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  "title": "LRDW J021729.36-050657.2 — Cerin Amroth",
  "description": "LRDW J021729.36-050657.2: a SILVER object in the LRD Watch DR1 catalog, in UDS (PRIMER UDS-2), with images in NIRCam bands, its spectral energy distribution, vetting, redshifts and literature matches.",
  "date_modified": "2026-10-17",
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  "links": [
    {
      "text": "Home",
      "url": "https://cerinamroth.com/"
    },
    {
      "text": "JWST",
      "url": "https://cerinamroth.com/jwst/"
    },
    {
      "text": "Little red dots",
      "url": "https://cerinamroth.com/jwst/lrds/"
    },
    {
      "text": "LRD Watch DR1",
      "url": "https://cerinamroth.com/jwst/lrds/dr1/"
    },
    {
      "text": "SIMBAD within 2″",
      "url": "https://simbad.cds.unistra.fr/simbad/sim-coo?Coord=34.372373+-5.115912&Radius=2&Radius.unit=arcsec"
    },
    {
      "text": "ESASky",
      "url": "https://sky.esa.int/esasky/?target=34.372373%20-5.115912&fov=0.02&sci=true"
    },
    {
      "text": "About the release",
      "url": "https://cerinamroth.com/jwst/lrds/dr1/"
    },
    {
      "text": "← LRDW J021729.32-021228.1",
      "url": "https://cerinamroth.com/jwst/lrds/dr1/j021729.32-021228.1/"
    },
    {
      "text": "LRDW J021729.66-051330.7 →",
      "url": "https://cerinamroth.com/jwst/lrds/dr1/j021729.66-051330.7/"
    }
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  "content_markdown": "[Home](https://cerinamroth.com/) › [JWST](https://cerinamroth.com/jwst/) › [Little red dots](https://cerinamroth.com/jwst/lrds/) › [LRD Watch DR1](https://cerinamroth.com/jwst/lrds/dr1/) › LRDW J021729.36-050657.2  \n\n \n\nLRD Watch DR1 · catalog object\n\n \n\n# LRDW J021729.36-050657.2\n\n \n\ncatalogSILVERmain classBH* channelcolour laneUDS (PRIMER UDS-2)\n\n \n\n \n\n \n\nRA 02:17:29.370 34.3723733°\n\n \n\nDec −05:06:57.28 -5.1159122°\n\n \n\n[SIMBAD within 2″](https://simbad.cds.unistra.fr/simbad/sim-coo?Coord=34.372373+-5.115912&Radius=2&Radius.unit=arcsec) · [ESASky](https://sky.esa.int/esasky/?target=34.372373%20-5.115912&fov=0.02&sci=true)\n\n \n\n  \n\n \n\n## Images\n\n \n\n F090W image, 3.2 arcsec across, north up \n\nF090W0.03″ px\n\n F115W image, 3.2 arcsec across, north up \n\nF115W0.03″ px\n\n F150W image, 3.2 arcsec across, north up \n\nF150W0.03″ px\n\n F200W image, 3.2 arcsec across, north up \n\nF200W0.03″ px\n\n F277W image, 3.2 arcsec across, north up \n\nF277W0.06″ px\n\n F356W image, 3.2 arcsec across, north up \n\nF356W0.06″ px\n\n F410M image, 3.2 arcsec across, north up \n\nF410M0.06″ px\n\n F444W image, 3.2 arcsec across, north up \n\nF444W0.06″ px\n\n Colour composite: F444W red, F356W green, F277W blue, 3.2 arcsec across, north up NE\n\ncompositebar 1″\n\n \n\n3.2″ across, north up, east left, resampled from the deepest mosaic covering the object in each band; ticks mark the catalogue position. Each band is stretched on its own noise; the composite shares one flux scale, so its colour is real.\n\n \n\n \n\n \n\n  \n\n## Spectral energy distribution\n\n  \n- NIRCam wide\n- NIRCam medium\n- MIRI\n- 2σ upper limit (S/N < 2)\n\n Aperture fluxes in a 0.16″-radius circle, not corrected to total; the values are in the photometry table below. The gold line marks the Balmer limit (3646 Å rest) at z = 7.197.  \n\n \n\n## At a glance\n\n \n\nTierSILVER main class\n\nFound byBH* channel + colour lane\n\nRedshift7.197 DJA grade 3, PRISM\n\nSpectral shapeinconclusive de Graaff+25 criteria\n\nF444W26.55 AB S/N 34, 0.16″ aperture\n\nF277W − F444W2.00 mag strict redness\n\nBH* share0.73 bhs_bb4200_b8; Δχ² galaxy 4.3, dwarf 9.4\n\nCompactnessgrowth ratio 1.688 stars 2.271\n\nBalmer break3.94 ± 1.14 F356W/F200W, blue:far-uv\n\nImage vettinghalf-stack pass; no flags raised\n\nLiterature6 catalogue(s), 2 AGN paper(s) within 0.009″\n\n \n\n \n\n \n\n \n\n \n\n## Vetting\n\n \n- Image vettingpassed\n- Half-stack testpass\n- Artifact risknone\n- Neighbournone\n- Extendedno\n\n \n- BH* channelevidence dchi2_gal=4.3 dchi2_bd=9.4\n- BH* channelBH* share 0.73 below 0.8 (composite)\n\n \n\n \n\n \n\n## Redshifts\n\n \n\nEach redshift keeps its own column. Photometric redshifts of little red dots are unreliable: against spectra, about a third of AGN-template redshifts (`z_agn`; 31 of 95 in the last purity run) and about half of galaxy-template redshifts at z > 3 were catastrophic outliers (methods Section 8).