Galaxy rotation curves in 2020s

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1 Galaxy rotation curves in 2020s Se-Heon OH (Korea Astronomy & Space Science Institute) Note some images in the slides taken from internet, belonging to respective owners...

2 I. Galaxy rotation curves ~25 min II. Dark matter distribution in galaxies ~15 min III. Square Kilometre Array (SKA) ~10 min IV. Q &A ~10 min 2/68

3 I. Galaxy Rotation Curves 3/68

4 Galaxy formation & evolution: a key towards understanding the cosmic history of the Universe 4/68

5 Galaxy? 5/68

6 Galaxy? 6/68

7 Galaxy? M31 7/68

8 Galaxy? M87 M31 8/68

9 Galaxy? DDO 210 9/68

10 Galaxy? M87 M80 DDO /68

11 Galaxy? M87 Sextans B M80 DDO /68

12 Galaxy? NGC /68

13 Galaxy? VirgoH21 13/68

14 Galaxy? VirgoH21 M. Hilker, 2.5-Meter du Pont Teleskop (Las Campanas Observatory); (insets) M. Drinkwater, Hubble Space Telescope 14/68

15 Galaxy? How do we define a galaxy? : luminosity? : morphology? : size? : mass? 15/68

16 Galaxy? Forbes & Kroupa 16/68

17 Galaxy? na y D cs mi i m e h st er t t a!!! Forbes & Kroupa (PASA, 2011) 17/68

18 Galaxy Rotation Galaxies form via collapse of (baryonic + non-baryonic) matter due to gravity By the conservation of angular momentum (vr = const), the galaxy rotation increases as it collapses When the gravitationally equilibrium is eventually reached: Gravitational force = Rotational force 18/68

19 Galaxy Rotation Inward force: Gravity f g= GMm 2 r mv 2 f c= Outward force: Centripetal r where v is the rotation velocity at radius r mv 2 GMm = 2 r r v (r)= GM r v2 r M (r )= G 19/68

20 Mass distribution M(r) The surface brightness of a disc galaxy is given by σ (r)=σ 0 e r /h Mass within the galaxy radius r is derived rr M (r )=2 π ρ0 dr r e r /h r 0 R / h)] M (r )=2 π ρ0 h2 [1 e r / h (1+r R by assuming a constant M/L, dr ρ(r)=ρ0 e r /h 20/68

21 A predicted rotation curve from Newtonian dynamics v (r)= GM r M (r )=2 π ρ0 h2 [1 e r / h (1+r / h)] r / h 1 e (1+r /h) 2 v (r)= 2π G ρ0 h r, which rises steeply to peak near r/h~2 and then falls of 21/68

The observed galaxy rotation curve In the 1970s, Rubin showed that speed at which stars orbit around the centres of spiral galaxies remains high even at the outskirts.

22 The observed galaxy rotation curve In the 1970s, Rubin showed that speed at which stars orbit around the centres of spiral galaxies remains high even at the outskirts. This contradicts the Newtonian theory of gravitation, which predicts that the speeds of distant stars should fall off as the pull of gravity declines, just as the farthest planets in the Solar System orbit more slowly around the Sun than do closer ones 22/68

23 The observed galaxy rotation curve 23/68

24 The observed galaxy rotation curve In the late 1970s, the flat rotation curves of spiral galaxies were further reached out beyond the stellar disc by tracing motions of HI gas using interferometers like VLA and WSRT All the resulting rotation curves traced in HI were flat and, or even rising in the outermost part of some galaxies (e.g., Albert Bosma, PhD thesis 1978) implies (an) additional mass component(s) to the galactic mass If it is spherically distributed, dm (r)=4 π ρ r 2 (r) dr r M (r )=4 π dr ρ(r)r ρ(r) 1 r /68

25 The observed galaxy rotation curve In the late 1970s, the flat rotation curves of spiral galaxies were further reached out beyond the stellar disc by tracing motions of HI gas using interferometers like VLA and WSRT All the resulting rotation curves traced in HI were flat and, or even rising in the outermost part of some galaxies (e.g., Albert Bosma, PhD thesis 1978) implies (an) additional mass component(s) to the galactic mass If it is spherically distributed, dm (r)=4 π ρ r 2 (r)dr r M (r )=4 π dr ρ(r)r ρ(r) 1 r /68

Deriving kinematics Bulge Stellar disc Gas

cm is often used for measuring the dynamics of

poor galaxies like elliptical and spherical

26 Deriving kinematics Bulge Stellar disc Gas disc Observe either emission or absorption lines from stars or gas in the ISM The emission line of neutral hydrogen (HI) at 21 cm is often used for measuring the dynamics of spiral and irregular gas rich galaxies For gas poor galaxies like elliptical and spherical galaxies, velocity dispersions of stars are instead used 26/68

Additionally, can derive the HI mass of the galaxy directly: 2.

