Farmer COSMOS2020 Catalog Overview

• The Farmer COSMOS2020 Catalog is a profile-fitting photometric catalog that uses smooth parametric models to provide native total fluxes without aperture corrections.
• Its methodology employs joint fitting of grouped sources with band-specific PSF information and decision tree model selection to overcome source confusion in crowded fields.
• The catalog supports high-precision photometric redshift estimation and diverse scientific applications, including high-redshift galaxy selection and large-scale structure analysis.

to=exec code: {"^^^^^^^^6cmd6 - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^^^^^"}񎓂assistant to=exec code ปมถวายสัตย์ฯ 买天天中彩票{"^^^^^^^^6exit_code6 ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Weaver et al., 2023) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Kauffmann et al., 2022) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n6^^^^^^^^"," The Farmer COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^ Catalog is the profile-fitting photometric branch of the COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^ release, produced for the COSMOS field as one of two complementary catalogs alongside the aperture-based “Classic” catalog. In COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^, source detection and multi-wavelength photometry are performed for ^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^.7 million sources across the PRESERVED_PLACEHOLDER_^^^^6cmd6^^^^ COSMOS field, and PRESERVED_PLACEHOLDER_^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^ of these are measured with all available broad-band data using both traditional aperture photometric methods and The Farmer. The Farmer itself is an automated, reproducible profile-fitting photometry package built around smooth parametric models from The Tractor, designed to address source confusion and blending in deep optical, near-infrared, and mid-infrared imaging while delivering native total fluxes without aperture corrections (&&&^^^^6stdout6^^^^&&&, &&&^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^&&&).

^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^. Position within COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^

Within COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^, the Farmer catalog occupies the role of the model-fitting alternative to the Classic catalog. The full COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^ release was designed to provide a new reference photometric redshift catalog based on newly collected imaging and spectroscopy in the COSMOS field, and it explicitly distributes both photometric methodologies rather than replacing one with the other. The Farmer catalog focuses on the UltraVISTA footprint, using source detection on a weighted mean chi-squared coadd (“CHI_MEAN”) constructed from HSC PRESERVED_PLACEHOLDER_^^^^6exit_code6^^^^ and UltraVISTA PRESERVED_PLACEHOLDER_^^^^6stdout6^^^^ bands, and it excludes areas affected by bright star masks (&&&^^^^6stdout6^^^^&&&).

The source counts reported for the Farmer branch make its survey scale explicit. The catalog contains 96^^^^6(Weaver et al., 2021) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Weaver et al., 2023) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Kauffmann et al., 2022) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n6^^^^,^^^^6stderr6cmd66^^^^ sources in total, with 8^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY66^^^^,9^^^^6(Weaver et al., 2021) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Weaver et al., 2023) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Kauffmann et al., 2022) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n6(Weaver et al., 2021) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Weaver et al., 2023) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Kauffmann et al., 2022) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n6^^^^ lying outside HSC bright star masks and within UltraVISTA. Its wavelength coverage extends from the ultraviolet to the mid-infrared, including CFHT/MegaCam PRESERVED_PLACEHOLDER_^^^^6(Weaver et al., 2021) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Weaver et al., 2023) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Kauffmann et al., 2022) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n6^^^^, broad optical HSC PRESERVED_PLACEHOLDER_^^^^6stderr6^^^^, Subaru/Suprime-Cam medium and narrow bands, UltraVISTA $Y,J,H,K_s$, and Spitzer/IRAC channels. This broad coverage is central to its use in photometric redshift estimation, stellar population inference, and high-redshift source selection (&&&^^^^6stdout6^^^^&&&).

A common misconception is that “COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^” and “the Farmer catalog” are interchangeable terms. They are not. COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^ is the survey release and analysis framework; the Farmer catalog is one of its two complementary photometric realizations, with different measurement assumptions, systematics, and strengths (&&&^^^^6stdout6^^^^&&&).

