Resolved mass assembly and star formation in Milky Way Progenitors since $z = 5$ from JWST/CANUCS: From clumps and mergers to well-ordered disks

Understand

We present a resolved study of 877 progenitors of Milky Way Analogs (MWAs) at $0.3<z<5$ selected with abundance matching in the ten fields of the Canadian NIRISS Unbiased Cluster Survey (CANUCS).

• Utilizing 18-21 bands of deep NIRCam, NIRISS, and HST photometry, we create resolved stellar mass maps and star formation rate maps via spectral energy distribution fitting with Dense Basis.
• We examine their resolved stellar mass and specific star formation rate (sSFR) profiles as a function of galactocentric radius, and find clear evidence for inside-out mass assembly.
• The total $\mstar$ of the inner 2 kpc regions of the progenitors remain roughly constant ($10^{9.3-9.4}\msun$) at $2<z<5$, while the total $\mstar$ of the regions beyond 2 kpc increases by 0.8 dex, from $10^{7.5}\msun$ to $10^{8.3}\msun$.