Gupta, S and Nath, BB and Sharma, P (2018) Constraining cosmic ray acceleration in young star clusters using multi-wavelength observations. In: Monthly Notices of the Royal Astronomical Society, 479 (4). pp. 5220-5234.
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Abstract
We use 1D and 3D two-fluid cosmic ray (CR) hydrodynamic simulations to investigate the role of CRs in the vicinity of a compact young star cluster. We model a self-gravitating cloud (density profile ρ∝r-1), include important thermal and non-thermal processes, and explore two different CR injection scenarios. We show that if internal shocks in the wind-driving region are the main site for CR acceleration, then the resulting γ-ray luminosity (Lγ) can reach ≈5 per cent of the mechanical luminosity (Lw), independent of the fraction of wind energy (~1-20 per cent) injected into CRs. In contrast, if the forward/reverse shock of a bubble is the injection site then Lγ increases linearly with the CR injection fraction, as expected analytically. We find that the X-ray luminosity (Lx) in the forward/reverse shock injection scenario is ≳ 10-3Lw, which is ~10 times larger than in the central wind-driving injection case. We predict the corresponding range of the synchrotron radio luminosity. We show how multi-wavelength observations can constrain the CR parameters. Comparing the predicted multi-wavelength luminosities with those of 30 Doradus and Westerlund 2 we identify the reverse shock as the most probable CR injection site. We do not find significant dynamical impact of CRs in our models.
| Item Type: | Journal Article |
|---|---|
| Publication: | Monthly Notices of the Royal Astronomical Society |
| Publisher: | Oxford University Press |
| Additional Information: | The copyright for this article belongs to the Authors. |
| Keywords: | Cosmic rays; Galaxies: star clusters: general; Hydrodynamics; ISM: bubbles |
| Department/Centre: | Division of Physical & Mathematical Sciences > Joint Astronomy Programme Division of Physical & Mathematical Sciences > Physics |
| Date Deposited: | 26 Aug 2022 06:37 |
| Last Modified: | 26 Aug 2022 06:37 |
| URI: | https://eprints.iisc.ac.in/id/eprint/76241 |
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