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Circumstellar Environments. The Team. Historical Group (from IRA-Noto): G.Umana, C.S. Buemi INAF-OACt C. Trigilio INAF-OACt and Università di Catania P. Leto INAF-IRA, Noto. PhD students: L. Cerrigone, CfA-Università di Catania - PowerPoint PPT Presentation
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Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
Circumstellar Environments
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
The Team
Historical Group (from IRA-Noto):
G.Umana, C.S. Buemi INAF-OACt
C. Trigilio INAF-OACt and Università di Catania
P. Leto INAF-IRA, Noto
PhD students:L. Cerrigone, CfA-Università di Catania
S. Dolei, P. Manzitto, C. Siringo Università di Catania
Collaborators:F. Leone, Università di CataniaJ. Hora, G. Fazio, M. Marengo SAO-CfAC. Burigana INAF-IASFH. Olofsson OSO, G. Giardino (ESA), R. Paladini (JPL)
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
The project
The study of circumstellar environments
by means of radio observations Radio techniques very useful in multi-frequency approaches
Unique for some classes of Galactic objects
Circumstellar environments:• Coronae around active stellar systems• Stellar Magnetosphere• Stellar ejecta, late stage of stellar evolution
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
The project
Funds (since 2004):
Besides normal (small) INAF science funding….
2005-2007 ASI-Planck Science
18 k€
2007-2008 ASI-Planck Science
7.5 k€
2006-2008 INAF/Alma 6.2 k€
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
Radio Emission from CP stars
• Anomalous abundances
• Strong (>3000 G) dipolar magnetic field
• Variability (continuum, lines, B) - Oblique Rotator Model
Explained in terms of oblique rotator model
Radio emission (also variable ) consistent with Gyrosynchrotron plus a coherent component
radio
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
Goal Understanding the origin of variable radio emission from CP
Method
By modeling the radio flux density light-curve
VLA and ATCA project (multi-frequency, multi-configuration)
Principal Results:
o Full coverage of radio curve at different frequency for 3 stars
o Development of a 3D code to reconstruct the magnetosphere of CP and modeling of radio light curve
o Discovery of a new component in the radio emission
o Use of coherent emission as a period marker
Radio Emission from CP stars
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
18 cm, 4 cm, 1 cm
-Gyrosynchrotron from the magnetosphere
The 3D code for radio emission
Trigilio C., Leto, P., Umana, G., Buemi, C., Leone, F., 2004
Leto P., Trigilio, C., Buemi, C. Umana, G., Leone, F. ,2006
Good agreement with observations
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
Discovery of a new component of radio emission:
CU Vir: the coherent radio component
• occurring only at particular rotational phases • 100% circularly polarized • highly directive• persistent over years
Consistent withCyclotron Maser Emission
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
Marker of the rotational period
Consistent withCyclotron Maser Emission
• occurring only at particular rotational phases
• persistent over years
CU Virginis is slowing downdP/dt ~ 10-9 s yr-1 Trigilio C., Leto, P., Umana, G., Buemi, C., Leone, F.,
2008
CU Vir: the coherent radio component
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
Stellar Ejecta
Observed around stellar objects in late evolutionary phases:
-AGB PNe Mass-loss CSE
-LBV
Open questions:o Shaping: mass-loss (asymmetric) or evolution in an asymmetric environment?o Mass and T (gas & dust content)o Multiple components (different mass-loss episodes?)o Chemistry and its evolution with time (photodissociation, shocks)
o Chemical evolution of Galaxy (processed material return to ISM)o Ideal laboratory to study wind/shocks interaction with ISM
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
O B A F G K M
104 L
102 L
1 L
10-2 L
10-4 L
MMS 1 -8 Mo Stellar Ejecta: AGB PNe
~800~1000
yrs
* VisibleUV
IRIR-farIR
IR-radio
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
Goal Understanding the shaping of PNe, through observation of YPNe where the shaping mechanism is still active
Method
Select a sample of TO (AGBPNe) objects; Detect radio to find YPNe
VLA and ATCA project (multi-frequency, multi-configuration) 42 objects
Principal Results: o Detected 17 sources; Established their evolutionary status
(YPNe)
o Other 25 objects are genuine hot post-AGB stars.
o Radio spectra consistent with a PN in the early stage of its evolution
o High-resolution mapping Bi-polar morphology
Hunting for Young PNe
far-IR characteristics (excess) Optical characteristics
B spectral type spectral and photometric variability
-The onset of ionization can be marked by the presence of free-free emission…
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
YPNe: sub-arc observations
VLA-A, 3.6cm
1
Radio morphology: bi-polar shaping is already active!
