<!doctype html><html lang="en" class="no-js"><head><meta charset="utf-8"> <!-- begin SEO --><title> Far-Infrared Polarization Spectrum of the OMC-1 Star-Forming Region - Joseph M. Michail Astrophysicist</title><meta property="og:locale" content="en-US"><meta property="og:site_name" content="Joseph M. Michail | Astrophysicist"><meta property="og:title" content="Far-Infrared Polarization Spectrum of the OMC-1 Star-Forming Region"><link rel="canonical" href="https://joemichail.github.io/publication/2020-08-paper-OMC1-number10.md"><meta property="og:url" content="https://joemichail.github.io/publication/2020-08-paper-OMC1-number10.md"><meta property="og:description" content="Abstract: We analyze the wavelength-dependence of the far-infrared degree of polarization toward the OMC-1 star forming region using observations from HAWC+/SOFIA at 53, 89, 154, and 214 μ m. We find that the shape of the far-infrared polarization spectrum is variable across the cloud and that there is evidence of a correlation between the slope of the polarization spectrum and the average line-of-sight temperature. The slope of the polarization spectrum tends to be negative (falling towards longer wavelengths) in cooler regions and positive or flat in warmer regions. This is very similar to what was discovered in ρ Oph A via SOFIA polarimetry at 89 and 154 μ m. Like the authors of this earlier work, we argue that the most natural explanation for our falling spectra is line-of-sight superposition of differing grain populations, with polarized emission from the warmer regions and less-polarized emission from the cooler ones. In contrast with the earlier work on ρ Oph A, we do not find a clear correlation of polarization spectrum slope with column density. This suggests that falling spectra are attributable to variations in grain alignment efficiency in a heterogeneous cloud consistent with Radiative Alignment Torques theory. Alternative explanations in which variations in grain alignment efficiency are caused by varying gas density rather than by varying radiation intensity are disfavored."><meta property="og:type" content="article"><meta property="article:published_time" content="2020-08-01T00:00:00-05:00"> <script type="application/ld+json"> { "@context" : "http://schema.org", "@type" : "Person", "name" : "Joe Michail", "url" : "https://joemichail.github.io", "sameAs" : null } </script> <!-- end SEO --><link href="https://joemichail.github.io/feed.xml" type="application/atom+xml" rel="alternate" title="Joseph M. 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We find that the shape of the far-infrared polarization spectrum is variable across the cloud and that there is evidence of a correlation between the slope of the polarization spectrum and the average line-of-sight temperature. The slope of the polarization spectrum tends to be negative (falling towards longer wavelengths) in cooler regions and positive or flat in warmer regions. This is very similar to what was discovered in ρ Oph A via SOFIA polarimetry at 89 and 154 μ m. Like the authors of this earlier work, we argue that the most natural explanation for our falling spectra is line-of-sight superposition of differing grain populations, with polarized emission from the warmer regions and less-polarized emission from the cooler ones. In contrast with the earlier work on ρ Oph A, we do not find a clear correlation of polarization spectrum slope with column density. This suggests that falling spectra are attributable to variations in grain alignment efficiency in a heterogeneous cloud consistent with Radiative Alignment Torques theory. Alternative explanations in which variations in grain alignment efficiency are caused by varying gas density rather than by varying radiation intensity are disfavored."><meta itemprop="datePublished" content="August 01, 2020"><div class="page__inner-wrap"><header><h1 class="page__title" itemprop="headline">Far-Infrared Polarization Spectrum of the OMC-1 Star-Forming Region</h1><p>Published in <i>arXiv</i>, 2020</p><p>Recommended citation: Michail et al. (2020). &quot;Far-Infrared Polarization Spectrum of the OMC-1 Star-Forming Region&quot; <i>arXiv:2008.00310 (Submitted to ApJ)</i> <a href="https://ui.adsabs.harvard.edu/#abs/2020arXiv200800310M/abstract"><u>https://ui.adsabs.harvard.edu/#abs/2020arXiv200800310M/abstract</u></a></p></header><section class="page__content" itemprop="text"><p><a href="https://ui.adsabs.harvard.edu/link_gateway/2020arXiv200800310M/EPRINT_PDF">Download paper here</a></p></section><footer class="page__meta"></footer><section class="page__share"><h4 class="page__share-title">Share on</h4><a href="https://twitter.com/intent/tweet?text=https://joemichail.github.io/publication/2020-08-paper-OMC1-number10.md" class="btn btn--twitter" title="Share on Twitter"><i class="fab fa-twitter" aria-hidden="true"></i><span> Twitter</span></a> <a href="https://www.facebook.com/sharer/sharer.php?u=https://joemichail.github.io/publication/2020-08-paper-OMC1-number10.md" class="btn btn--facebook" title="Share on Facebook"><i class="fab fa-facebook" aria-hidden="true"></i><span> Facebook</span></a> <a href="https://www.linkedin.com/shareArticle?mini=true&url=https://joemichail.github.io/publication/2020-08-paper-OMC1-number10.md" class="btn btn--linkedin" title="Share on LinkedIn"><i class="fab fa-linkedin" aria-hidden="true"></i><span> LinkedIn</span></a></section><nav class="pagination"> <a href="https://joemichail.github.io/publication/2020-07-paper-OMC1-number9.md" class="pagination--pager" title="Maps of Magnetic Field Strength in the OMC-1 using HAWC+ FIR Polarimetric data ">Previous</a> <a href="https://joemichail.github.io/publication/2020-08-paper-SgrA-number11.md" class="pagination--pager" title="Evidence for a jet and outflow from Sgr A*: a continuum and spectral line study ">Next</a></nav></div></article></div><div class="page__footer"><footer> <!-- start custom footer snippets --> <a href="/sitemap/">Sitemap</a> <!-- end custom footer snippets --><div class="page__footer-follow"><ul class="social-icons"><li><strong>Follow:</strong></li><li><a href="http://github.com/JoeMichail"><i class="fab fa-github" aria-hidden="true"></i> GitHub</a></li><li><a href="https://joemichail.github.io/feed.xml"><i class="fa fa-fw fa-rss-square" aria-hidden="true"></i> Feed</a></li></ul></div><div class="page__footer-copyright">&copy; 2020 Joe Michail. 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