting planet. Nevertheless, the existence of planet g remained controversial: Vogt responded in the media that he stood by the discovery and questions arose as to whether the effect was due to the assumption of circular rather than eccentric orbits or the statistical methods used.