The VIMOS VLT Deep Survey - Evolution of the major merger rate since z ~ 1 from spectroscopically confirmed galaxy pairs

By L. Ravel, O. Fèvre, L. Tresse, D. Bottini, Bianca Garilli, V. Brun, D. Maccagni, R. Scaramella, M. Scodeggio, G. Vettolani and 41 more. 2008

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Context: The rate at which galaxies grow via successive mergers is a key element in understanding the main phases of galaxy evolution. Aims: We measure the evolution of the fraction of galaxies in pairs and the merging rate since redshift z 1 assuming a (H0 = 70 km s-1 Mpc-1, ΩM = 0.3 and ΩΛ = 0.7) cosmology. Methods: From the VIMOS VLT Deep Survey we use a sample of 6464 galaxies with I_AB ≤ 24 to identify 314 pairs of galaxies, each member with a secure spectroscopic redshift, which are close in both projected separation and in velocity. Results: We estimate that at z 0.9, 10.9 ± 3.2% of galaxies with MB(z) ≤ -18-Qz (Q = 1.11) are in pairs with separations Δ rp ≤ 20 h-1 kpc, Δ v≤ 500 km s-1, and with Δ MB ≤ 1.5, significantly larger than 3.8 ± 1.7% at z 0.5; thus, the pair fraction evolves as (1 + z)m with m = 4.73 ± 2.01. For bright galaxies with MB(z = 0) ≤ -18.77, the pair fraction is higher and its evolution with redshift is flatter with m = 1.50 ± 0.76, a property also observed for galaxies with increasing stellar masses. Early-type pairs (dry mergers) increase their relative fraction from 3% at z 0.9 to 12% at z 0.5. The star formation rate traced by the rest-frame [OII] EW increases by 26 ± 4% for pairs with the smallest separation rp ≤ 20 h-1 kpc. Following published prescriptions to derive merger timescales, we find that the merger rate of MB(z) ≤ -18-Qz galaxies evolves as N_mg = (4.96 ± 2.07)×10-4×(1 + z)2.20 ± 0.77 mergers Mpc-3 Gyr-1. Conclusions: The merger rate of galaxies with MB(z) ≤ -18-Qz has significantly evolved since z 1 and is strongly dependent on the luminosity or stellar mass of galaxies. The major merger rate increases more rapidly with redshift for galaxies with fainter luminosities or stellar mass, while the evolution of the merger rate for bright or massive galaxies is slower, indicating that the slow evolution reported for the brightest galaxies is not universal. The merger rate is also strongly dependent on the spectral type of galaxies involved. Late-type mergers were more frequent in the past, while early-type mergers are more frequent today, contributing to the rise in the local density of early-type galaxies. About 20% of the stellar mass in present day galaxies with log(M/M{ȯ}) ≥ 9.5 has been accreted through major merging events since z = 1. This indicates that major mergers have contributed significantly to the growth in stellar mass density of bright galaxies over the last half of the life of the Universe. based on observations obtained with the European Southern Observatory Telescopes at the Paranal Observatory, under programs 072.A-0586 and 073.A-0647.

Subfields: Astronomy and Astrophysics, Electrical and Electronic Engineering, Instrumentation

View Paper: https://www.semanticscholar.org/paper/82477fbae7d67b905524755ac8c0f0bfe3df9ced

