Galaxy Formation and Evolution: Hubbles Legacy ! achel somervi - - PowerPoint PPT Presentation

Galaxy Formation and Evolution: Hubble’s Legacy

!achel somervi"e# $utgers Universi%#

high resolution deep imaging surveys

HDF (N&S) GOODS GE MS HUDF AE GI S COSMOS CL ASH

Szo mo ru e t a l. 2012 HST a llo ws us to study a nd disse c t g a la xy struc tura l pro pe rtie s fo r statistic ally

ro bust sample s:

• size (e ffe c tive ra dius)
• sha pe o f lig ht pro file (Se rsic )
• lig ht c o nc e ntra tio n
• fra c tio n o f lig ht in a ‘ sphe ro id’
• vs. ‘ disk’ (“b ulg e -disk de c o mpo sitio n”)
• c o lo r g ra die nts

c a n e ve n c o nstruc t ste llar mass maps ste lla r ma ss we ig hte d e ffe c tive ra dius B/ T , Se rsic , e tc …

Brinc hma nn e t a l. 2003

global and structural properties are correlated

• disk-do mina te d

g a la xie s te nd to lie

• n a fa irly tig ht “sta r-

fo rming se q ue nc e ”

• sphe ro id-do mina te d

g a la xie s te nd to b e ‘ q uie sc e nt’

(K

a uffma nn e t a l. 2003) ra te o f ne w sta rb irth pe r unit ste lla r ma ss ste lla r ma ss z~0 (to da y)

• this SF

se q ue nc e inc re a se s in its no rma liza tio n, b ut re ma ins ra the r tig ht, up to hig h re dshift (z~4-6? )

• a distinc t q uie sc e nt po pula tio n c a n b e ide ntifie d up to a t le a st z~2

Cia mb ur e t a l. 2013 z~0 z~1 z~2 Muzzin e t a l. 2013 ste lla r ma ss a sse mb ly b uild-up o f the q uie sc e nt po pula tio n ma ss o n the SF se q ue nc e ~c o nsta nt sinc e z~2

Wuyts e t a l. 2011

• a ltho ug h g a la xy de mo g ra phic s ha ve c ha ng e d ra the r

dra ma tic a lly sinc e ‘ c o smic hig h no o n’ , the se c o rre la tio ns se e m to ha ve re ma ine d q ua lita tive ly simila r

disk-like sphe ro id-like se e a lso Be ll e t a l. 2008, 2012; Che ung +’ 12; F a ng +‘ 13

va n de r We l e t a l. sub mitte d

• q uie sc e nt g a la xie s mo re c o mpa c t
• size s e vo lve mo re ra pidly
• ma ss-de pe nde nt size e vo lutio n (struc tura l

do wnsizing )

• SF

g a la xie s mo re e xte nde d

• size s e vo lve slo wly
• se lf-simila r size e vo lutio n

q uie sc e nt sta r-fo rming

Big Questions

• why do we see two populations (spheroids &

disks)?

• why is star formation abruptly quenched in some

galaxies?

• how are the correlations between global and

structural properties imprinted on galaxies?

• what physical processes are driving the evolution of

global and structural properties?

z=5.7 (t=1.0 Gyr) z=1.4 (t=4.7 Gyr) z=0 (t=13.6 Gyr)

Hirsc hma nn e t a l. 2012

Mille nnium Simula tio n

mass assembly in a hierarchical universe

massive stars & SNae heating and winds photoionization/ photoevaporation AGN feedback heating & winds

halo mass (Msun)

no HI cooling gravitational heating

The Angular Momentum Catastrophe

spe c ific a ng ula r mo me ntum ro ta tio n ve lo c ity Na va rro & Ste inme tz 2001; Ab a di e t a l. 2003

Gue de s e t a l. 2011; se e a lso e .g . Bro o ks e t a l. 2011 Christe nse n e t a l. 2012

