TY - JOUR

T1 - Major merging history in CANDELS

T2 - I. Evolution of the incidence of massive galaxy–galaxy pairs from z = 3 to z ∼ 0

AU - Mantha, Kameswara Bharadwaj

AU - Mcintosh, Daniel H

AU - Brennan, Ryan

AU - Ferguson, Henry C

AU - Kodra, Dritan

AU - Newman, Jeffrey A

AU - Rafelski, Marc

AU - Somerville, Rachel S

AU - Conselice, Christopher J

AU - Cook, Joshua S

AU - Hathi, Nimish P

AU - Koo, David C

AU - Lotz, Jennifer M

AU - Simmons, Brooke D

AU - Straughn, Amber N

AU - Snyder, Gregory F

AU - Wuyts, Stijn

AU - Bell, Eric F

AU - Dekel, Avishai

AU - Kartaltepe, Jeyhan

AU - Kocevski, Dale D

AU - Koekemoer, Anton M

AU - Lee, Seong-kook

AU - Lucas, Ray A

AU - Pacifici, Camilla

AU - Peth, Michael A

AU - Barro, Guillermo

AU - Dahlen, Tomas

AU - Finkelstein, Steven L

AU - Fontana, Adriano

AU - Galametz, Audrey

AU - Grogin, Norman A

AU - Guo, Yicheng

AU - Mobasher, Bahram

AU - Nayyeri, Hooshang

AU - Pérez-gonzález, Pablo G

AU - Pforr, Janine

AU - Santini, Paola

AU - Stefanon, Mauro

AU - Wiklind, Tommy

PY - 2018/4/1

Y1 - 2018/4/1

N2 - The rate of major galaxy–galaxy merging is theoretically predicted to steadily increase with redshift during the peak epoch of massive galaxy development (1 ≤ z ≤ 3). We use close-pair statistics to objectively study the incidence of massive galaxies (stellar M1 > 2 × 1010 M⊙) hosting major companions (1 ≤ M1/M2 ≤ 4; i.e. <4:1) at six epochs spanning 0 < z < 3. We select companions from a nearly complete, mass-limited (≥5 × 109 M⊙) sample of 23 696 galaxies in the five Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey fields and the Sloan Digital Sky Survey. Using 5–50 kpc projected separation and close redshift proximity criteria, we find that the major companion fraction fmc(z) based on stellar mass-ratio (MR) selection increases from 6 per cent (z ∼ 0) to 16 per cent (z ∼ 0.8), then turns over at z ∼ 1 and decreases to 7 per cent (z ∼ 3). Instead, if we use a major F160W flux-ratio (FR) selection, we find that fmc(z) increases steadily until z = 3 owing to increasing contamination from minor (MR > 4:1) companions at z > 1. We show that these evolutionary trends are statistically robust to changes in companion proximity. We find disagreements between published results are resolved when selection criteria are closely matched. If we compute merger rates using constant fraction-to-rate conversion factors (Cmerg,pair = 0.6 and Tobs,pair = 0.65 Gyr), we find that MR rates disagree with theoretical predictions at z > 1.5. Instead, if we use an evolving Tobs,pair(z) ∝ (1 + z)−2 from Snyder et al., our MR-based rates agree with theory at 0 < z < 3. Our analysis underscores the need for detailed calibration of Cmerg,pair and Tobs,pair as a function of redshift, mass, and companion selection criteria to better constrain the empirical major merger history.

AB - The rate of major galaxy–galaxy merging is theoretically predicted to steadily increase with redshift during the peak epoch of massive galaxy development (1 ≤ z ≤ 3). We use close-pair statistics to objectively study the incidence of massive galaxies (stellar M1 > 2 × 1010 M⊙) hosting major companions (1 ≤ M1/M2 ≤ 4; i.e. <4:1) at six epochs spanning 0 < z < 3. We select companions from a nearly complete, mass-limited (≥5 × 109 M⊙) sample of 23 696 galaxies in the five Cosmic Assembly Near-Infrared Deep Extragalactic Legacy Survey fields and the Sloan Digital Sky Survey. Using 5–50 kpc projected separation and close redshift proximity criteria, we find that the major companion fraction fmc(z) based on stellar mass-ratio (MR) selection increases from 6 per cent (z ∼ 0) to 16 per cent (z ∼ 0.8), then turns over at z ∼ 1 and decreases to 7 per cent (z ∼ 3). Instead, if we use a major F160W flux-ratio (FR) selection, we find that fmc(z) increases steadily until z = 3 owing to increasing contamination from minor (MR > 4:1) companions at z > 1. We show that these evolutionary trends are statistically robust to changes in companion proximity. We find disagreements between published results are resolved when selection criteria are closely matched. If we compute merger rates using constant fraction-to-rate conversion factors (Cmerg,pair = 0.6 and Tobs,pair = 0.65 Gyr), we find that MR rates disagree with theoretical predictions at z > 1.5. Instead, if we use an evolving Tobs,pair(z) ∝ (1 + z)−2 from Snyder et al., our MR-based rates agree with theory at 0 < z < 3. Our analysis underscores the need for detailed calibration of Cmerg,pair and Tobs,pair as a function of redshift, mass, and companion selection criteria to better constrain the empirical major merger history.

U2 - 10.1093/mnras/stx3260

DO - 10.1093/mnras/stx3260

M3 - Journal article

VL - 475

SP - 1549

EP - 1573

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 2

ER -