Galaxy And Mass Assembly (GAMA): extended intragroup light in a group at z = 0.2 from deep Hyper Suprime-Cam images
Abstract
We present a pilot study to assess the potential of Hyper Suprime-Cam Public Data Release 2 (HSC-PDR2) images for the analysis of extended faint structures within groups of galaxies. We examine the intragroup light (IGL) of the group 400138 (Mdyn = 1.3 ± 0.5 × 1013 M⊙, z ~ 0.2) from the Galaxy And Mass Assembly (GAMA) survey using Hyper Suprime-Cam Subaru Strategic Program Public Data Release 2 (HSC-SSP PDR2) images in g, r, and i bands. We present the most extended IGL measurement to date, reaching down to $\mu _{g}^{\rm {lim}}=30.76$ mag arcsec-2 (3σ; 10 × 10 arcsec2) at a semimajor axis of 275 kpc. The IGL shows mean colour values of g - i = 0.92, g - r = 0.60, and r - i = 0.32 (±0.01). The IGL stellar populations are younger (2-2.5 Gyr) and less metal rich ([Fe/H] ~ -0.4) than those of the host group galaxies. We find a range of IGL fractions as a function of total group luminosity of ${\sim} 2\!-\!36 {{\ \rm per\ cent}}$ depending on the definition of IGL, with larger fractions the bluer the observation wavelength. The early-type to late-type galaxy ratio suggests that 400138 is a more evolved group, dominated by early-type galaxies, and the IGL fraction agrees with that of other similarly evolved groups. These results are consistent with tidal stripping of the outer parts of Milky Way-like galaxies as the main driver of the IGL build-up. This is supported by the detection of substructure in the IGL towards the galaxy member 1660615 suggesting a recent interaction (<1 Gyr ago) of that galaxy with the core of the group.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- January 2023
- DOI:
- 10.1093/mnras/stac3119
- arXiv:
- arXiv:2211.12749
- Bibcode:
- 2023MNRAS.518.1195M
- Keywords:
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- galaxies: clusters: intracluster medium;
- galaxies: groups: general;
- galaxies: groups: individual: 400138;
- galaxies: haloes;
- galaxies: photometry;
- galaxies: evolution;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 19 pages, 8 figures, 2 tables, accepted for publication in MNRAS