27 Integrated/(spatially) unresolved HI global profiles The recessional velocity gives a measure of how distant galaxy is d (Mpc) ~ V (km/s) / H0 W50 ~ 2 Vmax sin(i) Additionally, can derive the HI mass of the galaxy directly: D 2Mpc M HI = dv S ( v) 1+ z where v is in km/s and S(v) is in Jy The HI mass to luminosity ratio (MHI/L) 27/68

28 Integrated/(spatially) unresolved HI global profiles Parkes Telescope, NSW, Australia 28/68

29 Deriving kinematics: interferometric HI observations Very Large Array, Socorro, New Mexico 29/68

30 (spatially) resolved HI profiles : moment analysis of spectral pixels (spaxels) Moment 1: central velocities Moment 0: Integrated intensities Moment 2: Velocity dispersions Australia Telescope Compact Array 30/68

31 (spatially) resolved HI profiles : multiple Gaussian decomposition Profile decomposition of an asymmetric non-gaussian velocity profile 31/68

32 The Large Magellanic Cloud : multiple Gaussian decomposition A color composite image of the Large Magellanic Cloud from Spitzer SAGE (blue: 3.6 micron Green: 8 micon Red: 24 micron) Oh et al. in prep. 32/68

33 II. Dark matter distribution in galaxies 33/68

34 Small-scale crisis in ΛCDM cosmology Missing satellites Angular momentum Central density 34/68

35 The 'cusp/core' problem 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) Ogiya et al. (2013) Ishiyama et al. (2013) DM halo : cusp α ~ -1.0 ρ R α DM density Rotation Velocity Galaxy Radius 35/68

The 'cusp/core' problem 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.

0 DM halo : core α ~ 0.0 ρ R α DM density 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.

36 The 'cusp/core' problem 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) Ogiya et al. (2013) Ishiyama et al. (2013) SIMULATIONS OBSERVATIONS DM halo : cusp α ~ -1.0 DM halo : core α ~ 0.0 ρ R α DM density 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) McGaugh et al. (2007) Gentile et al. (2007) Oh et al. (2008) de Blok et al. (2008) de Blok (2009) Oh et al. (2011a, b) Hague & Wilkinson (2013) Kuzio de Naray (2014) Adams et al. (2014) Oh et al. (2015) Rotation Velocity Galaxy Radius Galaxy Radius 36/68

37 The HI Nearby Galaxy Survey (THINGS) See THINGS AJ Special issue (~6 ;(2008) 5.2 km/s; ~500 hours) VLA HI 21-cm survey nearby (< 10 Mpc) 34 galaxies VLA of Spitzer GALEX Commensality with optical, Spitzer SINGS, GALEX uv, CO data etc.) All observations ended in late 2005 Data available at Visit IRAM Optical ` 37/68

38 The HI Nearby Galaxy Survey (THINGS) 38/68

39 The HI Nearby Galaxy Survey (THINGS) 39/68

40 The HI Nearby Galaxy Survey (THINGS) 40/68

6 km/s) high-resolution deep VLA HI survey (B+C+D, 376 hours) of 41 nearby (< 10 Mpc) dwarf galaxies Commensality with optical, IR, UV and

41 LITTLE THINGS (Local Irregulars That Trace Luminous Extremes The HI Nearby Galaxy Survey) LITTLE THINGS poster HI (red) V (green) FUV (blue) VLA HI CARMA THINGS-like (~6, <2.6 km/s) high-resolution deep VLA HI survey (B+C+D, 376 hours) of 41 nearby (< 10 Mpc) dwarf galaxies Commensality with optical, IR, UV and CO observations Star formation, ISM, mass distribution & interaction among them Follow-up observations with CARMA / APEX / ALMA / GBT / KVN / Gemini / JCMT etc. Herschel Spitzer Optical GALEX GBT ALMA KASI-CNU KASI 15/Oct/ /68

42 Sample galaxies LITTLE THINGS poster 26 sample galaxies, circular rotation dominated HI (red) V (green) FUV (blue) KASI-CNU KASI 15/Oct/ /68

43 Sample galaxies LITTLE THINGS poster 26 sample galaxies, circular rotation dominated HI (red) V (green) FUV (blue) KASI-CNU KASI 15/Oct/ /68

