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- Costagliola, Francesco, 1981, et al.
(författare)
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An ALMA Spectral Scan of the Obscured Luminous Infrared Galaxy NGC 4418
- 2015
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Ingår i: 4th ALMA Science Conference on Revolution in Astronomy with ALMA: The Third Year, Tokyo, Japan, 8-11 December. - 9781583818831 ; 499, s. 95-98
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Konferensbidrag (refereegranskat)abstract
- Until recently, the study of the molecular interstellar medium of galaxies has been mostly focused on a few, relatively abundant, molecular species. Recent attempts at modeling the molecular emission of active galaxies have shown that standard high-density tracers do not provide univocal results and are not able to discriminate between different relevant environments (e.g., star-formation vs AGN). Spectral lines surveys allow us to explore the richness of the molecular spectrum of galaxies, provide tighter constrains to astrochemical models, and find new more sensitive tracers of specific gas properties. What started as a time-consuming pioneering work has become now routinely accessible with the advent of ALMA. Here we report the results of the first ALMA spectral scan of an obscured luminous infrared galaxy (LIRG), NGC 4418. The galaxy has a very compact IR core and narrow emission lines that make it the perfect target for the study of vibrationally excited molecules. More than 300 emission lines from 45 molecular species were identified and modeled via an LTE and NLTE analysis. The molecular excitation and abundances derived offer a unique insight into the chemistry of obscured LIRGs.
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| 2. |
- Costagliola, Francesco, 1981, et al.
(författare)
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Exploring the molecular chemistry and excitation in obscured LIRGs: An ALMA mm-wave spectral scan of NGC 4418
- 2016
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Ingår i: EAS Publications Series. - : EDP Sciences. - 1633-4760 .- 1638-1963. - 9782759820221 ; 75-76, s. 67-68
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Konferensbidrag (refereegranskat)abstract
- The compact, obscured nuclei (CON) of luminous infrared galaxies (LIRG) combine large molecular columns with intense infrared (IR), ultra-violet (UV), and X-radiation and represent ideal laboratories for the study of the chemistry of the interstellar medium (ISM) under extreme conditions. Here we present the first ALMA wide-band spectral scan of a dusty LIRG, the CON NGC 4418. We derive molecular abundances and compare them with other Galactic and extragalactic sources. Our spectral scan confirms that the chemical complexity in the nucleus of NGC 4418 is one of the highest ever observed outside our Galaxy. We suggest that the galaxy may be a template for a new kind of chemistry and excitation, typical of CON.
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| 3. |
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| 4. |
- Costagliola, Francesco, 1981, et al.
(författare)
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Vibrationally Excited HC3N in NGC 4418
- 2010
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Ingår i: Proceedings of the International Astronomical Union. - : Cambridge University Press (CUP). - 1743-9213 .- 1743-9221. - 9781107005334 ; 15, s. 421-422
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Konferensbidrag (refereegranskat)abstract
- Luminous infrared galaxies (LIRGs) emit most of their radiation in the infrared region of the spectrum in the form of dust thermal continuum, with typical luminosities of LIR > 1010 L⊙. The central power source responsible for the total energy output is deeply buried in the dusty central regions of these objects and its origin still unclear. Recent studies by Spoon et al. (2007) and Aalto et al. (2007) suggest that some LIRGs might represent early obscured stages of active galaxies, either AGNs or starbursts, and thus play a fundamental role in galaxy formation and evolution.
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