RoboPol: a four-channel optical imaging polarimeter. Issue 2 (26th February 2019)

• Record Type: Journal Article
• Authors: Ramaprakash, A N; Rajarshi, C V; Das, H K; Khodade, P; Modi, D; Panopoulou, G; Maharana, S; Blinov, D; Angelakis, E; Casadio, C; Fuhrmann, L; Hovatta, T; Kiehlmann, S; King, O G; Kylafis, N; Kougentakis, A; Kus, A; Mahabal, A; Marecki, A; Myserlis, I; Paterakis, G; Paleologou, E; Liodakis, I; Papadakis, I; Papamastorakis, I; Pavlidou, V; Pazderski, E; Pearson, T J; Readhead, A C S; Reig, P; Słowikowska, A; Tassis, K; Zensus, J A;
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 485:Issue 2(2019)
• Page Start: 2355
• Page End: 2366
• Publication Date: 2019-02-26
• Subjects: instrumentation: polarimeters -- techniques: polarimetric; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stz557
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: We present the design and performance of RoboPol, a four-channel optical polarimeter operating at the Skinakas Observatory in Crete, Greece. RoboPol is capable of measuring both relative linear Stokes parameters q and u (and the total intensity I) in one sky exposure. Though primarily used to measure the polarization of point sources in the R band, the instrument features additional filters ( B, V, and I ), enabling multiwavelength imaging polarimetry over a large field of view (13.6′ × 13.6′). We demonstrate the accuracy and stability of the instrument throughout its 5 yr of operation. Best performance is achieved within the central region of the field of view and in the R band. For such measurements the systematic uncertainty is below 0.1 per cent in fractional linear polarization, p (0.05 per cent maximum likelihood). Throughout all observing seasons the instrumental polarization varies within 0.1 per cent in p and within ∼1° in polarization angle.