{"id":439,"date":"2017-05-03T13:21:38","date_gmt":"2017-05-03T12:21:38","guid":{"rendered":"http:\/\/auditore.cab.inta-csic.es\/galaxias\/?p=439"},"modified":"2017-11-16T13:40:00","modified_gmt":"2017-11-16T12:40:00","slug":"first-detection-of-the-448-ghz-h2o-transition-in-space","status":"publish","type":"post","link":"http:\/\/auditore.cab.inta-csic.es\/galaxias\/first-detection-of-the-448-ghz-h2o-transition-in-space\/","title":{"rendered":"First detection of the 448 GHz H2O transition in space"},"content":{"rendered":"<div id=\"attachment_441\" style=\"width: 1431px\" class=\"wp-caption alignleft\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-441\" class=\"wp-image-441 size-full\" src=\"http:\/\/auditore.cab.inta-csic.es\/galaxias\/files\/2017\/11\/30851Pereira.gif.png\" alt=\"\" width=\"1421\" height=\"971\" \/><p id=\"caption-attachment-441\" class=\"wp-caption-text\">Left: Map of the 448\u2009GHz (rest frequency) continuum (top panel) and zeroth moment of the H2O 423 \u2212 330 emission (bottom panel) of ESO 320-G030. Right: Continuum subtracted profile of the H2O 423 \u2212 330 448\u2009GHz emission. See Pereira-Santaella et al. 2017 for further details.<\/p><\/div>\n<p>Water is a key molecule to probe dense and warm regions in the interstellar medium, because of its chemistry as well as its coupling to the far-infrared. This work presents the first detection of the ortho-H2O 4_23 &#8211; 3_30 transition at 448 GHz in space. <!--more-->Due to a strong opacity in the terrestrial atmosphere, this line had not till now been observed in nearby molecular clouds. The line is found in emission with ALMA in a redshifted luminous infrared (IR) galaxy ESO 320-G030. Water excitation models have long predicted the maser nature of this transition, pumped by collisions when the kinetic temperature is around 1000K and the hydrogen density 10<sup>5<\/sup> cm<sup>-3<\/sup>. On the contrary, and surprisingly, the line is primarily excited by the intense far-IR radiation field that is present in the nucleus of this galaxy. This field extends over a region of 65 pc in diameter and shows a regular rotation pattern compatible with the global molecular and ionized gas kinematics. This H2O transition is therefore a probe of deeply buried galactic nuclei thanks to the high dust optical depths (NH &gt; 4 10<sup>24<\/sup> cm<sup>2<\/sup>) required to efficiently excite it.<\/p>\n<p>M. Pereira-Santaella, E. Gonzalez-Alfonso, A. Usero, et al. A&amp;A 601, L3. DOI: <a href=\"https:\/\/doi.org\/10.1051\/0004-6361\/201730851\">https:\/\/doi.org\/10.1051\/0004-6361\/201730851<\/a><\/p>\n<p>with participation of J. Mart\u00edn-Pintado, <a href=\"http:\/\/auditore.cab.inta-csic.es\/galaxias\/people\/lcolina\/\">L. Colina<\/a>, <a href=\"http:\/\/auditore.cab.inta-csic.es\/galaxias\/people\/aalonso\/\">A. Alonso-Herrero<\/a>, <a href=\"http:\/\/auditore.cab.inta-csic.es\/galaxias\/people\/sarribas\/\">S. Arribas<\/a> and F. Rico from CAB<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Water is a key molecule to probe dense and warm regions in the interstellar medium, because of its chemistry as well as its coupling to the far-infrared. This work presents the first detection of the ortho-H2O 4_23 &#8211; 3_30 transition &hellip; <a href=\"http:\/\/auditore.cab.inta-csic.es\/galaxias\/first-detection-of-the-448-ghz-h2o-transition-in-space\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":72,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[20],"tags":[17,41,40,43,42],"class_list":["post-439","post","type-post","status-publish","format-standard","hentry","category-news","tag-alma","tag-eso320-g030","tag-h20","tag-lirgs","tag-luminous-infrared-galaxies"],"_links":{"self":[{"href":"http:\/\/auditore.cab.inta-csic.es\/galaxias\/wp-json\/wp\/v2\/posts\/439","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/auditore.cab.inta-csic.es\/galaxias\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/auditore.cab.inta-csic.es\/galaxias\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/auditore.cab.inta-csic.es\/galaxias\/wp-json\/wp\/v2\/users\/72"}],"replies":[{"embeddable":true,"href":"http:\/\/auditore.cab.inta-csic.es\/galaxias\/wp-json\/wp\/v2\/comments?post=439"}],"version-history":[{"count":6,"href":"http:\/\/auditore.cab.inta-csic.es\/galaxias\/wp-json\/wp\/v2\/posts\/439\/revisions"}],"predecessor-version":[{"id":446,"href":"http:\/\/auditore.cab.inta-csic.es\/galaxias\/wp-json\/wp\/v2\/posts\/439\/revisions\/446"}],"wp:attachment":[{"href":"http:\/\/auditore.cab.inta-csic.es\/galaxias\/wp-json\/wp\/v2\/media?parent=439"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/auditore.cab.inta-csic.es\/galaxias\/wp-json\/wp\/v2\/categories?post=439"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/auditore.cab.inta-csic.es\/galaxias\/wp-json\/wp\/v2\/tags?post=439"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}