Fall-elujah! An infalling gas bridge surrounding two Class 0/I systems in L1448N revealed by PRODIGE

Caroline Gieser

Tuesday, Dec. 3rd, 9:55CET

The formation of stars has been subject to extensive studies in the past decades from molecular cloud to protoplanetary disk scales. It is still not fully understood how the surrounding material in a protostellar system, that often shows asymmetric structures with complex kinematic properties, feeds the central protostar(s) and their disk(s). We present 1 mm NOEMA observations of the PRODIGE large program and analyze the kinematic properties of molecular lines of the IRS3A and IRS3B Class 0/I protostellar systems in L1448N located in the Perseus molecular cloud. Given the complexity of the spectral profiles, the lines are fitted with up to three Gaussian velocity components. The clustering algorithm DBSCAN is used to disentangle the velocity components into the underlying physical structure. We discover an extended gas bridge (≈3000 au) surrounding both the IRS3A and IRS3B systems in six molecular line tracers (C18O, SO, DCN, H2CO, HC3N, and CH3OH). This gas bridge is oriented along the northeast-southwest direction and shows clear velocity gradients on the order of 100 km/s/pc towards the IRS3A system. We find that the observed velocity profile is consistent with analytical streamline models of gravitational infall towards IRS3A. In high angular resolution continuum data IRS3A and IRS3B often appeared to have formed isolated from each other. The PRODIGE molecular gas observations reveal that these systems are still embedded within a common large-scale mass reservoir with a complex spatial morphology as well as velocity profiles.