The SRG/eROSITA all-sky survey
The properties of the warm-hot intergalactic medium (WHIM) in cosmic filaments are among the least quantified units in modern astrophysics. The Spectrum Roentgen Gamma/eROSITA All Sky Survey (SRG/eRASS) provides a unique opportunity to study the X-ray emission of the WHIM. We applied both imaging and spectroscopic stacking techniques to the data of the first four eRASS scans to inspect the X-ray emissions from 7817 cosmic filaments identified from Sloan Digital Sky Survey (SDSS) optical galaxy samples. We obtained a 9 σ significant detection of the total X-ray signal from filaments in the 0.3–1.2 keV band. Here, we introduce a novel method to estimate the contamination fraction from unmasked X-ray halos, active galactic nuclei, and X-ray binaries associated with filament galaxies. We found an approximately 40% contamination fraction for these unmasked sources, suggesting that the remaining 60% of the signal could be coming from the WHIM and a 5.4 σ detection significance of the WHIM. Moreover, we modeled the temperature and baryon density contrast of the detected WHIM by fitting the stacked spectrum and surface brightness profile. The best-fit temperature log( T /K) = 6.84 ± 0.07, obtained by using a single temperature model, is marginally higher than in the simulation results. This could be due to the fitting of a single temperature model on a multi-temperature spectrum. Assuming a 0.2 solar abundance, the best-fit baryon density contrast logΔ b = 1.88 ± 0.18 is in general agreement with the X-ray emitting phases in the IllustrisTNG simulation. This result suggests that the broadband X-ray emission traces the high end of the temperature and density values that characterize the entire WHIM population.
Authors
- Y. E. Bahar (ORCID: https://orcid.org/0000-0002-4893-7615)
- Y. Zhang (ORCID: https://orcid.org/0000-0001-7849-6593)
- Xiaoyuan Zhang (ORCID: https://orcid.org/0000-0001-6019-6373)
- A. Veronica (ORCID: https://orcid.org/0000-0002-8635-0030)
- V. Ghirardini (ORCID: https://orcid.org/0000-0002-3736-8058)
- G. Ponti (ORCID: https://orcid.org/0000-0003-0293-3608)
- M. Freyberg
- Michael C. H. Yeung (ORCID: https://orcid.org/0000-0002-5697-0001)
- S. Grandis (ORCID: https://orcid.org/0000-0002-4577-8217)
- T. H. Reiprich (ORCID: https://orcid.org/0000-0003-2047-2884)
- A. Merloni
- E. Artis (ORCID: https://orcid.org/0009-0001-6055-8503)
- C. Garrel (ORCID: https://orcid.org/0000-0002-1332-5694)
- M. Brüggen
- Johan Comparat (ORCID: https://orcid.org/0000-0001-9200-1497)
- Matthias Kluge (ORCID: https://orcid.org/0000-0002-9618-2552)
- Frank Balzer (ORCID: https://orcid.org/0000-0002-6228-6839)
- Sven Krippendorf (ORCID: https://orcid.org/0000-0001-6374-6828)
- A. Liu
- Nicola Malavasi (ORCID: https://orcid.org/0000-0001-9033-7958)
- Miriam E. Ramos-Ceja (ORCID: https://orcid.org/0000-0002-9117-3251)
- K. Nandra
- Efraín Gatuzz (ORCID: https://orcid.org/0000-0002-3252-9633)
- J. S. Sanders (ORCID: https://orcid.org/0000-0003-2189-4501)
- Esra Bülbül (ORCID: https://orcid.org/0000-0002-7619-5399)
- P. Predehl
- S. Zelmer (ORCID: https://orcid.org/0009-0003-0136-7648)
Institutions
- University of Bonn (DE)
- Universität Hamburg (DE)
- Universität Innsbruck (AT)
- Brera Astronomical Observatory (IT)
- Center for Theoretical Physics (PL)
- Max Planck Institute for Extraterrestrial Physics (DE)
- Hamburger Fern-Hochschule (DE)
- Osservatorio di Astrofisica e Scienza dello Spazio
- Ludwig-Maximilians-Universität München (DE)
- National Institute for Astrophysics (IT)
Publication Details
- Journal
- Astronomy and Astrophysics
- Published
- 2024-09-10
- DOI
- https://doi.org/10.1051/0004-6361/202450933
- Citations
- 11
- Primary Topic
- Galaxies: Formation, Evolution, Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 3.65
Funders
- Deutsche Forschungsgemeinschaft
- Istituto Nazionale di Astrofisica
- European Research Council
- HORIZON EUROPE Marie Sklodowska-Curie Actions