학술논문
Bright-Moon Sky as a Wide-Field Linear Polarimetric Flat Source for Calibration
Document Type
Working Paper
Author
Maharana, S.; Kiehlmann, S.; Blinov, D.; Pelgrims, V.; Pavlidou, V.; Tassis, K.; Kypriotakis, J. A.; Ramaprakash, A. N.; Anche, R. M.; Basyrov, A.; Deka, K.; Eriksen, H. K.; Ghosh, T.; Gjerløw, E.; Mandarakas, N.; Ntormousi, E.; Panopoulou, G. V.; Papadaki, A.; Pearson, T.; Potter, S. B.; Readhead, A. C. S.; Skalidis, R.; Wehus, I. K.
Source
A&A 679, A68 (2023)
Subject
Language
Abstract
Next-generation wide-field optical polarimeters like the Wide-Area Linear Optical Polarimeters (WALOPs) have a field of view (FoV) of tens of arcminutes. For efficient and accurate calibration of these instruments, wide-field polarimetric flat sources will be essential. Currently, no established wide-field polarimetric standard or flat sources exist. This paper tests the feasibility of using the polarized sky patches of the size of around ten-by-ten arcminutes, at a distance of up to 20 degrees from the Moon, on bright-Moon nights as a wide-field linear polarimetric flat source. We observed 19 patches of the sky adjacent to the bright-Moon with the RoboPol instrument in the SDSS-r broadband filter. These were observed on five nights within two days of the full-Moon across two RoboPol observing seasons. We find that for 18 of the 19 patches, the uniformity in the measured normalized Stokes parameters $q$ and $u$ is within 0.2 %, with 12 patches exhibiting uniformity within 0.07 % or better for both $q$ and $u$ simultaneously, making them reliable and stable wide-field linear polarization flats. We demonstrate that the sky on bright-Moon nights is an excellent wide-field linear polarization flat source. Various combinations of the normalized Stokes parameters $q$ and $u$ can be obtained by choosing suitable locations of the sky patch with respect to the Moon
Comment: 8 pages including appendix, 6 figures and 3 tables. Submitted to Astronomy and Astrophysics for review. Comments are welcome
Comment: 8 pages including appendix, 6 figures and 3 tables. Submitted to Astronomy and Astrophysics for review. Comments are welcome