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Modeling the Milky Way disk dynamics

Modeling the Milky Way disk dynamics

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Dynamics of <strong>the</strong> spiral armsand <strong>the</strong> bar of <strong>the</strong> MWwith RAVETeresa AntojaKapteyn Astronomical Institute, University of Groningen<strong>the</strong> Ne<strong>the</strong>rlandsA. Helmi and <strong>the</strong> RAVE collaborationSydney, 24th July 2012


IntroductionVelocities of stars in <strong>the</strong> solarneighbourhood (~150 pc)GCS (Hipparcos + Geneva-Copenhagen)T. Antoja Sydney, 24/07/2012


IntroductionVelocities of stars in <strong>the</strong> solarneighbourhood (~150 pc)GCS (Hipparcos + Geneva-Copenhagen)T. Antoja Sydney, 24/07/2012


IntroductionVelocities of stars in <strong>the</strong> solarneighbourhood (~150 pc)GCS (Hipparcos + Geneva-Copenhagen)• Disrupted stellar clusterse.g. HR1614 (Feltzing and Holmberg 2000, DeSilva et al. 2007)•Tidal debris of accreted satellitese.g. Arcturus ? (Navarro et al. 2004)•Perturbations in <strong>the</strong> disc due toexternal dynamical effects (e.g. due tointeraction events)Quillen et al. 2009, Minchev et al. 2009•Orbital and resonant effects of <strong>the</strong>spiral arms and barKalnajs 1991, Dehnen 2000, Fux 2000, Quillen &Minchev 2005, Chakrabarty 2007, Antoja et al.2009T. Antoja Sydney, 24/07/2012


Y (kpc)Outline:X (kpc)• Models: orbital effects on <strong>the</strong> disc kinematics• RAVE: kinematic groups across <strong>the</strong> discT. Antoja


Y (kpc)Outline:X (kpc)• Models: orbital effects on <strong>the</strong> disc kinematics• RAVE: kinematic groups across <strong>the</strong> discT. Antoja


Groups and resonances (Monari et al, in prep.)BAR model20 o Ωp=49 km/s/kpcORBITALFREQUENCIESbar reference frameωR (=κ)ωϕ (=|Ω-Ωp|)Fourier transformT. Antoja Sydney, 24/07/2012


Groups and resonances (Monari et al, in prep.)BAR model20 o Ωp=49 km/s/kpcORBITALFREQUENCIESbar reference frameωR (=κ)ωϕ (=|Ω-Ωp|)Fourier transformωϕ (km/s/kpc)ωR (km/s/kpc)T. Antoja Sydney, 24/07/2012


Groups and resonances (Monari et al, in prep.)BAR model20 o Ωp=49 km/s/kpcORBITALFREQUENCIESbar reference frameωR (=κ)ωϕ (=|Ω-Ωp|)Fourier transformωR=nωϕωϕ (km/s/kpc)ωR (km/s/kpc)T. Antoja Sydney, 24/07/2012


Groups and resonances (Monari et al, in prep.)BAR model20 o Ωp=49 km/s/kpcORBITALFREQUENCIESbar reference frameωR (=κ)ωϕ (=|Ω-Ωp|)Fourier transformωϕ (km/s/kpc)ωR (km/s/kpc)ωR/ωϕT. Antoja Sydney, 24/07/2012


Groups and resonances (Monari et al, in prep.)BAR model20 o Ωp=49 km/s/kpcORBITALFREQUENCIESbar reference frameωR (=κ)ωϕ (=|Ω-Ωp|)Fourier transformωϕ (km/s/kpc)ωR (km/s/kpc)ωR/ωϕT. Antoja Sydney, 24/07/2012


Bar effects: a model for HerculesDehnen 2000/Fux 200020 o Ωp=49 km/s/kpcModelObservedOLRT. Antoja Sydney, 24/07/2012


VOLR for different bar propertiesfrom Dehnen 2000Pattern speedBar orientation4147 0 90Slope of <strong>the</strong> rotation curvedecr flat incrT. Antoja Sydney, 24/07/2012


Bar effects: Hercules accross <strong>the</strong> discΩp=49 km/s/kpc20 oT. Antoja Sydney, 24/07/2012


Bar effects: Hercules accross <strong>the</strong> discΩp=49 km/s/kpc20 o•Kinematic response to <strong>the</strong> bar depends ondisc position•The Hercules gap moves to lowerazimuthal velocities for largerGalactocentric radius•More changes in radius than azimuthT. Antoja Sydney, 24/07/2012


