The effects of ionization feedback on star formation: a case study of the M 16 H II region

Abstract

Aims. We aim to investigate the impact of the ionized radiation from the M16 H II region on the surrounding molecular cloud and on its hosted star formation. Methods. To present comprehensive multi-wavelength observations towards the M16 H II region, we used new CO data and existing infrared, optical, and submillimeter data. The 12 CO J=1-0, 13 CO J=1-0, and C 18 O J=1-0 data were obtained with the Purple Mountain Observatory (PMO) 13.7m radio telescope. To trace massive clumps and extract young stellar objects (YSOs) associated with the M16 H II region, we used the ATLASGAL and GLIMPSE I catalogs, respectively. Results. From CO data, we discern a large-scale filament with three velocity components. Because these three components overlap with each other in both velocity and space, the filament may be made of three layers. The M16 ionized gas interacts with the largescale filament and has reshaped its structure. In the large-scale filament, we find 51 compact cores from the ATLASGAL catalog, 20 of them being quiescent. The mean excitation temperature of these cores is 22.5 K, while this is 22.2 K for the quiescent cores. This high temperature observed for the quiescent cores suggests that the cores may be heated by M16 and do not experience internal heating from sources in the cores. Through the relationship between the mass and radius of these cores, we obtain that 45% of all the cores are massive enough to potentially form massive stars. Compared with the thermal motion, the turbulence created by the nonthermal motion is responsible for the core formation. For the pillars observed towards M16, the H II region may give rise to the strong turbulence.

APEX CO observations towards the photodissociation region of RCW 120

“…Some observations have shown that several components can be observed toward bright rimmed clouds (BRCs) due to the internal dynamics caused by the interaction, although the presence of an IBL and/or 8 µm is often taken as proof of an interaction with the ionizing flux. Statistical studies using Spitzer, ATLASGAL, and Herschel showed that H II bubbles host at least 25−30% of the high-mass Galactic sources (Deharveng et al 2010;Kendrew et al 2012Kendrew et al , 2016Palmeirim et al 2017) and dedicated studies show the same behavior (Tigé et al 2017;Russeil et al 2019;Xu et al 2019). Therefore, this high percentage of young high-mass sources was mainly thought to be the result of different triggering mechanisms.…”

Evolution of Stellar Feedback in HII Regions

“…Individual feedback modes have been assessed for large samples of sources (e.g., Rosero et al 2019), and measurements of the relative role of multiple feedback modes have been done for particular starforming regions (e.g. Lopez et al 2011;Pellegrini et al 2011;Ginsburg et al 2017;Lee et al 2019;Xu et al 2019) and across many regions (e.g. Lopez et al 2014;Chevance et al 2019;Kruijssen et al 2019;McLeod et al 2019; Barnes et al 2020;McLeod et al 2020).…”

Investigating the physical properties and fragmentation of the AFGL 333-Ridge

“…However, Eden et al (2013) found that most of the molecular clouds associated with H II regions have CFE as high as 40%. The clump formation efficiency obtained in the M16 H II region is 22±3% (Xu et al 2019). Figueira et al (2020) estimated that the CFE of H II region RCW 120 varies between 12 and 26%.…”