44 44/68

45 45/68

46 46/68

47 Dark matter distribution in dwarf galaxies HI (red) V (green) FUV (blue) 47/68

48 Modelling the line-of-sight velocities of a galaxy : orbital motion (precession & nutation) + proper motion (transverse velocity) + internal kinematics Precession + Nutation + Internal rotation Transverse velocity 48/68

(transverse velocity) + internal kinematics Precession

49 Modelling the line-of-sight velocities of a galaxy : orbital motion (precession & nutation) + proper motion (transverse velocity) + internal kinematics Precession + Nutation + Internal rotation Transverse velocity 49/68

50 50/68

1974) An example of conventional TR analysis where Oh et

51 Deriving galaxy rotation curves: (2D) Tilted-ring analysis 2D tilted-ring model (Rogstad et al. 1974) An example of conventional TR analysis where Oh et al. (2009) XPOS VSYS PA YPOS INCL VROT NGC 5055 (Battaglia et al. 2005) 51/68

52 Disk-halo decomposition of galaxies = Mtotal = + Mgas + Rotation velocity = V2gas total gas Mstar + M/L(3.6 micron) based on SPS 1.4 MHI V2total? + + V2star stars + Mhalo cusp or core? V2halo halo Galaxy radius 52/68

53 Dark matter distribution in dwarf galaxies : THINGS + LITTLE THINGS + SPH+N-body ΛCDM simulations 7 THINGS + 26 LITTLE THINGS Rotation curve shape (Rotation velocity) cusps α ~ -1.0 cores α ~ -0.3 (Galaxy Radius) KASI-CNU KASI 15/Oct/2012 (Galaxy Radius) 53 Oh et al. (2008; 2011a; 2011b; 2015) See also Governato et al. (2012) 53/68 (DM density) DM density profile

54 SN-feedback on the central cusps in CDM haloes (Inner density slope α) cusp core : Observations vs. simulations In low mass haloes: SN-feedback gets less efficient so cores at fixed radius get smaller (cuspy) In intermediate mass haloes: SN-feedback is efficient enough to change the cusps into cores In high mass haloes: SN-feedback is surpassed by the deep gravitational potential caused by stars in the central region (halo contraction rather than expansion) Low-mass dwarfs are the key for the ultimate test of the SNfeedback scenario in ΛCDM simulations low mass haloes high mass haloes (Stellar mass) Oh et al. (2015); see also Pontzen & Governato (Nature, 2014) 54/68

55 SN-feedback on the central cusps in CDM haloes (Inner density slope α) cusp core Observational selection effect? : Observations vs. simulations In low mass haloes: SN-feedback gets less efficient so cores at fixed radius get smaller (cuspy) In intermediate mass haloes: SN-feedback is efficient enough to change the cusps into cores In high mass haloes: SN-feedback is surpassed by the deep gravitational potential caused by stars in the central region (halo contraction rather than expansion) Low-mass dwarfs are the key for the ultimate test of the SNfeedback scenario in ΛCDM simulations low mass haloes high mass haloes (Stellar mass) Oh et al. (2015); see also Pontzen & Governato (Nature, 2014) 55/68

56 III. Square Kilometre Array (SKA) 56/68

57 Square Kilometre Array (SKA) The largest radio telescope array in the 21st, with the total collecting area over 1,000,000 square metres Initiated by the Large Telescope Working Group at the international Union of Radio Science (URSI) in 1993 Aimed at observing EM waves (50 MHz ~ 15 GHz) in the Universe since the cosmic re-ionization, covering a wide range of science: - chronological distribution of HI in the Universe - large scale structure (~1010 pc) - origin of life (~10-10 pc) /68

58 SKA Key Science Cosmic dark age & recombination era Galaxy formation/evolution, cosmology & dark energy Origin of comic magnetism & its evolution Strong-field tests of gravity using pulsars & black holes Origin of life 58/68

59 SKA key specifications needed SKA phase I design reference 50 MHz ~ 15 GHz ~ 15m x 2,000 dishes + ~1,000,000 dipoles in a spiral layout design 59/68

~130,000 aperture arrays (dipoles) - maximum baseline : 65 km + ASKAP (12m x 36) - 350 MHz 14 GHz -

60 SKA hosting to be split: South Africa + Australia (decision made in 2012) Australia + New Zealand South Africa + 8 African countries + SKA1 LOW ( ) SKA1 MID ( ) - 50 MHz 350 MHz - ~130,000 aperture arrays (dipoles) - maximum baseline : 65 km + ASKAP (12m x 36) MHz 14 GHz - 15x200 dishs - maximum baseline: 150 km + MeerKAT (13.5m x 64) SKA2 LOW (> 2023) SKA2 MID (> 2023) 60/68

