The NANTEN CO survey and SKA Kengo Tachihara (Nagoya University) - PowerPoint PPT Presentation

The NANTEN CO survey and SKA Kengo Tachihara (Nagoya University) and the NANTEN team

The NANTEN2 project • 4m radio telescope at the Atacama desert in Chile • Large-scale survey of ISM in the milky way and nearby galaxies • Observe in mm and submm wavelengths • Conducted under international collaboration • Nagoya U., Osaka Prefecture U. • Universität zu Köln, Universität Bonn • University of New South Wales, Sydney, Macquarie and so on • Universidad de Chile Seoul National U. ETH Zurich

Instruments • Low frequency receiver (by Nagoya Univ.) • 100GHz : CO (J=1-0) and its isotopes • 200GHz : CO (J=2-1) • to be upgraded to the 4-beam 2-band receiver • High frequency (2-band) receiver (by U. Köln) • 500GHz : CO (J=4-3), CI ( 3 P 1 - 3 P 0 ) • 800GHz : 12 CO (J=7-6), 13 CO (J=8-7), CI ( 3 P 2 - 3 P 1 )

Instruments • Low frequency receiver (by Nagoya Univ.) • 100GHz : CO (J=1-0) and its isotopes • 200GHz : CO (J=2-1) • to be upgraded to the 4-beam 2-band receiver !"# � • High frequency (2-band) receiver (by U. Köln) • 500GHz : CO (J=4-3), CI ( 3 P 1 - 3 P 0 ) • 800GHz : 12 CO (J=7-6), 13 CO (J=8-7), CI ( 3 P 2 - 3 P 1 )

The NANTEN Galactic Plane Survey (NGPS) • 1st generation NANTEN CO survey • Covering 6350 deg 2 • Revealed many molecular clouds/cores • 8´ grid spacing with 2.6´ beam

The NANTEN2 Super CO Survey (NASCO) Cover 70% of the whole sky with the multi- beam receiver and the On-The-Fly mapping Image: Planck 1 year result , Black shade: MCs by NGPS

NASCO survey initial result

Cluster-forming cloud • Westerlund 2 cloud • 5000 M o at 5 kpc • Clusters of ~300 Galactic latitude young stars • 2 molecular clouds with different V • Formation model by Cloud-cloud collision Galactic longitude (Ohama et al. 2010)

TeV ! -ray from SNR RX J1713.7 ! 3946 (Fukui et al. 2012) proton origin scenario of high energy ! -ray Azimuthal intensity Color: N p (H 2 +H I ) distribution Contours: TeV ! -ray

High latitude clouds —sites where molecular clouds form— LAB all-sky HI 21 cm survey

High latitude clouds —sites where molecular clouds form— LAB all-sky HI 21 cm survey

MBM 53, 54, 55 complex Magnani et al. 1985 � 12 CO(J=1-0) � MBM53 � MBM54 � MBM55 � Complex cloud morphology Yamamoto et al. 2003

Planck’s Dust clouds

The Planck all-sky CO map

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Two phase gas model • ISM consist of warm (~ 10 4 K) and cold (< 100 K) neutral SHOCK! medium (WNM and CNM) • shock compression of diffuse WNM => small-scale CNM formed by thermal instability • Turbulent molecular cloud formation • Turbulence is sustained long due to subsonic random motion wrt. the warm gas Thermal instability of shocked layer (Koyama & Inutsuka 2000, 2002)

Numerical simulations • 3D MHD simulation of colliding flow z • Chemical reaction • Radiative heating & cooling, • Thermal conduction, etc... lo g n [cm -3 ] y x 10 0 probability density 10 -1 10 -2 10 -3 10 -4 1.0 10 100 Larson’s law nember density : n [ cm -3 ] Thermal instability Inoue & Inutsuka 2012

Small scale structures of the cloud surface Peak T a Channel map 18 3.1-3.4 km/s 3.4-3.7 km/s 3.7-4.0 km/s HPBW 10000 AU 16 14 12 4.0-4.3 km/s 4.3-4.6 km/s 4.6-4.9 km/s 10 8 6 4.9-5.2 km/s 5.2-5.5 km/s 5.5-5.8 km/s 4 2 0 NRO 45m telescope (Tachihara et al. 2012)

Complex velocity field 6 average V = 1.48 km/s A V = 0.57 km/s 5 B V = 0.63, 0.59 km/s Super-sonic turbulence is by C V = 0.51 km/s clump 4 R = 6300 AU, M ensemble of small-scale structures = 0.03 M o 3 Ta (K) pillar 2 arc 1 0 -1 1 2 3 4 5 6 7 V LSR (km/s) 12 CO spectra " V small ~ 0.6 km/s, " V ave ~ 1.5 km/s Channel map

Conclusion • NANTEN2 is surveying our Galaxy in CO • Many interesting astronomical objects • Collaborating with Planck satellite • Interest in molecular formation from HI • SKA will be a nice complementary partner of NANTEN2!