Most pseudo-bulges can be formed at later stages of major mergers

Abstract

Most giant spiral galaxies have pseudo or disk-like bulges that are considered to be the result of purely secular processes. This may challenge the hierarchical scenario predicting about one major merger per massive galaxy ($>$$3\times 10^{10}{M}_{\odot }$) since the last $\sim$ 9 billion years. Here we verify whether or not the association between pseudo-bulges and secular processes is irrevocable. Using GADGET2 N-body/SPH simulations, we have conducted a systematic study of remnants of major mergers which progenitors have been selected (1) to follow the gas richness-look back time relationship, and (2) with a representative distribution of orbits and spins in a cosmological frame. Analyzing the surface-mass density profile of both nearby galaxies and merger remnants with two components, we find that most of them show pseudo-bulges or bar dominated centers. Even if some orbits lead to classical bulges just after the fusion, the contamination by the additional gas that gradually accumulates to the center and forming stars later on, leads to remnants apparently dominated by pseudo-bulges. We also found that simple SPH simulations should be sufficient to form realistic spiral galaxies as remnants of ancient gas-rich mergers without need for specifically tuned feedback conditions. We then conclude that pseudo-bulges and bars in spiral galaxies are natural consequences of major mergers when they are realized in a cosmological context, i.e., with gas-rich progenitors as expected when selected in the distant Universe.

arXiv comment25 pages, 16 figures, 11 tables

References in corpus (58)

• The cosmological simulation code GADGET-2
• The Eleventh and Twelfth Data Releases of the Sloan Digital Sky Survey: Final Data from SDSS-III
• Detailed Decomposition of Galaxy Images. II. Beyond Axisymmetric Models
• Secular Evolution and the Formation of Pseudobulges in Disk Galaxies
• 3D-HST+CANDELS: The Evolution of the Galaxy Size-Mass Distribution since $z=3$
• GIZMO: A New Class of Accurate, Mesh-Free Hydrodynamic Simulation Methods
• Structural Properties of Pseudo-Bulges, Classical Bulges and Elliptical Galaxies: an SDSS Perspective
• Updated Nearby Galaxy Catalog
• A Merger-Driven Scenario for Cosmological Disk Galaxy Formation
• The Frequency of Barred Spiral Galaxies in the Near-IR
• The size evolution of galaxies since z~3: combining SDSS, GEMS and FIRES
• The effect of galaxy mass ratio on merger--driven starbursts
• The Secular Evolution of Disk Structural Parameters
• Mergers and Bulge Formation in Lambda-CDM: Which Mergers Matter?
• Galaxy Merger Morphologies and Time-Scales from Simulations of Equal-Mass Gas-Rich Disc Mergers
• Formation of gas disks in merging galaxies
• A Near-Infrared Study of 2MASS Bars in Local Galaxies: An Anchor for High Redshift Studies
• A subarcsecond resolution near-infrared study of Seyfert and `normal' galaxies: II. Morphology
• The Structure of Classical Bulges And Pseudobulges: The Link Between Pseudobulges And Sersic Index
• Bar formation and evolution in disc galaxies with gas and a triaxial halo: Morphology, bar strength and halo properties
• Hubble Space Telescope imaging of the CFRS and LDSS redshift surveys - IV. Influence of mergers in the evolution of faint field galaxies from z~1
• Feedback in simulations of disc-galaxy major mergers
• The population of barred galaxies in the local universe I. Detection and characterisation of bars
• Bulgeless Giant Galaxies Challenge our Picture of Galaxy Formation by Hierarchical Clustering
• Bulge n and B/T in High Mass Galaxies: Constraints on the Origin of Bulges in Hierarchical Models
• The Milky Way: An Exceptionally Quiet Galaxy; Implications for the formation of spiral galaxies
• Merger Histories of Galaxy Halos and Implications for Disk Survival
• Did most present-day spirals form during the last 8 Gyrs? A formation history with violent episodes revealed by panchromatic observations
• GEMS: The Size Evolution of Disk Galaxies
• Bars in Disk-Dominated and Bulge-Dominated Galaxies at z~0: New Insights from ~3600 SDSS Galaxies
• The Luminosity Profile and Structural Parameters of the Andromeda Galaxy
• Bulges Of Nearby Galaxies With Spitzer: Scaling Relations in Pseudobulges and Classical Bulges
• The Tully-Fisher Relation and Its Residuals for a Broadly Selected Sample of Galaxies
• A Model for Star Formation, Gas Flows and Chemical Evolution in Galaxies at High Redshifts
• Comparison of bar strengths in active and non-active galaxies
• Near-Infrared and Optical Luminosity Functions from the 6dF Galaxy Survey
• The Impact of Feedback on Disk Galaxy Scaling Relations
• Demographics of Bulge Types within 11 Mpc and Implications for Galaxy Evolution
• Secular Evolution and Structural Properties of Stellar Bars in Galaxies
• Forming disk galaxies in wet major mergers. I. Three fiducial examples
• Does M31 result from an ancient major merger?
• The Hubble sequence: just a vestige of merger events?
• How was the Hubble sequence 6 Gyrs ago?
• Two Disk Components from a Gas Rich Disk-Disk Merger
• Kinematic Signatures of Bulges Correlate with Bulge Morphologies and Sérsic Index
• The baryonic content and Tully-Fisher relation at z~0.6
• Structure Formation Inside Triaxial Dark Matter Halos: Galactic Disks, Bulges and Bars
• Galaxy disks do not need to survive in the L-CDM paradigm: the galaxy merger rate out to z~1.5 from morpho-kinematic data
• An Observational Guide to Identifying Pseudobulges and Classical Bulges in Disk Galaxies
• Velocity Dispersion, Size, Sérsic Index and $D_{n}4000$: The Scaling of Stellar Mass with Dynamical Mass for Quiescent Galaxies
• Morpho-kinematics of z~1 galaxies probe the hierarchical scenario
• The Large-Scale Atomic and Molecular Gas in the Circinus Galaxy
• Loops formed by tidal tails as fossil records of a major merger
• Towards a robust estimate of the merger rate evolution using near-IR photometry
• Correlations between kinematics and metallicity in the Galactic bulge: a review
• A decrease of the gas exchanges between galaxies and the IGM, from 12 to 6 billion years ago
• The NGC 4013 tale: a pseudo-bulged, late-type spiral shaped by a major merger
• Forming disc galaxies in major mergers: III. The effect of angular momentum on the radial density profiles of disc galaxies

