The Star Formation History and Dynamics of the Ultra-diffuse Galaxy Dragonfly 44 in MOND and MOG

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F19%3A10406869" target="_blank" >RIV/00216208:11320/19:10406869 - isvavai.cz</a>

Výsledek na webu

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=heH4pGJFyC" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=heH4pGJFyC</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3847/2041-8213/ab4517" target="_blank" >10.3847/2041-8213/ab4517</a>

Jazyk výsledku

angličtina

Název v původním jazyce

The Star Formation History and Dynamics of the Ultra-diffuse Galaxy Dragonfly 44 in MOND and MOG

Popis výsledku v původním jazyce

The observed line-of-sight velocity dispersion sigma(los) of the ultra-diffuse galaxy Dragonfly 44 (DF44) requires a Newtonian dynamical mass-to-light ratio of M-dyn/L-I = 26(-6)(+7) solar units. This is well outside the acceptable limits of our stellar population synthesis (SPS) models, which we construct using the integrated galactic initial mass function (IGIMF) theory. Assuming DF44 is in isolation and using Jeans analysis, we calculate slos profiles of DF44 in Milgromian dynamics (MOND) and modified gravity (MOG) theories without invoking dark matter. Comparing with the observed kinematics, the best-fitting MOND model has M-dyn/L-I = 3.6(-1.2)(+1.6) and a constant orbital anisotropy of beta = -0.5(-1.6)(+0.4) . In MOG, we first fix its two theoretical parameters alpha and mu based on previous fits to the observed rotation curve data of The HI Nearby Galaxy Survey (THINGS). The DF44 sigma(los) profile is best fit with M-dyn/L-I = 7.4(-1.4)(+1.5) larger than plausible SPS values. MOG produces a sigma(los) profile for DF44 with acceptable M-dyn/L-I and isotropic orbits if alpha and mu are allowed to vary. MOND with the canonical a(0) can explain DF44 at the 2.40 sigma confidence level (1.66%) if considering both its observed kinematics and typical star formation histories in an IGIMF context. However, MOG is ruled out at 5.49 sigma (P-value of 4.07 x 10(-8)) if its free parameters are fixed at the highest values consistent with THINGS data.

Název v anglickém jazyce

The Star Formation History and Dynamics of the Ultra-diffuse Galaxy Dragonfly 44 in MOND and MOG

Popis výsledku anglicky

The observed line-of-sight velocity dispersion sigma(los) of the ultra-diffuse galaxy Dragonfly 44 (DF44) requires a Newtonian dynamical mass-to-light ratio of M-dyn/L-I = 26(-6)(+7) solar units. This is well outside the acceptable limits of our stellar population synthesis (SPS) models, which we construct using the integrated galactic initial mass function (IGIMF) theory. Assuming DF44 is in isolation and using Jeans analysis, we calculate slos profiles of DF44 in Milgromian dynamics (MOND) and modified gravity (MOG) theories without invoking dark matter. Comparing with the observed kinematics, the best-fitting MOND model has M-dyn/L-I = 3.6(-1.2)(+1.6) and a constant orbital anisotropy of beta = -0.5(-1.6)(+0.4) . In MOG, we first fix its two theoretical parameters alpha and mu based on previous fits to the observed rotation curve data of The HI Nearby Galaxy Survey (THINGS). The DF44 sigma(los) profile is best fit with M-dyn/L-I = 7.4(-1.4)(+1.5) larger than plausible SPS values. MOG produces a sigma(los) profile for DF44 with acceptable M-dyn/L-I and isotropic orbits if alpha and mu are allowed to vary. MOND with the canonical a(0) can explain DF44 at the 2.40 sigma confidence level (1.66%) if considering both its observed kinematics and typical star formation histories in an IGIMF context. However, MOG is ruled out at 5.49 sigma (P-value of 4.07 x 10(-8)) if its free parameters are fixed at the highest values consistent with THINGS data.

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

2019

Kód důvěrnosti údajů

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

Název periodika

Astrophysical Journal Letters

ISSN

2041-8205

e-ISSN

—

Svazek periodika

884

Číslo periodika v rámci svazku

1

Stát vydavatele periodika

US - Spojené státy americké

Počet stran výsledku

8

Strana od-do

L25

Kód UT WoS článku

000504275400004

EID výsledku v databázi Scopus

2-s2.0-85074332565