On the absence of backsplash analogues to NGC 3109 in the Lambda CDM framework

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F21%3A10438777" target="_blank" >RIV/00216208:11320/21:10438777 - isvavai.cz</a>

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=R_zYc6a59C" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=R_zYc6a59C</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1093/mnras/stab751" target="_blank" >10.1093/mnras/stab751</a>

Jazyk výsledku

angličtina

Název v původním jazyce

On the absence of backsplash analogues to NGC 3109 in the Lambda CDM framework

Popis výsledku v původním jazyce

The dwarf galaxy NGC 3109 is receding 105 km s(-1) faster than expected in a Lambda cold dark matter (ACDM) timing argument analysis of the Local Group and external galaxy groups within 8 Mpc. If this few-body model accurately represents long-range interactions in ACDM, this high velocity suggests that NGC 3109 is a backsplash galaxy that was once within the virial radius of the Milky Way and was slingshot out of it. Here, we use the Illustris TNG300 cosmological hydrodynamical simulation and its merger tree to identify backsplash galaxies. We find that backsplashers as massive (&gt;= 4.0 x 10(10) M-circle dot) and distant (&gt;= 1.2 Mpc) as NGC 3109 are extremely rare, with none having also gained energy during the interaction with their previous host. This is likely due to dynamical friction. Since we identified 13 225 host galaxies similar to the Milky Way or M31, we conclude that postulating NGC 3109 to be a backsplash galaxy causes &gt;3.96 sigma tension with the expected distribution of backsplashers in ACDM. We show that the dark matter only version of TNG300 yields much the same result, demonstrating its robustness to how the baryonic physics is modelled. If instead NGC 3109 is not a backsplasher, consistency with ACDM would require the 3D timing argument analysis to be off by 105 km s(-1) for this rather isolated dwarf, which we argue is unlikely. We discuss a possible alternative scenario for NGC 3109 and the Local Group satellite planes in the context of MOND, where the Milky Way and M31 had a past close flyby 7-10 Gyr ago.

Název v anglickém jazyce

On the absence of backsplash analogues to NGC 3109 in the Lambda CDM framework

Popis výsledku anglicky

The dwarf galaxy NGC 3109 is receding 105 km s(-1) faster than expected in a Lambda cold dark matter (ACDM) timing argument analysis of the Local Group and external galaxy groups within 8 Mpc. If this few-body model accurately represents long-range interactions in ACDM, this high velocity suggests that NGC 3109 is a backsplash galaxy that was once within the virial radius of the Milky Way and was slingshot out of it. Here, we use the Illustris TNG300 cosmological hydrodynamical simulation and its merger tree to identify backsplash galaxies. We find that backsplashers as massive (&gt;= 4.0 x 10(10) M-circle dot) and distant (&gt;= 1.2 Mpc) as NGC 3109 are extremely rare, with none having also gained energy during the interaction with their previous host. This is likely due to dynamical friction. Since we identified 13 225 host galaxies similar to the Milky Way or M31, we conclude that postulating NGC 3109 to be a backsplash galaxy causes &gt;3.96 sigma tension with the expected distribution of backsplashers in ACDM. We show that the dark matter only version of TNG300 yields much the same result, demonstrating its robustness to how the baryonic physics is modelled. If instead NGC 3109 is not a backsplasher, consistency with ACDM would require the 3D timing argument analysis to be off by 105 km s(-1) for this rather isolated dwarf, which we argue is unlikely. We discuss a possible alternative scenario for NGC 3109 and the Local Group satellite planes in the context of MOND, where the Milky Way and M31 had a past close flyby 7-10 Gyr ago.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10308 - Astronomy (including astrophysics,space science)

Projekt

—

Návaznosti

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Rok uplatnění

2021

Kód důvěrnosti údajů

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

Název periodika

Monthly Notices of the Royal Astronomical Society

ISSN

0035-8711

e-ISSN

—

Svazek periodika

503

Číslo periodika v rámci svazku

4

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

17

Strana od-do

6170-6186

Kód UT WoS článku

000649001600103

EID výsledku v databázi Scopus

2-s2.0-85118087628