English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

We present a study of the physical and chemical properties of the ExtendedGreen Object (EGO) G19.01$-$0.03 using sub-arcsecond angular resolution AtacamaLarge Millimeter/submillimeter Array (ALMA) 1.05mm and Karl G. Jansky VeryLarge Array (VLA) 1.21cm data. G19.01$-$0.03 MM1, the millimetre sourceassociated with the central massive young stellar object (MYSO), appearedisolated and potentially chemically young in previous Submillimeter Arrayobservations. In our $\sim0.4''$-resolution ALMA data, MM1 has four low-massmillimetre companions within 0.12pc, all lacking maser or outflow emission,indicating they may be prestellar cores. With a rich ALMA spectrum full ofcomplex organic molecules, MM1 does not appear chemically young, but hasmolecular abundances typical of high-mass hot cores in the literature. At the1.05mm continuum peak of MM1,$\mathrm{N}(\mathrm{CH}_{3}\mathrm{OH})=(2.22\pm0.01)\times10^{18}$cm$^{-2}$and $T_{\mathrm{ex}} = 162.7\substack{+0.3 \\ -0.5}$K based on pixel-by-pixelBayesian analysis of LTE synthetic methanol spectra across MM1. Intriguingly,the peak CH$_{3}$OH $T_{\mathrm{ex}}=165.5\pm0.6$ K is offset from MM1'smillimetre continuum peak by $0.22''\sim880$au, and a region of elevatedCH$_{3}$OH $T_{\mathrm{ex}}$ coincides with free-free VLA 5.01cm continuum,adding to the tentative evidence for a possible unresolved high-mass binary inMM1. In our VLA 1.21cm data, we report the first NH$_{3}$(3,3) maser detectionstowards G19.01$-$0.03, along with candidate 25GHz CH$_{3}$OH $5(2,3)-5(1,4)$maser emission; both are spatially and kinematically coincident with 44GHzClass I CH$_{3}$OH masers in the MM1 outflow. We also report the ALMA detectionof candidate 278.3GHz Class I CH$_{3}$OH maser emission towards this outflow,strengthening the connection of these three maser types to MYSO outflows.

ALMA observations of the Extended Green Object G19.01$-$0.03: II. A  massive protostar with typical chemical abundances surrounded by four  low-mass prestellar core candidates