The influence of gas on the structure of merger remnants

By T. Naab, R. Burkert. 2006

221 citations recorded by the source corpus.

We present a large set of merger simulations of early-type disc galaxies with mass ratios of 1:1 and 3:1 and 10 per cent of the total disc mass in gas. The internal orbital structure and the kinematic and photometric properties of the remnants are analysed in detail and compared to pure stellar mergers. In contrast to the collisionless case, equal-mass mergers with gas do not result in very boxy remnants which is caused by the suppression of box orbits and the change of the projected shape of minor-axis tube orbits in the more axisymmetric remnants. The isophotal shape of 3:1 remnants and the global kinematic properties of 1:1 and 3:1 remnants are only weakly affected by the presence of gas. 1:1 remnants are slowly rotating, whereas 3:1 remnants are fast rotating and discy. The shape of the stellar line-of-sight velocity distributions (LOSVDs) is strongly influenced by gas. Within the effective radius, the LOSVDs of collisionless remnants have broad leading wings while their gaseous counterparts show steep leading wings, more consistent with observations of elliptical galaxies. We show that this change is also caused by the suppressed populating of box orbits and it is amplified by the formation of extended gas discs in the merger remnants which might eventually turn into stars. If elliptical galaxies have formed from mergers, our results indicate that massive, slowly rotating boxy elliptical galaxies cannot have formed from dissipative mergers of discs. Pure stellar (dry) mergers are the more likely candidates. On the other hand, lower mass, fast rotating and discy ellipticals can have formed from dissipative (wet) mergers of early-type discs. So far, only unequal-mass disc mergers with gas can successfully explain their observed substructure. This is consistent with the revised morphological classification scheme of increasing importance of gas dissipation when moving from boxy to discy ellipticals and then to spiral galaxies, proposed by Kormendy & Bender.

Subfields: Astronomy and Astrophysics, Instrumentation

View Paper: https://www.semanticscholar.org/paper/172a22639b04f81f7be2ce74e0c46fd86eddd037

