The Star Formation History and Dynamics of the Ultra-diffuse Galaxy Dragonfly 44 in MOND and MOG
The result's identifiers
Result code in 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>
Result on the web
<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>
Alternative languages
Result language
angličtina
Original language name
The Star Formation History and Dynamics of the Ultra-diffuse Galaxy Dragonfly 44 in MOND and MOG
Original language description
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.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - 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)
Result continuities
Project
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Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2019
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Astrophysical Journal Letters
ISSN
2041-8205
e-ISSN
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Volume of the periodical
884
Issue of the periodical within the volume
1
Country of publishing house
US - UNITED STATES
Number of pages
8
Pages from-to
L25
UT code for WoS article
000504275400004
EID of the result in the Scopus database
2-s2.0-85074332565