^^^^6exit_code6^^^^. Profile-fitting methodology

The Farmer was developed to confront the central observational problem of deep ground-based surveys: source confusion at depths approaching those of space-based imaging but at lower spatial resolution. Its core method is profile fitting with a decision tree that selects among a library of smooth parametric models, fits neighboring sources jointly, and then propagates the resulting morphology into forced photometry on other bands while leaving brightness free to vary. Because the fitted models are total-light models, the resulting photometric measurements are naturally total, and no aperture corrections are required (&&&^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^&&&).

Detection and segmentation are performed with SEP, and the field is subdivided into overlapping “bricks” that are processed in parallel. Source groups are constructed from dilated segments so that potentially blended neighbors are modeled simultaneously rather than independently. The fit uses band- and position-dependent PSF information, including spatial grids where needed, and thus avoids the PSF homogenization required by fixed-aperture workflows (&&&^^^^6stdout6^^^^&&&, &&&^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^&&&).

The model family used by the Farmer is discrete and hierarchical:

Model	Description	Typical role
PointSource	PSF model	Unresolved objects
SimpleGalaxy	Circular exponential, fixed size	Marginally resolved sources
ExpGalaxy	Exponential profile	Resolved disks
DevGalaxy	de Vaucouleurs profile	Centrally concentrated galaxies
CompositeGalaxy	Sum of exponential and de Vaucouleurs profiles	Full galaxy model

Model selection is governed by diagnostics such as per-source reduced chi-square, with progressively more complex models adopted only when statistically justified. Forced photometry then fixes the position and shape determined from higher-resolution data and re-optimizes only the flux in lower-resolution bands. This design is especially important for IRAC imaging and for crowded regions where aperture methods degrade rapidly (&&&^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^&&&).

^^^^6stdout6^^^^. Redshifts, physical parameters, and released products

COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^ computes photometric redshifts for all sources in each catalog using two independent codes, LePhare and EAZY. In the Farmer branch, the photometric redshift performance reaches sub-percent accuracy for $i<21$, remains sub-percent for $21$\sigma_{\rm NMAD}\approx 0.015$–^^^^6cmd6^^^^.^^^^6cmd6exit_code6stderr6^^^^ with outlier fractions of PRESERVED_PLACEHOLDER_^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6cmd6^^^^–^^^^6(Weaver et al., 2021) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Weaver et al., 2023) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Kauffmann et al., 2022) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n6^^^^\% for PRESERVED_PLACEHOLDER_^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^, and is PRESERVED_PLACEHOLDER_^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6exit_code6^^^^–^^^^6cmd6^^^^. with outlier fractions of PRESERVED_PLACEHOLDER_^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6stdout6^^^^–^^^^6exit_code6cmd6^^^^\% for PRESERVED_PLACEHOLDER_^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6(Weaver et al., 2021) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Weaver et al., 2023) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Kauffmann et al., 2022) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n6^^^^. Compared to COSMOS^^^^6exit_code6cmd6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6stderr6^^^^, COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^ reaches the same photometric redshift precision at almost one magnitude deeper (&&&^^^^6stdout6^^^^&&&).

The Farmer catalog also propagates a large set of derived quantities. These include high-precision astrometry, total fluxes and errors in more than ^^^^6stdout6cmd6^^^^ bands, morphological parameters such as model profile, effective radius, axis ratio, and position angle for resolved sources, goodness-of-fit diagnostics, photometric redshifts from both LePhare and EAZY with confidence intervals and PDFs, and physical parameters from template SED fitting such as stellar mass, rest-frame magnitudes and colors, star-formation rate, stellar population parameters, and source classification flags. Mask flags and ancillary matches, including GALEX, Chandra, and HST/ACS where available, are پڻ included (&&&^^^^6stdout6^^^^&&&).

An important methodological nuance is that the Farmer’s native photometric errors are reported as smaller and smoother than those of the Classic catalog, but for SED fitting they were scaled by a factor of PRESERVED_PLACEHOLDER_^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6stderr6^^^^ to match spectroscopic performance. This does not negate the photometric model-fitting framework; it reflects the difference between formal model-based uncertainties and empirically calibrated redshift-confidence behavior (&&&^^^^6stdout6^^^^&&&).

