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arXiv · 2204.06569

Overestimated inclinations of Milgromian disc galaxies: the case of the ultradiffuse galaxy AGC 114905

Indranil Banik·Srikanth Togere Nagesh·Hosein Haghi·Pavel Kroupa·Hongsheng Zhao
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Abstract

We present hydrodynamical star-forming simulations in the Milgromian dynamics (MOND) framework of a gas-rich disc galaxy with properties similar to AGC 114905, which has recently been argued to have a rotation curve (RC) that is inconsistent with the MOND prediction. Our first model considers the galaxy in isolation, while our second model includes an external field of $0.05 \, a_{_0}$, the estimated gravitational field from large-scale structure. We show that isophotes in the face-on view can differ from circular at the 50% level. This could mislead observers into overestimating the inclination $i$ between disc and sky planes. Because RCs require a correction factor of $1/\sin i$, the actual RC could be much higher than reported by observers. This plausibly reconciles AGC 114905 with MOND expectations.

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Indranil Banik, Srikanth Togere Nagesh, Hosein Haghi, Pavel Kroupa, Hongsheng Zhao. 2022-04-13. Overestimated inclinations of Milgromian disc galaxies: the case of the ultradiffuse galaxy AGC 114905. https://doi.org/10.1093/mnras/stac1073

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