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• Chemodynamical history of the Galactic Bulge
• Kinematic signatures of nuclear discs and bar-driven secular evolution in nearby galaxies of the MUSE TIMER project
• Formation of S0 galaxies through mergers. Morphological properties: tidal relics, lenses, ovals, and other inner components
• The Carnegie-Irvine Galaxy Survey. IX. Classification of Bulge Types and Statistical Properties of Pseudo Bulges
• A Recent Major Merger Tale for the Closest Giant Elliptical Galaxy Centaurus A
• Disc galaxies formed from major mergers in Illustris
• FAST reveals new evidence for M94 as a merger
• High-resolution MEGARA IFU spectroscopy and structural analysis of a fast-rotating, disky bulge in NGC 7025
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• Why are classical bulges more common in S0 galaxies than in spiral galaxies?
• High sensitivity HI image of diffuse gas and new tidal features in M51 observed by FAST
• The relation between globular cluster systems and supermassive black holes in spiral galaxies III. The link to the $M_{\bullet }-M_{\ast }$ correlation
• The clustering of galaxies with pseudo bulge and classical bulge in the local Universe
• The Milky Way accretion history compared to cosmological simulations -- from bulge to dwarf galaxy infall
• Photometric properties of classical bulge and pseudo-bulge galaxies at $0.5\le z<1.0$
• Time-average properties of $z\sim 0.6$ major mergers: mergers significantly scatter high-z scaling relations
• SDSS-IV MaNGA: Stellar rotational support in disk galaxies vs. central surface density and stellar population age
• The Formation of Dwarf Galaxy Disks