Se-Heon Oh. Se-Heon Oh

Transcription

1 High-resolution mass models of rotation curves & LITTLE THINGS 1,2 1. International Centre for Radio Astronomy Research (ICRAR) The University of Western Australia 2. ARC Centre for All-sky Astrophysics (CAASTRO) with LITTLE THINGS team

2 Contents HI kinematics of galaxies Dark matter distribution in dwarf galaxies High-resolution mass models of LITTLE THINGS Dark matter distribution in LITTLE THINGS Summary & Future works

3 HI kinematics of resolved galaxies Dynamical structure : (dark) matter distribution in galaxies Interplay between ISM and star formation in galaxies on small (sub-kpc) scales Dynamical information about galaxy evolution : warps, bars spiral arms, tidal interaction, high-velocity clouds etc.

4 cusp/core problem in ΛCDM cosmology ΛCDM dark-matter-only simulations Moore (1994) Flores & Primack (1994) Navarro, Frenk & White (1995) Navarro, Frenk & White (1996) Moore et al. (1998) Ghigna et al. (2000) Klypin et al. (2001) Power et al. (2002) Navarro et al. (2004) Diemand et al. (2008) Stadel et al. (2009) Navarro et al. (2010) etc. cusp Observations core Flores & Primack (1994) Moore (1994) de Blok et al. (2001) de Blok & Bosma (2002) Bolatto et al. (2002) Weldrake et al. (2003) Simon et al. (2003) Swaters et al. (2003) Kuzio de Naray et al. (2006) Gentile et al. (2007) Oh et al. (2008) Trachternach et al. (2008) de Blok et al. (2008) Oh et al. (2011a, b) etc.

5 HI kinematics of resolved galaxies Dynamical structure : (dark) matter distribution in galaxies Interplay between ISM and star formation in galaxies on small (sub-kpc) scales Dynamical information about galaxy evolution : warps, bars spiral arms, tidal interaction, high-velocity clouds etc.

6 HI kinematics of resolved galaxies Dynamical structure : (dark) matter distribution in galaxies Interplay between ISM and star formation in galaxies on small (sub-kpc) scales Dynamical information about galaxy evolution : warps, bars spiral arms, tidal interaction, high-velocity clouds etc.

7 High-resolution SPH+ΛCDM simulations of dwarf galaxies (Governato et al. 2010; 2012) N-body+SPH tree-code GASOLINE Flat Λ-dominated cosmology HI 21cm 3.6 micron Baryonic processes are included, such as - gas cooling - cosmic UV field heating - star formation - SN-driven gas outflows ~3.3 million particles within the virial radius at z = 0 DM ~ M ; gas particle ~ M The force resolution (gravitational softening) ~ 86 pc

8 Simulations vs. Observations Rotation curve shape DM density profiles yti col ev noi t at o R DM density cusps α ~ -1.0 Radius Radius scaled at R0.3 where dlogv/dlogr = 0.3. Radius Oh et al. (2011)

9 LITTLE THINGS LITTLE THINGS (L ocal I rregulars T hat T race L uminosity E xtremes T he HI N earby G alaxy S urvey) - THINGS-like (~6 ; < 5.2 km/s) high-resolution VLA HI 21cm survey (B+C+D; 376 hours) for 41 nearby (< 10 Mpc) dwarf (dim, BCD) galaxies - Commensality with Spitzer (+ Herschel) optical, GALEX uv, CO data etc.) - VLA observations ended in Further observations with EVLA, CARMA, APEX etc.

10 LITTLE THINGS science - What regulates star formation in dwarf galaxies? - What is the relative importance of sequential triggering for star formation in dwarf galaxies? - How (dark) matter is distributed in dwarf galaxies? - What is the relative importance of triggering by random turbulence compression in dwarf galaxies? - What is happening in the far outer parts of dwarf galaxies? - What happens to the star formation process at breaks in the exponential light profiles? - What happens in Blue Compact Dwarf (BCD) galaxies?

11 LITTLE THINGS sample CVnIdwA DDO 43 DDO 46 DDO 47 DDO 50 DDO 52 DDO 53 DDO 63 DDO 69 DDO 70 DDO 75 DDO 87 DDO 101 DDO 126 DDO 133 DDO 154 DDO 155 DDO 165 DDO 167 DDO 168 DDO 187 DDO 210 DDO 216 F564-V3 IC 10 IC 1613 LGS3 M81dwA NGC 1569 Mrk 178 NGC 2366 NGC 3738 NGC 4163 NGC 4214 NGC 6822 SagDIG UGC 8508 WLM Haro 29 Haro 36 VIIZw 403

12 LITTLE THINGS sample CVnIdwA DDO 43 DDO 46 DDO 47 DDO 50 DDO 52 DDO 53 DDO 63 DDO 69 DDO 70 ` DDO 75 DDO 87 DDO 101 DDO 126 DDO 133 DDO 154 DDO 155 DDO 165 DDO 167 DDO 168 DDO 187 DDO 210 DDO 216 F564-V3 IC 10 IC 1613 LGS3 M81dwA NGC 1569 Mrk 178 NGC 2366 NGC 3738 NGC 4163 NGC 4214 NGC 6822 SagDIG UGC 8508 WLM Haro 29 Haro 36 VIIZw 403