Christe nse n e t a l. 2012 a ng ula r mo me ntum c a ta stro phe so lve d (? ) – c o mb ina tio n o f re so lutio n, mo re physic a l tre a tme nt o f I SM, sta r fo rma tio n, ste lla r fe e db a c k

GASOL I NE simula tio n inc luding me ta l c o o ling , H

2 c he mistry & simplifie d ra dia tive tra nsfe r

Aq uila Pro je c t

Sc a nna pie c o e t a l. 2011

Y . Guo +CANDE L S in pre p

Clumpy disks at z~2

c a n simula tio ns pro duc e the rig ht numb e r o f c lumpy g a la xie s & ‘ c lump sta tistic s’ a t z~2 a nd simulta ne o usly re pro duc e MW-like disks a t z~0?

• [dry or moist] major mergers transform disks into

spheroids – ‘wet’ (gas rich) may reform into a disk

• minor mergers scatter stars from disk and add to spheroid
• bar instabilities can build (pseudo?) spheroids
• ‘violent disk instabilities’ fueled by rapid ‘stream-fed’

accretion at high-z may lead to Violent Disk Instabilities, building a classical bulge

• these processes may also be responsible for driving gas
• nto a supermassive black hole

Co x e t a l. 2006

Ceverino et al. 2012

Me rg e rs a nd `Disk I nsta b ilitie s’

Po rte r , rss, Prima c k & Jo ha nsso n sub mitte d sphe ro ids fo rm e a rlie r a nd mo re e ffic ie ntly in mo de ls with “Disk insta b ilitie s”

lo g

galaxy structure & quenching: z~2

se mi-a na lytic mo de l Bre nna n, Pa ndya , rss e t a l. in pre p

galaxy morphology & quenching: z~1

se mi-a na lytic mo de l Bre nna n, Pa ndya , rss e t a l. in pre p

disk insta b ilitie s o ff disk insta b ilitie s o n Bre nna n, Pa ndya , rss e t a l. in pre p

Wuyts e t a l. 2011

• b se rva tio ns

simple model for understanding disk sizes

r

d ~ λ r H f(c , λ, fd)

Blume ntha l e t a l. 1986 Da lc a nto n e t a l. 1997 Mo , Ma o & White 1998 So me rville e t a l. 2008

• smo o thly a c c re te d g a s ~ c o nse rve s its a ng ula r mo me ntum
• de nsity pro file g e ts mo difie d a b it b y ‘ b a ryo nic c o ntra c tio n’

Orbital parameters, ! gas fraction, mass ratio!

+ +

L a ure n Po rte r UCSC PhD T he sis with J. Prima c k; Po rte r , rss e t a l. MN sub mitte d fo rm fa c to rs c a lib ra te d fro m SPH simula tio ns o f b ina ry ide a lize d g a la xy me rg e rs (Co x e t a l.; Jo ha nnso n e t a l. 2009) ‘ dry’ me rg e rs pro duc e re mna nts tha t a re la rg e r in ra dius tha n the ir pro g e nito rs ‘ we t’ me rg e rs pro duc e re mna nts tha t a re mo re c o mpa c t tha n the ir pro g e nito rs se e a lso Co ving to n e t a l. 2008; 2011

simple model for spheroid sizes

• b se rva tio ns fro m va n de r We l e t a l. (sub mitte d)

rss, Po rte r+CANDE L S in pre p;

Co smo lo g ic a l hydro dyna mic a l “zo o m-in” simula tio ns inc luding AGN fe e db a c k (the rma l, ra dia tive , a nd me c ha nic a l) 20 ha lo s (1.1E 12<Mh(z=0)<1.0E 13) Msun (8.9E 10<M*(z=0)<1.0E 12) Msun sta r a nd g a s pa rtic le s 6E 06 Msun DM pa rtic le s 3.6E 07 Msun c o mo ving so fte ning 571 pc E . Cho i e t a l. a rXiv:1403.1257

looking ahead…

Ca ppe lla ri e t a l. 2011

kinematics with new generation of! Integral Field Spectrographs! cold gas content with ALMA! black hole masses with ! 20m space telescope!

