Jun Ma

The Beijing-Arizona Sky Survey (BASS) is a wide-field two-band photometric survey of the Northern Galactic Cap using the 90Prime imager on the 2.3 m Bok telescope at Kitt Peak. It is a four-year collaboration between the National Astronomical Observatory of China and Steward Observatory, the University of Arizona, serving as one of the three imaging surveys to provide photometric input catalogs for target selection of the Dark Energy Spectroscopic Instrument (DESI) project. BASS will take up to 240 dark/grey nights to cover an area of about 5400 deg$^2$ in the $g$ and $r$ bands. The 5$\sigma$ limiting AB magnitudes for point sources in the two bands, corrected for the Galactic extinction, are 24.0 and 23.4 mag, respectively. BASS, together with other DESI imaging surveys, will provide unique science opportunities that cover a wide range of topics in both Galactic and extragalactic astronomy.

Open clusters (OCs) have long been used as important tools in the study of the Galactic disc. The young clusters have been used to determine spiral arm structure, and to map the rotation curve of the Galaxy. The old clusters are excellent

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<i>Context. <i/>Linearly polarized Galactic synchrotron emission provides valuable information about the properties of the Galactic magnetic field and the interstellar magneto-ionic medium, when Faraday rotation along the line of sight is properly taken into account.<i>Aims. <i/>We aim to survey the Galactic plane at <i>λ<i/>6 cm including linear polarization. At such a short wavelength Faraday rotation effects are in general small and the Galactic magnetic field properties can be probed to larger distances than at long wavelengths.<i>Methods. <i/>The Urumqi 25-m telescope is used for a sensitive <i>λ<i/>6 cm survey in total and polarized intensities. WMAP K-band (22.8 GHz) polarization data are used to restore the absolute zero-level of the Urumqi <i>U<i/> and <i>Q<i/> maps by extrapolation.<i>Results. <i/>Total intensity and polarization maps are presented for a Galactic plane region of 129° <i>≤<i/> <i>≤<i/> 230° and |<i>b<i/>| <i>≤<i/> 5° in the anti-centre with an angular resolution of and an average sensitivity of 0.6 mK and 0.4 mK <i>T<i/><sub>B<sub/> in total and polarized intensity, respectively. We briefly discuss the properties of some extended Faraday Screens detected in the <i>λ<i/>6 cm polarization maps.<i>Conclusions. <i/>The Sino-German <i>λ<i/>6 cm polarization survey provides new information about the properties of the magnetic ISM. The survey also adds valuable information for discrete Galactic objects and is in particular suited to detect extended Faraday Screens with large rotation measures hosting strong regular magnetic fields.