Gas kinematics and star formation in the filamentary molecular cloud G47.06+0.26 ^⋆

¹ National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012, PR China,
e-mail: xujl@bao.ac.cn
² Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008, PR China
³ Tibet University, Lhasa, Tibet 850000, PR China
⁴ Purple Mountain Observatory, Qinghai Station, Delingha 817000, PR China
⁵ NAOC-TU Joint Center for Astrophysics, Lhasa 850000, PR China
⁶ Key Laboratory of Radio Astronomy, Chinese Academy of Sciences, PR China

Received: 27 June 2016
Accepted: 21 August 2017

Abstract

Aims. We performed a multi-wavelength study toward the filamentary cloud G47.06+0.26 to investigate the gas kinematics and star formation.

Methods. We present the ¹²CO (J = 1−0), ¹³CO (J = 1−0) and C¹⁸O (J = 1−0) observations of G47.06+0.26 obtained with the Purple Mountain Observation (PMO) 13.7 m radio telescope to investigate the detailed kinematics of the filament. Radio continuum and infrared archival data were obtained from the NRAO VLA Sky Survey (NVSS), the APEX Telescope Large Area Survey of the Galaxy (ATLASGAL), the Galactic Legacy Infrared Mid-Plane Survey Extraordinaire (GLIMPSE) survey, and the Multi-band Imaging Photometer Survey of the Galaxy (MIPSGAL). To trace massive clumps and extract young stellar objects in G47.06+0.26, we used the BGPS catalog v2.0 and the GLIMPSE I catalog, respectively.

Results. The ¹²CO (J = 1−0) and ¹³CO (J = 1−0) emission of G47.06+0.26 appear to show a filamentary structure. The filament extends about 45′ (58.1 pc) along the east-west direction. The mean width is about 6.8 pc, as traced by the ¹³CO (J = 1−0) emission. G47.06+0.26 has a linear mass density of ~361.5 M_⊙pc^-1. The external pressure (due to neighboring bubbles and H II regions) may help preventing the filament from dispersing under the effects of turbulence. From the velocity-field map, we discern a velocity gradient perpendicular to G47.06+0.26. From the Bolocam Galactic Plane Survey (BGPS) catalog, we found nine BGPS sources in G47.06+0.26, that appear to these sources have sufficient mass to form massive stars. We obtained that the clump formation efficiency (CFE) is ~18% in the filament. Four infrared bubbles were found to be located in, and adjacent to, G47.06+0.26. Particularly, infrared bubble N98 shows a cometary structure. CO molecular gas adjacent to N98 also shows a very intense emission. H II regions associated with infrared bubbles can inject the energy to surrounding gas. We calculated the kinetic energy, ionization energy, and thermal energy of two H II regions in G47.06+0.26. From the GLIMPSE I catalog, we selected some Class I sources with an age of ~10⁵ yr, which are clustered along the filament. The feedback from the H II regions may cause the formation of a new generation of stars in filament G47.06+0.26.