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The Herschel View of the Galactic Center John Bally 1 Hi-GAL PI: Sergio Molinari (Rome) + Hi-GAL team … (~150 researchers). 1 Center for Astrophysics and Space Astronomy (CASA) Department of Astrophysical and Planetary Sciences (APS) University of Colorado, Boulder.
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The Herschel View of the Galactic Center John Bally1 Hi-GAL PI: Sergio Molinari (Rome) + Hi-GAL team … (~150 researchers) 1Center for Astrophysics and Space Astronomy (CASA) Department of Astrophysical and Planetary Sciences (APS) University of Colorado, Boulder
Sgr B2 Sgr B1 G0.25 GCB 50 km/s Sgr A 20 km/s 8 m70 m350 m
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:(May 2009 - April 2013) D = 3.5 meter @ L2 PACS:70, 100, 160m SPIRE:250, 350, 500m HIFI: THz heterodyne 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, 270oyear 3 Images & Catalogs in preparation (release in late 2013) ~ 500,000 band-merged compact sources (YSOs, compact HII regions, post-MS stars, PNe, …)
The CMZ: Orbits in a Bar (tri-axial) potential: x1 vs. x2 Inner Lindblad Resonance (ILR) R ~ 450 pc ? Epicyclic frequency Bar rotation frequency ~ 2:1 1.3 kpc
Barred Spiral : NGC1097 HST 1 kpc starburst ring
Orbits: x1 - elongated along bar x2 - elongated orthogonal to bar V l Bally 2010 cartoon Rodriguez-Fernandez 2006, 2008; model Molinari et al. (2011) ring
Bania’s Clump 2 l = 1.3 Sgr B2 / B1 Sgr A Sgr C 24 m (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)
Bania’s Clump 2 l = 1.3 Sgr B2 / B1 Sgr A Sgr C 24 m (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
Central Molecular Zone 24 m, 70 m, 350 m
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 m 350 m 2/3 gas, dust: @ Pos. longitudes 2/3 24 m sources: @ Neg. longitudes 1o => R ~ 150 pc, torbit ~ 8 Myr Sgr B2 Sgr A* Inert, stable CMZStarburst region
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(H2) Battersby (2011, A&A, 535, 128) algorithm T cold ~ 14 K warm ~ 50 K N(H2) 2 x 1021 to 2 x 1024 cm-2
Sgr A (CNR) N(H2) from dust(Rome algorithm)
Sgr A (CNR) Tdustcold ~ 14 Kwarm ~ 50 K(Rome algorithm)
Sgr A (CNR) The Molinari et al. (2011) ~100 pc ring
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?
Sgr A (CNR) Galactic Center: 8 m Sgr B2
Sgr A (CNR) Galactic Center Bubble: 24m
Sgr A (CNR) 8 m70 m350 m
Sgr A (CNR) Galactic Center: 20 cm
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) Caution: Sco-Cen superbubble 150 pc from Sun Sofue- Handa Lobe 3.5 cm (GBT) 2 deg. Law et al. (2009, 2010)
Sgr B2Continuum CO SED (Etxaluze+ 2013)
Sgr C (G359.44-.10)Kendrew et al. poster 3.6, 4.5, 8m 280 GHz continuum2.12 m H2
Bania’s Clump 2 l = 3.2o 106 Mo Most CMZ molecular gas at positive Longitudes, & 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+0.016 (the “Brick” or “Lima Bean”) 105 Mo 3 pc, dense cloud in CMZ VERY LITTLE STAR FORMATION ! (the most extreme IRDC in the Galaxy?) 3.6 - 8.0 m (Spitzer) 70 m (Hi-GAL) 450 m (SCUBA) (Longmore et al. 2012) - ALMA Cycle 0 data (Rathborne et al. 2013)
HCO+ J = 1-0 21 km/s 18 km/s 14 km/s ALMA Cycle 0 data Rathborne et al. 2013 Bally et al. 2013
HCO+ J = 1-0 28 km/s 24 km/s 21 km/s ALMA Cycle 0 data Rathborne et al. 2013 Bally et al. 2013
HCO+ J = 1-0 34 km/s 31 km/s 28 km/s ALMA Cycle 0 data Rathborne et al. 2013 Bally et al. 2013