NIHAO VII: predictions for the galactic baryon budget in dwarf to Milky Way mass haloes

Liang Wang, Aaron A. Dutton, Gregory S. Stinson, Andrea V. Maccio, Thales A. Gutcke, X. Kang

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

We use the Numerical Investigation of a Hundred Astrophysical Objects (NIHAO) galaxy formation simulations to make predictions for the baryonic budget in present day galaxies ranging from dwarf (M-200 similar to 10(10)M circle dot) toMilkyWay (M-200 similar to 10(12)M circle dot) masses. The sample is made of 88 independent high-resolution cosmological zoom-in simulations. NIHAO galaxies reproduce key properties of observed galaxies, such as the stellar mass versus halo mass and cold gas versus stellar mass relations. Thus they make plausible predictions for the baryon budget. We present the mass fractions of stars, cold gas (T< 10(4) K), cool gas (10(4) < T< 10(5) K), warm-hot gas (10(5) < T < 5 x 10(6) K) and hot gas (T > 5 x 10(6) K), inside the virial radius, R200. Compared to the predicted baryon mass, using the dark halo mass and the universal baryon fraction, f(b) = Omega(b)/Omega(m) = 0.15, we find that all of our haloes are missing baryons. The missing mass has been relocated past 2 virial radii, and cool gas dominates the corona at low mass (M-200 Alpha less than or similar to 3 x 10(11)M circle dot) while the warm-hot gas dominates at high mass (M-200 less than or similar to 3 x 10(11)M circle dot). Haloes of mass M-200 greater than or similar to 10(10)M circle dot are missing similar to 90 per cent of their baryons. More massive haloes (M-200 similar to 10(12)M circle dot) retain a higher fraction of their baryons, with similar to 30 per cent missing, consistent with recent observational estimates. Moreover, these more massive haloes reproduce the observed fraction of cold, warm-hot and hot gases. The fraction of cool gas we predict (0.11 +/- 0.06) is significantly lower than the observation from COS-Halos (0.3-0.47), but agrees with the alternative analysis of Stern et al. (2016).
Original languageEnglish
Pages (from-to)4858-4867
JournalMonthly Notices of the Royal Astronomical Society
Volume466
Issue number4
DOIs
Publication statusPublished - May 2017

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