A Dwarf Galaxy Debris Stream Associated with Palomar 1 and the Anticenter Stream

We report the discovery of a new stream (dubbed as Yangtze) detected in $Gaia$ Data Release 3. The stream is at a heliocentric distance of $\sim$ 9.12 kpc and spans nearly 27$\mathrm{°}$ by 1.9$\mathrm{°}$ on sky. The colour-magnitude diagram of Yangtze indicates a stellar population of Age $\sim$ 11 Gyr and [M/H] $\sim$ -0.7 dex. It has a number density of about 5.5 stars degree${}^{-2}$ along with a surface brightness of ${\mathrm{\Sigma }}_G\simeq$ 34.9 mag arcsec${}^{-2}$. The dynamics and metallicity estimate suggest that Yangtze may be closely related to Palomar 1 and the Anticenter stream.