\n\n \n\n | Column | What it is | z | Source\n | `z_spec` | Spectroscopic, DJA grade 3 | 7.1974 | rubies-uds31-v4_prism-clear_4233_981721.spec.fits\n | `z_vet` | Adopted by vetting | 7.1974 | zspec:dja_specz_grade3.csv:981721\n | `z_phot` | Photometric (P(z) peak) | 8.299 | 68%: 7.417–8.629\n | `z_bhs` | BH* channel fit | 7.486 | bhs_bb4200_b8\n | `z_agn` | Colour-lane fit | 8.30 | AGN-inclusive templates\n\n \n\n \n\n \n\n \n\n \n\n## Spectral checks\n\n \n\nV-shape (spectrum)inconclusive\n\nStar (spectrum)no\n\nV-shape (photometry)fails βUV −2.32, βopt −0.98 at z_agn\n\nLine in F410MHb, OIII 1 line-free optical band(s)\n\nLine-ambiguousyes\n\nSettling verdictLRD-like continuum\n\n \n\n \n\n \n\n## Literature\n\n \n\nPublished objects within 1″ of this position. A match is a positional recovery, not an adopted classification.\n\n \n- Barro et al. (2026)\n- de Graaff et al. (2025)\n- Kocevski et al. (2024)\n- Kokorev et al. (2024)\n- Leung et al. (2024)\n- Weibel et al. (2026), BH*-dominated sample\n- Hviding+2025 broad-line AGN\n- Yanagisawa+2026 (ATLAS I) broad-line AGN\n\n \n\n \n\n \n\n \n\n \n\n## Photometry\n\n \n\nCircular aperture of radius 0.16″ at each band's native resolution, background from a 0.40–0.65″ annulus, programmes combined by inverse variance. For a point source multiply by the field's aperture correction (r = 0.16″ → 0.70″). Grey rows are below S/N 2.\n\n \n\n | Band | Instrument | Pivot (µm) | f (nJy) | σ (nJy) | AB mag | S/N | Ap. corr.\n | F090W | NIRCam wide | 0.902 | 1.53 | 4.82 | 30.94 | 0.3 | 1.15\n | F115W | NIRCam wide | 1.154 | 6.06 | 4.59 | 29.44 | 1.3 | 1.12\n | F150W | NIRCam wide | 1.501 | 12.04 | 3.85 | 28.70 | 3.1 | 1.11\n | F200W | NIRCam wide | 1.989 | 11.01 | 3.18 | 28.80 | 3.5 | 1.09\n | F277W | NIRCam wide | 2.762 | 13.81 | 2.03 | 28.55 | 6.8 | 1.20\n | F356W | NIRCam wide | 3.568 | 43.26 | 1.94 | 27.31 | 22.2 | 1.23\n | F410M | NIRCam medium | 4.082 | 80.29 | 3.89 | 26.64 | 20.6 | 1.26\n | F444W | NIRCam wide | 4.404 | 86.85 | 2.58 | 26.55 | 33.6 | 1.27\n | F1280W | MIRI | 12.809 | 78.60 | 61.34 | 26.66 | 1.3 | 3.12\n | F1500W | MIRI | 15.048 | 123.37 | 75.95 | 26.17 | 1.6 | 3.86\n\n \n\n \n\n \n\n## Provenance\n\n \n\n FieldUDS (PRIMER UDS-2) (`primeruds2`) Programmes`01837, 07814` behind every mosaic the field measured Pipeline rows merged3 all at one position Detection passoriginal Release build`33af9933d1cc` 2026-10-17T14:29:44Z \n\n \n\n## Image sources\n\n | Band | Mosaic | Native pixel | Coverage\n | F090W | `jw01837-c1001_t000_nircam_clear-f090w_i2d.fits` | 0.031″ | 1.00\n | F115W | `jw01837-c1001_t000_nircam_clear-f115w_i2d.fits` | 0.031″ | 1.00\n | F150W | `jw01837-c1001_t000_nircam_clear-f150w_i2d.fits` | 0.031″ | 1.00\n | F200W | `jw01837-c1001_t000_nircam_clear-f200w_i2d.fits` | 0.031″ | 1.00\n | F277W | `jw01837-c1001_t000_nircam_clear-f277w_i2d.fits` | 0.063″ | 1.00\n | F356W | `jw01837-c1001_t000_nircam_clear-f356w_i2d.fits` | 0.063″ | 1.00\n | F410M | `jw01837-c1001_t000_nircam_clear-f410m_i2d.fits` | 0.063″ | 1.00\n | F444W | `jw01837-c1001_t000_nircam_clear-f444w_i2d.fits` | 0.063″ | 1.00\n\n \n\n \n\n \n\n## Cite\n\n \n\nAnderson, Jordan (2026). LRD Watch DR1: little red dot candidates from an independent search of public JWST imaging (Version DR1) [Data set]. Cerin Amroth Research. Zenodo. https://doi.org/10.5281/zenodo.23062632 Object LRDW J021729.36-050657.2.\n\n \n\nCC BY 4.0. Please also acknowledge the JWST programmes that took the data. LRD Watch DR1 is a vetted candidate catalogue, not a complete census: it has no selection function and cannot on its own give number densities. [About the release](https://cerinamroth.com/jwst/lrds/dr1/).\n\n \n\n [← LRDW J021729.32-021228.1](https://cerinamroth.com/jwst/lrds/dr1/j021729.32-021228.1/)[LRDW J021729.66-051330.7 →](https://cerinamroth.com/jwst/lrds/dr1/j021729.66-051330.7/)\n",
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