Bar effects: Hercules accross <strong>the</strong> discΩp=49 km/s/kpc-60 km/s20 o-40 km/s-20 km/s0 km/s•Kinematic response to <strong>the</strong> bar depends ondisc position•The Hercules gap moves to lowerazimuthal velocities for largerGalactocentric radius•More changes in radius than azimuthT. Antoja Sydney, 24/07/2012


VOLR as a function of RT. Antoja Sydney, 24/07/2012


VOLR as a function of RT. Antoja Sydney, 24/07/2012


VOLR as a function of RT. Antoja Sydney, 24/07/2012


VOLR as a function of RT. Antoja Sydney, 24/07/2012


VOLR as a function of RT. Antoja Sydney, 24/07/2012


Spiral arms effectsΩsp=15 km/s/kpcΩsp=20 km/s/kpc•Kinematic response to <strong>the</strong> spiral arms is strong and depends on disc position•Significant changes: ~0.6 kpc in radius, ~2 kpc in azimuth•Strong effects: close to <strong>the</strong> 4:1 inner resonance•Where do we find more substructure? It depends on <strong>the</strong> pattern speedT. Antoja Sydney, 24/07/2012


Y (kpc)Outline:X (kpc)• Models: orbital effects on <strong>the</strong> disc kinematics• RAVE: kinematic groups across <strong>the</strong> discT. Antoja


Y (kpc)Outline:X (kpc)• Models: orbital effects on <strong>the</strong> disc kinematics• RAVE: kinematic groups across <strong>the</strong> discT. Antoja


RAVE sample• multi-fiber spectroscopic survey•DR3 (Siebert et al. 2012): 500000 spectra•Proper motions: UCAC2, PPMX•Spectro-photometric distances: Burnett & Binney 2010•6D phase space for 2·10 5 stars•6D phase space for 10 5 stars•|Z| ≤ 300 pc• Our goal: velocity distribution at different positions• Regional Standard of Rest (McMillan & Binney 2010):R☉=7.8 kpc, v☉=247 km/s , U☉=10 km/s, V☉=11 km/sT. Antoja Sydney, 24/07/2012


RAVE sample• multi-fiber spectroscopic survey•DR3 (Siebert et al. 2012): 500000 spectra•Proper motions: UCAC2, PPMX•Spectro-photometric distances: Burnett & Binney 2010•6D phase space for 2·10 5 stars•6D phase space for 10 5 stars•|Z| ≤ 300 pc• Our goal: velocity distribution at different positions• Regional Standard of Rest (McMillan & Binney 2010):R☉=7.8 kpc, v☉=247 km/s , U☉=10 km/s, V☉=11 km/sT. Antoja Sydney, 24/07/2012


Finding substructure: Wavelet TransformMR Software (CEA, Saclay)Starck & Murtagh 2002Slezak et al. 19931) Point distributionT. Antoja Sydney, 24/07/2012


Finding substructure: Wavelet TransformMR Software (CEA, Saclay)Starck & Murtagh 2002Slezak et al. 19931) Point distribution2) Wavelet transformT. Antoja Sydney, 24/07/2012


Finding substructure: Wavelet TransformMR Software (CEA, Saclay)Starck & Murtagh 2002Slezak et al. 19931) Point distribution2) Wavelet transform3) Significant peaks 2σ and 3σT. Antoja Sydney, 24/07/2012


Revisiting <strong>the</strong> solar neighbourhoodRAVE Local sample•Similar significant groups in GC and RAVE local sample•Main groups: Coma Berenices, Hyades, Sirius, Pleiades,Hercules57178 starseU,V~4 km/s•New group at (U, V)∼ (90, -20) km/sRAVEGCT. Antoja Sydney, 24/07/2012


Revisiting <strong>the</strong> solar neighbourhoodRAVE Local sample•Similar significant groups in GC and RAVE local sample•Main groups: Coma Berenices, Hyades, Sirius, Pleiades,Hercules57178 starseU,V~4 km/s•New group at (U, V)∼ (90, -20) km/sRAVEGCT. Antoja Sydney, 24/07/2012


Revisiting <strong>the</strong> solar neighbourhoodRAVE Local sample•Similar significant groups in GC and RAVE local sample•Main groups: Coma Berenices, Hyades, Sirius, Pleiades,Hercules57178 starseU,V~4 km/s•New group at (U, V)∼ (90, -20) km/sRAVEGCT. Antoja Sydney, 24/07/2012


Revisiting <strong>the</strong> solar neighbourhoodRAVE Local sample•Similar significant groups in GC and RAVE local sample•Main groups: Coma Berenices, Hyades, Sirius, Pleiades,Hercules57178 starseU,V~4 km/s•New group at (U, V)∼ (90, -20) km/sRAVEGCT. Antoja Sydney, 24/07/2012


