Galaxy–galaxy lensing in the VOICE deep survey

¹ School of Physics and Astronomy, Sun Yat-sen University Zhuhai Campus, 2 Daxue Road, Tangjia, Zhuhai, Guangdong 519082, PR China
e-mail: napolitano@mail.sysu.edu.cn
² Shanghai Key Lab for Astrophysics, Shanghai Normal University, Shanghai 200234, PR China
e-mail: fuliping@shnu.edu.cn
³ CAS Key Laboratory for Research in Galaxies and Cosmology, University of Science and Technology of China, Hefei, Anhui 230026, PR China
e-mail: wtluo@ustc.edu.cn
⁴ Department of Astronomy, School of Physical Sciences, University of Science and Technology of China, Hefei, Anhui 230026, PR China
⁵ INAF – Osservatorio Astronomico di Padova, Via dell’Osservatorio 5, 35122 Padova, Italy
⁶ South-Western Institute for Astronomy Research, Yunnan University, Kunming, 650500 Yunnan, PR China
⁷ Dipartimento di Fisica ‘E. Pancini’, Universita degli Studi Federio II, Napoli 80126, Italy
⁸ INFN, Sezione di Napoli, Napoli 80126, Italy
⁹ INAF – Osservatorio Astronomico di Capodimonte, Salita Moiariello 16, Napoli 80131, Italy
¹⁰ Inter-University Institute for Data Intensive Astronomy, Department of Astronomy, University of Cape Town, 7701 Rondebosch, Cape Town, South Africa
¹¹ Inter-University Institute for Data Intensive Astronomy, Department of Physics and Astronomy, University of the Western Cape, 7535 Bellville, Cape Town, South Africa
¹² INAF – Istituto di Radioastronomia, Via Globetti 101, 40129 Bologna, Italy

Received: 12 April 2022
Accepted: 13 September 2022

Abstract

The multi-band photometry of the VOICE imaging data, overlapping with 4.9 deg² of the Chandra Deep Field South (CDFS) area, enables both shape measurement and photometric redshift estimation to be the two essential quantities for weak lensing analysis. The depth of mag_AB is up to 26.1 (5σ limiting) in r-band. We estimate the excess surface density (ESD; ΔΣ) based on galaxy–galaxy measurements around galaxies at lower redshift (0.10 < z_l < 0.35) while we select the background sources as those at higher redshift ranging from 0.3 to 1.5. The foreground galaxies are divided into two major categories according to their colour (blue and red), each of which has been further divided into high- and low-stellar-mass bins. The halo masses of the samples are then estimated by modelling the signals, and the posterior of the parameters are sampled using a Monte Carlo Markov chain process. We compare our results with the existing stellar-to-halo mass relation (SHMR) and find that the blue low-stellar-mass bin (median M_* = 10^8.31 M_⊙) deviates from the SHMR relation whereas the other three samples agree well with empirical curves. We interpret this discrepancy as the effect of the low star-formation efficiency of the low-mass blue dwarf galaxy population dominated in the VOICE-CDFS area.