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1Center for Astrophysics and Space Astronomy (CASA) Department of Astrophysical and Planetary Sciences (APS) University of Colorado, Boulder
The Herschel ViewThe Herschel Viewof theof the
Galactic CenterGalactic Center
John BallyJohn Bally11
Hi-GAL PI: Sergio Molinari (Rome)Hi-GAL PI: Sergio Molinari (Rome)+ Hi-GAL team … (~150 researchers)+ Hi-GAL team … (~150 researchers)
8 m 70 m 350 m
Sgr B2 Sgr B1 G0.25 GCB 50 km/s Sgr A 20 km/s
Outline
• Herschel Hi-GAL: 70, 160, 250, 350, 500 m
• The Central Molecular Zone:
Context
Dust Cold dust, (warm gas); Column density
Star Formation Distribution, Asymmetries, Rate
• Galactic Center Bubble:
Relation to: Sofue-Handa Lobe, Fermi/LAT, …
Nature of 70 m sources
• Star Formation vs. SMBH activity:
Feeding vs. Shielding
Herschel Space Observatory:Herschel Space Observatory: (May 2009 - April 2013)
D = 3.5 meter @ L2 PACS: 70, 100, 160 m SPIRE: 250, 350, 500 m HIFI: THz heterodyne
Herschel Galactic Plane Survey (Hi-GAL)
Herschel Galactic Plane Survey (Hi-GAL)Herschel Galactic Plane Survey (Hi-GAL)PI: Sergio Molinari (Rome) + 150 co-Is ~900 hrs
Galactic Plane [360o X 2o] 720 square degree survey
= 70, 160, 250, 350, 500 m = 6 , 11, 15 , 22 , 35 arcsec resolution
Hi-GAL - inner Galaxy 120o year 1 Hi-GAL360 - outer Galaxy 120o year 2 2-GAL - 60o segments at l = 90o, 270o year 3
Images & Catalogs in preparation (release in late 2013)
~ 500,000 band-merged compact sources (YSOs, compact HII regions, post-MS stars, PNe, …)
Inner Lindblad Resonance (ILR)
R ~ 450 pc ?
Epicyclic frequency
Bar rotation frequency
~ 2:1
1.3
kpc
The CMZ:
Orbits in a Bar(tri-axial) potential:x1 vs. x2
Barred Spiral : NGC1097 HSTBarred Spiral : NGC1097 HST 1 kpc starburst ring
Orbits: x1 - elongated along bar x2 - elongated orthogonal to bar
Bally 2010 cartoon Rodriguez-Fernandez 2006, 2008; model Molinari et al. (2011) ring
V
l
24 m
Bania’s Clump 2 l = 1.3 Sgr B2 / B1 Sgr A Sgr C
(Hinz 2008; Yusef-Zadeh 2009)
Bania’s Clump 2 l = 1.3 Sgr B2 / B1 Sgr A Sgr C
70 m
Bania’s Clump 2 l = 1.3 Sgr B2 / B1 Sgr A Sgr C
160 m
Bania’s Clump 2 l = 1.3 Sgr B2 / B1 Sgr A Sgr C
250 m
Bania’s Clump 2 l = 1.3 Sgr B2 / B1 Sgr A Sgr C
350 m
Bania’s Clump 2 l = 1.3 Sgr B2 / B1 Sgr A Sgr C
500 m
Bania’s Clump 2 l = 1.3 Sgr B2 / B1 Sgr A Sgr C
1100 m
(Bolocam Galactic Plane Survey
Ginsburg et al. 2012)
Bania’s Clump 2 l = 1.3 Sgr B2 / B1 Sgr A Sgr C
20 cm(Yusef-Zadeh 2009)
24 m
Bania’s Clump 2 l = 1.3 Sgr B2 / B1 Sgr A Sgr C
(Hinz 2008; Yusef-Zadeh 2009)
Bania’s Clump 2 l = 1.3 Sgr B2 / B1 Sgr A Sgr C
70 m
Central Molecular Zone
24 m, 70 m, 350 m
24 m, 70 m, 350 m
Central Molecular Zone
Central Molecular Zone
20 cm, 70 m, 350 m
Central Molecular Zone
20 cm, 70 m, 350 m
Central Molecular Zone
20 cm, 70 m, 350 m
24 24 mm 350 350 mm2/3 gas, dust: @ Pos. longitudes 2/3 24 m sources: @ Neg. longitudes
Sgr A*
Inert, stable CMZ Starburst region
1o => R ~ 150 pc, torbit ~ 8 Myr
Sgr B2
Central Molecular Zone (CMZ)
- x10 - x100 denser, more turbulent than disk GMCs
Traced by HCN, HNCO, CS, SiO, NH3, etc.
V > 20 km/s
- Asymmetry:
Gas & cold dust:
2/3 at POSITIVE longitude, velocity
24 m sources:
2/3 at NEGATIVE longitude
Note: torbit ~ 6 Myr r100 pc V100 km/s-1 (+ 3 to 30
Myr)
Dust T, N(HDust T, N(H22) ) Battersby (2011, A&A, 535, 128) algorithm
TT
N(HN(H22))
cold ~ 14 K warm ~ 50 K
2 x 1021 to 2 x 1024 cm-2
Sgr A (CNR)
N(H2) from dust (Rome algorithm)
Tdust cold ~ 14 K warm ~ 50 K (Rome algorithm)
Sgr A (CNR)
The Molinari et al. (2011) ~100 pc ring
Sgr A (CNR)
The Molinari et al. (2011) R ~100 pc ring Region of Starburst activity in CMZ But … Sgr B2 Proper Motion ~ 80 km/s => R ~ 150 to 200 pc?
