The rapid transition from star formation to AGN-dominated rest-frame ultraviolet light at z ≃ 4
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...
| Main Authors: | , , , |
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| Format: | Journal article |
| Language: | English |
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Oxford University Press
2021
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| _version_ | 1797105962475061248 |
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| author | Bowler, RAA Adams, NJ Jarvis, MJ Häußler, B |
| author_facet | Bowler, RAA Adams, NJ Jarvis, MJ Häußler, B |
| author_sort | Bowler, RAA |
| collection | OXFORD |
| description | 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 ultraviolet (UV). We find a rapid transition to AGN-dominated sources brightward of MUV ≃ −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 (LF) for the SF- and AGN-dominated subsamples. 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 MUV ≃ −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 α = −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.
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| first_indexed | 2024-03-07T06:54:53Z |
| format | Journal article |
| id | oxford-uuid:fdcbc517-a814-4049-a6ff-c1dfc096fe4b |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-07T06:54:53Z |
| publishDate | 2021 |
| publisher | Oxford University Press |
| record_format | dspace |
| spelling | oxford-uuid:fdcbc517-a814-4049-a6ff-c1dfc096fe4b2022-03-27T13:31:33ZThe rapid transition from star formation to AGN-dominated rest-frame ultraviolet light at z ≃ 4Journal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:fdcbc517-a814-4049-a6ff-c1dfc096fe4bEnglishSymplectic ElementsOxford University Press2021Bowler, RAAAdams, NJJarvis, MJHäußler, BWith 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 ultraviolet (UV). We find a rapid transition to AGN-dominated sources brightward of MUV ≃ −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 (LF) for the SF- and AGN-dominated subsamples. 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 MUV ≃ −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 α = −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. |
| spellingShingle | Bowler, RAA Adams, NJ Jarvis, MJ Häußler, B The rapid transition from star formation to AGN-dominated rest-frame ultraviolet light at z ≃ 4 |
| title | The rapid transition from star formation to AGN-dominated rest-frame ultraviolet light at z ≃ 4 |
| title_full | The rapid transition from star formation to AGN-dominated rest-frame ultraviolet light at z ≃ 4 |
| title_fullStr | The rapid transition from star formation to AGN-dominated rest-frame ultraviolet light at z ≃ 4 |
| title_full_unstemmed | The rapid transition from star formation to AGN-dominated rest-frame ultraviolet light at z ≃ 4 |
| title_short | The rapid transition from star formation to AGN-dominated rest-frame ultraviolet light at z ≃ 4 |
| title_sort | rapid transition from star formation to agn dominated rest frame ultraviolet light at z ≃ 4 |
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