CHIMPS2: Survey description and $^{12}$CO emission in the Galactic Centre

TL;DR

CHIMPS2 is a new high-resolution survey of the Inner Galaxy's molecular gas using $^{12}$CO, $^{13}$CO, and C$^{18}$O emissions, providing valuable data for understanding star formation and galactic environment effects.

Contribution

This paper introduces the first data release of CHIMPS2, a survey of the Inner Galaxy with high-resolution CO observations, complementing existing Galactic plane surveys.

Findings

Detection of foreground spiral arms in absorption and emission.

High-resolution maps of the Central Molecular Zone in $^{12}$CO J=3→2.

Coverage of $-3^ ext{o}$ to $5^ ext{o}$ in Galactic longitude.

Abstract

The latest generation of Galactic-plane surveys is enhancing our ability to study the effects of galactic environment upon the process of star formation. We present the first data from CO Heterodyne Inner Milky Way Plane Survey 2 (CHIMPS2). CHIMPS2 is a survey that will observe the Inner Galaxy, the Central Molecular Zone (CMZ), and a section of the Outer Galaxy in $^{12}$CO, $^{13}$CO, and C$^{18}$O $(J = 3\rightarrow2)$ emission with the Heterodyne Array Receiver Program on the James Clerk Maxwell Telescope (JCMT). The first CHIMPS2 data presented here are a first look towards the CMZ in $^{12}$CO J = 3$\rightarrow$2 and cover $-3^{\circ}\leq\,\ell\,\leq\,5^{\circ}$ and $\mid$b$\mid \leq 0.5^{\circ}$ with angular resolution of 15 arcsec, velocity resolution of 1 km s$^{-1}$, and rms $\Delta T_A ^\ast =$ 0.58 K at these resolutions. Such high-resolution observations of the CMZ will be a valuable data set for future studies, whilst complementing the existing Galactic Plane surveys, such as SEDIGISM, the Herschel infrared Galactic Plane Survey, and ATLASGAL. In this paper, we discuss the survey plan, the current observations and data, as well as presenting position-position maps of the region. The position-velocity maps detect foreground spiral arms in both absorption and emission.