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dc.contributor.authorGallerani, Sen
dc.contributor.authorPallottini, Andreaen
dc.contributor.authorFeruglio, Cen
dc.contributor.authorFerrara, Aen
dc.contributor.authorMaiolino, Robertoen
dc.contributor.authorVallini, Len
dc.contributor.authorRiechers, DAen
dc.contributor.authorPavesi, Ren
dc.date.accessioned2018-05-03T10:11:01Z
dc.date.available2018-05-03T10:11:01Z
dc.date.issued2018-01-01en
dc.identifier.issn0035-8711
dc.identifier.urihttps://www.repository.cam.ac.uk/handle/1810/275485
dc.description.abstractWe present the first attempt to detect outflows from galaxies approaching the Epoch of Reionization (EoR) using a sample of 9 star-forming ($\rm SFR=31\pm 20~M_{\odot}~yr^{-1}$) $z\sim 5.5$ galaxies for which the [CII]158$\mu$m line has been previously obtained with ALMA. We first fit each line with a Gaussian function and compute the residuals by subtracting the best fitting model from the data. We combine the residuals of all sample galaxies and find that the total signal is characterised by a flux excess of $\sim 0.5$ mJy extended over $\sim 1000$ km~s$^{-1}$. Although we cannot exclude that part of this signal is due to emission from faint satellite galaxies, we show that the most probable explanation for the detected flux excess is the presence of broad wings in the [CII] lines, signatures of starburst-driven outflows. We infer an average outflow rate of $\rm \dot{M}=54\pm23~ M_{\odot}~yr^{-1}$, providing a loading factor $\eta=\rm \dot{M}/SFR=1.7\pm1.3$ in agreement with observed local starbursts. Our interpretation is consistent with outcomes from zoomed hydro-simulations of {\it Dahlia}, a $z\sim 6$ galaxy ($\rm SFR\sim 100~\rm M_{\odot}~yr^{-1}$) whose feedback-regulated star formation results into an outflow rate $\rm \dot{M}\sim 30~ M_{\odot}~yr^{-1}$. The quality of the ALMA data is not sufficient for a detailed analysis of the [CII] line profile in individual galaxies. Nevertheless, our results suggest that starburst-driven outflows are in place in the EoR and provide useful indications for future ALMA campaigns. Deeper observations of the [CII] line in this sample are required to better characterise feedback at high-$z$ and to understand the role of outflows in shaping early galaxy formation.
dc.publisherOxford University Press
dc.titleALMA suggests outflows in z ~ 5.5 galaxiesen
dc.typeArticle
prism.endingPage1917
prism.issueIdentifier2en
prism.publicationDate2018en
prism.publicationNameMonthly Notices of the Royal Astronomical Societyen
prism.startingPage1909
prism.volume473en
dc.identifier.doi10.17863/CAM.22718
dcterms.dateAccepted2017-09-20en
rioxxterms.versionofrecord10.1093/mnras/stx2458en
rioxxterms.versionVoR*
rioxxterms.licenseref.urihttp://www.rioxx.net/licenses/all-rights-reserveden
rioxxterms.licenseref.startdate2018-01-01en
dc.contributor.orcidPallottini, Andrea [0000-0002-7129-5761]
dc.contributor.orcidMaiolino, Roberto [0000-0002-4985-3819]
dc.identifier.eissn1365-2966
rioxxterms.typeJournal Article/Reviewen
pubs.funder-project-idECH2020 EUROPEAN RESEARCH COUNCIL (ERC) (695671)
pubs.funder-project-idSTFC (ST/M001172/1)
pubs.funder-project-idSTFC (ST/K003119/1)
cam.orpheus.successThu Jan 30 13:04:40 GMT 2020 - The item has an open VoR version.*
rioxxterms.freetoread.startdate2100-01-01


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