CO imaging surveys of nearby galaxies Nario Kuno Nobeyama Radio Observatory

CO imaging survey of nearby galaxies Gas distribution & dynamics structures of galaxies Molecular gas Star formation Physical properties of molecular gas Causes of difference of galaxy type Formation mechanism of various structures of galaxies Galaxy evolution

CO imaging survey of nearby galaxies Molecular gas distribution and dynamics Molecular gas - Star formation Physical properties of molecular gas Hubble type AGN activity Starburst activity Environmental effects (cluster/isolated) Galaxy interaction Structures – Bar properties – Spiral arm strength

CO imaging survey of nearby galaxies Many sample covering various type of galaxies High angular resolution to resolve main structures of galaxies Wide-field imaging to cover whole distribution of molecular gas

CO survey of nearby galaxies with interferometer OVRO + NMA (20 galaxies, central region) (Sakamoto et al. 1999a, Sakamoto et al. 1999b, …) BIMA (44 galaxies) – The BIMA CO Survey of Nearby Galaxies (SONG) (Regan et al. 2001, Regan et al. 2002, …) PdBI (25 galaxies, central region) – Molecular Gas in NUclei of Galaxies (NUGA) (Garcia-Burillo, et al. 2003, Combes et al. 2004, …)

CO survey of nearby galaxies with single dish telescope NRO 45-m – Nobeyama CO Atlas of Nearby Spiral Galaxies (Kuno et al. 2007, Nakanishi et al. 2006, …) IRAM 30-m – The HERA CO Line Extragalactic Survey (HERACLES) (Leroy et al. 2009, Bigiel et al. 2011, …) JCMT 15-m – JCMT Nearby Galaxy Legacy Survey (NGLS) (Wilson et al. 2009, Warren et al. 2010, …) FCRAO 14m – Virgo spiral galaxy survey (Chung et al. 2009)

Imaging survey with single dish NRO45mIRAM30mJCMT15m LineCO(1-0)CO(2-1)CO(3-2) Number of sample Number of beam 259 X dual pol.16 Angular resolution 15”13”14.5” Velocity resolution 5km/s2.6km/s20km/s Sensitivity (3sigma) Kkm/s 0.2 Kkm/s1.9 Kkm/s

Target selection Complementary to other wavelength data – HI : The HI Nearby Galaxy Survey (THINGS) (34 galaxies) – IR : The Spitzer Infrared Nearby Galaxy Survey (SINGS) (75 galaxies) – UV : The GALEX Nearby Galaxy Atlas (1034 galaxies) – Ha : many

Imaging with single dish telescope Importance of single dish – Total flux measurement – Wide field imaging NRO CO Atlas (Kuno et al. 2007) BIMA SONG (Regan et al. 2001)

Integrated intensity map Many GMCs are resolved [K km/s][km/s] Velocity field M33 Tosaki et al. 2011

Imaging with single dish telescope Total flux measurement Wide field imaging Large scale distribution of molecular gas Molecular gas fraction Star formation efficiency Line ratio : physical properties of molecular gas

R bar Central concentration of molecular gas R cen R K20 R cen

R bar Concentration of molecular gas in bar region R cen R K20 R cen

Bar strength (Laurikainen, Salo 2002) vs. f in Comparisons with properties of galaxies

Molecular gas vs. star formation rate Schruba et al. 2011

HIHI+H2H2 Molecular gas vs. star formation rate

Warren et al SFE vs. CO(3-2)/CO(1-0)

Muraoka et al CO(1-0) CO(3-2)

CO imaging survey of nearby galaxies with new single dish telescope Increase number of sample galaxies drastically – High performance of mapping observations Multi-beam + wide band spectrometer – Multi-line CO(1-0), CO(2-1), CO(3-2), 13CO Complementary to other wavelength data – Ha Galaxy Survey (HaGS) (James et al. 2004) (334 galaxies) – GALEX Nearby Galaxy Survey (1034 galaxies) – Local Volume HI Survey (120 galaxies) – Hershel ATLAS (250,000 galaxies < z~3,4) High demand of a large CO imaging survey

CO survey of nearby galaxies with ALMA Sakamoto (2008) – CO(2-1) Tsys=170K – Beam size=1” Trms=0.1K (3σ~10Mo/pc 2 ) dV=10km/s – D = 1-25Mpc later than S0/a – R < 25mag arcsec -2 in B band – 622 galaxies 2 deg 2 – 1000 hours

New telescope – Diameter =50m – CO(2-1) Tsys=170K – Beam size = 7” – OTF 3.5” grid – main-beam efficiency 0.5 – 1 beam : 3’x3’ 0.1K ~50hr – Total : 2 arcdeg^ hr/N beam – Multi-beam100 beams : 800 hr 50 beams : 1600 hr 25 beams : 3200 hr Survey of nearby galaxies with new single dish telescope

CO survey with new multi-beam RX FOREST on NRO 45-m telescope FOREST – 2 x 2 beam x 2 pol. x 2 SB – Mapping efficiency will be 3-4 times higher than BEARS (much lower Tsys than BEARS) – Wide bandwidth (USB4-12GHz) (12CO + 13CO) – OTF technique Science cases for nearby galaxies with FOREST – Large CO(1-0) survey of nearby galaxies – Mapping of nearby galaxies by denser gas tracer than 12CO (e.g., 13CO)

Hirota et al IC342 13CO(1-0) 12CO(1-0)

CO imaging survey of nearby galaxies with new single dish telescope Increase number of sample galaxies drastically – High performance of mapping observations Multi-beam + wide band spectrometer – Multi-line CO(1-0), CO(2-1), CO(3-2), 13CO Complementary to other wavelength data – Ha Galaxy Survey (HaGS) (James et al. 2004) (334 galaxies) – GALEX Nearby Galaxy Survey (1034 galaxies) – Local Volume HI Survey (120 galaxies) – Hershel ATLAS (250,000 galaxies < z~3,4) High demand of a large CO imaging survey