Forming a large disc galaxy from a z < 1 major merger

By Fabio Governato, C. Brook, A. Brooks, Lucio Mayer, B. Willman, P. Jonsson, Adrienne M. Stilp, L. Pope, C. Christensen, James Wadsley and 1 more. 2008

191 citations recorded by the source corpus.

Using high-resolution SPH simulations in a fully cosmological Λ cold dark matter context, we study the formation of a bright disc-dominated galaxy that originates from a 'wet' major merger at z = 0.8 . The progenitors of the disc galaxy are themselves disc galaxies that formed from early major mergers between galaxies with blue colours. A substantial thin stellar disc grows rapidly following the last major merger and the present-day properties of the final remnant are typical of early-type spiral galaxies, with an i-band bulge-to-disc ratio ~0.65, a disc scalelength of 7.2 kpc, g−r = 0.5 mag , an HI linewidth (W_(20)/2) of 238 km s^(−1) and total magnitude i = −22.4. The key ingredients for the formation of a dominant stellar disc component after a major merger are (i) substantial and rapid accretion of gas through cold flows followed at late times by cooling of gas from the hot phase, (ii) supernova feedback that is able to partially suppress star formation during mergers and (iii) relative fading of the spheroidal component. The gas fraction of the progenitors' discs does not exceed 25 per cent at z < 3 , emphasizing that the continuous supply of gas from the local environment plays a major role in the regrowth of discs and in keeping the galaxies blue. The results of this simulation alleviate the problem posed for the existence of disc galaxies by the high likelihood of interactions and mergers for galaxy-sized haloes at relatively low z.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/65c8cdfe595f17f685a7ef81296e1094ec085d32

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In Astronomy and Astrophysics

1. P. Hopkins
2. L. Hernquist
3. Volker Springel
4. R. Somerville
5. T. Naab
6. R. Dav'e
7. A. Dekel
8. Simon D. M. White

Citations in the corpus

• The formation of disc galaxies in a ΛCDM universe (2010, methodology): “These studies place galaxies closer to the observed relation, but this is in part achieved by circumventing the large measured vrot (caused by the dominant bulge) by using the exponential disc assumption discussed above (but see Governato et al. 2009), i.e. using vrot,2.2.”
• The Romulus cosmological simulations: a physical approach to the formation, dynamics and accretion models of SMBHs (2016, methodology): “…of the procedure is the following (see Appendix A for a more detailed description): (i) We simulate a large number of sets of 4 ‘zoomed-in’ galaxies (Governato et al. 2007, 2009) at the same resolution as Romulus, with halo masses ranging from 1010.5 to 1012 M , with dozens of different sub-grid…”
• Cosmic Dawn (CoDa): the first radiation-hydrodynamics simulation of reionization and galaxy formation in the Local Universe (2015, methodology): “To summarize, we used for this simulation rather standard galaxy formation recipes, which have proven quite successful in reproducing various properties of galaxy evolution (Ocvirk et al. 2008; Governato et al. 2009, 2010).”
• The z ∼ 6 Luminosity Function Fainter than −15 mag from the Hubble Frontier Fields: The Impact of Magnification Uncertainties (2016, methodology): “The simulations include standard prescriptions for star formation and supernovae explosions following standard recipes (Ocvirk et al. 2008; Governato et al. 2009, 2010).”
• THE DEPENDENCE OF QUENCHING UPON THE INNER STRUCTURE OF GALAXIES AT 0.5 ⩽ z < 0.8 IN THE DEEP2/AEGIS SURVEY (2012, background): “…of the gas35 is exhausted (depending on gas fraction; see Springel & Hernquist 2005; Okamoto et al. 2005; Robertson et al. 2006; Cox et al. 2008; Governato et al. 2007, 2009), and through subsequent feedback, from supernovae and/or AGN (Springel et al. 2005; Murray et al. 2005; Ciotti et al.…”
• Simulations of binary galaxy mergers and the link with fast rotators, slow rotators, and kinematically distinct cores (2011, background): “…and mass resolution (see also Bois et al. 2010; Teyssier, Chapon & Bournaud 2010; Powell et al. 2011) and for realistic physical inputs: e.g. the treatment of the gas with models capable of resolving the main dense gas clouds/SF regions (see Governato et al. 2009, in a cosmological context).”
• Chemical signatures of formation processes in the stellar populations of simulated galaxies (2011, methodology): “Several methods for separating spheroids and discs have been proposed (e.g. Abadi et al. 2003; Governato et al. 2009; Scannapieco et al. 2009).”
• Physical Models of Galaxy Formation in a Cosmological Framework (2014, background): “Feedback also makes star formation less efficient, keeping galaxies gas rich, which makes disks more resiliant to mergers (Governato et al. 2009, Robertson et al. 2006a).”
• BULGES OF NEARBY GALAXIES WITH SPITZER: SCALING RELATIONS IN PSEUDOBULGES AND CLASSICAL BULGES (2010, background): “The formation of a disk galaxy in a late merger by Governato et al. (2009) is indeed remarkable; however, the resulting bulge-tototal ratio of the simulated galaxy of 0.65 is far greater than any pseudobulge in our sample.”
• THE TWO PHASES OF GALAXY FORMATION (2010, background): “Compared to some other recent cosmological zoom simulations (Scannapieco et al. 2009; Governato et al. 2009; Piontek & Steinmetz 2009; Feldmann et al. 2010) the resolution level of our simulations at Mhalo ≈ 1012M⊙ is slightly lower.”
• THE EPOCH OF DISK SETTLING: z ∼ 1 TO NOW (2012, methodology): “The simulations which have been run to lower redshifts generally focus on reproducing the photometric and structural properties of galaxies (e.g., Governato et al. 2007, 2009; Brook et al. 2011; Martig et al. 2012, and references therein), and not σg, Vrot, and S0.”
• The Aquila comparison project: the effects of feedback and numerical methods on simulations of galaxy formation (2011, methodology): “Recent examples of simulations that use similar physics include Governato et al. (2007, 2009, 2010), Stinson et al. (2010), Brooks et al. (2011) and Guedes et al. (2011).”
• CANDELS: THE PROGENITORS OF COMPACT QUIESCENT GALAXIES AT z ∼ 2 (2012, background): “This feature might be explained if cQGs developed an extended component surrounding the compact core, perhaps via minor mergers (Naab & Ostriker 2009) or regrowth of a remnant disk that survived the major merger (Governato et al. 2009; Hopkins et al. 2009).”
• THE CENTRAL SLOPE OF DARK MATTER CORES IN DWARF GALAXIES: SIMULATIONS VERSUS THINGS (2010, background): “…turbulent (∼ 5–10 kms−1 at z = 0), consistent with observations, and the galaxies match the observed stellar and baryonic Tully–Fisher relation (Governato et al. 2009), as the SF efficiency is regulated to form an amount of stars similar to that of real dwarf galaxies of similar rotation…”
• HYDRODYNAMICS OF HIGH-REDSHIFT GALAXY COLLISIONS: FROM GAS-RICH DISKS TO DISPERSION-DOMINATED MERGERS AND COMPACT SPHEROIDS (2010, background): “…2) show some variations, as stronger feedback fuels more extended and hotter gas reservoirs in the early phases of the merger, which adds mass to a re-formed disk component in the post-merger phases (following the process discussed, e.g., by Springel & Hernquist 2005 and Governato et al. 2009).”