Cerrigone,L., Umana, G., trigilio, C., Buemi, C., Leto, P. ., 2008
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
H-alpha
IRAS 22568+6141
VLA-C, 3.6cm VLA-A, 3.6cm
Total flux= 32mJyCentral component 1.65 0.05 mJyConsistent with stellar wind? (Mass-loss)
new VLA, high resolution, multi-frequency data already available (AU119), waiting for reduction!
1
Umana, G., Trigilio, C., Cerrigone, L., Buemi, C., Leto, P., 2008
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
CSE: the dust component
Goal Understanding the dust contribution to the shaping
Method
Inspecting the dust properties of envelope in TO (AGBPNe) objects: -systematic differences between radio detected (YPNe) and post-AGB?
SST project on YPNe, part of the SST-GTO on Stellar ejecta (PI G. Fazio)IRAC + IRS observations of 42 TO (with radio infos)
Principal Results:
o CSE around TO generally very compact (not resolved by IRAC)
o IRS spectra dominated by thermal dust emission plus spectral structures due to dust (crystalline silicates)
o besides recombination lines, no evident differences between radio (YPNe) and not radio detected (hot post-AGB) objects.
o about 50% of the sample shows mixed chemistry
o necessity to introduce big grains to fit SEDs
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
The dust component: Results
- IRS spectra dominated by thermal dust emission plus spectral
structures due to crystalline silicates - part of the sample shows mixed chemistry: not consistent with evolution theory
Silicates
Cerrigone, L., Hora, J., Umana, G., Trigilio, C., 2007Cerrigone, L., PhD Thesis, 2008
[ArII][NeII]
PAH PAHSilicates
When SED (up to mm) are modeled:- necessity to consider multi-component CSE - big grains (0.05-100 m)
- Consistent with a reservoir of O-rich material, probably an equatorial disk (PPNe Red Rectangle) strong clue for stellar ejecta being collimated by such structures!
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
Stellar Ejecta: LBV
log L/L ~ 5.0-6.3 strong mass-loss ~ 10-6 ÷10-4 Myr-1
Variability Outbursts ΔV ~ 1-2 mag
MMS > 25 Mo
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
LBVs: the ionized gas
Goal Understanding the LBV phenomenon through the study of their ejecta (morphology and physics of the nebula)
Method
Determine the properties of the radio emission, tracing the ionized gas component of the ejecta -Symmetric versus Asymmetric morphology
- Mass-loss of the central objects (current-day mass-loss)
VLA Multi-frequency, multi-configuration project
Principal Results:
o Radio morphologies in general asymmetric and structured
o High-resolution allows to resolve the core component
o High-resolution, multi-frequency allows to determine mass-loss
o Radio observations more efficient than usual H (no extinction) essential to probe the ionized component in strongly reddened object
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
LBVs in Radio
Probing the ionized component in a very dusty environment
Umana, G., Buemi, C.S., Trigilio, C. , Leto, P. et al., 2005
IRAS 18576+0341
Strongly reddened object: no optical counterpart VLA-A, C-band-Multi-frequency, high resolution VLA observations:-a core component (LBV’s wind)-an extended, asymmetric nebula
Current day mass-loss 3.7 10-5 Myr-1
B0-B0.5 I, Teff ~ 2.6 104 K
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
LBVs: the dust component
Goal Understanding the LBV phenomenon through the study of their ejecta (morphology and physics of the nebula)
Method
Determine the properties of the mid-IR emission, tracing the dust component of the ejecta -Symmetric versus Asymmetric morphology
- Comparison with ionized gas component to derive clues for shaping
VISIR@VLT project multi-frequency sub-arcsec imaging
Principal Results:
o Ejecta morphologies: highly structured
o Thermal dust morphologies DIFFERENT from radio.
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
Mapping with VISIR@VLT pixel scale 0.075
17.65 m12.27 m
11.26 m
IRS@SST
IRAS 18576+0341
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
Comparison between ionized gas and dust: sub-arcsec mapping
IRAS 18576+0341
4
-4VLA-A, 5 GHz (6cm) VISIR 12.25
m
Clues on mass-loss and shaping:A) Mass-loss can occur asymmetrically; outflows may be shaped by dusty structures
B) dust distribution not homogeneous dust competes with gas in absorbing UV radiation: holes in dust allow gas to glow!
