Toshiki Saito toshiki.saito@nao.ac.jp

ALMA Observations of the IR-bright merger VV114 D. Iono(PI), M. Yun, J. Ueda, R. Kawabe, D. Espada, Y. Hagiwara, M. Imanishi, K. Motohara, K. Nakanishi, H. Sugai, K. Tateuchi

2013.1.26, Hokudai

Introduction & Observation

Introduction & Observation Results Summary

Introduction : Merger § LIRGs, U/LIRGs: Luminous and UltraLuminous InfraRed Galaxies ●star formation crossed the galaxy disks (Saitoh+ 2010) ●SFR is continuously high during merging (Matsui+ 2011)

Saitoh et al. 2010

Key to understanding the formation and evolution of galaxies and their associate

star forming environment

Matsui et al. 2011

Introduction : VV114

・One of the nearest LIRG (4.1 × 1011 Lsun)

・D = 77 Mpc ・systemic velocity = 6016 km/s ・RA = 1 h 7 m 47 s ・Decl. = -17 ° 30 ’ 3 “ ・+ are the nuclei of each galaxy ・projected nuclei separation ~ 6 kpc (1 arcsec = 370 pc)

VV114W

VV114E

HST / ACS

Previous works

A compact starburst (mid-IR) and/or

A highly obscured AGN (X-ray)

Diffuse starburst (mid-IR)

Star formation is extended over the whole system. (NIR & Paα)

Grimes+ 2006, Le Floc’h+ 2002, Alonso+ 2002, Tateuchi+ 2012

VV114E VV114W

UV - HST/STIS Ks-band – miniTAO Paα – miniTAO/ANIR Soft X-ray - Chandra

Global SFRPaα ~ 45.1 Msun/year

Science goals: Cycle0 § (1) Determine the distribution and kinematics of the high density gas.

・HCN(4-3) & HCO+(4-3) ・200 pc (0.5 ”) resolution

§ (2) Map dense gas mass fraction and global gas kinematics. ・12CO(1-0), 13CO(1-0), 12CO(3-2) & 13CO(3-2) lines ・640 pc (1.6 “) resolution

§ (3) Quantify the density and temperature of the molecular gas using a radiative transfer model analysis.

ALMA data for VV114

Obs freq [GHz]

FOV [“]

On source time [min]

Beam size (1” = 370pc)

Critical density[cm-3]

12CO(1-0) 112.96 53.7 38 2.0” × 1.3” 4.1 × 102 13CO(1-0) 107.99 56.2 41 1.8” × 1.2” 1.5 × 103 12CO(3-2) 338.86 17.9 82 1.3" × 1.0” 8.4 × 103

HCO+(4-3) 349.58 17.4 86 0.44" × 0.36” 1.8 × 106

HCN(4-3) 347.50 17.6 86 0.45" × 0.39” 8.5 × 106

§ 17 × 12m antennas § Compact and/or extended configurations § Continuum emission in each MS

Results

Introduction & Observation Results Summary

§ 12CO(1-0) § Clearly two arm-like structures

→ South-east one traces dust lane § High velocity dispersions(>100km/s)

between two nuclei →

§ Calculated M(H2) = 4.7 × 1010 Msun

→ consisitent with Yun et al. 1994

13CO(1-0)

2,3,4,5,6,7 Jy/beam.km/s

Distribution & Kinematics(Band 3)

Overlap region

12CO(1-0)

§ 13CO(1-0)

§  VV114E and the overlap region §  consistent with 12CO(1-0) strong emission

region

2,4,8,16,32,48,64,128,256 Jy/beam.km/s

Overlap region

6200km/s 5600km/s

Extra-results(Band 3)

6200km/s 5600km/s

CN N = 1-0, J = 3/2-1/2 CN N = 1-0, J = 1/2-1/2

CS(2-1) CH3OH(2(-1,2)-1(-1,1))

Overlap region

Overlap region

1, 3, 5, 7, 9, 11, 13, 15 Jy/beam.km/s 1, 2, 3, 4, 5, 6 Jy/beam.km/s

0.5, 1.5, 2.5 Jy/beam.km/s 0.5, 1.5, 2.5, 3.5, 4.5 Jy/beam.km/s

Overlap region

§ HCN(4-3) & HCO+(4-3) § A few components at VV114E nucleus

→ point source(E0) and compact regions → E0 is the Ks-band peak region

§ And the overlap region (only HCO+) → consistent with 13CO(1-0) detection

Distribution & Kinematics(Band 7)