Galactic Center: 8 m
Sgr B2Sgr A (CNR)
Galactic Center Bubble: 24 m
Sgr A (CNR)
8 m 70 m 350 m
Sgr A (CNR)
Galactic Center: 20 cm
Sgr A (CNR)
Galactic Center Bubble
- Brightest super-bubble in Galaxy at 24 m
- D ~ 30 pc
- Arches, Pistol clusters, Sgr A East SNR
A nested set of Bubbles?
Sgr A East: 1 pc
GCB: 30 pc
Sofue-Handa (84) lobe: 150 pc
Fermi-LAT bubble: 5,000 pc
A weak `nuclear super-wind’ ?
Star-formation -or- SMBH ?
Galactic Center Bubble => Sofue-Handa Lobe => Fermi-LAT Bubble ?
Finkbeiner et al. (2010)
Law et al. (2009, 2010)
3.5 cm(GBT)
Sofue-HandaLobe
Caution: Sco-Cen superbubble 150 pc from Sun
2 deg.
Sgr B2 Continuum
CO SED
(Etxaluze+ 2013)
3.6, 4.5, 8 m 280 GHz continuum 2.12 m H2
Sgr C (G359.44-.10) Kendrew et al. poster
Bania’s Clump 2
l = 3.2o
106 Mo
Most CMZ molecular gasat positiveLongitudes,& positive Velocities
Dense Gas with little / no star formation
Bania’s Clump 2 (l = 3.2o) & l = 1.3o - 1.5o
- Little 8, 24, 70 m emission
- Little or no star-formation
- Strong thermal SiO => shocks?
Location:
At end of innermost x1 orbit ?
Along length of x1 orbit ?
Where x1 and x2 intersect ?
Bania’s Clump 2
24 um, 70 um, 350 um
G0.253+0.016G0.253+0.016 (the “Brick” or “Lima Bean”) (the “Brick” or “Lima Bean”)
105 Mo 3 pc, dense cloud in CMZ VERY LITTLE STAR FORMATION ! (the most extreme IRDC in the Galaxy?)
(Longmore et al. 2012) - ALMA Cycle 0 data (Rathborne et al. 2013)
3.6 - 8.0 m (Spitzer) 70 m (Hi-GAL) 450 m (SCUBA)
HCO+ J = 1-0
21 km/s 18 km/s 14 km/s
ALMA Cycle 0 data Rathborne et al. 2013Bally et al. 2013
HCO+ J = 1-0
28 km/s 24 km/s 21 km/s
ALMA Cycle 0 data Rathborne et al. 2013Bally et al. 2013
HCO+ J = 1-0
34 km/s 31 km/s 28 km/s
ALMA Cycle 0 data Rathborne et al. 2013Bally et al. 2013
HCO+ J = 1-0
41 km/s 38 km/s 34 km/s
ALMA Cycle 0 data Rathborne et al. 2013Bally et al. 2013
HCO+ J = 1-0
48 km/s 44 km/s 41 km/s
ALMA Cycle 0 data Rathborne et al. 2013Bally et al. 2013
HCO+ J = 1-0
55 km/s 51 km/s 48 km/s
ALMA Cycle 0 data Rathborne et al. 2013Bally et al. 2013
HCO+ J = 1-0
62 km/s 58 km/s 55 km/s
ALMA Cycle 0 data Rathborne et al. 2013Bally et al. 2013
Sgr A clusterL-band: (Viehmann 06)
Sgr A & Circum Nuclear Ring (CNR): 70 um, 160 um, 350 um (SHARC/CSO)
HCN (1-0) + P
50 km/s cloud 20 km/s cloud
Black Hole
Feeding star formation in the CNR?
Sgr A PACS/SPIRE spectrum (Goicoechea+ 2013)
Hot (400 K), dense molecular gas CO in 3 pc ring
CNR HIFI (Herschel) (Sonnentrucker+ 2013)
50 km/s cloud
20 km/s cloud
CNR HIFI (Herschel)/GREAT (SOFIA)(Requena-Torres+ 2013)
Hot (400 K) CO in 3 pc ringHF & para H2O in CMZ
Future
- ALMA
small-scale line / continuum / polarization
- SOFIA HAWC++ MIR continuum / polarization / narrow-band GREAT CII, NII, OI, OIII, etc. FORCAST 11 - 37 um continuum
- JVLA NH3, SiO, CS, H2CO / high-f continuum / RRLs
- CCAT large-scale CI, CO 4-3 / continuum
- JWST small-scale 2 - 28 um
Summary• ~ 90 - 150 pc ring of cold dust and gas
Contains Sgr B2, Sgr B1, Brick, Sgr C Most extreme star formation at r < 100 pc• Large V features: l = 1.3o, Bania’s Clump 2 (l = 3.2o), No (or little) star formation: • Galactic Center Bubble: 70 m: YSOs or externally heated?
Multiple SN, massive star winds, ionization
Feeds Sofue-Handa Lobe (~1 deg.) ? Fermi-LAT Bubble (> 20 deg.) ?• Star Formation in the CMZ: “Mini-starbursts” in Sgr B2 Asymmetry: Gas-dust at Positive longitude/velocity 24 m sources at Negative longitude 24 m sources: MYSOs, MS-stars - or - externally illuminated OH/IR, RSG, PNe, …• <SFR> 0.007 - 0.1 Mo/yr ? Variable?