GALFIT-ing AGN Host Galaxies in COSMOS: HST versus Subaru
The COSMOS field has been extensively observed by most major telescopes, including Chandra, HST, and Subaru. HST imaging boasts very high spatial resolution and is used extensively in morphological studies of distant galaxies. Subaru provides lower spatial resolution imaging than HST but a substanti...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2023-01-01
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| Series: | The Astrophysical Journal |
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| Online Access: | https://doi.org/10.3847/1538-4357/ac9400 |
| _version_ | 1827827820210946048 |
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| author | Callum Dewsnap Pauline Barmby Sarah C. Gallagher C. Megan Urry Aritra Ghosh Meredith C. Powell |
| author_facet | Callum Dewsnap Pauline Barmby Sarah C. Gallagher C. Megan Urry Aritra Ghosh Meredith C. Powell |
| author_sort | Callum Dewsnap |
| collection | DOAJ |
| description | The COSMOS field has been extensively observed by most major telescopes, including Chandra, HST, and Subaru. HST imaging boasts very high spatial resolution and is used extensively in morphological studies of distant galaxies. Subaru provides lower spatial resolution imaging than HST but a substantially wider field of view with greater sensitivity. Both telescopes provide near-infrared imaging of COSMOS. Successful morphological fitting of Subaru data would allow us to measure morphologies of over 10 ^4 known active galactic nucleus (AGN) hosts, accessible through Subaru wide-field surveys, currently not covered by HST. The morphological parameters indicate the types of galaxies that host AGNs. For 4016 AGNs between 0.03 < z < 6.5, we study the morphology of their galaxy hosts using GALFIT, fitting components representing the AGN and host galaxy simultaneously using the i -band imaging from both HST and Subaru. Comparing the fits for the differing telescope spatial resolutions and image signal-to-noise ratios, we identify parameter regimes for which there is strong disagreement between distributions of fitted parameters for HST and Subaru. In particular, the Sérsic index values strongly disagree between the two sets of data, including sources at lower redshifts. In contrast, the measured magnitude and radius parameters show reasonable agreement. Additionally, large variations in the Sérsic index have little effect on the ${\chi }_{\nu }^{2}$ of each fit, whereas variations in other parameters have a more significant effect. These results indicate that the Sérsic index distributions of high-redshift galaxies that host AGNs imaged at ground-based spatial resolution are not reliable indicators of galaxy type and should be interpreted with caution. |
| first_indexed | 2024-03-12T03:36:56Z |
| format | Article |
| id | doaj.art-9f9071b96e794060ab4df66585a080ec |
| institution | Directory Open Access Journal |
| issn | 1538-4357 |
| language | English |
| last_indexed | 2024-03-12T03:36:56Z |
| publishDate | 2023-01-01 |
| publisher | IOP Publishing |
| record_format | Article |
| series | The Astrophysical Journal |
| spelling | doaj.art-9f9071b96e794060ab4df66585a080ec2023-09-03T13:08:37ZengIOP PublishingThe Astrophysical Journal1538-43572023-01-01944213710.3847/1538-4357/ac9400GALFIT-ing AGN Host Galaxies in COSMOS: HST versus SubaruCallum Dewsnap0https://orcid.org/0000-0003-1225-3462Pauline Barmby1https://orcid.org/0000-0003-2767-0090Sarah C. Gallagher2https://orcid.org/0000-0001-6217-8101C. Megan Urry3https://orcid.org/0000-0002-0745-9792Aritra Ghosh4https://orcid.org/0000-0002-2525-9647Meredith C. Powell5https://orcid.org/0000-0003-2284-8603Department of Physics & Astronomy, The University of Western Ontario , London, ON N6A 3K7, Canada ; cdewsnap@uwo.caDepartment of Physics & Astronomy, The University of Western Ontario , London, ON N6A 3K7, Canada ; cdewsnap@uwo.ca; Institute for Earth & Space Exploration, The University of Western Ontario , London, ON N6A 3K7, CanadaDepartment of Physics & Astronomy, The University of Western Ontario , London, ON N6A 3K7, Canada ; cdewsnap@uwo.ca; Institute for Earth & Space Exploration, The University of Western Ontario , London, ON N6A 3K7, CanadaYale Center for Astronomy and Astrophysics, Department of Physics, Yale University , New Haven, CT 06520-8120, USAYale Center for Astronomy and Astrophysics, Department of Astronomy, Yale University , New Haven, CT 06520-8120, USAKavli Institute of Particle Astrophysics and Cosmology, Stanford University , Stanford, CA 94305, USAThe COSMOS field has been extensively observed by most major telescopes, including Chandra, HST, and Subaru. HST imaging boasts very high spatial resolution and is used extensively in morphological studies of distant galaxies. Subaru provides lower spatial resolution imaging than HST but a substantially wider field of view with greater sensitivity. Both telescopes provide near-infrared imaging of COSMOS. Successful morphological fitting of Subaru data would allow us to measure morphologies of over 10 ^4 known active galactic nucleus (AGN) hosts, accessible through Subaru wide-field surveys, currently not covered by HST. The morphological parameters indicate the types of galaxies that host AGNs. For 4016 AGNs between 0.03 < z < 6.5, we study the morphology of their galaxy hosts using GALFIT, fitting components representing the AGN and host galaxy simultaneously using the i -band imaging from both HST and Subaru. Comparing the fits for the differing telescope spatial resolutions and image signal-to-noise ratios, we identify parameter regimes for which there is strong disagreement between distributions of fitted parameters for HST and Subaru. In particular, the Sérsic index values strongly disagree between the two sets of data, including sources at lower redshifts. In contrast, the measured magnitude and radius parameters show reasonable agreement. Additionally, large variations in the Sérsic index have little effect on the ${\chi }_{\nu }^{2}$ of each fit, whereas variations in other parameters have a more significant effect. These results indicate that the Sérsic index distributions of high-redshift galaxies that host AGNs imaged at ground-based spatial resolution are not reliable indicators of galaxy type and should be interpreted with caution.https://doi.org/10.3847/1538-4357/ac9400AGN host galaxiesActive galactic nucleiGalaxy classification systemsSurveys |
| spellingShingle | Callum Dewsnap Pauline Barmby Sarah C. Gallagher C. Megan Urry Aritra Ghosh Meredith C. Powell GALFIT-ing AGN Host Galaxies in COSMOS: HST versus Subaru The Astrophysical Journal AGN host galaxies Active galactic nuclei Galaxy classification systems Surveys |
| title | GALFIT-ing AGN Host Galaxies in COSMOS: HST versus Subaru |
| title_full | GALFIT-ing AGN Host Galaxies in COSMOS: HST versus Subaru |
| title_fullStr | GALFIT-ing AGN Host Galaxies in COSMOS: HST versus Subaru |
| title_full_unstemmed | GALFIT-ing AGN Host Galaxies in COSMOS: HST versus Subaru |
| title_short | GALFIT-ing AGN Host Galaxies in COSMOS: HST versus Subaru |
| title_sort | galfit ing agn host galaxies in cosmos hst versus subaru |
| topic | AGN host galaxies Active galactic nuclei Galaxy classification systems Surveys |
| url | https://doi.org/10.3847/1538-4357/ac9400 |
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