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Investigation of PAH conditionsin Galactic Planetary Nebulaewith the AKARI/IRC and the Spitzer/IRS
Ryou OhsawaTakashi Onaka, Itsuki Sakon,
Issei Yamamura, Mikako Matsuura, Hidehiro Kaneda, Jeronimo Bernard-Salas,
Oliver Berné, Christine Joblin
AKARI ISMGN Workshop on 16 Dec. 2
Introduction
dust in the universe
AKARI ISMGN Workshop on 16 Dec. 3
Introduction
ISM&CSM dust evolutionformation, chemical evolution, destruction, and so on...
AKARI ISMGN Workshop on 16 Dec. 4
Introduction
Lifecycle of dust grains:dust-formation in evolved starsdust-alternation in various radiation fieldsdust-destruction by radiations/shocks
There are few observational studies.e.g., Giard+(1994), Bernard+(1994), García-Lario+(2003),
Lebouteiller+(2007), Berné+(2008), Kaneda+(2011), Mori+(2011), ...
AKARI ISMGN Workshop on 16 Dec. 5
Introduction
the UIR bands in planetary nebulaeWhy the UIR bands? Why PNe?
AKARI ISMGN Workshop on 16 Dec. 6
Why the UIR bands?Polycyclic Aromatic Hydrocarbons
Stochastically heated carbonaceous dust grains
Strong emission bands in the near and midinfrared
Significant variations in the band profiles and strengths
Sensitive to changes in local environments
AKARI ISMGN Workshop on 16 Dec. 7
Why the UIR bands?
(Peeters+, 2002)
AKARI ISMGN Workshop on 16 Dec. 8
Why planetary nebulae?Platenary Nebulae
Typical objects showing the PAH features
Drastically changes in radiation fields with evolution
Transitional objects from cirumstellar to interstellar
Hajian+(unpublished)
AKARI ISMGN Workshop on 16 Dec. 9
Why planetary nebuale?
(Blöcker+, 1995)
AKARI ISMGN Workshop on 16 Dec. 10
Introduction
Observing the UIR bands in PNe,
We can investigate PAH conditions with different radiation fields.
(CSM environments, extremely hard radiation fields)
AKARI ISMGN Workshop on 16 Dec. 11
ObservationsPNSPC:Phase 3 spectral observation of Galacitc PNe
IRC grismspectroscopy (2.55.0μm)
Point source window (Npwindow; 1'x1')
Total number of targets = 84 objects(diameter less than 8”, Ks less than 10mJy)
AKARI ISMGN Workshop on 16 Dec. 12
ObservationsNear to midIR Spectra of 20 PNe in Milky Way
2.55.0μm from the AKARI/IRC(R~120, including the 3.3 and 3.4μm UIR bands)
5.514.0μm from the Spitzer/IRS(R~60100, including the 6.2 to 12.7μm UIR bands)
Data Reduction:AKARI: official pipeline, removing hot pixelsSpitzer: PostBCD, scaled to NIRspectra
AKARI ISMGN Workshop on 16 Dec. 13
Observations
AKARI ISMGN Workshop on 16 Dec. 14
Observations
AKARI ISMGN Workshop on 16 Dec. 15
Data analysis
A linear combination of freefree, freebound emissions blackbody emission (100K, 200K)
line features (H, He, H2, Mg, Ar, Ne, and S)
dust features (PAHs and broad features)
Decomposition:
AKARI ISMGN Workshop on 16 Dec. 16
Results
Define two groups by stellar temperature
1. correlations with radiation fields
2. PAH conditions in PNe
3. aliphatic-aromatic variations
AKARI ISMGN Workshop on 16 Dec. 17
Radiation FieldsPAH destructions in harsh environments
H II regionNGC 3603Lebouteiller+ (2007)
AKARI ISMGN Workshop on 16 Dec. 18
Radiation Fields
A steep decline at I([SIV])/I([NeII])~1Destruction of small PAHs??
AKARI ISMGN Workshop on 16 Dec. 19
Radiation Fields
I([SIV])/I([NeII]) traces evolution,where it lower than ~1
AKARI ISMGN Workshop on 16 Dec. 20
PAH conditionsSiz
e/ E
xcit
ati
on
Cationic Neutral
7.7μm
6.2μm
11.2μm
3.3μm
(8.6μm)
(e.g., Allamandola+, 1989)
CH
CH
CH
CC
CC
AKARI ISMGN Workshop on 16 Dec. 21
PAH conditions
(Mori+, 2011)
Diagnostic tools for PAH conditions
AKARI ISMGN Workshop on 16 Dec. 22
PAH conditions
Preliminary
AKARI ISMGN Workshop on 16 Dec. 23
Aliphatic-Aromatic
Aliphatic C-H bonds
Aromatic C-H bonds
the 3.4-3.5 μm feature
the 3.3 μm feature
(e.g., Allamandola+, 1989)
AKARI ISMGN Workshop on 16 Dec. 24
Aliphatic-Aromatic
AKARI ISMGN Workshop on 16 Dec. 25
Summary
For PNe where [SIV]/[NeII]>1,
1. a large dispersion in size distribution
2. a low ionization factor (??)
3. enhanced aliphatic features
AKARI ISMGN Workshop on 16 Dec. 26
Problemsscatter or evolution ?
PAH destruction?
PAH hydrogenation?
AKARI ISMGN Workshop on 16 Dec. 27
Next to do
Another RF estimator where [SIV]/[NeII] > 1[ArV]@7.90, [MgV]@13.1, [NeV]@14.32, etc...
Discussion on broad (amorphous) dust emissionsevolution of amorphous silicate and carbon
Comparing with the FIR colorsusing AKARI MIR & FIR point source catalog
Quantitative discussions on PAH conditionsradiation hardness and G0 with H-coverages and ionizations
AKARI ISMGN Workshop on 16 Dec. 28
Thank you!
AKARI ISMGN Workshop on 16 Dec. 29
Appendix
AKARI ISMGN Workshop on 16 Dec. 30
Appendix
AKARI ISMGN Workshop on 16 Dec. 31
Appendix
AKARI ISMGN Workshop on 16 Dec. 32
Appendix
AKARI ISMGN Workshop on 16 Dec. 33
Appendix