A Galactic survey of radio jets from massive protostars. Issue 1 (16th March 2021)

• Record Type: Journal Article
• Authors: Purser, S J D; Lumsden, S L; Hoare, M G; Kurtz, S
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 504:Issue 1(2021)
• Page Start: 338
• Page End: 355
• Publication Date: 2021-03-16
• Subjects: surveys -- stars: formation -- stars: massive -- stars: protostars -- ISM: jets and outflows -- radio continuum: ISM; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stab747
• Languages: English
• ISSNs: 0035-8711

Abstract

ABSTRACT: In conjunction with a previous southern-hemisphere work, we present the largest radio survey of jets from massive protostars to date with high-resolution (∼0.04 arcsec) Jansky Very Large Array observations towards two subsamples of massive star-forming regions of different evolutionary statuses: 48 infrared-bright, massive, young, stellar objects (MYSOs) and 8 infrared dark clouds (IRDCs) containing 16 luminous ($\hbox{$\, L_{\rm {bol}}$}\gt 10^3\hbox{${\rm \, L_{\odot }}$}$ ) cores. For 94 per cent of the MYSO sample, we detect thermal radio (α ≥ −0.1 whereby S ν ∝ ν α ) sources coincident with the protostar, of which 84 per cent (13 jets and 25 candidates) are jet like. Radio luminosity is found to scale with $\hbox{$\, L_{\rm {bol}}$}$ similarly to the low-mass case supporting a common mechanism for jet production across all masses. Associated radio lobes tracing shocks are seen towards 52 per cent of jet-like objects and are preferentially detected towards jets of higher radio and bolometric luminosities, resulting from our sensitivity limitations. We find jet mass-loss rate scales with bolometric luminosity as $\hbox{$\dot{m}_{\rm jet}$}\propto \hbox{$\, L_{\rm {bol}}$}^{0.9\pm 0.2}$, thereby discarding radiative, line-driving mechanisms as the dominant jet-launching process. Calculated momenta show that the majority of jets are mechanically capable of driving the massive, molecular outflow phenomena since p jet > p outflow . Finally, from their physical extent we show that the radio emission cannot originate from small, optically thick H ii regions. Towards the IRDC cores, we observe increasing incidence rates/radio fluxes with age using the proxy of increasing luminosity-to-mass ( L / M ) and decreasing infrared flux ratios $({S_{70{\rm \, \mu m}}}/{S_{24{\rm \, \mu m}}})$ . Cores with $({L}/{M})\, \lt \, 40\, \hbox{${\rm \, L_{\odot }}$}\hbox{${\rm \, M_{\odot }}$}^{-1}$ are not detected above ($5.8{\rm \, GHz}$ ) radio luminosities of ${\sim}1{\rm \, mJy}{\rm \, kpc}^2$ .