Exploring ISM dust with IRSIS. Emmanuel DARTOIS IAS-CNRS

Transcription

1 Exploring ISM dust with IRSIS Emmanuel DARTOIS IAS-CNRS IRSIS meeting

2 Overview Intestellar ice mantles Hydrocarbons in the galaxy and outside Polycyclic Aromatic Hydrocarbons (PAHs)

3 Interstellar ice mantles Ices observation in the milky-way

4 Dense clouds : the ice mantles interface Extracted from the ISO database Refractory grains (C,Si) acquire an ice mantle

5 Studying the onset of ice formation Ice correlate with Av above a given extinction threshold. Abundance higher than gas phase timescale Surface reactions involving atomic oxygen are needed e.g. Murakawa et al. 2000

6 Massive protostars full of ice features D'Hendecourt et al The ice mantles stability domain

7 An important constituent for dust evolution Dartois et al. 2004, Gibbb et al. 2004, Van Dishoeck 2004

8 H2O ice mapping capabilites : Heiles 2 cloud 40 of resolution Murakawa et al. 2000

9 H2O ice mapping of entire clouds (limited to K Mag around 10) Murakawa et al. 2000

10 IRSIS capabilites Map dense clouds in water ice with a deeper limit to produce fully sampled «dense cloud ice maps» Sample the water ice profile, including short and long wavelength wings (better optical depth and scattering determination) A catalog of Young sources (both new ones and complementary to Spitzer)

11 CO2 and CO ISO/SWS spectrum rebinned to various resolutions

12 IRSIS capabilites For CO2 and CO ice, important to go to the highest spectral resolution Would allow to correlate the onset of various ice features with extinction with large sky coverage

13 Hydrocarbons in the galaxy and outside UV bump (extinction) DISM Carbonaceous dust evidence : e.g. Fitzpatrick 1999, PASP 111, 63 Aromatic Infrared Bands (emission)

14 Hydrocarbons dust features Hydrogenated Amorphous Carbons a-c:h - Observed initially at 3.4 microns against GC sources Allen & Wickramasinghe, Nature 294, 239, early associated to sp3 CH3 and CH2 stretching modes «Interstellar amorphous carbon dust with chemisorbed CH2 and CH3 groups may be a significant component of interstellar dust in diffuse clouds.» Duley & Williams, MNRAS 205, 67, since then numerous experiments/observations to constrain its origin Mennella et al. 2002, Pendleton & Allamandola 2002, Chiar et al. 2002, Geballe et al. 1997, Tielens et al. 1996, Sandford et al. 1995, Pendleton et al. 1994, Sandford et al. 1991, Ehrenfreund et al. 1991, McFadzean et al. 1989, Butchart et al. 1986, Jones et al. 1983

15 a-c:h Galactic observations NIR CH stretches absorptions against IR GC Bkgd sources NIR mixed a-c:h/aromatic thermal emission Pendleton et al. ApJ 437, 683, 1994 Goto et al. ApJ 598, 419, 2003

16 The observational constraint : mid-infrared fingerprints - but confusion with ices in Galactic center LOS - & confusion with background IR source circumstellar material e.g. Chiar et al. 2002; Dartois et al Viehmann et al. A&A 433, 117, 2004

17 a-c:h substructure unit Dartois et al., 432, 895, 2005

18 Several extragalactic obscured AGNs sources observed with a-c:h Risaliti et al. MNRAS 365, 303, 2006 Mason et al. ApJ 613, 770, 2004 Pendleton et al Imanishi et al., AJ 637, 114, 2006

19 ... Obscured AGNs with a-c:h IRAS NGC7172 NGC1068 NGC5506 Dartois et al. A&A 423, 549, 2004

20 Constraining structure and assessing a-c:h importance : the extragalactic DISMs insight - Obscured AGNs probe large dust column densities in front of an extended infrared continuum -> no local circumstellar contamination -> parsec scale IR probing pencil - Moderate galaxy redshifts shift observations to favorable atm. windows -> access to aromatic stretching mode region - Some are free of dense cloud ice absorptions -> some ice free clear mid-ir continuum

21 Test case : IRAS UKIRT SPITZER OBSERVED LAB PHOTOPRODUCED a-c:h Dartois et al. A&A 463, 635, 2007

22 The aromatic versus aliphatic content of interstellar HACs OBSERVED Arom. CH UPPER LIMIT LAB PHOTOPRODUCED a-c:h OLEF. OLEF./AROM. BACKBONE Dartois et al. A&A 463, 635, 2007

23 The future: extend to other Galaxies LOS Spitzer reveals a-c:h is abundant & ubiquitous DISM component through mid-ir features Dartois & Munoz-Caro, A&A accepted

24 The fate of interstellar a-c:h Observation much more difficult than PAHs Av / τ(3.4) ~ 250 Av / τ(6.85) ~ 640 e.g. Sandford et al. ApJ 440, 697, 1995 Dartois & Munoz-Caro, A&A submitted Contrast easily hidden by PAHs emission (PAHs emit at low τ) Major ISM component Containing up to 30% of ISM carbon (typical ~ 15%)

25 The fate of interstellar a-c:h Ubiquitous in the Galactic DISM Observed in ~ 70 external galaxies In agreement with laboratory plasma and/or photoproduced a-c:h A possible precursor to PAHs upon energetic processing

26 IRSIS capabilites A possibility to map hydrocarbons in the galactic plane with this feature using background sources. Extension to extragalactic sources (ULIRGs ones) when picked into the field.

27 Polycyclic Aromatic Hydrocarbons (PAHs) A spread source of emission carriers ISO database extract

28 PAHs in reflection nebulae Uchida et al Lack of spectroscopic information at low flux below 5 mi - crons.

29 A puzzling continuum under the PAHs 3.3 emission line in the DISM observed (Spitzer) Predicted without IR excess Flagey et al Based on photometry, important to make spectra. Are the continuum carriers independent from the 3.3 emission

30 IRSIS capabilites Decipher the interplay between 3.3 microns feature and underlying continuum Map reflection nebulae both in the 3.3 feature and up to the NIR, giving a good insight into deredenning of data due to extinction

31 A few other topics... Hydrated silicates do present an infrared signature (OH stretching mode) around microns Whittet et al Circumstellar disks acess to spectral energy distribution in complement to already observed other wavelengths.

32 A few other topics (...tbc...) Measure/put limits to Cosmological Infrared 1 to 6 microns Ned Wright

33 A few other topics (...tbc...) Measure/put limits to Cosmological Infrared 3 microns Necessary to properly take the Zodiacal light into account in models and obs modes strategy Matsumoto et al. 1997

34 Thank you for your attention!

35 Additional slides

36 The astrochemistry IR dedicated laboratory

37 Prospective tests started in the lab.

38 Prospective tests started in the lab.