0.5,1,2,3,4,5,6,7,8,9,1.2,1.6,2.0 Jy/beam.km/s

Overlap region

HCN(4-3)

HCO+(4-3) 0.5,1,2,3,4,5,6,7,8,9,1.2,1.6,2.0,2.4 Jy/beam.km/s

E0 E2 E1

E3

§ Extra-detection

CS(7-6)

0.2,0.3,0.4 Jy/beam.km/s

6200km/s 5600km/s

HCO+(4-3)

E0, E1-3,and Overlap

E0 E1-3

Overlap

12CO(1-0) ■ Source size (MIRIAD/imfit) ■ Line width (FWZI) ■ Line ratio (Kohno+2001, Imanishi+2007, Aalto+1997, Aalto+2007, Costagliola+2011…) ■ Other wavelength

E0? HCO+(4-3)

HCN(4-3)

Pa alpha

Soft X-ray

(1)  Unresolved 100pc beam (2)  Broad HCN,HCO+ line widths (FWZI ≈ 300km/s) (3)  High HCN/HCO+ ratio (>1) (4)  Low HCN/CS(~6) and high HCN/CO ratio(>0.6)

(1)  → point source (2)  → Large Mdyn and possibly tarbulent (3)  → Seyfert nuclei (4)  → denser than E1-3 and Overlap

Hard & Soft X-ray

Compact Pa alpha & Hard X-ray…

A hidden AGN (MSMBH < 1.1 × 109Msun)

(1)  Resolved 150pc beam (2)  HCN,HCO+ line widths (FWZI ≈ 150 - 200km/s) (3)  Low HCN/HCO+ ratio (<1) (4)  High HCN/CS(>30) and low HCN/CO ratio(>0.2)

E1-3? HCO+(4-3)

HCN(4-3)

Pa alpha

(1)  → extended source (2)  → narrower than E0 (3)  → pure starburst (4)  → diffuser than E0 (HCN/CO: Seyfert nuclei)

Soft X-ray

Strong Pa alpha & Soft X-ray…

A compact starburst near the nucleus!!!

The overlap region? HCO+(4-3)

CN N = 1-0, J = 3/2-1/2

Pa alpha

(1)  Slightly HCO+ detection (2)  Low HCN/HCO+ ratio (<0.2) (3)  High CO/13CO(~20) and low HCN/CO ratio(>0.2)

(4)  CN: a tracer of UV radiation (Rodriguez+ 1998) → from OB stars (UV image) → from recent star-formation

(5)  Non-strong X-ray emission

UV radiation A star-forming region: Different physical background

The overlap region? HCO+(4-3)

CN N = 1-0, J = 3/2-1/2

Pa alpha

UV radiation

CS(2-1) CH3OH(2(-1,2)-1(-1,1))

Comparing with models of shock chemistry!

■ These molecular lines sometimes trace shocked regions

Kinematics and Distribution

Optical CO(1-0)

UV Pa alpha

Ks-band X-ray

AGN

Starburst Star formation

Dust lane

Summary

Introduction & Observation Results Summary

Summary

§ SMG detection?: - ALMA observations have very high capabilities !

§ High resolution mapping of HCO+(4-3) and HCN(4-3): - VV114E nucleus has an AGN and a compact starburst

§ 12CO(1-0) line emission: - Will reveal the large scale kinematics and distribution

§ Many lines detection in VV114: - CH3OH(2-1), CS(2-1), CN(1-0), and CS(7-6) - Physical condition differences at AGN, Starburst, Overlap

A new SMG detection

Line profile in this position Line width ~ 400 km/s

350GHz continuum(contour) overlaid X-ray(color)

350GHz continuum consistent with X-ray source !!!

Line detection in Band3 !!!

Thank you!

Back up

Line ratio & gaussian fitting Band7

[resolution] HCN/HCO+

[0.4”] HCN/CS(7-6)

[0.4”] E0 1.5 6 E1 0.3 > 30 E2 0.4 > 35 E3 0.5 > 35

Overlap < 0.2 -

Band3 [resolution]

CO/13CO

[1.5”] HCN/CO

[1.0”] CN/CO [1.5”]

CH3OH(2-1) detection

CS(2-1) detection

E0 30 - 40 0.6 – 1.2 0.06 – 0.1 × ×

E1 - E3 20 - 25 0.2 – 0.6 0.03 – 0.06 × △

Overlap 20 - 25 < 0.2 0.02 ○ ○

HCO+ dispersion [km/s]

CO dispersion [km/s]

27, 74 52, 79

47 36, 77 39 -

13, 46 - 40 33, 65