61 Square Kilometre Array (SKA) : movie 61/68

62 SKA timeline & cost SKA 1 ( ) SKA 2 ( ) 10% of the full SKA 100% of the full SKA Low-mid frequencies focused High-frequency antennas AUS: ~500 stations with 250 dipoles each AUS: ~1,000,000 dipoles SA: ~15m x 200 dishes SA: ~2000 dishes Pre-construction (~ 150M) SKA 1 ~ ( 650M) SKA 3 (> 2034) (~ 1.5B) + Extended to higher frequencies Will be in operation over 50 years? 62 62/68

63 Finding & paving the way to the SKA1 : SKA pathfinders Australian SKA Pathfinder (ASKAP) : 12m x 36 South African Karro Array Telescope (MeerKAT) : 13.5m x 64 Westerbork Synthesis Radio Telescope (WSRT) Apertif : 25m x 14 Five hundred meter Aperture Spherical Telescope (FAST) : 500m Murchison Widefield Array (MWA) + PAPER : 256 tiles of dipoles will open a new golden age for HI science for the next decade... 63/68

ASKAP large survey proposals PAF (radio camera) 12m x 36 dishes, 10 30 beam (up to 6 km

8 GHz (32,768 channels over 300 MHz BW) 188 phase array elements 30 deg2 FOV Continuum &

start from early 2017 10 ASKAP Large Survey Projects Evolutionary Map of the Universe (EMU)

Survey in HI (FLASH) An ASKAP Survey for Variables and Slow Transients (VAST) The Galactic

(POSSUM) The Commensal Real-time ASKAP Fast Transients survey (CRAFT) Deep Investigations of

64 ASKAP large survey proposals PAF (radio camera) 12m x 36 dishes, beam (up to 6 km baseline) 700 MHz 1.8 GHz (32,768 channels over 300 MHz BW) 188 phase array elements 30 deg2 FOV Continuum & spectral lines 12 Phased Array Feeds (PAFs) installed ASKAP-12 early science observation will start from early ASKAP Large Survey Projects Evolutionary Map of the Universe (EMU) Widefield ASKAP L-Band Legacy All-Sky Blind Survey (WALLABY) The First Large Absorption Survey in HI (FLASH) An ASKAP Survey for Variables and Slow Transients (VAST) The Galactic ASKAP Spectral Line Survey (GASKAP) Polarization Sky Survey of the Universe's Magnetism (POSSUM) The Commensal Real-time ASKAP Fast Transients survey (CRAFT) Deep Investigations of Neutral Gas Origins (DINGO) The High Resolution Components of ASKAP: Meeting the Long Baseline Specifications for the SKA (VLBI) Compact Objects with ASKAP: Surveys and Timing (COAST) 64/68

5 GHz (32,768 channels over 300 MHz BW) Continuum & spectral lines MeerKAT AR1 (16 dishes) will start its early science observation from early 2017 10 MeerKAT Large Survey Projects Radio Pulsar

65 MeerKAT large survey proposals This is not a CG but a real photo! 13.5m x 64 dishes, 8 beam over 1.8 deg2 FOV Antenna layout: a dense inner component (70%) + an outer component (30%) over 30m to 8 km 580 MHz 14.5 GHz (32,768 channels over 300 MHz BW) Continuum & spectral lines MeerKAT AR1 (16 dishes) will start its early science observation from early MeerKAT Large Survey Projects Radio Pulsar Timing: Testing Einstein's theory of gravity and gravitational radiation LADUMA (Looking at the Distant Universe with the MeerKAT Array) MESMER (MeerKAT Search for Molecules in the Epoch of Re-ionisation) MeerKAT Absorption Line Survey for atomic hydrogen and OH lines in absorption against distant continuum sources MHONGOOSE (MeerKAT HI Observations of Nearby Galactic Objects: Observing Southern Emitters) TRAPUM (Transients and Pulsars with MeerKAT) A MeerKAT HI Survey of the Fornax Cluster (Galaxy formation and evolution in the cluster environment) MeerGAL (MeerKAT High Frequency Galactic Plane Survey) MIGHTEE (MeerKAT International GigaHertz Tiered Extragalactic Exploration Survey) ThunderKAT (The Hunt for Dynamic and Explosive Radio Transients with MeerKAT) 65/68

