The Merian survey: design, construction, and characterization of a filter set optimized to find dwarf galaxies and measure their dark matter halo properties with weak lensing

Yifei Luo, Alexie Leauthaud, Jenny Greene, Song Huang, Erin Kado-Fong, Shany Danieli, Ting S. Li, Jiaxuan Li, Diana Blanco, Erik J. Wasleske, Joseph Wick, Abby Mintz, Runquan Guan, Annika H.G. Peter, Vivienne Baldassare, Alyson Brooks, Arka Banerjee, Joy Bhattacharyya, Zheng Cai, Xinjun ChenJim Gunn, Sean D. Johnson, Lee S. Kelvin, Mingyu Li, Xiaojing Lin, Robert Lupton, Charlie Mace, Gustavo E. Medina, Justin Read, Rodrigo Córdova Rosado, Allen Seifert

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

The Merian survey is mapping ∼ 850 deg2 of the Hyper Suprime-Cam Strategic Survey Program (HSC-SSP) wide layer with two medium-band filters on the 4-m Victor M. Blanco telescope at the Cerro Tololo Inter-American Observatory, with the goal of carrying the first high signal-to-noise (S/N) measurements of weak gravitational lensing around dwarf galaxies. This paper presents the design of the Merian filter set: N708 (λc = 7080 Å, Δλ = 275 Å) and N540 (λc = 5400 Å, Δλ = 210 Å). The central wavelengths and filter widths of N708 and N540 were designed to detect the Hα and [OIII] emission lines of galaxies in the mass range 8 < log M/M☉ < 9 by comparing Merian fluxes with HSC broad-band fluxes. Our filter design takes into account the weak lensing S/N and photometric redshift performance. Our simulations predict that Merian will yield a sample of ∼ 85 000 star-forming dwarf galaxies with a photometric redshift accuracy of σΔz/(1 + z) ∼ 0.01 and an outlier fraction of η = 2.8 per cent over the redshift range 0.058 < z < 0.10. With 60 full nights on the Blanco/Dark Energy Camera (DECam), the Merian survey is predicted to measure the average weak lensing profile around dwarf galaxies with lensing S/N ∼32 within r < 0.5 Mpc and lensing S/N ∼90 within r < 1.0 Mpc. This unprecedented sample of star-forming dwarf galaxies will allow for studies of the interplay between dark matter and stellar feedback and their roles in the evolution of dwarf galaxies.

Original languageEnglish (US)
Pages (from-to)4988-5005
Number of pages18
JournalMonthly Notices of the Royal Astronomical Society
Volume530
Issue number4
DOIs
StatePublished - Jun 1 2024

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • cosmology: observations
  • galaxies: dwarf
  • gravitational lensing: weak

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