Mapper of Narrow Galaxy Lines (MaNGaL): new tunable filter imager for Caucasian telescopes
- PDF / 6,741,493 Bytes
- 16 Pages / 439.642 x 666.49 pts Page_size
- 66 Downloads / 169 Views
Mapper of Narrow Galaxy Lines (MaNGaL): new tunable filter imager for Caucasian telescopes Alexei Moiseev1,2
· Aleksander Perepelitsyn1 · Dmitry Oparin1
Received: 29 May 2020 / Accepted: 17 August 2020 / © Springer Nature B.V. 2020
Abstract We described the design and operation principles of a new tunable-filter photometer developed for the 1-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences and the 2.5-m telescope of the Sternberg Astronomical Institute of the Moscow State University. The instrument is mounted on the scanning Fabry-Perot interferometer operating in the tunable-filter mode in the spectral range of 460-800 nm with a typical spectral resolution of about 1.3 nm. It allows one to create images of galactic and extragalactic nebulae in the emission lines having different excitation conditions and to carry out diagnostics of the gas ionization state. The main steps of observations, data calibration, and reduction are illustrated by examples of different emission-line objects: galactic H II regions, planetary nebulae, active galaxies with extended filaments, starburst galaxies, and Perseus galaxy cluster. Keywords Instrumentation: interferometers · Techniques: imaging spectroscopy · Interstellar medium (ISM): lines and bands · Galaxies: ISM
1 Introduction Tunable filter (TF) imaging systems based on low-order scanning Fabry-Perot interferometers (FPIs) have a long history of astronomical applications related to the study of extended emission-line targets: galactic and extragalactic nebulae, solar system objects [1–3]. The main idea of observations are well described in the above references and also illustrated in Fig. 1. If the gap between FPI plates is small and Alexei Moiseev
[email protected] 1
Special Astrophysical Observatory, Russian Academy of Sciences, Nizhny, Arkhyz, 369167, Russia
2
Lomonosov Moscow State University, Sternberg Astronomical Institute, Universitetsky pr. 13, Moscow, 119234, Russia
Experimental Astronomy
Fig. 1 Tunable filter operating principle. The regions filled with various tones of orange show the transmission profiles of the FPI tuned for observations in the Hα (1) and [N II]λ6583 (2) emission lines and in the continuum (3). The blue dashed line shows the transmission curve of the medium-band filter which isolates only one transmission peak of the interferometer. The parameters of FPI and medium-band filter are similar to those used in the MaNGaL; the integrated spectrum of the NGC 4460 starburst galaxy was taken from [4]
corresponds to the interference orders n = 10−30, then it is easy to attain the FWHM of the instrumental profile δλ = 1 − 2 nm. Since the distance between neighbouring interference orders (interfringe) Δλ = λ/n, we can cut the desired transmission peaks by the medium-band filter with a typical bandwidth of about 15–30 nm. The peak transmission central wavelength (CWL) can be switched between the desired emission line and neighboring continuum using a piezoelectrically-tuned and servostabilized FPI; the redshif
Data Loading...
