ACTIVE GALACTIC NUCLEUS HOST GALAXY MORPHOLOGIES IN COSMOS
Bibliographic record
Abstract
We use Hubble Space Telescope/Advanced Camera for Surveys images and a\nphotometric catalog of the Cosmic Evolution Survey (COSMOS) field to\nanalyze morphologies of the host galaxies of ~400 active galactic\nnucleus (AGN) candidates at redshifts 0.3 < z < 1.0. We compare\nthe AGN hosts with a sample of nonactive galaxies drawn from the COSMOS\nfield to match the magnitude and redshift distribution of the AGN hosts.\nWe perform two-dimensional surface brightness modeling with GALFIT to\nyield host galaxy and nuclear point source magnitudes. X-ray-selected\nAGN host galaxy morphologies span a substantial range that peaks between\nthose of early-type, bulge-dominated and late-type, disk-dominated\nsystems. We also measure the asymmetry and concentration of the host\ngalaxies. Unaccounted for, the nuclear point source can significantly\nbias results of these measured structural parameters, so we subtract the\nbest-fit point source component to obtain images of the underlying host\ngalaxies. Our concentration measurements reinforce the findings of our\ntwo-dimensional morphology fits, placing X-ray AGN hosts between early-\nand late-type inactive galaxies. AGN host asymmetry distributions are\nconsistent with those of control galaxies. Combined with a lack of\nexcess companion galaxies around AGN, the asymmetry distributions\nindicate that strong interactions are no more prevalent among AGN than\nnormal galaxies. In light of recent work, these results suggest that the\nhost galaxies of AGN at these X-ray luminosities may be in a transition\nfrom disk-dominated to bulge-dominated, but that this transition is not\ntypically triggered by major mergers.\n\nBased on observations with the NASA/ESA Hubble Space Telescope, obtained\nat the Space Telescope Science Institute, which is operated by AURA Inc,\nunder NASA contract NAS 5-26555; also based on data collected at: the\nSubaru Telescope, which is operated by the National Astronomical\nObservatory of Japan; the XMM-Newton, an ESA science mission with\ninstruments and contributions directly funded by ESA Member States and\nNASA; the European Southern Observatory under Large Program 175.A-0839,\nChile; Kitt Peak National Observatory, Cerro Tololo Inter-American\nObservatory, and the National Optical Astronomy Observatory, which are\noperated by the Association of Universities for Research in Astronomy,\nInc. (AURA) under cooperative agreement with the National Science\nFoundation; the National Radio Astronomy Observatory which is a facility\nof the National Science Foundation operated under cooperative agreement\nby Associated Universities, Inc; and the Canada-France-Hawaii Telescope\nwith MegaPrime/MegaCam operated as a joint project by the CFHT\nCorporation, CEA/DAPNIA, the National Research Council of Canada, the\nCanadian Astronomy Data Centre, the Centre National de la Recherche\nScientifique de France, TERAPIX and the University of Hawaii.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".