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Citations in the corpus

The VIMOS VLT Deep Survey final data release: a spectroscopic sample of 35 016 galaxies and AGN out to z ~ 6.7 selected with 17.5 ≤ iAB ≤ 24.75 (2013, background): “…above, based on a complete census of the galaxy population (e.g. Ilbert et al. 2005; Le Fèvre et al. 2005b; Cucciati et al. 2006; Arnouts et al. 2007; Franzetti et al. 2007; Pozzetti et al. 2007; Tresse et al. 2007; Guzzo et al. 2008; Zucca et al. 2008; de Ravel et al. 2009; Meneux et al. 2009).”
MERGERS AND BULGE FORMATION IN ΛCDM: WHICH MERGERS MATTER? (2009, background): “For example, de Ravel et al. (2009) use pair-selected samples to estimate that∼ 20−25% of theM∗ > 1010M⊙ population has experienced a merger with mass ratioµ > 0.25 sincez= 1; Conselice et al. (2009) estimate a similar number of mergers for M∗ > 1010M⊙ galaxies sincez= 1 and about again as many…”
The zCOSMOS redshift survey: the role of environment and stellar mass in shaping the rise of the morphology-density relation from z ~ 1 (2009, background): “…and analysis (Cucciati et al. 2009; Kovač et al. 2009; Iovino et al. 2009) to understand how star forming history, stellar mass, environment and merger history (de Ravel et al. 2009b; Kampczyk et al. 2009; Tresse et al. 2009) differently act to determine the properties of individual galaxies.”
THE EVOLVING RELATIONS BETWEEN SIZE, MASS, SURFACE DENSITY, AND STAR FORMATION IN 3 × 104 GALAXIES SINCE z = 2 (2009, background): “…major dry merger rate sincez∼ 1 indicate that these are indeed a factor in the buildup of massive galaxies (Bell et al. 2006; Bundy et al. 2009; de Ravel et al. 2009), but the remnants of such major mergers would also have correspondingly larger masses and so it is unclear whether major dry…”
The Herschel census of infrared SEDs through cosmic time (2013, result): “…half of LIRGs at z > 0.7 are gas-rich isolated spirals, whereas other studies (e.g. Le Fevre et al. 2000; Cassata et al. 2005; Bridge et al. 2007; de Ravel et al. 2009) claim an increase in the merger rate out to z ∼ 1 suggesting that more than half of IRLD out to z ∼ 1 is a result of some merger…”
The effect of gas fraction on the morphology and time-scales of disc galaxy mergers (2009, background): “The fraction of galaxies in blue galaxy − blue galaxy pairs increases strongly from z ∼ 0 to z ∼ 1 (Lin et al. 2008, Bundy et al. 2009, Ravel et al. 2009).”
Dissecting the size evolution of elliptical galaxies since z∼ 1: puffing-up versus minor-merging scenarios (2011, result): “This evolution is not strong enough to be compatible with the low number of major mergers observed at least since z ∼ 1 (Bundy et al. 2009; de Ravel et al. 2009; Wild et al. 2009; López-Sanjuan et al. 2010), as well as with recent numerical simulations (Khochfar & Silk 2009).”
Integral field spectroscopy with SINFONI of VVDS galaxies I. Galaxy dynamics and mass assembly at 1.2 < z < 1.6 (2009, background): “…through direct evidence of on-going events, orindirect fossil remnants (e.g. Conselice et al. 2003; Lotz et al.2008), and the merger rate and its evolution is now demonstrated to be strongly dependent on the luminosity or stellar mass of the galaxies involved (e.g. de Ravel et al. 2009).”
Tracking the impact of environment on the galaxy stellar mass function up to z ~ 1 in the 10 k zCOSMOS sample (2009, background): “Future investigations will also concern the impact of merging in different environments (de Ravel et al. 2009a; Kampczyk et al. 2009) and of the role of the dark matter halo mass functionin different environments (e.g. Abbas & Sheth 2007) in the galaxy formation efficiency.”
CAN MINOR MERGING ACCOUNT FOR THE SIZE GROWTH OF QUIESCENT GALAXIES? NEW RESULTS FROM THE CANDELS SURVEY (2011, background): “1, our measurements are broadly in agreement with previous results when analogous samples are compared and search apertures are matched (e.g., Kartaltepe et al. 2007; Lin et al. 2008; Rawat et al. 2008; de Ravel et al. 2009).”
GAS-PHASE OXYGEN GRADIENTS IN STRONGLY INTERACTING GALAXIES. I. EARLY-STAGE INTERACTIONS (2010, background): “Understanding chemical evolution during a major merger will shed light on galaxy evolution at the peak of cosmic star formation, since the major merger rate, especially involving gas-rich galaxies, was higher in the past (de Ravel et al. 2009; Bundy et al. 2009).”