arXiv:0805.3533v2 [astro-ph] 27 Oct 2008 utn ea 78712 Texas Austin, Astrophysics ieal upr oti itr eg ans&Hernquist & Barnes established (e.g. now around the picture in con- features this 1980; Furthermore, lent 1992). to have tidal Schweizer 1996) support and 1983; Schweizer siderable 1992; 1980, shells 2004, Seitzer & Carter Joseph Schweizer faint al. & & et (Malin Rothberg Tacconi e.g. 2007; ellipticals 2001; and 2006, al. Fischer et & Genzel 2006a) al. Shier et Dasyra 1999; 1994; 2002; al. al. 1982; et et James Doyon detaile (Schweizer 1998; of 1986; remnants combination Dressler merger & the re- Lake recent and could of galaxies, spirals observations elliptical between in mergers sult major that hypothesis,” h ihms n hs-pc este fnab ellipti- mass low nearby relatively of of densities those phase-space (especially and cals mass e high cannot disks the stellar of mergers (collisionless) tionless formation. galaxy in element 1978 inescapable Rees an & mergers White making (e.g. hierarchically grows structure ogy, rde A02138 MA bridge, r a oedneta oa tla ik ftesm mass same the of 1989). Kormendy disks 1987; stellar Gunn 1986; local Carlberg than 1980; (Ostriker dense more far are 4 3 2 hryyasao ome(97 rpsdte“merger the proposed (1977) Toomre ago, years Thirty oee,i a ogbe eonzdta ueydissipa- purely that recognized been long has it However, 1 rpittpstuigL using typeset Preprint S ainlOtclAtooyOsraoy usn Z85726 AZ Tucson, Observatory, Astronomy Optical National eateto srnm,Uiest fTxs University 1 Texas, of University Astronomy, of Department .M ekPsdcoa elwa h avr-mtsna C Harvard-Smithsonian the at Fellow Postdoctoral Keck M. W. avr-mtsna etrfrAtohsc,6 adnSt Garden 60 Astrophysics, for Center Harvard-Smithsonian BITDTO UBMITTED P HILIP o h eta ih)de o eedo as ihama out mean a with mass, on and depend simulated not in does profile light) light central the the of dissi shape for more densiti outer mass with the and systems that phase-space that show maximum sense the the in discrepancy in the mass, fixed at radius n oo rdet fcs litcl,adw aepredict headings: make Subject we formation. spheroid and in ellipticals, dissipation cusp of brightness degree of surface observed gradients match color to and needed s content imp and and gas diskier, the properties, and rounder kinematic remnants shapes, making to the contributes e.g. to relates this togfnto fselrms,ruhytaigteobser the tracing roughly range mass, merger redshift stellar spheroid-forming of the function in o strong dissipation a the sep of that robustly degree demonstrate to the and how of profile, show We relaxed compo this violently galaxies. of outer, the mass tw and of properties a properties motivate the other how to examine simulations ellipt to our cusp us use allows observed we that and co show structure, we population light” hydrodynamic masses, stellar of various inner set at large an profiles a combining and By merger, al starburst. the central stars of on acting stages merg relaxation final Dissipational violent by galaxies. established profile elliptical power-law or cusp .H F. esuyteoii n rpriso eta r“xes cen “excess” or “extra” of properties and origin the study We OPKINS A P ISPTO N XR IH NGLCI ULI I CS”E “CUSP” II. NUCLEI: GALACTIC IN LIGHT EXTRA AND DISSIPATION A ,J J, T E tl mltajv 08/22/09 v. emulateapj style X ANUARY 1. 1 T , z INTRODUCTION ∼ HOMAS 0 aais uli—glxe:srcue—csooy theory cosmology: — structure galaxies: — nuclei galaxies: aais litcladlniua,c aais evolut galaxies: — cD lenticular, and elliptical galaxies: 3 2008 23, − .W eosrt orlto ewe h tegho this of strength the between correlation a demonstrate We 2. .C J. OX 1,2 S , UVENDRA Λ D cosmol- CDM . umte oAJ aur 3 2008 23, January ApJ, to Submitted L ∗ ,which ), et Cam- reet, ne for enter .D N. xplain Station, ABSTRACT UTTA ), d 1 L , elrpplto rdet felpias xr light Extra ellipticals. of gradient