13 DDO IC Cvn I dwa 2 kpc DDO 87 HI images of 27 LITTLE THINGS 3 kpc DDO 168 DDO 101 DDO 126 DDO 216 Haro 29 DDO 8508 UGC 168 DDO 46 F564-V3 DDO 52 DDO 43 DDO 133 DDO DDO 70 NGC 2366 DDO 50 DDO 63 DDO 53 DDO 154 NGC 1569 DDO DDO 168 WLM NGC 4214 NGC 3738 DDO IC DDO 168 X 2

14 IC 10 Cvn I dwa HI images of 27 LITTLE THINGS Haro 29 DDO 87 3 kpc DDO 168 DDO 101 DDO 126 DDO 216 DDO 8508 UGC 101 DDO 168 DDO 133 DDO 46 F564-V3 DDO 52 DDO 43 DDO 70 NGC 2366 DDO 50 DDO 63 DDO 53 DDO 154 NGC 1569 DDO 210 WLM NGC 4214 NGC 3738 IC 1613 DDO 47

15 DDO IC Cvn I dwa 2 kpc DDO 87 HI images of 27 LITTLE THINGS 3 kpc DDO 168 DDO 101 DDO 126 DDO 216 Haro 29 DDO 8508 UGC 168 DDO 46 F564-V3 DDO 52 DDO 43 DDO 133 DDO DDO 70 NGC 2366 DDO 50 DDO 63 DDO 53 DDO 154 NGC 1569 DDO DDO 168 WLM NGC 4214 NGC 3738 DDO IC DDO 168

16 DDO IC Cvn I dwa Haro 29 IRAC1 images of 27 LITTLE THINGS DDO 87 3 kpc DDO 168 DDO 101 DDO 126 DDO UGC 8508 DDO 133 DDO 46 F564-V3 DDO 52 DDO 43 DDO 70 NGC 2366 DDO 50 DDO 63 DDO 53 DDO 154 NGC 1569 DDO 210 WLM NGC 4214 NGC 3738 IC 1613 DDO 47

17 I. Data Tilted-ring models + Fit tilted-ring models to 2-D velocity fields (e.g., Rogstad et al. 1974; rotcur in GIPSY) Suited for well-resolved galaxies with moderate inclinations

18 II. Rotation curves & Asymmetric drift correction Tilted-ring models + - Fit tilted-ring models to 2D velocity field (Rogstad et al. 1974; e.g., rotcur in GIPSY) Asymmetric drift correction - Gas drift correction (mainly) for the outer regions (Bureau & Carignan 2002)

19 III. Position-velocity diagram ` `

20 III. Mass models of baryons stars gas TR models + +

21 IV. Decomposition of baryonic disk and dark matter halo Mass modelling of 27 LITTLE THINGS dwarf galaxies using VLA HI data, Spitzer 3.6 micron and ancilliary optical images

22 Comparison with THINGS + Simulations Rotation curve shape DM density profiles yti col ev noi t at o R DM density Radius Radius Radius Oh et al. (2011)

23 Comparison with THINGS + Simulations Rotation curve shape DM density profiles yti col ev noi t at o R DM density Radius Radius Radius Oh et al. in prep.

24 Comparison with THINGS + simulations Rotation curve shape The rotation curves are scaled with respect to the V0.3 at R0.3 where dlogv/dlogr = 0.3. The scaled rotation curves rise too slowly to match the cuspy CDM halos. Instead, they are mostly consistent with core-like pseudo isothermal halo models showing a linear increase in the inner rotation curves. yti col ev noi t at o R Radius

25 Comparison with THINGS + Simulations DM density profiles The mean value of the slopes of 17 L.T. Galaxies except 5 THINGS dwarfs, α= 0.40 ± 0.07 is consistent with the value of α = 0.29 ± 0.07 found from 7 THINGS dwarf galaxies in Oh et al. (2011). cusps α ~ -1.0 This is in contrast with the steep slope of α -1.0 predicted from ΛCDM (DM only) simulations. yti s n e d MD The core-like DM distributions of L.T. Galaxies are similar to those of new simulations which include baryonic feedback processes. Radius

26 yti s n ed r enni eli for p MD Slope vs. Stellar Mass Stellar Mass See Governato et al. 2012

27 Summary High-quality multi-λ data (VLA HI, Spitzer 3.6μm and optical data) from LITTLE THINGS significantly reduce the observational uncertainties and allow us to derive a more accurate dark matter distribution The rotation curve shape and inner mass density slopes of LITTLE THINGS are mostly consistent with those of new simulations including baryonic feedback processes as well as THINGS dwarf galaxies. The mean of inner density slopes of 24 THINGS+LITTLE THINGS dwarf galaxies is α= 0.37±0.13 which is consistent with α= 0.2±0.2 found from LSB galaxies (de Blok et al. 2002) but significantly deviating from ~ 1.0 predicted from dark-matter-only ΛCDM simulations The central DM distribution of 24 dwarf galaxies from LITLE THINGS + THINGS appears to be cored. Low mass dwarf galaxies will be the key for the complete discussion of the cusp/core controversy.