Optical follow-up of PKS 0336-01 (CTA 26)
ATel #6577; R. Nesci, INAF/IAPS
on 14 Oct 2014; 09:17 UT
Credential Certification: Roberto Nesci (Roberto.Nesci@iaps.inaf.it)
Following the report in ATel #6568 by Ciprini et al. of a Gamma-ray flare of PKS 0336-01 (2FGL J0339.4-0144) we observed the source on 2014-10-13.90 with the 30cm telescope of the Foligno Observatory (MPC K56) in the V band. Twenty nearby comparison stars were taken from the UCAC4 catalog, ranging from V=12.92 to V=17.19. Aperture photometry was made with IRAF/apphot. The sky conditions were rather veiled, with moon light, but we detected the source at V=17.0 +-0.1.
Literature data on the source luminosity are not easy to find in V band. The paper by Wills & Lynds (ApJS 36,317, 1978) report V magnitudes which actually are just eye estimates from POSS prints. The polarimetric measures of Wills et al. 2011 (ApJS 194,19) were made without filter for this source. Catalog data from APM report R=17.3, B=17.8, similar to the later values reported by USNO-B1 (R2=17.35, B2=17.33) within the quoted 0.4 mag uncertainty.
The source therefore in the optical is not much brighter then its historical level, despite its present Gamma-ray emission, 20 times stronger than the average intensity.
