Issue |
A&A
Volume 673, May 2023
|
|
---|---|---|
Article Number | L9 | |
Number of page(s) | 5 | |
Section | Letters to the Editor | |
DOI | https://doi.org/10.1051/0004-6361/202346430 | |
Published online | 12 May 2023 |
Letter to the Editor
Supermassive black hole wake or bulgeless edge-on galaxy?
1
Instituto de Astrofísica de Canarias, c/ Vía Láctea s/n, 38205 La Laguna, Tenerife, Spain
e-mail: jos@iac.es
2
Departamento de Astrofísica, Universidad de La Laguna, 38203 La Laguna, Tenerife, Spain
Received:
16
March
2023
Accepted:
22
April
2023
A recent paper reported the serendipitous discovery of a thin linear object interpreted as the trail of star-forming regions left behind by a runaway supermassive black hole (SMBH) kicked out from the center of a galaxy. Despite the undeniable interest in the idea, the actual physical interpretation is not devoid of difficulty. The wake of a SMBH produces only small perturbations in the external medium, which has to be in exceptional physical conditions to collapse gravitationally and form a long (40 kpc) massive (3 × 109 M⊙) stellar trace in only 39 Myr. Here we offer a more conventional explanation: the stellar trail is a bulgeless galaxy viewed edge-on. This interpretation is supported by the fact that its position–velocity curve resembles a rotation curve, which, together with its stellar mass, puts the object exactly on the Tully–Fisher relation characteristic of disk galaxies. Moreover, the rotation curve (Vmax ∼ 110 km s−1), stellar mass, extension, width (z0 ∼ 1.2 kpc), and surface brightness profile of the object are very much like those of IC 5249, a well-known local bulgeless edge-on galaxy. These observational facts are difficult to interpret within the SMBH wake scenario. We discuss in detail the pros and cons of the two options.
Key words: Galaxy: halo / galaxies: individual: IC 5249 / galaxies: kinematics and dynamics / galaxies: fundamental parameters / galaxies: peculiar / galaxies: structure
Note to the reader: the author's email address has been corrected on 17 May 2023.
© The Authors 2023
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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