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Astronomy and Astrophysics

In Instrumentation

Citations in the corpus

HYDRODYNAMICS OF HIGH-REDSHIFT GALAXY COLLISIONS: FROM GAS-RICH DISKS TO DISPERSION-DOMINATED MERGERS AND COMPACT SPHEROIDS (2010, background): “…is known that a major merger of two spiral galaxies typically produces a remnant resembling an elliptical or early-type galaxy (ETG) (Barnes & Hernquist 2 1996; Mihos & Hernquist 1996; Naab & Burkert 2003; Bournaud et al. 2004a; Naab et al. 2006, 2007; Bournaud et al. 2007b; Hoffman et al. 2010).”
A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies. II. Formation of Red Ellipticals (2007, background): “The extremely slow rotation (Naab et al. 2006b; Cox et al. 2006b), roundness, and metallicity (Pipino & Matteucci 2006; Naab & Ostriker 2007) of such galaxies have historically been difficult tomatch inmajor-merger simulations (but see alsoMihos & Hernquist1994b; Weil & Hernquist1996; Khochfar &…”
Discriminating Between the Physical Processes that Drive Spheroid Size Evolution (2009, background): “…subsequent merger history, potentially mapping between gas-rich or equal density mergers and dry, lower density mergers (Mihos & Hernquist 1994a; Barnes & Hernquist 1996; Cox et al. 2006b; Naab et al. 2006a; Oñorbe et al. 2006; Robertson et al. 2006a; Jesseit et al. 2007; Hopkins et al. 2009b,e).”
SPITZER QUASAR AND ULIRG EVOLUTION STUDY (QUEST). IV. COMPARISON OF 1 Jy ULTRALUMINOUS INFRARED GALAXIES WITH PALOMAR-GREEN QUASARS (2009, methodology): “This merging process had long been suspected to lead to the formation of an elliptical galaxy (e.g., Toomre & Toomre 1972) and subsequent numerical simulations have lent support to this idea (e.g., Barnes 1989; Kormendy & Sanders 1992; Springel et al. 2005; Bournaud et al. 2005; Naab et al. 2006).”
HOW DO DISKS SURVIVE MERGERS? (2008, methodology): “…and halo gas; Hernquist 1989; Barnes & Hernquist 1991, 1996; Hernquist et al. 1993; Mihos & Hernquist 1994b, 1996; Di Matteo et al. 2005; Naab et al. 2006; Jesseit et al. 2007; Cox et al. 2006a,b; Robertson et al. 2006b; Springel et al. 2005a; Burkert et al. 2007; Hopkins et al. 2007c,…”
The SAURON project – XII. Kinematic substructures in early-type galaxies: evidence for discs in fast rotators (2008, background): “In addition, the observed higher order moments of the LOSVD can be used to constrain the possible merger scenarios of early-type galaxies and their formation in general (e.g. Balcells 1991; Bendo & Barnes 2000; González-Garcı́a et al. 2006; Naab et al. 2006; Jesseit t al.”
A Cosmological Framework for the Co-Evolution of Quasars, Supermassive Black Holes, and Elliptical Galaxies. I. Galaxy Mergers and Quasar Activity (2007, background): “…can reproduce the observed kinematic properties of elliptical galaxies and ‘‘classical’’ bulges (Hernquist 1989, 1992, 1993;Barnes 1988, 1992; Schweizer 1992; Naab et al. 1999, 2006a, 2006b; Naab & Burkert 2003; Naab & Trujillo 2006; Bournaud et al. 2005; Jesseit et al. 2007; Cox et al. 2006b).”
WHAT TURNS GALAXIES OFF? THE DIFFERENT MORPHOLOGIES OF STAR-FORMING AND QUIESCENT GALAXIES SINCE z ∼ 2 FROM CANDELS (2011, background): “…and the quiescent galaxy formation rate (e.g., Hopkins et al. 2010; Robaina et al. 2010); the detailed kinematic structure of early-type galaxies (Naab et al. 2006; Hoffman et al. 2010); and, the empirical association between relatively younger stellar populations and substructure (tidal tails,…”
Kinematic properties of early-type galaxy haloes using planetary nebulae (2008, unknown): “…profiles for the total and dark matter distributions (e.g. Dekel et al. 2005; Naab et al. 2007), for the V/σ ratio (e.g. Abadi, Navarro & Steinmetz 2006), the angular momentum, orbital distribution and isophotal shape (e.g. Naab et al. 2006), depending on which cosmology or merger type is assumed.”
Formation of Early-Type Galaxies from Cosmological Initial Conditions (2005, methodology): “…most galaxies are expected to experience mergers, but it has been argued for a long time that dissipation is essential to explain properties of elliptical galaxies and in particular intermediate-mass ellipticals (Kormendy 1989 and references therein; Kormendy & Bender 1996; Naab et al. 2006a).”
Simulations of minor mergers - I. General properties of thick discs (2008, background): “More recently, also the effects of gas, star formation and feedback have been taken into account (Bournaud et al. 2005; Naab et al. 2006; di Matteo et al. 2007; Cox et al. 2008).”
Ongoing assembly of massive galaxies by major merging in large groups and clusters from the SDSS (2007, background): “We find a variety of strong tidal features including broad tails (e.g., 311008, 352171, and 274752) such as seen during the period between seco d close passage and final coalescence in dissipationless merger simulations (Naab et al. 2006b) andobservations (see Fig.”
DISSIPATION AND EXTRA LIGHT IN GALACTIC NUCLEI. IV. EVOLUTION IN THE SCALING RELATIONS OF SPHEROIDS (2008, background): “…with central cusps (power-law nuclear slopes), rapid rotation, or disky isophotal shapes as opposed to central cores, slow rotation, or boxy isophotal shapes (indicators of wet versus dry mergers, discussed in detail in e.g. Paper II and Faber et al. 1997; Naab et al. 2006a; Cox et al. 2006).”
The SAURON project – IX. A kinematic classification for early‐type galaxies (2007, background): “2000; Bournaud et al. 2005; Naab et al. 2006).”
DISSIPATION AND EXTRA LIGHT IN GALACTIC NUCLEI. II. “CUSP” ELLIPTICALS (2008, background): “…from progenitor stars which experienced violent relaxation (e.g., Barnes 1988, 1992; Hernquist 1993b), and the dissipation-induced starburst appropriately boosting the concentration and central phase-space density (Hernquist et al. 1993; Robertson et al. 2006b; Naab et al. 2006a; Cox et al. 2006b).”
The ATLAS3D project - II. Morphologies, kinemetric features and alignment between photometric and kinematic axes of early-type galaxies (2011, unknown): “V/σ distributions that, generally, agree well with the observations (GonzálezGarcı́a, Balcells & Olshevsky 2006; Naab et al. 2006).”
MERGERS AND BULGE FORMATION IN ΛCDM: WHICH MERGERS MATTER? (2009, background): “…L∗ ellipticals (in terms of their profile shapes, effective radii and fundamental plane correlations, rotation and higher-order kinematics, isophotal shapes, triaxiality, and other prope ties; see e.g. Naab et al. 2006; Cox et al. 2006a; Jesseit et al. 2007, 2009; Hopkins et al. 2008c,a, 2009c)23.”