Beyond <strong>the</strong> solar neighbourhoodAntoja et al. 2012T. Antoja Sydney, 24/07/2012


Beyond <strong>the</strong> solar neighbourhoodAntoja et al. 2012R~8.4 kpcR~7.8 kpcR~7.2 kpcT. Antoja Sydney, 24/07/2012


Beyond <strong>the</strong> solar neighbourhoodAntoja et al. 2012•First detection ofnon-local disckinematic substructureR~8.4 kpcR~7.8 kpcR~7.2 kpc•Local known groupsare still observed at 1kpc in <strong>the</strong> solar circle•Known groups areshifted in velocityinside and outside solarcircle•More changes inradius than in azimuthT. Antoja Sydney, 24/07/2012


Hercules changes with R in RAVET. Antoja Sydney, 24/07/2012


Hercules changes with R in RAVE8 kpc 8.2 kpc 8.4 kpc 8.6 kpcT. Antoja Sydney, 24/07/2012


Hercules changes with R in RAVE8 kpc 8.2 kpc 8.4 kpc 8.6 kpcT. Antoja Sydney, 24/07/2012


Hercules changes with R in RAVE8 kpc 8.2 kpc 8.4 kpc 8.6 kpcT. Antoja Sydney, 24/07/2012


Hercules changes with R in RAVE8 kpc 8.2 kpc 8.4 kpc 8.6 kpcT. Antoja Sydney, 24/07/2012


Hercules changes with R in RAVE8 kpc 8.2 kpc 8.4 kpc 8.6 kpcT. Antoja Sydney, 24/07/2012


Hercules changes with R in RAVE8 kpc 8.2 kpc 8.4 kpc 8.6 kpc?T. Antoja Sydney, 24/07/2012


Constrains on bar properties β=0Ωp (km/s/kpc)ϕ ( o )T. Antoja Sydney, 24/07/2012


Constrains on bar properties β=0Ωp (km/s/kpc)ϕ ( o )T. Antoja Sydney, 24/07/2012


Constrains on bar properties β=0Ωp (km/s/kpc)ϕ ( o )T. Antoja Sydney, 24/07/2012


Constrains on bar properties β=0Ωp (km/s/kpc)ϕ ( o )Lopez-Corredoira et al. 2000Robin et al. 2012Hammersley et al. 2000Benjamin et al. 2005ϕ~10 oϕ~45 oΩp= 56.7+1.7-1.9(km/s/kpc)T. Antoja Sydney, 24/07/2012


Integrating for all βΩp =56.8+1.9-2.0(km/s/kpc)For v⊙=220km/s & R⊙=8.5kpcΩp= 46.4+1.6-1.6(km/s/kpc)Ωp= 1.79+0.06-0.06Ω⊙T. Antoja Sydney, 24/07/2012


Integrating for all βΩp =56.8+1.9-2.0(km/s/kpc)For v⊙=220km/s & R⊙=8.5kpcΩp= 46.4+1.6-1.6(km/s/kpc)Ωp= 1.79+0.06-0.06Ω⊙T. Antoja Sydney, 24/07/2012


Bar effects: a model for HerculesModelObs• Peaks in Hercules?• O<strong>the</strong>r groups: related to spiral arms? related to <strong>the</strong> bar?• Which models can explain <strong>the</strong>m also for o<strong>the</strong>r disc positions?T. Antoja Sydney, 24/07/2012


Hot population•Some groupspersist at low |Z|below <strong>the</strong> plane:Hercules, γLeo•Hercules seen for hotvertical orbits!T. Antoja Sydney, 24/07/2012


ConclusionsOBSERVATIONS vs DYNAMICAL MODELS✦The models predict kinematic substructure beyond <strong>the</strong> local volume✦We have detected it for <strong>the</strong> first time with RAVE✦Most of <strong>the</strong> main local kinematic groups can still be detected at ~1 kpc distance✦Large-scale features + age dispersionfavour dynamical origin✦The groups shift in <strong>the</strong> velocity plane for distant samples, as expected✦Scales of variation of <strong>the</strong> groups are roughly consistent with models✦Hercules trend of azimuthal velocity with radius is consistent with effects of <strong>the</strong>2:1 OLR✦We have used <strong>the</strong> magnitude and direction of <strong>the</strong> shift of Hercules to constrain<strong>the</strong> pattern speed of <strong>the</strong> barFUTURE WORK✦Explore <strong>the</strong> vertical variation of <strong>the</strong> groups with models✦Use shifts of o<strong>the</strong>r groups to constrain more properties of <strong>the</strong> bar or <strong>the</strong> spiralarmsT. Antoja Groningen, 02/05/2012

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