Author Institution: Ritter Astrophysical Research Center, Univeristy of Toledo, Toledo, OH 43606; University of Chicago, Chicago, IL 60637; NASA Goddard Space Flight Center, Greenbelt, MD 20771; McDonald Observatory, University of Texas at Austin, Austin, TX 78712Electronic flurescence spectra (peak $\sim$ 375 nm) in reflection nebulae have helped to identify the largest molecules that have been detected so far in the interstellar medium: 3-4 ringed polycyclic aromatic hydrocarbons (PAHs). This detection of blue luminescence (BL) by small, neutral PAHs  was first made in the peculiar, proto-planetary nebula, the Red Rectangle. This first detection and subsequent observations in other reflection nebulae reveal spatial variations in the BL spectrum indicating a change in the size distribution/ionisation state of the emitters. Data from an ongoing, complete spectroscopic survey and narrow-band imaging of the Red Rectangle will be presented. This study sheds light on the spatial distribution, ionization state and the size distributions of the small PAHs in this nebula

Dwarkadas, Vikram

Palunas, Povilas

Vijh, Uma P.

Witt, Adolf N.

Woodgate, Bruce E.

York, Donald G.

KnowledgeBank at OSU

The Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryA Complete Spectroscopic Map andNarrow-Band Imaging of Small PAHs in theRed Rectangle NebulaUma P. Vijh, A. N. Witt1 D. G. York, V. V. Dwarkadas2B. E. Woodgate3 P. Palunas41University of Toledo2University of Chicago 3NASA Goddard Space Flight Center 4McDonaldObservatory, University of Texas at AustinMolecular Spectroscopy Symposium: Large AstronomicalMolecules, 2005Vijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryOutline1 The Red RectangleIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic Map2 Neutral PAHs in the Red RectangleThe BL SpectrumIdentification of the BL Spectrum3 Spatial Distributions of Nebular Emissions in the RRThe BLExtended Red EmissionSharp Emission FeaturesVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryOutline1 The Red RectangleIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic Map2 Neutral PAHs in the Red RectangleThe BL SpectrumIdentification of the BL Spectrum3 Spatial Distributions of Nebular Emissions in the RRThe BLExtended Red EmissionSharp Emission FeaturesVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryOutline1 The Red RectangleIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic Map2 Neutral PAHs in the Red RectangleThe BL SpectrumIdentification of the BL Spectrum3 Spatial Distributions of Nebular Emissions in the RRThe BLExtended Red EmissionSharp Emission FeaturesVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic MapOutline1 The Red RectangleIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic Map2 Neutral PAHs in the Red RectangleThe BL SpectrumIdentification of the BL Spectrum3 Spatial Distributions of Nebular Emissions in the RRThe BLExtended Red EmissionSharp Emission FeaturesVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic MapDifferent Morphology at Different Wavelengths.HST WFPC2 (F622W +F467M)AAT Kodak IIa-O + 380 nmcut-on filter (Courtesy DavidMalin)Vijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic MapDifferent Morphology at Different Wavelengths.HST WFPC2 (F622W +F467M)AAT Kodak IIa-O + 380 nmcut-on filter (Courtesy DavidMalin)Vijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic MapThe Red Rectangle SystemSource of many dust-related emissions: ERE, UIR/AEF, BLFirst discovered source of the ERE, BLBrightest source of the UIR/AEFThe central star HD44179 is a ∼ 6000 L A III post-AGBstar, in a stage of active dust productionClose hot white dwarf companion (Teff ∼ 60,000 K)Optically thick circum-binary dust torus obscures centralsource from direct viewOutflow through polar openings produces bipolar structureVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic MapSchematic GeometryMen’shchikov et al. 2002, A& A,393,867Vijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic MapOutline1 The Red RectangleIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic Map2 Neutral PAHs in the Red RectangleThe BL SpectrumIdentification of the BL Spectrum3 Spatial Distributions of Nebular Emissions in the RRThe BLExtended Red EmissionSharp Emission FeaturesVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic MapISO Spectrum of the RRRR is the brightestsource of mid-IR UIRbandsMixed O-rich/C-richchemistryStrong mid-IR UIRbands, attributed toaromatic hydrocarbons(PAH)Emission bands ofcrystalline silicatesVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic MapOutline1 The Red RectangleIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic Map2 Neutral PAHs in the Red RectangleThe BL SpectrumIdentification of the BL Spectrum3 Spatial Distributions of Nebular Emissions in the RRThe BLExtended Red EmissionSharp Emission FeaturesVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic MapThe Spectroscopic Map of the RRAt the 3.5 m telescope at Apache Point ObservatoryUsing the Dual Imaging Spectrograph: coverage from 370 -900 nmThe team:Uma Vijh, Adolf Witt (U. Toledo)Don York, Lew Hobbs, Takeshi Oka (U. Chicago)Ben McCall (UIUC)Ted Snow (U. Colorado)John Barentine & Russet McMillan (APO)Vijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic MapSpectroscopic Coverage1."5 wide slitVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic MapNarrow-band Imaging3.5 m at APO: Images using Narrow-band filters and GoddardFabry-Perot etalon:Narrow-band Filters: 3934/27, 4050/57, 4596/135, 5704/135,6403/135Etalon: 5800/15, 5855/15The team:Uma Vijh, Adolf Witt (U. Toledo)Don York, Vikram Dwarkadas (U. Chicago)Bruce Woodgate (NASA GSFC)Povilas Palunas (U. Texas, Austin)Vijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryThe BL SpectrumIdentification of the BL SpectrumOutline1 The Red RectangleIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic Map2 Neutral PAHs in the Red RectangleThe BL SpectrumIdentification of the BL Spectrum3 Spatial Distributions of Nebular Emissions in the RRThe BLExtended Red EmissionSharp Emission FeaturesVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryThe BL SpectrumIdentification of the BL SpectrumInitial Detection of the BL SpectrumSpectrum from 2."5 S 3."9 E, compared to fluorescence fromsmall, neutral PAHs (Vijh et al. 2004, ApJ, 606, L65)Vijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryThe BL SpectrumIdentification of the BL SpectrumThe Resolved BL SpectrumNebular spectra along a slit at PA -24◦. (Vijh et al. 2005, ApJLsubmitted)Vijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryThe BL SpectrumIdentification of the BL SpectrumOutline1 The Red RectangleIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic Map2 Neutral PAHs in the Red RectangleThe BL SpectrumIdentification of the BL Spectrum3 Spatial Distributions of Nebular Emissions in the RRThe BLExtended Red EmissionSharp Emission FeaturesVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryThe BL SpectrumIdentification of the BL SpectrumIdentification of the BL Spectrum.BL spectrum consists ofseven bands between370 nm and 470 nmLikely source:Fluorescence by two ormore different aromatichydrocarbon moleculespeciesVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryThe BLExtended Red EmissionSharp Emission FeaturesOutline1 The Red RectangleIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic Map2 Neutral PAHs in the Red RectangleThe BL SpectrumIdentification of the BL Spectrum3 Spatial Distributions of Nebular Emissions in the RRThe BLExtended Red EmissionSharp Emission FeaturesVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryThe BLExtended Red EmissionSharp Emission FeaturesNarrow Band Images3934 Å (27 Å wide): BL band 6400 Å (135 Å wide) : EREbandVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryThe BLExtended Red EmissionSharp Emission FeaturesContour ImagesBL image and 4050 Å scattered-light imageVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryThe BLExtended Red EmissionSharp Emission FeaturesDistribution of the BL(Vijh et al. 2005, ApJL, submitted)Vijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryThe BLExtended Red EmissionSharp Emission FeaturesOutline1 The Red RectangleIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic Map2 Neutral PAHs in the Red RectangleThe BL SpectrumIdentification of the BL Spectrum3 Spatial Distributions of Nebular Emissions in the RRThe BLExtended Red EmissionSharp Emission FeaturesVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryThe BLExtended Red EmissionSharp Emission FeaturesERE Images6400 ERE image and 6400/5700 ratio imageVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryThe BLExtended Red EmissionSharp Emission FeaturesOutline1 The Red RectangleIntroductionAromatic Molecules in the Red RectangleThe Spectroscopic Map2 Neutral PAHs in the Red RectangleThe BL SpectrumIdentification of the BL Spectrum3 Spatial Distributions of Nebular Emissions in the RRThe BLExtended Red EmissionSharp Emission FeaturesVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryThe BLExtended Red EmissionSharp Emission FeaturesSharp Red Emission Features(Schmidt & Witt, 1991, ApJ, 383, 698)Vijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummaryThe BLExtended Red EmissionSharp Emission FeaturesSharp Red Emission Features5800 Å image and 5800/5700 ratio imageVijh et al. Small PAHs in the Red RectangleThe Red RectangleNeutral PAHs in the Red RectangleSpatial Distributions of Nebular Emissions in the RRSummarySummaryBL spectrum resolved into seven discrete bands between370 nm and 480 nmInterpreted as evidence for fluorescence by neutral PAHmolecules (3-, 4-, 5-ringed PAHs)Extended Red Emission (ERE) is seen preferentially on thewalls of the outflow cones (Consistent with ERE excitationrequiring E > 10.5 eV photons)Blue luminescence and ERE are observed in mutuallyexclusive environments in the RRVijh et al. Small PAHs in the Red Rectangle

A COMPLETE SPECTROSCOPIC MAP AND NARROW-BAND IMAGING OF SMALL PAHS IN THE RED RECTANGLE NEBULA

https://kb.osu.edu/bitstream/handle/1811/30251/molspec-2005.pdf?sequence=2&isAllowed=y

A COMPLETE SPECTROSCOPIC MAP AND NARROW-BAND IMAGING OF SMALL PAHS IN THE RED RECTANGLE NEBULA

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