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
LBVs: ionized gas and dust comparison
Different situation in HD168625 - The ionized gas appears contained by dust:
- Outflow channeled by a dusty equatorial torus??
kinematical information necessary!
VISIR 12.25 m
VLA-A 3.6cm
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
LBV: more on the dust component
Goal Determine the characteristics of dust component: yield to ISM Chemistry; mass-loss history
Method
Determine mid-IR spectral and morphological propertiesModeling the SEDs (CLOUDY) Mass-loss history
-SST project on Galactic LBVs, part of the SST-GTO on Stellar ejecta (PI G. Fazio)
IRAC+IRS (low + high res) of nine Galactic LBV
-SAGE Collaboration on LBVs in MCs (IRAC+IRS+MIPS)
First Results:
o Dusty CSE around Galactic LBV can be very extended
o Both regular (spherical) and asymmetric morphology observed.
o IRS spectra: dominated by emission lines and dust spectral features (PAHs)
o [Fe II] mid-IR lines detected: possible diagnostics for shocks
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
Stellar ejectaWray17-96
SST-IRAC mosaicIRAC LBV GTO program
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
In the next years new instrumentations will come on-line
ALMA: mm interferometer ( 30-900 GHz)spectral and continuum capabilities (sub-mJy) , sub-arcsec imaging 2011
EVLA: cm interferometer (1.4-50 GHz) :spectral and continuum capabilities (sub-mJy) , sub-arcsec imaging 2009
Stellar ejecta: the future
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
Stellar ejecta possible foregrounds for CMB:- from a feasibility study ~400 CSE will be detected by PLANCK (Umana, G. Burigana, C., Trigilio, C.- 2006)
- PLANCK will provide flux measurements, between 30 and 900 GHz, for the radio brightest PNe SEDs Umana, Leto, Trigilio, Buemi, Toscano, Manzitto, Dolei, Cerrigone, 2008
(based on 43 GHz single dish INAF-IRA teleacope Obs)
PLANCK mission, full sky coverage (30 to 900 GHz)-end 2008
Stellar ejecta:the future
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
Stellar ejecta:ALMA
ALMA will provide detailed (sub-arcsec, sub-mJy) maps of: ionized gas continuum (30 GHz…..) morphology molecular gas CO (100 GHz) morphology (Kinematic) dust continuum (100 GHz…) morphologyMorphological and spectral studies of different components
coexisting in the ejecta CLUES on shaping
ALMA (sub-arc, sub-mJy)VISIR@VLT (sub-arc, mJy)HST (sub-arc)EVLA (sub-arc, sub-mJy)
SYNERGIES
ionized gas continuum continuum (1.4-50 GHz) RRLs (1.4-50 GHz) molecular gas CO H2 (near-IR) Dust continuum continuum (mid-IR)
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
ALMA-2011+…… putting together the pieces
Radio jet that makes its way through the CO cocoon
Dusty disk/torus
Molecular Cocoon
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
mm and submm observations provide strong constraints for SED modeling
Post-AGB starsmm obs MAMBO@Iram 30m + SEDs modeling (DUSTY): = 0.9-1.6
R =1016 10 17 cm dM/dt~ 10-6-10-5
Stellar ejecta:ALMA
Buemi, C, Umana, G., Leto,P., Trigilio, C 2007
ALMA: Detailed maps of CSE dimension, structure…
VERY strong constraints to the SED Modeling!
Visiting CommitteeCatania, 17 dicembre 2007
G. Umana
The link to the Catania University
Radioastronomy (C. Trigilio) Undergraduate course (Physics)Galactic Radiosources (G. Umana) Lectures for PhD program
PhD students:L. Cerrigone, Infrared and Radio properties of YPNeCfA-Università di Catania Thesis defence next February
P. Manzitto, SEDs modeling of PNeUniversità di Catania, III year
C. Siringo, SiO maser in CSE
Università di Catania, begin III year S. Dolei, Radio modeling of PNeUniversità di Catania, begin II year
All the students trained at INAF-IRA 32m Radiotelescope: acquisition techniques,
data reductions …..
Science for ALMA
Science for ALMAPLANCK, HERSCHEL
Science for ALMA
Science for ALMAPLANCK, HERSCHEL