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
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 … Szo mo ru e t a l. 2012
global and structural properties are correlated z~0 (to da y) • disk-do mina te d ra te o f ne w sta rb irth pe r unit ste lla r ma ss g a la xie s te nd to lie o 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’ ste lla r ma ss Brinc hma nn e t a l. 2003 ( K a uffma nn e t a l. 2003 )
• 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 z~0 z~1 z~2 Cia mb ur 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 Muzzin e t a l. 2013
• 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 Wuyts e t a l. 2011 se e a lso Be ll e t a l. 2008, 2012; Che ung +’ 12; F a ng +‘ 13
• q uie sc e nt g a la xie s mo re c o mpa c t • SF g a la xie s mo re e xte nde d • size s e vo lve mo re ra pidly • size s e vo lve slo wly • ma ss-de pe nde nt size e vo lutio n (struc tura l • se lf-simila r size e vo lutio n do wnsizing ) sta r-fo rming q uie sc e nt va n de r We l e t a l. sub mitte d
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) mass assembly in a hierarchical universe 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
massive stars & SNae AGN feedback heating and winds heating & winds photoionization/ gravitational photoevaporation heating no HI cooling halo mass (M sun )
The Angular Momentum Catastrophe spe c ific a ng ula r mo me ntum Na va rro & Ste inme tz 2001; ro ta tio n ve lo c ity 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
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 , Christe nse n e t a l. 2012 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
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? Y . Guo +CANDE L S in pre p
Me rg e rs a nd `Disk I nsta b ilitie s ’ Ceverino et al. 2012 [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 • onto a supermassive black hole Co x e t a l. 2006
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” Po rte r , rss, Prima c k & Jo ha nsso n sub mitte d
galaxy structure & quenching: z~2 se mi-a na lytic mo de l lo g 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
Wuyts e t a l. 2011 o b se rva tio ns 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
simple model for understanding disk sizes d ~ λ r r H f(c , λ , f d ) • 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’ 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
simple model for spheroid sizes Orbital parameters, ! gas fraction, mass ratio ! 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 L a ure n Po rte r UCSC PhD T he sis with J. Prima c k; se e a lso Co ving to n e t a l. 2008; 2011 Po rte r , rss e t a l. MN sub mitte d
o 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<M h (z=0)<1.0E 13) M sun (8.9E 10<M * (z=0)<1.0E 12) M sun sta r a nd g a s pa rtic le s 6E 06 M sun DM pa rtic le s 3.6E 07 M sun c o mo ving so fte ning 571 pc E . Cho i e t a l. a rXiv:1403.1257
looking ahead… kinematics with new generation of ! Integral Field Spectrographs ! Ca ppe lla ri e t a l. 2011 black hole masses with ! 20m space telescope ! cold gas content with ALMA !
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 observed 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?
• 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 o nly in me rg e rs. mo de l sho wn inc lude s ‘disk instabilitie s’ CANDE L S Ultra VI ST A mo de l mo de l, c e ntra ls o nly Bre nna n e t a l. in pre p; o 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 the se sa me mo de ls pre dic t numb e r de nsitie s o 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 o b se rva tio ns Hirschmann, rss et al. 2012
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