The Magellanic Clouds Are Very Rare in the IllustrisTNG Simulations

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F24%3A10493635" target="_blank" >RIV/00216208:11320/24:10493635 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=ZGdGxXvs8q" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=ZGdGxXvs8q</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3390/universe10100385" target="_blank" >10.3390/universe10100385</a>

Result language

angličtina

Original language name

The Magellanic Clouds Are Very Rare in the IllustrisTNG Simulations

Original language description

The Large and Small Magellanic Clouds (LMC and SMC) form the closest interacting galactic system to the Milky Way, therewith providing a laboratory to test cosmological models in the local Universe. We quantify the likelihood for the Magellanic Clouds (MCs) to be observed within the Lambda CDM model using hydrodynamical simulations of the IllustrisTNG project. The orbits of the MCs are constrained by proper motion measurements taken by the Hubble Space Telescope and Gaia. The MCs have a mutual separation of d(MCs) = 24.5 kpc and a relative velocity of v(MCs) = 90.8km s(-1), implying a specific phase-space density of f(MCs,obs) = (d(MCs) center dot v(MCs))(-3) = 9.10 x 10(-11) km(-3) s(3) kpc(-3). We select analogues to the MCs based on their stellar masses and distances inMW-like halos. None of the selected LMC analogues have a higher total mass and lower Galactocentric distance than the LMC, resulting in &gt;3.75 sigma tension. We also find that the f(MCs) distribution in the highest resolution TNG50 simulation is in 3.95 sigma tension with observations. Thus, a hierarchical clustering of two massive satellites like the MCs in a narrow phase-space volume is unlikely in Lambda CDM, presumably because of short merger timescales due to dynamical friction between the overlapping dark matter halos. We show that group infall led by an LMC analogue cannot populate the Galactic disc of satellites (DoS), implying that the DoS and the MCs formed in physically unrelated ways in Lambda CDM. Since the 20 degrees alignment of the LMC and DoS orbital poles has a likelihood of P = 0.030 (2.17 sigma), adding this chi(2) to that of f(MCs) gives a combined likelihood of P = 3.90 x 10(-5) (4.11 sigma).

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10308 - Astronomy (including astrophysics,space science)

Project

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Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2024

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Universe

ISSN

2218-1997

e-ISSN

2218-1997

Volume of the periodical

10

Issue of the periodical within the volume

10

Country of publishing house

CH - SWITZERLAND

Number of pages

32

Pages from-to

385

UT code for WoS article

001343582700001

EID of the result in the Scopus database

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