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?