MIGHTEE-HI: the radial acceleration relation with resolved stellar mass measurements

Monthly Notices of the Royal Astronomical Society, vol. 541, pp. 2366–2392

Abstract

ABSTRACT The radial acceleration relation (RAR) is a fundamental relation linking baryonic and dark matter in galaxies by relating the observed acceleration derived from dynamics to the one estimated from the baryonic mass. This relation exhibits small scatter, thus providing key constraints for models of galaxy formation and evolution – allowing us to map the distribution of dark matter in galaxies – as well as models of modified dynamics. However, it has only been extensively studied in the very local Universe with largely heterogeneous samples. We present a new measurement of the RAR, utilizing a homogeneous sample of 19 H i-selected galaxies out to $z=0.08$. We introduce a novel approach of measuring resolved stellar masses using spectral energy distribution fitting across 10 photometric bands to determine the resolved mass-to-light ratio, which we show is essential for measuring the acceleration due to baryons in the low-acceleration regime. Our results reveal a tight RAR with a low-acceleration power-law slope of $\sim 0.5$, consistent with previous studies. Adopting a spatially varying mass-to-light ratio yields the tightest RAR with an intrinsic scatter of only $0.045 \pm 0.022$ dex, highlighting the importance of resolved stellar mass measurements in accurately characterizing the gravitational contribution of the baryons in low-mass, gas-rich galaxies. We also find the first tentative evidence for redshift evolution in the acceleration scale, but more data will be required to confirm this. Adopting a more general MOND interpolating function, we find that our results ameliorate the tension between previous RAR analyses, the Solar System quadrupole, and wide-binary test.

Authors 11

1. Andreea Vărăşteanu corresponding

   University of Oxford

   Affiliation as printed

   Oxford Astrophysics , Denys Wilkinson Building, University of Oxford, Keble Road, Oxford OX1 3RH ,

   Oxford Astrophysics , Denys Wilkinson Building, University of Oxford, Keble Road, Oxford, OX1 3RH ,

2. M. J. Jarvis

   University of Oxford · University of the Western Cape

   Affiliation as printed

   Oxford Astrophysics , Denys Wilkinson Building, University of Oxford, Keble Road, Oxford OX1 3RH ,

   University of the Western Cape Department of Physics and Astronomy, , Robert Sobukwe Road, 7535 Bellville, Cape Town ,

   Oxford Astrophysics , Denys Wilkinson Building, University of Oxford, Keble Road, Oxford, OX1 3RH ,

3. Anastasia A Ponomareva

   University of Hertfordshire · University of Oxford

   Affiliation as printed

   Centre for Astrophysics Research, School of Physics, Astronomy and Mathematics, University of Hertfordshire , College Lane, Hatfield AL10 9AB ,

   Oxford Astrophysics , Denys Wilkinson Building, University of Oxford, Keble Road, Oxford OX1 3RH ,

   Centre for Astrophysics Research, School of Physics, Astronomy and Mathematics, University of Hertfordshire , College Lane, Hatfield, AL10 9AB ,

   Oxford Astrophysics , Denys Wilkinson Building, University of Oxford, Keble Road, Oxford, OX1 3RH ,

4. Harry Desmond

   University of Portsmouth

   Affiliation as printed

   Institute of Cosmology and Gravitation, University of Portsmouth , Dennis Sciama Building, Portsmouth PO1 3FX ,

   Institute of Cosmology & Gravitation, University of Portsmouth , Dennis Sciama Building, Portsmouth, PO1 3FX ,

5. Ian Heywood

   Rhodes University · University of Oxford · South African Radio Astronomy Observatory

   Affiliation as printed

   Oxford Astrophysics , Denys Wilkinson Building, University of Oxford, Keble Road, Oxford OX1 3RH ,

   Rhodes University Centre for Radio Astronomy Techniques and Technologies, Department of Physics and Electronics, , PO Box 94, Makhanda 6140 ,

   South African Radio Astronomy Observatory , 2 Fir Street, Black River Park, Observatory, Cape Town 7925 ,

   Centre for Radio Astronomy Techniques and Technologies , Department of Physics and Electronics, Rhodes University, PO Box 94, Makhanda, 6140 ,

   Oxford Astrophysics , Denys Wilkinson Building, University of Oxford, Keble Road, Oxford, OX1 3RH ,

   South African Radio Astronomy Observatory , 2 Fir Street, Black River Park, Observatory, Cape Town, 7925 ,

6. Tariq Yasin

   University of Oxford

   Affiliation as printed

   Oxford Astrophysics , Denys Wilkinson Building, University of Oxford, Keble Road, Oxford OX1 3RH ,

   Oxford Astrophysics , Denys Wilkinson Building, University of Oxford, Keble Road, Oxford, OX1 3RH ,

7. Natasha Maddox

   University of Bristol

   Affiliation as printed

   School of Physics, H.H. Wills Physics Laboratory , Tyndall Avenue, University of Bristol, Bristol BS8 1TL ,

   School of Physics, H.H. Wills Physics Laboratory , Tyndall Avenue, University of Bristol, Bristol, BS8 1TL ,

8. Marcin Glowacki

   University of Cape Town · Royal Observatory · Inter-university Institute for Data Intensive Astronomy · University of Edinburgh

   Affiliation as printed

   Institute for Astronomy, University of Edinburgh , Royal Observatory, Edinburgh EH9 3HJ ,

   University of Cape Town Inter-University Institute for Data Intensive Astronomy, Department of Astronomy, , Cape Town ,

   Institute for Astronomy, University of Edinburgh , Royal Observatory, Edinburgh, EH9 3HJ ,

   Inter-University Institute for Data Intensive Astronomy , Department of Astronomy, University of Cape Town, Cape Town ,

9. Michalina Maksymowicz-Maciata

   University of Bristol

   Affiliation as printed

   School of Physics, H.H. Wills Physics Laboratory , Tyndall Avenue, University of Bristol, Bristol BS8 1TL ,

   School of Physics, H.H. Wills Physics Laboratory , Tyndall Avenue, University of Bristol, Bristol, BS8 1TL ,

10. Pavel E. Mancera Piña Aachen Leiden Observatory

    Leiden University · Leiden Observatory

    Affiliation as printed

    Leiden Observatory, Leiden University , P.O. Box 9513, NL-2300 RA Leiden ,

    Leiden Observatory, Leiden University , P.O. Box 9513, 2300 RA, Leiden , The

11. Hengxing Pan

    Chinese Academy of Sciences · National Astronomical Observatories

    Affiliation as printed

    National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101 ,

    National Astronomical Observatories, Chinese Academy of Sciences , Beijing 100101 , People’s Republic of China