Dry Merger Rate and Post-merger Fraction in the Coma Cluster Core

Abstract

We evaluate the dry merger activity in the Coma cluster, using a spectroscopically complete sample of 70 red-sequence (RS) galaxies, most of which (~75%) are located within 0.2R200 (~0.5 Mpc) from the cluster center, with data from the Coma Treasury Survey obtained with the Hubble Space Telescope. The fraction of close galaxy pairs in the sample is the proxy employed for the estimation of the merger activity. We identify 5 pairs and 1 triplet, enclosing a total of 13 galaxies, based on limits on projected separation and line-of-sight velocity difference. Of these systems, none show signs of ongoing interaction, and therefore we do not find any true mergers in our sample. This negative result sets a 1σ upper limit of 1.5% per Gyr for the major dry merger rate, consistent with the low rates expected in present-day clusters. Detailed examination of the images of all the RS galaxies in the sample reveals only one with low surface brightness features identifiable as the remnant of a past merger or interaction, implying a post-merger fraction below 2%.

7 pages, 4 figures, 1 table

References in corpus (12)

• Formation of Massive Galaxies at High Redshift: Cold Streams, Clumpy Disks and Compact Spheroids
• The Atlas3D project -- XXIX. The new look of early-type galaxies and surrounding fields disclosed by extremely deep optical images
• LoCuSS: The slow quenching of star formation in cluster galaxies and the need for pre-processing
• A calibration of the relation between the abundance of close galaxy pairs and the rate of galaxy mergers
• Dissipationless Mergers of Elliptical Galaxies and the Evolution of the Fundamental Plane
• The HST/ACS Coma Cluster Survey: I - Survey Objectives and Design
• The Evolution of Dusty Star Formation and Stellar Mass Assembly in Clusters: Results from the IRAC 3.6um, 4.5um, 5.8um and 8.0um Cluster Luminosity Functions
• The Late Stellar Assembly of Massive Cluster Galaxies Via Major Merging
• The Fundamental Plane of massive quiescent galaxies out to z~2
• Merger relics of cluster galaxies
• The HST/ACS Coma Cluster Survey - VII. Structure and Assembly of Massive Galaxies in the Center of the Coma Cluster
• A Novel Approach to Constrain the Mass Ratio of Minor Mergers in Elliptical Galaxies: Application to NGC 4889, the Brightest Cluster Galaxy in Coma

Cited by in corpus (2)

• New criteria for the selection of galaxy close pairs from cosmological simulations: evolution of the major and minor merger fraction in MUSE deep fields
• Galaxy Merger Candidates in High-Redshift Cluster Environments