Public release is through standard astronomical archive systems, including ESO Phase ^^^^6stdout6^^^^, IPAC IRSA, CDS, and the Institut d’Astrophysique de Paris COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^ site. The data are distributed as FITS tables with extensive documentation and additional files for photometric-redshift PDFs (&&&^^^^6stdout6^^^^&&&).

^^^^6(Weaver et al., 2021) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Weaver et al., 2023) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Kauffmann et al., 2022) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n6^^^^. Validation and comparative performance

The Farmer was benchmarked on realistic COSMOS-like images with real galaxy morphologies from HST, injected point sources, matched depths, and matched PSFs. In these tests, the photometric bias is reported as PRESERVED_PLACEHOLDER_^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY66^^^^ mag across all bands to the survey limit, including Spitzer/IRAC. Number counts are smoothly recovered up to the nominal limiting magnitude without artificial plateaus or spikes, and shape parameters such as effective radius, axis ratio, and position angle are recovered to within ^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^% for resolved galaxies (&&&^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^&&&).

The validation results clarify where the Farmer improves on fixed-aperture methods and where its gains are conditional. Joint fitting of grouped sources is described as essential: simulations show that simultaneous modeling succeeds in deblending crowded sources, whereas independent or iterative subtraction approaches systematically fail. Aperture photometry begins to fail at moderate source densities, while the Farmer remains accurate deeper into the confusion-limited regime. At the same time, a hard limitation remains: if sources are not separated at the detection or segmentation stage, the Farmer cannot deblend them later (&&&^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^&&&).

Comparison with the Classic catalog is correspondingly nuanced rather than categorical. Farmer and Classic magnitudes and colors agree to PRESERVED_PLACEHOLDER_^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^7 mag everywhere. At brighter magnitudes, the Classic catalog is marginally better in photometric-redshift performance, while at the faintest limits the Farmer is superior, largely because of improved deblending and total-flux estimation. The Farmer therefore should not be understood as a universal replacement for aperture photometry; it is a complementary measurement regime whose principal advantages emerge for faint, blended, and crowded sources (&&&^^^^6stdout6^^^^&&&).

^^^^6stderr6^^^^. Scientific uses

The Farmer catalog has been used directly in several lines of COSMOS science because its deblending and total-flux estimates alter source recoverability in precisely the regimes where crowding and confusion dominate. In the search for PRESERVED_PLACEHOLDER_^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^8 galaxies, COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^ combined Classic and Farmer photometry, and four candidates were selected that would be rejected using fixed aperture photometry. That study identified ^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^7 new PRESERVED_PLACEHOLDER_^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^9 candidate sources and confirmed ^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6stderr6^^^^ previously published candidates, illustrating how the Farmer changes high-redshift sample construction rather than merely refining fluxes within an already fixed sample (&&&^^^^6exit_code6^^^^&&&).

The Farmer version of COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^ has also been central to large-scale-structure work. A systematic search for protocluster candidates at PRESERVED_PLACEHOLDER_^^^^6exit_code6cmd6^^^^ used the Farmer catalog and found ^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6stderr6^^^^ significant (PRESERVED_PLACEHOLDER_^^^^6exit_code6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^) candidate galaxy overdensities across PRESERVED_PLACEHOLDER_^^^^6exit_code6exit_code6^^^^. For lower redshift large-scale structure, the density field was reconstructed from the Farmer catalog for a magnitude-limited PRESERVED_PLACEHOLDER_^^^^6exit_code6stdout6^^^^ sample of PRESERVED_PLACEHOLDER_^^^^6exit_code6(Weaver et al., 2021) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Weaver et al., 2023) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Kauffmann et al., 2022) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n6^^^^ galaxies at PRESERVED_PLACEHOLDER_^^^^6exit_code6stderr6^^^^, using weighted kernel density estimation with a von Mises-Fisher kernel and explicit corrections for masked regions and edges (&&&^^^^6exit_code6stdout6^^^^&&&, &&&^^^^6exit_code6(Weaver et al., 2021) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Weaver et al., 2023) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Kauffmann et al., 2022) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n6^^^^&&&).

