JWST PRIMER: A lack of outshining in four normal z =4-6 galaxies from the ALMA-CRISTAL Survey
| Autor: | Lines, N. E. P., Bowler, R. A. A., Adams, N. J., Fisher, R., Varadaraj, R. G., Nakazato, Y., Aravena, M., Assef, R. J., Birkin, J. E., Ceverino, D., da Cunha, E., Cullen, F., De Looze, I., Donnan, C. T., Dunlop, J. S., Ferrara, A., Grogin, N. A., Herrera-Camus, R., Ikeda, R., Koekemoer, A. M., Killi, M., Li, J., McLeod, D. J., McLure, R. J., Mitsuhashi, I., Pérez-González, P. G., Relano, M., Solimano, M., Spilker, J. S., Villanueva, V., Yoshida, N. |
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| Rok vydání: | 2024 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| Popis: | We present a spatially resolved analysis of four star-forming galaxies at $z = 4.44-5.64$ using data from the JWST PRIMER and ALMA-CRISTAL surveys to probe the stellar and inter-stellar medium properties on the sub-kpc scale. In the $1-5\,\mu{\rm m}$ JWST NIRCam imaging we find that the galaxies are composed of multiple clumps (between $2$ and $\sim 8$) separated by $\simeq 5\,{\rm kpc}$, with comparable morphologies and sizes in the rest-frame UV and optical. Using BAGPIPES to perform pixel-by-pixel SED fitting to the JWST data we show that the SFR ($\simeq 25\,{\rm M}_{\odot}/{\rm yr}$) and stellar mass (${\rm log}_{10}(M_{\star}/{\rm M}_{\odot}) \simeq 9.5$) derived from the resolved analysis are in close ($ \lesssim 0.3\,{\rm dex}$) agreement with those obtained by fitting the integrated photometry. In contrast to studies of lower-mass sources, we thus find a reduced impact of outshining of the older (more massive) stellar populations in these normal $z \simeq 5$ galaxies. Our JWST analysis recovers bluer rest-frame UV slopes ($\beta \simeq -2.1$) and younger ages ($\simeq 100\,{\rm Myr}$) than archival values. We find that the dust continuum from ALMA-CRISTAL seen in two of these galaxies correlates, as expected, with regions of redder rest-frame UV slopes and the SED-derived $A_{\rm V}$, as well as the peak in the stellar mass map. We compute the resolved IRX-$\beta$ relation, showing that the IRX is consistent with the local starburst attenuation curve and further demonstrating the presence of an inhomogeneous dust distribution within the galaxies. A comparison of the CRISTAL sources to those from the FirstLight zoom-in simulation of galaxies with the same $M_{\star}$ and SFR reveals similar age and colour gradients, suggesting that major mergers may be important in the formation of clumpy galaxies at this epoch. Comment: 16 pages, 8 figures, 3 tables, plus 4 page appendix. Submitted to MNRAS |
| Databáze: | arXiv |
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