The Milky Way Imaging Scroll Painting (MWISP): Project Details and Initial Results from the Galactic Longitude of 25.8deg to 49.7deg

TL;DR

The MWISP project provides high-quality, large-scale CO survey data of the Galactic plane, revealing detailed molecular cloud structures and Galactic features in the specified longitude range.

Contribution

This paper presents the initial results and data from a comprehensive CO survey of the Galactic plane, offering new insights into molecular cloud structures and Galactic features.

Findings

Detection of distant Galactic spiral arms via CO emission

Identification of bubble-like dense gas near HII region W40

Mapping of molecular cloud distribution perpendicular to the Galactic plane

Abstract

The Milky Way Imaging Scroll Painting (MWISP) project is an unbiased Galactic plane CO survey for mapping regions of l=-10deg to +250deg and |b|<5.2deg with the 13.7 m telescope of the Purple Mountain Observatory. The legacy survey aims to observe the 12CO, 13CO, and C18O (J=1-0) lines simultaneously with full sampling using the nine-beam Superconducting SpectroScopic Array Receiver (SSAR) system with an instantaneous bandwidth of 1 GHz. In this paper, the completed 250 deg^2 data from l=+25.8deg to +49.7deg are presented with a grid spacing of 30" and a typical rms noise level of ~0.5 K for 12CO at the channel width of 0.16 km/s and ~0.3 K for 13CO and C18O at 0.17 km/s. The high quality data with moderate resolution (50"), uniform sensitivity, and high spatial dynamic range, allow us to investigate the details of molecular clouds (MCs) traced by the three CO isotope lines. Three interesting examples are briefly investigated, including distant Galactic spiral arms traced by CO emission with VLSR<0 km/s, the bubble-like dense gas structure near the HII region W40, and the MCs distribution perpendicular to the Galactic plane.