slide1 n.
Skip this Video
Loading SlideShow in 5 Seconds..
BIMA SONG PowerPoint Presentation
play fullscreen
1 / 38
Download Presentation

BIMA SONG - PowerPoint PPT Presentation

rowdy
153 Views
Download Presentation

BIMA SONG

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

  1. Séminaire PHY6791 Automne 2009 Astrophysique Extragalactique BIMA SONG ZacharieKAM UdeM

  2. Plan 1- Introduction / Motivation 2- MolecularGas 3- SONG 4- Results 5- Conclusion Plan

  3. Introduction/Motivation Moleculargas: galaxies evolution, Star formation laws (rate & efficiency)usinggasproperties Emission from galaxies athigh Z. Intro Gasinflows: starburst, non stellarnuclearactivities, galacticchemicalevolution, central mass concentration.

  4. BIMA- SONG Goal • Distribution and physical conditions of the moleculargas in galacticdisk and its relation to star formation • Effects of stellar bar on the kinematics of moleculargas, including the possible inflow of gasalong the bar • The distribution and role of moleculargas in central few parsecs of active and quiescent galaxies.

  5. Gaz moléculaire Tracers : Ionizedgas atomicgas Moleculargas Gaz moléculaire Chemin, Carignan, Tyler 2009 Aalto et al. 1999 NGC 5427, *OB tracent SFR

  6. CO as H2 tracer De son moment dipolaire μ ~ 0.1 Debey Vallejo 2003. De ses raies intenses CO est dense et excité par collision. CO a même photo-dissociabilité que le H2, présent aux même point que H2. Les raies millimétriques du CO sont permises, les hyperfines de 21 cm de l'hydrogène elles non. le CO se trouve saturé dans les nuages moléculaires, cela permet de trouver la température cinétique en surface. Gaz moléculaire

  7. CO as H2 tracer Gaz moléculaire

  8. X factor Trois solutions sont généralement proposées pour calibrer rapport N(H2)/CO et la masse des nuages moléculaires Virial 3.6 x 1020 N(H2)/I_CO1-2 constante universelle. (2) Gama ray (3) Optical thinlines and dustemission. Gaz moléculaire

  9. X factor variations • H2 via CO est intéressant mais: • le taux de conversion H2/CO peut varier en fonction du type morphologique • le taux de conversion H2/CO peut varier en fonction du rayon dans la galaxie • ne peut être utilisé dans les galaxies naines p.e. si les abondances de C et O sont faibles (non-détection du CO ne veut rien dire sur la présence du H2) • Variation de CO/CO13 • Variation de l’activité de formation stellaire Gaz moléculaire

  10. X factor variations Paglione et al 2001

  11. Smith et al. (2000) proposed a new probe of H2 in galaxies. HI gas = isdissociatedmoleculargas, ρv(H2) deducedfrom the HI columndensitytogetherwith the FUV photon flux. Apply to M101, correction for the metallicity gradient extinction of the FUV emission  H2 densityis about constant over radius up to 26 kpcfrom the center (ie ~R25)

  12. A. Boselli et al (2002) X change factor 10 fromspirals galaxies to dwarfs Taking X cst - (2.3 - 2.8 x1020 ) one overestimate X about 2-3 times H2 mass in massives galaxies & one enderestimatethis mass 2 times in less massive Gaz moléculaire

  13. Someothermethods H2 Dustatλ mm dust = f(T) X factor definition Gaz moléculaire

  14. SONG sample SONG Criteria of sampleselection Galaxies from NED, Hubble types Sa-Sd Declinationsδ > -20 ° Visual magnitudes B < 11.0 Vys <2000km/s Inclinations i < 70° Hubble distance ~27Mpc Particularities of thissample M33 CO brightness not criterion Large area coveringsignificant fraction of disk Samereductionprocedure All CO flux isincluded for these galaxies Nuclearactivity

