{"id":131,"date":"2014-12-01T11:03:47","date_gmt":"2014-12-01T10:03:47","guid":{"rendered":"https:\/\/obas-matlas.u-strasbg.fr\/WP\/?p=131"},"modified":"2019-01-31T16:59:17","modified_gmt":"2019-01-31T15:59:17","slug":"accretion-inhibited-star-formation-in-the-warm-molecular-disk-of-the-green-valley-elliptical-galaxy-ngc-3226","status":"publish","type":"post","link":"https:\/\/matlas.astro.unistra.fr\/WP\/?p=131","title":{"rendered":"Accretion-Inhibited Star Formation in the Warm Molecular Disk of the Green-valley Elliptical Galaxy NGC 3226?"},"content":{"rendered":"\n<figure class=\"wp-block-image\"><a href=\"http:\/\/obas-matlas.u-strasbg.fr\/WP\/?attachment_id=132\"><img loading=\"lazy\" width=\"1024\" height=\"665\" src=\"http:\/\/obas-matlas.u-strasbg.fr\/WP\/wp-content\/uploads\/2019\/01\/NGC3226-1024x665.jpg\" alt=\"\" class=\"wp-image-132\" srcset=\"https:\/\/matlas.astro.unistra.fr\/WP\/wp-content\/uploads\/2019\/01\/NGC3226-1024x665.jpg 1024w, https:\/\/matlas.astro.unistra.fr\/WP\/wp-content\/uploads\/2019\/01\/NGC3226-300x195.jpg 300w, https:\/\/matlas.astro.unistra.fr\/WP\/wp-content\/uploads\/2019\/01\/NGC3226-768x498.jpg 768w, https:\/\/matlas.astro.unistra.fr\/WP\/wp-content\/uploads\/2019\/01\/NGC3226.jpg 1242w\" sizes=\"(max-width: 767px) 89vw, (max-width: 1000px) 54vw, (max-width: 1071px) 543px, 580px\" \/><\/a><figcaption>HI emission superimposed on a deep optical image of the galaxy from MATLAS (Appleton et al., 2014) <\/figcaption><\/figure>\n\n\n\n<p>We present archival Spitzer photometry and spectroscopy and Herschel photometry of the peculiar &#8220;Green Valley&#8221; elliptical galaxy NGC 3226. The galaxy, which contains a low-luminosity active galactic nucleus (AGN), forms a pair with NGC 3227 and is shown to lie in a complex web of stellar and H I filaments.<\/p>\n\n\n\n<!--more-->\n\n\n\n<p> Imaging at 8 and 16 \u03bcm reveals a curved plume structure 3 kpc in extent, embedded within the core of the galaxy and coincident with the termination of a 30 kpc long H I tail. In situ star formation associated with the infrared (IR) plume is identified from narrowband Hubble Space Telescope (HST) imaging. The end of the IR plume coincides with a warm molecular hydrogen disk and dusty ring containing 0.7-1.1 \u00d7 10<sup>7<\/sup>&nbsp;M&nbsp;<sub>\u2299<\/sub>&nbsp;detected within the central kiloparsec. Sensitive upper limits to the detection of cold molecular gas may indicate that a large fraction of the H<sub>2<\/sub>&nbsp;is in a warm state. Photometry derived from the ultraviolet (UV) to the far-IR shows evidence for a low star-formation rate of ~0.04 M&nbsp;<sub>\u2299<\/sub>&nbsp;yr<sup>-1<\/sup>&nbsp;averaged over the last 100 Myr. A mid-IR component to the spectral energy distribution (SED) contributes ~20% of the IR luminosity of the galaxy, and is consistent with emission associated with the AGN. The current measured star formation rate is insufficient to explain NGC 3226&#8217;s global UV-optical &#8220;green&#8221; colors via the resurgence of star formation in a &#8220;red and dead&#8221; galaxy. This form of &#8220;cold accretion&#8221; from a tidal stream would appear to be an inefficient way to rejuvenate early-type galaxies and may actually inhibit star formation.<\/p>\n\n\n\n<p>Published in <a href=\"http:\/\/adsabs.harvard.edu\/abs\/2014ApJ...797..117A\">Appleton et al., 2014, ApJ 797, 117<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>We present archival Spitzer photometry and spectroscopy and Herschel photometry of the peculiar &#8220;Green Valley&#8221; elliptical galaxy NGC 3226. The galaxy, which contains a low-luminosity active galactic nucleus (AGN), forms a pair with NGC 3227 and is shown to lie in a complex web of stellar and H I filaments.<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[4],"tags":[],"_links":{"self":[{"href":"https:\/\/matlas.astro.unistra.fr\/WP\/index.php?rest_route=\/wp\/v2\/posts\/131"}],"collection":[{"href":"https:\/\/matlas.astro.unistra.fr\/WP\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/matlas.astro.unistra.fr\/WP\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/matlas.astro.unistra.fr\/WP\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/matlas.astro.unistra.fr\/WP\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=131"}],"version-history":[{"count":4,"href":"https:\/\/matlas.astro.unistra.fr\/WP\/index.php?rest_route=\/wp\/v2\/posts\/131\/revisions"}],"predecessor-version":[{"id":342,"href":"https:\/\/matlas.astro.unistra.fr\/WP\/index.php?rest_route=\/wp\/v2\/posts\/131\/revisions\/342"}],"wp:attachment":[{"href":"https:\/\/matlas.astro.unistra.fr\/WP\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=131"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/matlas.astro.unistra.fr\/WP\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=131"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/matlas.astro.unistra.fr\/WP\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=131"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}