Show simple item record

Files in this item

Thumbnail

Item metadata

dc.contributor.authorTowner, APM
dc.contributor.authorBrogan, CL
dc.contributor.authorHunter, TR
dc.contributor.authorCyganowski, CJ
dc.date.accessioned2022-01-11T13:30:10Z
dc.date.available2022-01-11T13:30:10Z
dc.date.issued2021-12-28
dc.identifier276266883
dc.identifier76eb243f-4027-414c-b3f5-ee5a3746060a
dc.identifier000735199800001
dc.identifier85123605135
dc.identifier.citationTowner , APM , Brogan , CL , Hunter , TR & Cyganowski , CJ 2021 , ' VLA observations of nine extended green objects in the Milky Way : ubiquitous weak, compact continuum emission, and multi-epoch emission from methanol, water, and ammonia masers ' , Astrophysical Journal , vol. 923 , no. 2 , 263 . https://doi.org/10.3847/1538-4357/ac2c86en
dc.identifier.issn0004-637X
dc.identifier.otherArXiv: http://arxiv.org/abs/2110.04270v1
dc.identifier.otherRIS: urn:67B86FE570139268B83771D19C581C09
dc.identifier.urihttps://hdl.handle.net/10023/24641
dc.descriptionSupport for this work was provided by the NSF through the Grote Reber Fellowship Program administered by Associated Universities, Inc./National Radio Astronomy Observatory. Support for this work was provided by the NSF through award SOSP18A-007 from the NRAO. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under agreement by the Associated Universities, Inc.en
dc.description.abstractWe have observed a sample of nine Extended Green Objects (EGOs) at 1.3 and 5 cm with the Very Large Array (VLA) with subarcsecond resolution and ∼7–14 μJy beam−1-sensitivities in order to characterize centimeter continuum emission as it first appears in these massive protoclusters. We find an EGO-associated continuum emission—within 1'' of the extended 4.5 μm emission—in every field, which is typically faint (order 101–102 μJy) and compact (unresolved at 0''.3–0''.5). The derived spectral indices of our 36 total detections are consistent with a wide array of physical processes, including both non-thermal (19% of detections) and thermal free–free processes (e.g., ionized jets and compact H ii regions, 78% of sample) and warm dust (1 source). We also find an EGO-associated 6.7 GHz CH3OH and 22 GHz H2O maser emission in 100% of the sample and a NH3 (3,3) masers in ∼45%; we do not detect any NH3 (6,6) masers at ∼5.6 mJy beam−1 sensitivity. We find statistically-significant correlations between Lradio and Lbol at two physical scales and three frequencies, consistent with thermal emission from ionized jets, but no correlation between LH20 and Lradio for our sample. From these data, we conclude that EGOs likely host multiple different centimeter continuum-producing processes simultaneously. Additionally, at our ∼1000 au resolution, we find that all EGOs except G18.89−0.47 contain 1 ∼ 2 massive sources based on the presence of CH3OH maser groups, which is consistent with our previous work suggesting that these are typical massive protoclusters, in which only one to a few of the young stellar objects are massive.
dc.format.extent21
dc.format.extent5575387
dc.language.isoeng
dc.relation.ispartofAstrophysical Journalen
dc.subjectQB Astronomyen
dc.subjectQC Physicsen
dc.subjectNDASen
dc.subject.lccQBen
dc.subject.lccQCen
dc.titleVLA observations of nine extended green objects in the Milky Way : ubiquitous weak, compact continuum emission, and multi-epoch emission from methanol, water, and ammonia masersen
dc.typeJournal articleen
dc.contributor.institutionUniversity of St Andrews. School of Physics and Astronomyen
dc.identifier.doihttps://doi.org/10.3847/1538-4357/ac2c86
dc.description.statusPeer revieweden
dc.date.embargoedUntil2021-12-28
dc.identifier.urlhttps://arxiv.org/abs/2110.04270en


This item appears in the following Collection(s)

Show simple item record