Galatic HII region IRAS 17149$-$3916 -- A multiwavelength study

Abstract

This paper presents a multiwavelength investigation of the Galactic H ii region IRAS 17149−3916. Using the Giant Meterwave Radio Telescope, India, first low-frequency radio continuum observations at 610 and 1280 MHz for this region are presented. The ionized gas emission displays an interesting cometary morphology which is likely powered by the early type source, E4 (IRS-1). The origin of the cometary morphology is discussed under the framework of the widely accepted bow shock, champagne flow, and clumpy cloud mechanisms. The mid-and far-infrared data from Spitzer-GLIMPSE and Herschel-Hi-GAL reveal a complex network of pillars, clumps, bubble, filaments, and arcs suggesting the profound influence of massive stars on the surrounding medium. Triggered star formation at the tip of an observed pillar structure is reported. High-resolution ALMA continuum data show a string of cores detected within the identified clumps. The core masses are well explained by thermal Jeans fragmentation and support the hierarchical fragmentation scenario. Four 'super-Jeans' cores are identified which, at the resolution of the present data set, are suitable candidates to form high-mass stars.

ATOMS: ALMA three-millimeter observations of massive star-forming regions – XII: Fragmentation and multiscale gas kinematics in protoclusters G12.42+0.50 and G19.88−0.53

“…These results are in good agreement with the results of several statistical and dedicated studies (e.g. Sanhueza et al 2019;Potdar et al 2021;Palau et al 2013;Beuther et al 2018;Liu et al 2017) towards protoclusters where thermal pressure is inferred to be dominant in the hierarchical fragmentation process. Fragmentation where turbulence dominates over thermal pressure has also been inferred in several complexes.…”

“…where 𝑘 B , 𝑇 kin , 𝑚 H , and 𝜇 are the Boltzmann constant, the kinetic temperature, the mass of hydrogen atom and the mean molecular weight per free particle, respectively. We have considered 𝜇 = 2.37 (Kauffmann et al 2008;Sanhueza et al 2019;Wang et al 2014;Potdar et al 2021).…”