  15. SONG sample SONG 45-1(M33) = Sample M. Thornley et al 1999 Diversity of galaxies in the sample Sbc 1/3 of the sample 32 opticallybarred (SB, SAB), 18 GrdDisign , 13 Flct, 13 HII nuclei & 20 galaxies withemission line (Syfert and LINER) CO detection 80% of sample Non detections all Type early type (~ bar structure)

  16. SONG :Survey Of Nearby Galaxies BIMA+ for SONG SONG BIMA: Berkeley -Illilois-Maryland-AssociationInterferometer 6m antennaused in C and D Configurations

  17. BIMA+ for SONG SONG Resolution 5-7’’ ~350pc ataverage distance. correlatorresolution 1.56 MHz( 4 km/s) / total de 368 MHz.

  18. BIMA+ for SONG SONG NRAO 12 m for SONG single dishmaps in order to compare sensentivity and getwellresolutioncombinningwith BIMA

  19. Observations and data SONG Nov 1997- Jul 2004. Instuments Radio :BIMA Configurations C & D NRAO 12m sigle dish Optical/IR obs: Literature and usingalsosome telescope(.9-.2) 0.9m KittPeak, 1.5m Palomar, 2.5m Las Campanas Data 2/3 (29 galaxies) observation usingsevenfieldsmosaics 2 x 8hours. 1/3 (14)are distant : single BIMA pointingissufficient to cover the optical disc: 1 x8hours. M51 (NGC 5194) 26 field-mosaic = data of 3 x 8hours track

  20. Resolution: Reduction of BIMA Atmosphere correction Amplitude calibration self calibration CO maps Combination of BIMA and single dish data Same for each galaxies BIMA galaxies & binnedwith NRAO observations Inner 1/3 of opticaldisk the of each galaxie iscover examine innerdisks as well as the nuclearregions.

  21. Résultats SONG Results

  22. Diverse morphologies SONG Results CO emissionfrombaredglx GD structure

  23. Diverse morphologies SONG Results Large scalemolecular ring Floculent structure

  24. Radial profiles and Star formation laws SONG Results

  25. Kinematicstudies SONG galaxies data reveal large velocity gradients useful in probing the mass distributions in the centers of galaxies, or in assessing mass inflowalong bar features the combined CO and HI kinematicsmayreveallarge-scale radial gasflowswhichmaysustain star formation in the innerdisk, or whetherdynamical influences are relevant to the large-scale transition frommolecular to atomicgas SONG Results

  26. Résultats Fig- A projection of the data cube for NGC 3627. The vertical axis displays measuredvelocities, withhighervelocitiestoward the top. The total range in velocitiesis 400 km/s. The major axis of the galaxy lies along the line of sightthrough the center of the image, suchthat the minor axis of the galaxyisprojectedalong the horizontal axis of the image. SONG Results

  27. About the X factor Patern speed SFR & SFE SONG Results

  28. Résultats+ Dynamics Combes at al 2001: Bars, nuclear bar Conclusion pas évident sur les mvts non circulaire Gas in shells 50% of gas in shellsismolecular H2/HI same in the nucleardisk Tidal dwarfs Gas collapse= new SF Arp245 and Arp105 CO emission HI peaks = moleculargaspeaks => HI  mol gas

  29. Moleculargas and SF laws • Schmidt (1959): n=1-3, mostly 2-3 in ISM of our Galaxy. • Kennicutt (1989): Disk-average n is not well constrained. ~1-3, wide spread. • Kennicutt (1998): n=1.4 ? Total gas (HI + H2) vs. Dense gas

  30. More CO data of ULIGs (Solomon et al. 1997) that Lco > ~ 10^10 K km/s pc^2 Total Molecular Gas Mass

  31. Conclusion Moleculargas The means tracer of moleculargas N(H2)/CO Othermethods SONG Results Distribution of meleculargas CO profile. The role of moleculargas The the Kinematiks of moleculargas

  32. Merci

  33. Hyperlinks Regan Bosseli Tamara MThornely Combes