Please use this identifier to cite or link to this item:
Title: ALMA–IRDC – II. First high-angular resolution measurements of the 14N/15N ratio in a large sample of infrared-dark cloud cores
Authors: Fontani, F.
Barnes, A. T.
Caselli, P.
Henshaw, J. D.
Cosentino, G.
Jiménez Serra, I.
Tan, J. C.
Pineda, J. E.
Law, C. Y.
Keywords: Stars: formation;ISM: Clouds;ISM: molecules
Issue Date: 22-Mar-2021
Publisher: Oxford Academics: Oxford University Press
DOI: 10.1093/mnras/stab700
Published version:
Citation: Monthly Notices of the Royal Astronomical Society 503(3): 4320–4335(2021)
Abstract: The 14N/15N ratio in molecules exhibits a large variation in star-forming regions, especially when measured from N2H+ isotopologues. However, there are only a few studies performed at high-angular resolution. We present the first interferometric survey of the 14N/15N ratio in N2H+ obtained with Atacama Large Millimeter Array observations towards four infrared-dark clouds harbouring 3 mm continuum cores associated with different physical properties. We detect N15NH+ (1–0) in ∼20−40 per cent of the cores, depending on the host cloud. The 14N/15N values measured towards the millimetre continuum cores range from a minimum of ∼80 up to a maximum of ∼400. The spread of values is narrower than that found in any previous single-dish survey of high-mass star-forming regions and than that obtained using the total power data only. This suggests that the 14N/15N ratio is on average higher in the diffuse gaseous envelope of the cores and stresses the need for high-angular resolution maps to measure correctly the 14N/15N ratio in dense cores embedded in IRDCs. The average 14N/15N ratio of ∼210 is also lower than the interstellar value at the Galactocentric distance of the clouds (∼300–330), although the sensitivity of our observations does not allow us to unveil 14N/15N ratios higher than ∼400. No clear trend is found between the 14N/15N ratio and the core physical properties. We find only a tentative positive trend between 14N/15N and H2 column density. However, firmer conclusions can be drawn only with higher sensitivity measurements.
E-ISSN: 1365-2966
ISSN: 0035-8711
Appears in Collections:(CAB) Artículos

Files in This Item:
File Description SizeFormat 
acceso-restringido.pdf221,73 kBAdobe PDFThumbnail

Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.