Stacking the Cosmic Web in fluorescent Lyα emission with MUSE

Sofia G. Gallego et al.

Stacking 390 MUSE data cubes to look for the faint glow of cosmic web filaments between galaxies, and for what the gas around galaxies reveals.

Paper ↗arXiv ↗ADS ↗Project page

What was found

• Simulations place most of the matter in filaments between galaxies, which should glow faintly when the ionising background illuminates them.
• Stacking 390 MUSE cubes aligned on neighbouring Lyα emitters reached a sensitivity about three times below the predicted level of the glow.
• No emission appears between galaxies, which implies that most of the stacked cubes lack suitably oriented dense gas clouds under this background model.
• Clear emission shows up in the gas around galaxies, pointing toward their neighbours. It grows with the number of neighbours and does not depend on luminosity, redshift or separation, and satellite galaxies seem unlikely to explain it.

This summary is written for a general audience. The paper has the full details.

@article{gallego2018,
  author = {Gallego, Sofia G. and others},
  title = {{Stacking the Cosmic Web in fluorescent Lyα emission with MUSE}},
  journal = {Monthly Notices of the Royal Astronomical Society},
  year = {2018},
  volume = {475},
  pages = {3854--3869},
  doi = {10.1093/mnras/sty037},
  eprint = {1706.03785},
  archivePrefix = {arXiv}
}

Topics Cosmic web and UV background Circumgalactic and intergalactic gas