from gmc-snr interaction to gas-rich galaxy-galaxy merging

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From GMC-SNR interaction to gas-rich galaxy-galaxy merging Yu GAO Purple Mountain Observatory, Nanjing, China Chinese Academy of Sciences

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From GMC-SNR interaction to gas-rich galaxy-galaxy merging. Yu GAO Purple Mountain Observatory, Nanjing, China Chinese Academy of Sciences . SFR vs. M(H2): No Unique Slope:1, 1.4, 1.7?. H2-dominated LIRGs/ULIRGs. HI ~ H2. HI-dominated LSB galaxies. - PowerPoint PPT Presentation

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Page 1: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

From GMC-SNR interaction to gas-rich galaxy-galaxy merging

Yu GAOPurple Mountain Observatory, Nanjing, China

Chinese Academy of Sciences

Page 2: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

SFR vs. M(H2): No Unique Slope:1, 1.4, 1.7?

HI-dominatedLSB galaxies

HI ~ H2

H2-dom

inatedLIR

Gs/

ULIR

Gs

Gao & Solomon 2004b ApJExtragalactic SF=CO until 90’s

Page 3: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

Big

iel’s

talk

@S

FR50

SF thresholds maysimply reflect the change of the dominant cold gas phase in galaxiesfrom HI ->H2 & from H2->denseH2

Schruba+2011~linear in H2!

Page 4: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

13 HCN @high-z

Gao, Carilli, Solomon & Vanden Bout 2007 ApJ, 660, L93

Page 5: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

Poster by Liu+

Liu & Gao 2011 arXiv:1106.2813

Dense H2 show the best correlation with SFR (linear Liu & Gao 2011).

Page 6: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

Bi-modal SF laws in high-z gals (Daddi+2010; Genzel+2010) also exist in local gals

Page 7: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

Introduction and Outline1. R=CO/13CO line intensity ratios: R ~2-5 Galactic Ring Survey 13CO (Jackson+06; Simon+01) UMass-StonyBrook CO survey (Sanders+86), ~5-10 Galactic center GMCs + normal spirals, ~10-20 Starbursts (eg, Aalto+1995) ~30-50 (U)LIRGs (few 13CO published; Papadopoulos+11)high R10 associated with small, warm but compact molecular clouds of low to

moderate optical depth, or the high [12CO/13CO] abundance ratio

2. Best case studies: Arp220 (Greve+09; Matsushita+09), NGC6240(Greve+09; U+11)

3. Resolved measurements in Antennae galaxies (Gao+01; Zhu+03), Taffy (Gao+03; Braine+03; Zhu+07); nearby gals. (Tan+11)

4. Supernova remnant (SNR) IC 443: GMC-SNR interactions (Wang+Scoville92; Zhang+10)

5. Implications: the molecular gas conditions in (U)LIRGs

Page 8: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

R~43

Greve+09

2. Best case studies

Page 9: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

Matsushita+09

Page 10: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

R~45

Greve+09

Page 11: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

BIMA+12m CO on HST image VLA 20cm on HST Very tight FIR-radio continuum correlation

3. Resolved measurements in ongoing mergers

Page 12: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

Gao+01, SFE (20cm/CO) contour map

Page 13: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

Zhu+03

R32~25R32~15

Page 14: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

Zhu+03

R21~20-30@overlap ~15@Nuclei

Page 15: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

Gao 2008

Zhang, Gao, Kong 2010 MNRAS

Page 16: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

SCUBA: Zhu, Gao, Seaquist & Dunne 2007 CO: Gao, Zhu, Seaquist 2003

450um contours on 8um image 850um contours on CO image

Page 17: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

R~15, 50 (The 12CO line intensities are divided by 10, Braine+03)

HII

Page 18: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

Tan+11 arXiv1103.5540

Page 19: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

Dame et al. 2001

Columnbia CO Survey

CO (1-0) in Gem OB1 GMC

Lee et al. 2008

1.4GHz Continuum

4. Supernova remnant (SNR) IC 443 -- the Jellyfish Nebula

Page 20: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

Simultaneous observations: 12CO,13CO & C18O (1-0)Typical Tsys~180-300K (rms noise ~0.2K in 0.4 km/s)Total obs. points >1000, total spectra~7000, 2Months Beam size and sampling grid: ~ 55” (~1’)

Gateway 2 Lhasa by sky train Array 3x3 + OTF 2011

Page 21: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

Zhang, Gao & Wang arXiv: 0911.4815

Page 22: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

Zhang, Gao & Wang arXiv: 0911.481570um and 160um overlaid with CO(1-0)

Page 23: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

Zhang, Gao & Wang arXiv: 0911.4815HI and radio continuum images overlaid with CO(1-0)

Page 24: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

CO/13CO Line Ratio & FIR Maps

[FeII], [SI], H2 0-0 S(0)

[OI] [CII] + Dust?

Spitzer 24 um

Spitzer 70 um

Spitzer 160 um

1. Line ratios are much higher in shocked regions than in the rest regions.

2. Line ratio maps in IC443 are strikingly well matched with the FIR images.

Page 25: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

SNR IC443

Yellow: 12CO

Blue: 13CO

Background:

Spitzer 24μm

Spectra Analysis

Page 26: From GMC-SNR interaction to gas-rich galaxy-galaxy merging
Page 27: From GMC-SNR interaction to gas-rich galaxy-galaxy merging

5. Implications to (U)LIRGs• Concentrated molecular gas of ~10^10Msun in ~1kpc

(vs. >10 kpc 10^9 Msun H2 in the Galaxy) (~10^3)• Packed with dense cores (HCN-FIR) and even intercloud

(or inter-dense-core) medium is highly molecular• SNe rates in ULIRGs ~100 times that of the Milky Way• Most dense cores are shocked by SNRs in ULIRGs

(~10^5xMW) besides strong galaxy-galaxy collisions• Highly shocked regions higher R=CO/13CO in LIRGs• The abnormally high ratios of R (& CO/C18O) found in

SNR IC443 of shock-origin are comparable to the observed values in starbursts and (U)LIRGs, likely implying their same physical origin. Gao & Solomon 04, Gao+07: Dense H2 Dense Cores