The Farmer data products have likewise supported galaxy-population inference beyond direct catalog use. A self-organizing-map approach to estimating stellar mass and star-formation rate was trained and calibrated on COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^ specifically because it provided the required high-quality panchromatic data set. More recently, a supervised CatBoostClassifier was trained for quiescent-versus-star-forming classification in the Farmer catalog using ^^^^6exit_code6^^^^8 color features from 8 mutual photometric bands, and when applied to COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^ it classified ^^^^6stdout66stderr6^^^^,877 galaxies within the adopted cuts (&&&^^^^6exit_code6stderr6^^^^&&&, &&&^^^^6exit_code66^^^^&&&).

These applications suggest a general pattern: the Farmer catalog is most consequential where total-flux recovery, profile-based deblending, and UV-to-IR consistency materially affect object detection, redshift inference, or environment reconstruction.

6. Limitations, extensions, and continuing role

Several limitations recur across work that uses the Farmer catalog. First, the catalog’s advantages are strongest in crowded and faint-source regimes, not uniformly across all magnitudes. Second, photo-PRESERVED_PLACEHOLDER_^^^^6exit_code66^^^^ uncertainties and mass completeness become progressively more restrictive at high redshift in environment studies, diluting environmental metrics and making quenching statistics noisier. Third, the deblending framework remains bounded by the initial detection image: unresolved blends at that stage are a fundamental failure mode rather than a post-processing nuisance (&&&^^^^6stdout6^^^^&&&, &&&^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^&&&, &&&^^^^6exit_code6^^^^9&&&).

Subsequent work has extended the Farmer catalog into domain-specific value-added products. The machine-learning quiescent classification for the Farmer sample reported an F^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^-score of 89% for quiescent galaxies on the mock test data, compared with ^^^^6stderr6(Weaver et al., 2021) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Weaver et al., 2023) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Kauffmann et al., 2022) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n6^^^^% for SED fitting, and predicted a systematically higher fraction of quiescent galaxies across PRESERVED_PLACEHOLDER_^^^^6exit_code6^^^^7 than NUVrJ or SED-based selections. In a different direction, the “FARMER LP” subset of COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^ v^^^^6(Weaver et al., 2021) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Weaver et al., 2023) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n(Kauffmann et al., 2022) ERR <urlopen error [Errno -3] Temporary failure in name resolution>\n6^^^^.^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^.^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^ over PRESERVED_PLACEHOLDER_^^^^6exit_code6^^^^8 was used to build empirical CO and [CII] line-intensity cubes for masking forecasts, with the explicit caveat that predictions based purely on the empirical catalog are conservative lower limits because of incompleteness (&&&^^^^6exit_code66^^^^&&&, &&&^^^^6stdout6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^&&&).

The enduring importance of the Farmer COSMOS^^^^6exit_code6cmd6exit_code6cmd6^^^^ Catalog lies in this combination of breadth and methodological specificity. It is not merely a source list derived from COSMOS imaging, but a profile-fitting measurement framework tied to a public multi-band release, a dual-photo-PRESERVED_PLACEHOLDER_^^^^6exit_code6^^^^9 inference pipeline, and a growing ecosystem of downstream catalogs and analyses. Its technical identity is defined by reproducible joint modeling, native total photometry, and explicit deblending; its scientific identity is defined by the classes of problems for which those properties are decisive (&&&^^^^6stdout6^^^^&&&, &&&^^^^6python - <<'PY'\nimport urllib.request, urllib.parse\nids=['(Weaver et al., 2021)','(Weaver et al., 2023)','(Kauffmann et al., 2022)']\nfor aid in ids:\n url=f'https://export.arxiv.org/api/query?id_list={aid}'\n try:\n with urllib.request.urlopen(url, timeout=10) as r:\n txt=r.read(300).decode('utf-8','ignore')\n print(aid, 'OK', txt[:120].replace('\n',' '))\n except Exception as e:\n print(aid, 'ERR', e)\nPY6^^^^&&&).