What have we learned? – part I

• quenching of star formation in galaxies is

accompanied by structural and morphological transformation -- star-forming and quiescent galaxies grow at different rates

• studying the evolution of galaxy structure

provides invaluable constraints on ‘sub-grid physics’…greatest uncertainty in theoretical modeling.

What have we learned?– part II

• to first order, the following picture appears qualitatively

consistent with the observations:

– disk sizes set by angular momentum content of smoothly accreted gas – some process(es) [mergers? ‘disk instabilities’?] cause gas to lose angular momentum, fall to the center, make new stars, and feed a central SMBH – AGN feedback clears gas out and prevents further cooling – ‘quenched’ galaxies grow further primarily via ‘dry’ mergers/cannabalism

Puzzles (an incomplete list)

• what determines the angular momentum distribution of the baryons in galactic disks?

can stellar-driven winds preferentially remove low-angular momentum material? what implications does this have for disk size evolution and disk profiles?

• how do spheroids form and grow? what is the relative role of mergers, secular

evolution, violent disk instabilities, low J accretion, other? can we reproduce the

• bserved distribution of galaxy morphologies, from pure disks to pure spheroids?
• is ‘AGN feedback’ really the primary mechanism for stopping gas accretion and

quenching star formation? what are the relative roles of “bright mode” vs. “radio mode”?

• how and why does matter accrete onto supermassive black holes? do the above

processes all lead to the same spheroid/BH mass ratio? how is “feeding” on kpc scales connected with feeding on sub-pc scales?

Thank you!

What can we learn about the physics of galaxy formation and evolution from galaxy structure?

Bre nna n e t a l. in pre p;

• c urre nt mo de ls do o k (tho ug h no t g re a t) a t re pro duc ing the fra c tio n o f SF
• vs. q uie sc e nt g a la xie s a s a func tio n o f ste lla r ma ss up to z~1.5
• mo de ls se e m to unde rpro duc e q uie sc e nt a nd sphe ro id-do mina te d g a la xie s

a t z>1.5

• this pro b le m is muc h mo re se ve re in mo de ls in whic h sphe ro ids a re fo rme d
• nly in me rg e rs. mo de l sho wn inc lude s ‘disk instabilitie s’

mo de l

mo de l, c e ntra ls

• nly

CANDE L S Ultra VI ST A

• b se rva tio ns fro m L

a ng , Wuyts e t a l. in pre p; Muzzin e t a l. 2013

b o lo me tric AGN lumino sity func tio n

Hirschmann, rss et al. 2012

the se sa me mo de ls pre dic t numb e r de nsitie s

• f “b rig ht” a c c re ting BH

a s a func tio n o f lumino sity a nd o ve r c o smic time tha t a re c o nsiste nt with

• b se rva tio ns

spheroid potential tells BH how much it can grow smooth accretion forms rotationally supported disks, stars form

energy balance

diffuse halo gas heated by radio jets (‘maintenance mode’) mergers transform disks into spheroids and feed supermassive blackholes -- AGN-driven winds eject gas

q ue nc hing ? c o o ling c o ntinue s ‘ q uie sc e nt’ ne w disk c a n fo rm c o o ling

• ffse t b y

he a ting

it’s all about the gas

• me rg e rs a re mo re g a s-ric h a t hig h z
• lo w-ma ss g a la xie s ha ve hig he r g a s

fra c tio ns a t a ll z (se t b y SF e ffic ie nc y/ fe e db a c k)

• the mo re g a s, the mo re dissipa tio n,

the mo re c o mpa c t the re mna nt

• ma ssive g a la xie s b e c o me q ue nc he d

a t z~2 à tra nsitio n fro m pre do mina ntly we t to pre do mina ntly dry (g a s-po o r) me rg e rs a b o ve the c ritic a l (q ue nc hing ) ma ss

gas fraction in mergers

• P. Hopkins, rss et al. 2009