[email protected] alma observations of the ir-bright ......toshiki saito...
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Toshiki Saito [email protected]
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