# Extraction of $^{12}$CO and $^{13}$CO maps from $Planck$ data

## TL;DR

This paper introduces a method to produce separate $^{12}$CO and $^{13}$CO maps from Planck data, enabling detailed all-sky analysis of these isotopes' distributions in the Galaxy.

## Contribution

A novel technique to extract individual $^{12}$CO and $^{13}$CO maps from Planck's composite CO data, improving the understanding of Galactic molecular gas.

## Key findings

- First all-sky $^{13}$CO map from Planck data
- Enhanced resolution of Galactic molecular gas distribution
- New insights into isotopic variations across the Galaxy

## Abstract

Rotational transition lines of CO are one of the major tracers used to study star forming regions and Galactic structures. A large number of observations of CO rotational lines are covering the galactic plane, recently the $Planck$ collaboration release the first full sky coverage of J=1-0, J=2-1, and J=3-2 CO lines at a resolution of 10', 5', and 5' FWHM. However, the measured signal in $Planck$ detectors is integrated over large bandpass $(\Delta \nu)/\nu \simeq 0.2$. Consequently, the derived CO products are composite maps including several rotational lines. In the 100 GHz $Planck$ channel, the two main lines are the J=1-0 transitions of $^{12}$CO and $^{13}$CO at 115 and 110 GHz respectively. In the present paper, we present and applied a method to construct separate CO integrated intensity maps for the two isotopes. The measurement of the $^{13}$CO rotational transitions provide an unprecedented all-sky view of the Galaxy for this isotope.