Little Red Dots as self-gravitating discs accreting on supermassive stars: Spectral appearance and formation pathway of the progenitors to direct collapse black holes
Fuente:
arXiv
Enregistré dans:
| Auteurs principaux: | , , |
|---|---|
| Format: | Preprint |
| Publié: |
2025
|
| Sujets: | |
| Accès en ligne: | |
| Tags: |
Ajouter un tag
Pas de tags, Soyez le premier à ajouter un tag!
|
| _version_ | 1866915829431402496 |
|---|---|
| author | Zwick, Lorenz Tiede, Christopher Mayer, Lucio |
| author_facet | Zwick, Lorenz Tiede, Christopher Mayer, Lucio |
| contents | We propose an alternative physical interpretation and formation pathway for the recently discovered "little red dots" (LRDs). We model LRDs as super-massive stars (SMSs) surrounded by massive self-gravitating accretion discs (SMDs) that form as a consequence of gas-rich major galaxy mergers. The model provides an excellent match for numerous spectral features of LRDs, where the V-shape arises from the superposition of two black bodies, and Balmer line broadening is sourced by the intrinsic rotation of the SMD. No additional AGN, stellar, dust, or broadening component is strictly required. This results in a model with physically motivated parameters that are robust to variations in observed LRD properties. We perform MCMC fits for two representative LRD spectra, for which the full parameter posterior distributions are determined. Allowing for a compressed SMS mass-radius relation, the recovered parameters are compatible with sub-Eddington accretion in self-gravitating discs, and the recovered SMS masses of few $ 10^6$ M$_{\odot}$ imply the subsequent formation of massive black holes (BH) that squarely follow the expected BH mass--galaxy mass relation, while also predicting a cut-off luminosity of order few $10^{44}$ erg/s in quantitative agreement with current observations. While matching the abundance of LRDs is challenging, the association to galaxy mergers produces a redshift distribution that reflects observations. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_22014 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Little Red Dots as self-gravitating discs accreting on supermassive stars: Spectral appearance and formation pathway of the progenitors to direct collapse black holes Zwick, Lorenz Tiede, Christopher Mayer, Lucio Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics High Energy Astrophysical Phenomena We propose an alternative physical interpretation and formation pathway for the recently discovered "little red dots" (LRDs). We model LRDs as super-massive stars (SMSs) surrounded by massive self-gravitating accretion discs (SMDs) that form as a consequence of gas-rich major galaxy mergers. The model provides an excellent match for numerous spectral features of LRDs, where the V-shape arises from the superposition of two black bodies, and Balmer line broadening is sourced by the intrinsic rotation of the SMD. No additional AGN, stellar, dust, or broadening component is strictly required. This results in a model with physically motivated parameters that are robust to variations in observed LRD properties. We perform MCMC fits for two representative LRD spectra, for which the full parameter posterior distributions are determined. Allowing for a compressed SMS mass-radius relation, the recovered parameters are compatible with sub-Eddington accretion in self-gravitating discs, and the recovered SMS masses of few $ 10^6$ M$_{\odot}$ imply the subsequent formation of massive black holes (BH) that squarely follow the expected BH mass--galaxy mass relation, while also predicting a cut-off luminosity of order few $10^{44}$ erg/s in quantitative agreement with current observations. While matching the abundance of LRDs is challenging, the association to galaxy mergers produces a redshift distribution that reflects observations. |
| title | Little Red Dots as self-gravitating discs accreting on supermassive stars: Spectral appearance and formation pathway of the progenitors to direct collapse black holes |
| topic | Astrophysics of Galaxies Cosmology and Nongalactic Astrophysics High Energy Astrophysical Phenomena |
| url | https://arxiv.org/abs/2507.22014 |