Plenary Talk - Malta October 2017 #MaltaGiG Joss Bland-Hawthorn - PowerPoint PPT Presentation

Plenary Talk - Malta October 2017 #MaltaGiG

Joss Bland-Hawthorn ASTRO 3D Centre of Excellence SIfA, University of Sydney

u Lessons learned in this decade from the near field u Gas accre:on onto L* galaxies #MaltaGiG

� Stellar Mass & Baryon TF on same scaling rela:on for stars + gas SAMI survey: Cortese+ 2014, 1016 – large homogeneous IFS samples Kassin+ 2007

u One or two dominant spirals per group is the norm locally. M ≥ 10 12 M � virial radius decoupling E = 0 There’s nothing unusual about the Local Group, but it is a quiescent region within Lanikea . Corollary: binarity of L* galaxies (Sharma+ 2005, 2012) Kourkchi & Tully 2017

(2010) � Who needs stellar bulges ? Don’t we expect merger-built bulges in CDM? They don’t seem important within 8 Mpc of the LG. Few classical bulges in L* galaxies, but we’re in a quiescent region on supergalac^c scales.

We need a more nuanced understanding of environment. Our es^mators are based on sta^s^cal crowding. This may mean matching our best simula^ons with the best near field observa^ons. Going back to Kormendy’s claim, bulges are not essen:al elements of disk forma:on. Pichon 2017

� But old, red, thick disks appear to be the norm Yoachim & Dalcanton 2006 Do thick disks relate to high-z turbulent disks ? The Galaxy Bensby+ 2014

� Galaxy gas disks, like many NGC 3198 stellar disks, keep on going, Maloney 1993 and do not always truncate Kalberla & Dedes 2008

M31-M33 HI bridge Braun & Thilker 2004 Wolfe+16

“In search of cool flow accre^on onto galaxies – where does the gas disk end?” JBH et al 2017, 1709.08733 High cosmic UV background NGC 2997 Maloney 1993

� Gas inflows are hard to observe, Putman+ 98 but unequivocal in the nearest L* galaxies with HVCs, HI streams Deep observa^ons reveal 4x more cool to warm gas (Putman+ 12, Fox+ 14), s^ll not enough to sustain SFR today. Besla+ 10 We rarely, if ever, see Dekel-like cold streams that hit the disk. The gas breaks down high in the halo (d’Onghia & Fox 16).

NGC 891: prior inflow that has already cooled ? HI: <0.3 M � yr -1 (Oosterloo+ 2007) X-rays: <0.4 M � yr -1 (Hodges-Kluck+ 2016) Som X-ray emissivity today too low to EUV: <0.1 M � yr -1 (Miller+ 2000) explain 30 kpc HI feature ~ 2x10 7 M �

� Large-scale wind in the Galaxy: X: JBH & Cohen 2003 γ: Su et al 2010 “Galaxy scale ouplows (>10 56 erg) may be much more UV: Fox et al 2015 common than inferred so far, just difficult to detect.” HI: Lockman & NMG 2016

The biggest surprises are coming from the hot halo ?

� Hot halos are now detected in massive spirals Anderson & Bregman 2011, 2015 Li et al 2016 Gas accre:on rate < 0.4 M ¤ yr -1 in most massive systems (V rot ~ 400 km s -1 ), not enough to supply SFR

� The CGM and lower hot halo are complex regions, difficult to observe and to model Tumlinson, Peeples, Werk (2017) Most of the gas accre:on is sub-virial ? EAGLE (Schaye+ 15) Does not explain OVIII.

� Extraordinary claims on hidden baryonic mass The hot, metal rich halo dominates the baryon mass in the Galaxy. If this is true, accre^on from inefficiently cooling, hot halo may be viable for building disks since plenty of mass over a Hubble ^me. But what about J ?

Bertone+ 2013, same story with cosmic ^me

� Extraordinary claims on hidden ang. momentum RECAP Theory: TTT ensures DM and gas have iden^cal AMD in virialized systems (Fall & Efstathiou 1980). Gas conserves j = J/M during cooling (Mestel 1963). � R d α λ R vir CDM simula:ons (above) : Self-similar spin distribu^on for DM and cooling hot gas, no feedback (van den Bosch+ 2002).

� Extraordinary claims on hidden ang. momentum This unexpected value implies λ ≈ 0.25 Using different approaches, Pezzulli, Fraternali & Binney (2017), Tepper-Garcia & JBH (2017) find fast, hot, stable halos are very difficult to construct. Something has to give. Pezzulli+ 2017

Self-similar spin distribu:on broken in presence of feedback – SN in low mass galaxies, AGN in high mass galaxies (Zjupa <10 11 M ¤ & Springel 2017). <λ> ~ 0.08 averaged over all baryons for L* galaxies. 10 11-12 M ¤ Zjupa & Springel are unsure how the gas acquires the spin – mergers, gas/DM interac^on? – in the Illustris simula^ons. >10 12 M ¤

