Publication:
Molecular hydrogen line emission from the refelction nebula Parsamyan 18

dc.contributor.author Ryder, Stuart en_US
dc.contributor.author Allen, Lori en_US
dc.contributor.author Burton, Michael en_US
dc.contributor.author Ashley, Michael en_US
dc.contributor.author Storey, John en_US
dc.date.accessioned 2021-11-25T13:06:39Z
dc.date.available 2021-11-25T13:06:39Z
dc.date.issued 1998 en_US
dc.description.abstract The newly commissioned University of New South Wales Infrared Fabry-Perot (UNSWIRF) has been used to image molecular hydrogen emission at 2.12 and 2.25 μm in the reflection nebula Parsamyan 18. P 18 is known to exhibit low values of the (1-0)/(2-1) S(1) ratio, suggestive of UV-pumped fluorescence rather than thermal excitation by shocks. Our line ratio mapping reveals the full extent of this fluorescent emission from extended arc-like features, as well as a more concentrated thermal component in regions closer to the central exciting star. We show that the emission morphology, line fluxes and gas density are consistent with the predictions of photodissociation region (PDR) theory. Those regions with the highest intrinsic 1-0 S(1) intensities also tend to show the highest (1-0)/(2-1) S(1) line ratios. Furthermore, variations in the line ratio can be attributed to intrinsic fluctuations in the incident radiation field and/or the gas density, through the self-shielding action of H2. An isolated knot of emission discovered just outside P 18, and having both an unusually high (1-0)/(2-1) S(1) ratio and relative velocity, provides additional evidence for an outflow source associated with P 18. en_US
dc.identifier.issn 0035-8711 en_US
dc.identifier.uri http://hdl.handle.net/1959.4/39147
dc.language English
dc.language.iso EN en_US
dc.rights CC BY-NC-ND 3.0 en_US
dc.rights.uri https://creativecommons.org/licenses/by-nc-nd/3.0/au/ en_US
dc.source Legacy MARC en_US
dc.title Molecular hydrogen line emission from the refelction nebula Parsamyan 18 en_US
dc.type Journal Article en
dcterms.accessRights metadata only access
dspace.entity.type Publication en_US
unsw.accessRights.uri http://purl.org/coar/access_right/c_14cb
unsw.identifier.doiPublisher http://dx.doi.org/10.1046/j.1365-8711.1998.01256.x en_US
unsw.relation.faculty Science
unsw.relation.ispartofissue 2 en_US
unsw.relation.ispartofjournal Monthly Notices of the Royal Astronomical Society en_US
unsw.relation.ispartofpagefrompageto 338-346 en_US
unsw.relation.ispartofvolume 294 en_US
unsw.relation.originalPublicationAffiliation Ryder, Stuart, Physics, Faculty of Science, UNSW en_US
unsw.relation.originalPublicationAffiliation Allen, Lori, Physics, Faculty of Science, UNSW en_US
unsw.relation.originalPublicationAffiliation Burton, Michael, Physics, Faculty of Science, UNSW en_US
unsw.relation.originalPublicationAffiliation Ashley, Michael, Physics, Faculty of Science, UNSW en_US
unsw.relation.originalPublicationAffiliation Storey, John, Physics, Faculty of Science, UNSW en_US
unsw.relation.school School of Physics *
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