WSRT Apertif large survey proposals This is not a CG but a real

25m x 14 dishes with Apertif : being upgraded to an HI survey

7 GHz (16,384 channels over 300 MHz) Early science observations

telescope in northern sky comparable to ASKAP A large area,

emission covering ~3500 deg2 A medium-deep imaging survey of HI

66 WSRT Apertif large survey proposals This is not a CG but a real photo! 25m x 14 dishes with Apertif : being upgraded to an HI survey telescope with FOV of ~8 deg2; ~15 beam GHz (16,384 channels over 300 MHz) Early science observations has started from early 2017 Apertif large surveys An HI survey telescope in northern sky comparable to ASKAP A large area, shallow imaging survey of HI and polarised radio continuum emission covering ~3500 deg2 A medium-deep imaging survey of HI and polarsised radio continuum emission covering ~450 deg2 A time domain survey for pulsars and fast transients over 15,000 deg2 Follow-up of some LOFAR fields 66/68

67 Resolved kinematic analysis of galaxies (from HI surveys) 1970s 1990s 2010s 2020s onwards 25 spiral galaxies from WSRT observations (Bosma 1978) 21 spirals in the center of Virgo Cluster from VLA observations (Guhathakurta & van Gorkom 1988) 25 late-type and dwarf galaxies from WSRT WHISP (Swaters 1999) 30 spirals in the Ursa Major Cluster from WSRT observations (Verheijen 1997) 21 late-type and dwarf galaxies from VLA THINGS (de Blok et al. 2008; Oh et al. 2008) 52 dwarf galaxies from GMRT FIGGS (Begum et al. 2008) 33 dwarf galaxies from VLA THINGS + LITTLE THINGS (Oh et al. 2011; Oh et al. 2015) 24 spirals from WSRT HALOGAS (Heald et al. 2011) 26 late-type and dwarf galaxies from ATCA LVHIS (Kamphuis et al. 2015; Oh et al. 2018) 35 dwarf galaxies from VLA-ANGST (Ott et al. 2012) 12 dwarf galaxies from VLA SHIELD (McNichols et al. 2016) 300 SAMI galaxies from GMRT follow-up observations (Kamphuis et al.) 28 sprial galaxies from ATCA IMAGINE (Popping et al.) > 10,000 resolved galaxies from SKA pathfinders surveys (ASKAP, MeerKAT & Apertif) need to prepare for the unprecedented data flow from the upcoming 3D spectroscopic galaxy surveys including SKA pathfinders large surveys 67/68

Resolved kinematic analysis of galaxies (from HI surveys) 1970s 1990s 2010s 2020s onwards 25 spiral galaxies from WSRT observations (Bosma 1978) 21 spirals in the center of Virgo Cluster from VLA

68 Resolved kinematic analysis of galaxies (from HI surveys) 1970s 1990s 2010s 2020s onwards 25 spiral galaxies from WSRT observations (Bosma 1978) 21 spirals in the center of Virgo Cluster from VLA observations (Guhathakurta & van Gorkom 1988) 25 late-type and dwarf galaxies from WSRT WHISP (Swaters 1999) 30 spirals in the Ursa Major Cluster from WSRT observations (Verheijen 1997) 21 late-type and dwarf galaxies from VLA THINGS (de Blok et al. 2008; Oh et al. 2008) 52 dwarf galaxies from GMRT FIGGS (Begum et al. 2008) 33 dwarf galaxies from VLA THINGS + LITTLE THINGS (Oh et al. 2011; Oh et al. 2015) 24 spirals from WSRT HALOGAS (Heald et al. 2011) 26 late-type and dwarf galaxies from ATCA LVHIS (Kamphuis et al. 2015; Oh et al. 2018) 35 dwarf galaxies from VLA-ANGST (Ott et al. 2012) 12 dwarf galaxies from VLA SHIELD (McNichols et al. 2016) 300 SAMI galaxies from GMRT follow-up observations (Kamphuis et al.) 28 sprial galaxies from ATCA IMAGINE (Popping et al.) Popping et al.ska pathfinders surveys (ASKAP, MeerKAT & > 10,000 resolved galaxies from Apertif) need to prepare for the unprecedented data flow from the upcoming 3D spectroscopic galaxy surveys including SKA pathfinders large surveys 68/68

Central dark matter distribution in dwarf galaxies

Central dark matter distribution in dwarf galaxies Se-Heon Oh (ICRAR/UWA) Content cusp/core controversy in ΛCDM simulations Dark matter distribution of THINGS dwarf galaxies High-resolution N-body+SPH