Nitrogen X-ray absorption in the local ISM
Nitrogen is one of the most abundant metals in the interstellar medium (ISM), and thus it constitutes an excellent test to study a variety of astrophysical environments, ranging from nova to active galactic nuclei. We present a detailed analysis of the gaseous component of the N K-edge using high-resolution XMM–Newton spectra of 12 Galactic and 40 extragalactic sources. For each source, we have estimated column densities for N I, N II, N III, N V, N VI, and N VII ionic species, which trace the cold, warm, and hot phases of the local Galactic ISM. We have found that the cold-warm component column densities decrease with the Galactic latitude, while the hot component does not. Moreover, the cold column density distribution is in good agreement with UV measurements. This is the first detailed analysis of the nitrogen K-edge absorption due to ISM using high-resolution X-ray spectra.
Additional Information© 2021 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This article is published and distributed under the terms of the Oxford University Press, Standard Journals Publication Model (https://academic.oup.com/journals/pages/open_access/funder_policies/chorus/standard_publication_model) Accepted 2021 April 21. Received 2021 April 21; in original form 2020 September 17. We thank the anonymous referee for the careful reading of our manuscript and the valuable comments. JAG acknowledges support from the Smithsonian Astrophysical Observatory grant AR0-21003X, and from the Alexander von Humboldt Foundation. DATA AVAILABILITY. Observations analysed in this article are available in the XMM–Newton Science Archive (XSA) (http://nxsa.esac.esa.int/nxsa-web/#search). The ISMabs model is included in the XSPEC data analysis software (https://heasarc.gsfc.nasa.gov/xanadu/xspec/).
Published - stab1185.pdf
Accepted Version - 2104.11256.pdf