# The Molecular Structures of Local Arm and Perseus Arm in the Galactic Region of l=[139.75,149.75]$^\circ$, b=[-5.25,5.25]$^\circ$

## TL;DR

This study maps the molecular structures of the Local and Perseus Arms in a specific Galactic region, revealing warp and flare features and identifying new filamentary giant molecular clouds, enhancing understanding of Galactic structure.

## Contribution

First detailed molecular mapping of the Local and Perseus Arms in this region, identifying new filamentary clouds and analyzing warp and flare structures in atomic and molecular gas.

## Key findings

- Warp structure is evident in both atomic and molecular gas.
- Flare structure exists only in atomic gas.
- Five filamentary giant molecular clouds identified, four newly discovered.

## Abstract

Using the Purple Mountain Observatory Delingha (PMODLH) 13.7 m telescope, we report a 96-square-degree 12CO/13CO/C18O mapping observation toward the Galactic region of l = [139.75, 149.75]$^\circ$, b = [-5.25, 5.25]$^\circ$. The molecular structure of the Local Arm and Perseus Arm are presented. Combining HI data and part of the Outer Arm results, we obtain that the warp structure of both atomic and molecular gas is obvious, while the flare structure only exists in atomic gas in this observing region. In addition, five filamentary giant molecular clouds on the Perseus Arm are identified. Among them, four are newly identified. Their relations with the Milky Way large-scale structure are discussed.