How to build an arbitrarily high resolu^on, mul^-phase Galaxy CDM simula^ons are properly mo^vated but far too grainy. The constructed Galaxy can be used to study how gas breaks down in a fully MHD environment with a Galac^c magne^c field (A. Grønnow, PhD)

λ =0.08 RAMSES (Tepper-Garcia) Galactic parameters (ARAA 54) Z hot = 0.3 Z �� Static or live halo, constant mass Note hot halo non-spherical

By construction, impose hot halo spin at start, no SF/AGN feedback 23.0 RAMSES Milky Way model. Consider a DM halo filled with T vir ~10 6 K gas with prescribed amount of J . Allow 22.0 gas to cool and conserve J / M over Hubble time. Rotationally supported disk with correct mass forms 21.0 inside-out, scalelength set by spin. We never observe the correct EUVX emissivity to explain baryon disk. surface density [cm -2 ] 20.0 did not evolve λ =0.08 long enough 19.0 18.0 Standard λ =0.04 in CDM halos, i.e. 30 km s -1 hot halo gas. 17.0 λ =0.08 is consistent with Galactic HI, 16.0 both R d and total extent. AMR 15.0 true (exp[ -R/R d ]; R d = 7 kpc) 14.0 Kalberla & Dedes (2008) 13.0 0 10 20 30 40 50 60 70 80 Tepper-Garcia & JBH 2017 R (kpc)

λ=0.08 seems ~consistent with the Galaxy’s disk baryon content λ > 0.12 starts to break down 10% too low Faerman needs to raise curve by 0.6 dex Tepper-Garcia & JBH 2017

Coherent accre^on paradigm

Wher Where does a galaxy’ e does a galaxy’s spin come fr s spin come from ? om ?

Spin-up fr Spin-up from local tidal tor om local tidal torques ques ≤ 1 Mpc scale Grey shows domain of Q Tidal torque theory (Hoyle 1953)

Spin-up fr Spin-up from long-range tidal for om long-range tidal forces in filaments ces in filaments Local Group lives along one such filament extending to Virgo

This filament extending to a rich This filament extending to a rich gr group is clear oup is clearer in velocity space er in velocity space

Euler (fixed) vs Lagrange (co-moving) frame Three flow axes can project to rotation in the co-moving frame, an effect which is amplified by gravity. Thus, the size of the (low order) vorticity is roughly the Hubble Flow parameter. The effect increases with cosmic time. But vorticity is carried down to smaller scales…

100 3 Mpc 3 includes gas, AGN etc. (RAMSES: Teyssier et al) Critical mass where it switches over decreases with redshift (~10 12 M � today) More gas supply at higher z, but more vortex action today, delayed accretion. LSS connection goes back to: Katz+03; Birnboim & Dekel 03; Keres+05; Ocvirk+08 Codis+12,15; Dubois+14; Laigle+15; Chisari+16

Vort orticity icity ω = x v Δ ω ~ 100 km s -1 Mpc -1 cold flow down the filament Codis+12: motion down filament in co- moving frame generates spin. Local | vorticity sets up in plane __ to filament.

We use the SAMI mass distribution to simulate the expected signal for the Hector survey: SAMI : 3600 gals in 0.6 x 100 3 Mpc 3 (1dF: 2015-18) Hector-1: 20000 gals in 2 x 100 3 Mpc 3 Bryant+15 (2dF: 2019-23) Hector-2: 60000 gals in 6 x 100 3 Mpc 3 (3dF: unfunded)

New work from Sandrine Codis A (see also Codis+15) Signatures at z~1, want to extend to z~0. A: galaxy spin aligns with tidal tensor (e 1 points down filament) for low mass galaxies, opposite for high mass. B: blue galaxies align, red galaxies not so much. C: tensor contribution mostly < 3 Mpc but Align Perp. detectable to 10 Mpc. B Same volume as SAMI Same volume as SAMI but 20x more galaxies; but 20x mor e galaxies; some cosmic variance. some cosmic variance. If true, some galaxy If true, some galaxy C propert pr operties ar ies are af e affected fected by lar by largest scales. gest scales.

Integral field spectroscopy Integral field spectroscopy is giving us a new angle on environmental effects. But we need “cosmological” “cosmological” samples across large-scale structure at high density, cf. Stripe 82. 16000 galaxies to r p ~ 17.7 (3 o thick) STRIP IPE 82: 82:

Planned IFS surveys will get us to ~10 5 galaxies within a decade. The biggest omission is the lack of HI observa:ons for similar or larger samples…

Gas supply – missing ingredient in all surveys: Deep 21cm ( ≤ 10 19 cm -2 ) maps of nearby galaxies & groups only exist for small samples ~ 1000 galaxies. Austral Australian surveys wil ian surveys will del l deliver ~10 iver ~10 5 galaxies galaxies Deepest to date: M31-M33 map Deepest to date: wit within 3 yr hin 3 yr, ~10 , ~10 6 galaxies wit galaxies within 7 yr hin 7 yr. . reaches ~10 17 cm -2 (Wolfe+16). ASKAP 36 dishes Wallaby, Dingo surveys