%0 Generic %1 bowler2021rapid %A Bowler, R. A. A. %A Adams, N. J. %A Jarvis, M. J. %A Häußler, B. %D 2021 %K library %T The rapid transition from star-formation to AGN dominated rest-frame UV light at z ~ 4 %U http://arxiv.org/abs/2101.01195 %X With the advent of deep optical-to-near-infrared extragalactic imaging on the degree scale, samples of high-redshift sources are being selected that contain both bright star-forming (SF) galaxies and faint active galactic nuclei (AGN). In this study we investigate the transition between SF and AGN-dominated systems at $z 4$ in the rest-frame UV. We find a rapid transition to AGN-dominated sources bright-ward of $M_UV -23.2$. The effect is observed in the rest-frame UV morphology and size-luminosity relation, where extended clumpy systems become point-source dominated, and also in the available spectra for the sample. These results allow us to derive the rest-frame UV luminosity function for the SF and AGN-dominated sub-samples. We find the SF-dominated LF is best fit with a double-power law, with a lensed Schechter function being unable to explain the existence of extremely luminous SF galaxies at $M_UV -23.5$. If we identify AGN-dominated sources according to a point-source morphology criterion we recover the relatively flat faint-end slope of the AGN LF determined in previous studies. If we instead separate the LF according to the current spectroscopic AGN fraction, we find a steeper faint-end slope of $= -1.83 0.11$. Using a simple model to predict the rest-frame AGN LF from the $z = 4 $ galaxy LF we find that the increasing impact of host galaxy light on the measured morphology of faint AGN can explain our observations.

@misc{bowler2021rapid, abstract = {With the advent of deep optical-to-near-infrared extragalactic imaging on the degree scale, samples of high-redshift sources are being selected that contain both bright star-forming (SF) galaxies and faint active galactic nuclei (AGN). In this study we investigate the transition between SF and AGN-dominated systems at $z \simeq 4$ in the rest-frame UV. We find a rapid transition to AGN-dominated sources bright-ward of $M_{\rm UV} \simeq -23.2$. The effect is observed in the rest-frame UV morphology and size-luminosity relation, where extended clumpy systems become point-source dominated, and also in the available spectra for the sample. These results allow us to derive the rest-frame UV luminosity function for the SF and AGN-dominated sub-samples. We find the SF-dominated LF is best fit with a double-power law, with a lensed Schechter function being unable to explain the existence of extremely luminous SF galaxies at $M_{\rm UV} \simeq -23.5$. If we identify AGN-dominated sources according to a point-source morphology criterion we recover the relatively flat faint-end slope of the AGN LF determined in previous studies. If we instead separate the LF according to the current spectroscopic AGN fraction, we find a steeper faint-end slope of $\alpha = -1.83 \pm 0.11$. Using a simple model to predict the rest-frame AGN LF from the $z = 4 $ galaxy LF we find that the increasing impact of host galaxy light on the measured morphology of faint AGN can explain our observations.}, added-at = {2021-01-10T10:44:54.000+0100}, author = {Bowler, R. A. A. and Adams, N. J. and Jarvis, M. J. and Häußler, B.}, biburl = {https://www.bibsonomy.org/bibtex/2f7c0b55d99779e3ccf706e755746ee5b/gpkulkarni}, description = {The rapid transition from star-formation to AGN dominated rest-frame UV light at z ~ 4}, interhash = {589d2930de81df5d45c69c4ccac8d70c}, intrahash = {f7c0b55d99779e3ccf706e755746ee5b}, keywords = {library}, note = {cite arxiv:2101.01195Comment: 17 pages, 11 figures, 2 tables. Accepted to MNRAS}, timestamp = {2021-01-10T10:44:54.000+0100}, title = {The rapid transition from star-formation to AGN dominated rest-frame UV light at z ~ 4}, url = {http://arxiv.org/abs/2101.01195}, year = 2021 }