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
Aug 18, 2021
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