Oral Presentation

Unveiling Stellar Feedback and Cloud Structure in the Rho Ophiuchi A Region with ALMA and JWST

Author(s): Fumitaka Nakamura, Ryohei Kawabe (NAOJ) et al.

Presenter: Fumitaka Nakamura (NAOJ)

In clustered star-forming regions, stellar feedback such as HII regions/photon-dominated regions (PDRs) and protostellar jets/outflows shapes cloud structures and influences subsequent star formation process. Using high-resolution ALMA millimeter and JWST infrared data, we analyze the cloud structure and the impact of stellar feedback in the dense cluster-forming region Oph A.
The ALMA 1.3 mm dust continuum image reveals 7 small substellar cores:
Three core are associated with point-like near-infrared emission and therefore we propose that they are young substellar objects. Other cores without compact infrared emission have masses of ~ 0.01 Msun with a mean density of ~10^8 cm^{-3}. They are likely gravitationally-bound substellar cores. They appear to be connected by faint CO finger-like structures extended from VLA 1623A/B, suggesting that they might have been ejected from VLA 1623A. 12CO (J=2-1) and near-infrared observations reveal multiple protostellar outflows/jets from protostars. Strong 12CO emission traces the eastern edge of the Oph A ridge, forming a part of the expanding HII/PDR bubble driven by the nearby Herbig Be star S1. The northern ridge segment appears"blown out," with warm gas flowing westward toward the GSS 30 region.
We also found several C18O (J=2-1) striations in the S1 bubble which align with magnetic field structures. The position-velocity diagrams show a wave-like velocity pattern, possibly reflecting magnetohydrodynamic waves.
The stellar feedback in Oph A affects most of the area and plays a significant role in shaping Oph A's complex cloud structure.