[{"id":159,"title":"Sulfur-Bearing Polycyclic Aromatic Hydrocarbons in Interstellar Environments","sha":"c910680b94a3558d7ca47a4fe2046c4a","user_id":555,"state":"published","body":"Polycyclic aromatic hydrocarbons (PAHs) are widely studied in an astrophysical context. Studies have also been performed on nitrogen-bearing PAH species ([Hudgins+2005](http://adsabs.harvard.edu/abs/2005ApJ...632..316H)) and unsuccessful searches have been performed for interstellar nitrogen-bearing PAHs ([Ali-Haïmoud+2015](http://adsabs.harvard.edu/abs/2015MNRAS.447..315A)). Laboratory irradiation of ices containing aromatic hydrocarbons has recently been found to produce oxygen and nitrogen heterocycles ([Materese+2015](http://adsabs.harvard.edu/abs/2015ApJ...800..116M)), though previous astronomical searches for such heterocycles have proven unsuccessful ([Charnley+2005](http://adsabs.harvard.edu/abs/2005AdSpR..36..137C); [Dezafra+1972](http://adsabs.harvard.edu/abs/1972ApL....10....1D); [Kutner+1980](http://adsabs.harvard.edu/abs/1980ApJ...242..541K)). \r\n\r\nHowever, astrochemical studies on interstellar sulfur are quite neglected. Sulfur heterocycles have received little astrochemical attention, despite having been detected inside meteorites ([Krishnamurthy+1992](http://www.sciencedirect.com/science/article/pii/001670379290015B); [Sephton+2002](http://rsta.royalsocietypublishing.org/content/363/1837/2729)). Thiophenes are expected to be stable at interstellar medium (ISM) temperatures ([Guillemin+2010](http://adsabs.harvard.edu/abs/2010cosp...38.3235G)). Observed sulfur depletion does not follow the same pattern as other elements in dust grains ([White+2011](http://adsabs.harvard.edu/abs/2011AAS...21812923W)), and small sulfur compounds like H₂CS are detected in outflows where they are expected to form into more complex species ([Minh+2011](http://adsabs.harvard.edu/abs/2011ApJ...737L..25M)).\r\n\r\nGiven that sulfur and carbon have similar electronegativities and both have extensive chemistries, it is logical to consider heterocyclic sulfur-bearing PAH molecules in astrochemical studies, both experimentally and observationally. Vibrational wavelengths are expected to fall in the 6-9 µm region and at longer wavelengths, where it is well known that many observed emission bands are still poorly understood, with several unidentified or tentatively assigned lines remaining.","created_at":"2015-05-01T10:08:28.636Z","updated_at":"2015-05-14T21:28:20.848Z","zenodo_id":28346,"doi":"http://dx.doi.org/10.5281/zenodo.17292","subject":null,"tags":["astronomy","astrochemistry","molecular astrophysics","sulfur","hydrocarbons","pahs","interstellar medium"],"vote_count":2,"view_count":1,"score":2.1,"deleted":false,"muted":false,"tweeted":true,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null},{"id":291,"title":"Pre-registration of a test for statistical significance of a GALFA-HI -- WMAP ILC correlation ","sha":"464af33898155d92f8c2857e13e9512e","user_id":null,"state":"published","body":"In 2007 Gerrit Verschuur [proposed](http://dx.doi.org/10.1086/522685) that HI structures as seen in the Leiden-Argentina-Bonn 36' HI survey of the sky are correlated with structures in the WMAP sky, which are typically ascribed to the CMB. \r\n\r\nHe has recently proposed to see WMAP correlations in the higher-resolution GALFA-HI DR1 data. As the referee of this manuscript, I,([Joshua Peek](/users/5b0d532a4c510f697a292dec92d6c683)) required a test of statistical significance to publish.\r\n\r\nI proposed a test: I have fully reduced, but publicly unreleased GALFA-HI data that Verschuur has no access to. In the test, I select 34 WMAP peaks, to have [WMAP 7 year ILC brightness](http://lambda.gsfc.nasa.gov/product/map/dr4/ilc_map_get.cfm) greater than 0.1 mK, Galactic latitude \u003e 20 degrees, and extract ~2x2 degree regions in the unreleased area. I extract the same regions from GALFA-HI, and give both to Dr. Verschuur, without coordinates. If he can match many of these pairs, one can easily calculate the p-value -- 6 matches would be convincing. While it might be possible to leverage the dust-gas correlation using the Planck 353 maps to 'cheat', I believe this would be very difficult. \r\n\r\nDr. Verschuur, the editor, Dieter Hartmann, and I have agreed to this test. The test expires in Jan 1 2017, or when GALFA-HI DR2 become public, whichever comes first.","created_at":"2016-03-16T14:34:52.853Z","updated_at":"2016-04-14T20:42:29.676Z","zenodo_id":102226,"doi":"http://dx.doi.org/10.5281/zenodo.47726","subject":null,"tags":["pre-registration","test","interstellar medium"],"vote_count":1,"view_count":1,"score":1.1,"deleted":false,"muted":false,"tweeted":true,"attachment_file_name":null,"attachment_content_type":null,"attachment_file_size":null,"attachment_updated_at":null}]