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  "title": "LRDW J021728.15-051215.0 — Cerin Amroth",
  "description": "LRDW J021728.15-051215.0: a TENTATIVE object in the LRD Watch DR1 catalog, in UDS (PRIMER UDS-1); 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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      "text": "Spectral energy distribution"
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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=34.367305+-5.204194&Radius=2&Radius.unit=arcsec"
    },
    {
      "text": "ESASky",
      "url": "https://sky.esa.int/esasky/?target=34.367305%20-5.204194&fov=0.02&sci=true"
    },
    {
      "text": "About the release",
      "url": "https://cerinamroth.com/jwst/lrds/dr1/"
    },
    {
      "text": "← LRDW J021728.10-051736.6",
      "url": "https://cerinamroth.com/jwst/lrds/dr1/j021728.10-051736.6/"
    },
    {
      "text": "LRDW J021728.46-021134.3 →",
      "url": "https://cerinamroth.com/jwst/lrds/dr1/j021728.46-021134.3/"
    }
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      "name": "LRDW J021728.15-051215.0",
      "description": "LRDW J021728.15-051215.0: a TENTATIVE object in the LRD Watch DR1 catalog, in UDS (PRIMER UDS-1); UDS (PRIMER UDS-2), with images in NIRCam bands, its spectral energy distribution, vetting, redshifts and literature matches.",
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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 J021728.15-051215.0  \n\n \n\nLRD Watch DR1 · catalog object\n\n \n\n# LRDW J021728.15-051215.0\n\n \n\ncatalogTENTATIVEBH* channelcolour laneUDS (PRIMER UDS-1); UDS (PRIMER UDS-2)\n\n \n\n \n\n \n\nRA 02:17:28.153 34.3673053°\n\n \n\nDec −05:12:15.10 -5.2041938°\n\n \n\n[SIMBAD within 2″](https://simbad.cds.unistra.fr/simbad/sim-coo?Coord=34.367305+-5.204194&Radius=2&Radius.unit=arcsec) · [ESASky](https://sky.esa.int/esasky/?target=34.367305%20-5.204194&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 \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- 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 = 5.619.  \n\n \n\n## At a glance\n\n \n\nTierTENTATIVE \n\nFound byBH* channel + colour lane\n\nRedshift5.62 photometric\n\nSpectral shapeno labelled spectrum\n\nF444W24.94 AB S/N 67, 0.16″ aperture\n\nF277W − F444W1.78 mag strict redness\n\nBH* share0.85 bhs_bb4800_b8; Δχ² galaxy 2.7, dwarf 31.2\n\nCompactnessgrowth ratio 1.786 stars 2.245\n\nBalmer break2.27 ± 0.50 F277W/F200W, clean\n\nImage vettinghalf-stack no-coverage; 1 flag(s)\n\nLiterature3 catalogue(s), 0 AGN paper(s) within 0.005″\n\n \n\n \n\n \n\n \n\n \n\n## Vetting\n\n \n- Image vettingnot applicable\n- Half-stack testno-coverage\n- Artifact riskflagged\n- Neighbournone\n- Extendedno\n\n \n- colour laneartifact-risk low-coverage n_exp=2 < 3 (F444W)\n- BH* channelevidence dchi2_gal=2.7 dchi2_bd=31.2\n- BH* channelartifact-risk low-coverage n_exp=2 < 3 (F444W)\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 | — | —\n | `z_vet` | Adopted by vetting | 5.6190 | pz:z_map\n | `z_phot` | Photometric (P(z) peak) | 5.619 | 68%: 2.666–6.715\n | `z_bhs` | BH* channel fit | 6.108 | bhs_bb4800_b8\n | `z_agn` | Colour-lane fit | 5.62 | AGN-inclusive templates\n\n \n\n \n\n \n\n \n\n \n\n## Spectral checks\n\n \n\nV-shape (spectrum)no labelled spectrum\n\nStar (spectrum)no spectrum\n\nV-shape (photometry)not measurable βUV not measured, βopt 1.13 at z_agn\n\nLine in F410Mnone 2 line-free optical band(s)\n\nLine-ambiguousno\n\nSettling verdictnot evaluated\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- Kocevski et al. (2024)\n- Kokorev et al. (2024)\n- Weibel et al. (2026), BH*-dominated sample\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 | 9.14 | 11.05 | 29.00 | 0.8 | 1.14–1.15\n | F115W | NIRCam wide | 1.154 | 17.69 | 10.36 | 28.28 | 1.7 | 1.12–1.12\n | F150W | NIRCam wide | 1.501 | 28.06 | 8.68 | 27.78 | 3.2 | 1.10–1.11\n | F200W | NIRCam wide | 1.989 | 32.89 | 7.03 | 27.61 | 4.7 | 1.09–1.09\n | F277W | NIRCam wide | 2.762 | 74.58 | 4.21 | 26.72 | 17.7 | 1.20–1.20\n | F356W | NIRCam wide | 3.568 | 177.28 | 4.14 | 25.78 | 42.8 | 1.23–1.24\n | F410M | NIRCam medium | 4.082 | 183.10 | 7.45 | 25.74 | 24.6 | 1.26–1.26\n | F444W | NIRCam wide | 4.404 | 384.06 | 5.76 | 24.94 | 66.7 | 1.27–1.28\n\n \n\n \n\n \n\n## Provenance\n\n \n\n FieldUDS (PRIMER UDS-1); UDS (PRIMER UDS-2) (`primeruds1,primeruds2`) Programmes`01837, 07814` behind every mosaic the field measured Pipeline rows merged6 largest separation 0.024″ 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-c1002_t000_nircam_clear-f090w_i2d.fits` | 0.031″ | 1.00\n | F115W | `jw01837-c1001_t000_nircam_clear-f115w_i2d.fits` | 0.031″ | 0.94\n | F150W | `jw01837-c1001_t000_nircam_clear-f150w_i2d.fits` | 0.031″ | 0.94\n | F200W | `jw01837-c1002_t000_nircam_clear-f200w_i2d.fits` | 0.031″ | 1.00\n | F277W | `jw01837-c1002_t000_nircam_clear-f277w_i2d.fits` | 0.063″ | 1.00\n | F356W | `jw01837-c1002_t000_nircam_clear-f356w_i2d.fits` | 0.063″ | 1.00\n | F410M | `jw01837-c1001_t000_nircam_clear-f410m_i2d.fits` | 0.063″ | 0.69\n | F444W | `jw01837-c1001_t000_nircam_clear-f444w_i2d.fits` | 0.063″ | 0.68\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 J021728.15-051215.0.\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 J021728.10-051736.6](https://cerinamroth.com/jwst/lrds/dr1/j021728.10-051736.6/)[LRDW J021728.46-021134.3 →](https://cerinamroth.com/jwst/lrds/dr1/j021728.46-021134.3/)\n",
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