LRD Watch DR1 · catalog object

LRDW J021720.30-050636.9

catalogTENTATIVEBH* channelUDS (PRIMER UDS-2)

RA 02:17:20.306 34.3346091°

Dec −05:06:36.98 -5.1102730°

SIMBAD within 2″ · ESASky

Images

F090W image, 3.2 arcsec across, north up — F090W0.03″ px

F115W image, 3.2 arcsec across, north up — F115W0.03″ px

F150W image, 3.2 arcsec across, north up — F150W0.03″ px

F200W image, 3.2 arcsec across, north up — F200W0.03″ px

F277W image, 3.2 arcsec across, north up — F277W0.06″ px

F356W image, 3.2 arcsec across, north up — F356W0.06″ px

F410M image, 3.2 arcsec across, north up — F410M0.06″ px

F444W image, 3.2 arcsec across, north up — F444W0.06″ px

Colour composite: F444W red, F356W green, F277W blue, 3.2 arcsec across, north up — compositebar 1″

3.2″ 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.

Spectral energy distribution

NIRCam wide
NIRCam medium
MIRI
2σ upper limit (S/N < 2)

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 = 4.116.

At a glance

Tier: TENTATIVE
Found by: BH* channel
Redshift: 4.116 DJA grade 3, PRISM
Spectral shape: inconclusive de Graaff+25 criteria
F444W: 25.31 AB S/N 82, 0.16″ aperture
F277W − F444W: not in the colour lane
BH* share: 0.70 bhs_bb5400_b4; Δχ² galaxy 3.2, dwarf 80.6
Compactness: growth ratio 2.299 stars 2.271
Balmer break: 3.30 ± 0.27 F277W/F150W, red:Hb+OIII
Image vetting: half-stack pass; no flags raised
Literature: 5 catalogue(s), 1 AGN paper(s) within 0.010″

Vetting

Image vettingnot applicable
Half-stack testpass
Artifact risknone
Neighbournone
Extendedno

BH* channelevidence dchi2_gal=3.2 dchi2_bd=80.6
BH* channelBH* share 0.70 below 0.8 (composite)

Redshifts

Each 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).

Column	What it is	z	Source
`z_spec`	Spectroscopic, DJA grade 3	4.1157	rubies-uds23-v4_prism-clear_4233_167741.spec.fits
`z_vet`	Adopted by vetting	4.1157	zspec:dja_specz_grade3.csv:167741
`z_phot`	Photometric (P(z) peak)	—	not fitted
`z_bhs`	BH* channel fit	4.578	bhs_bb5400_b4
`z_agn`	Colour-lane fit	—	—

Spectral checks

V-shape (spectrum): inconclusive
Star (spectrum): no
V-shape (photometry): not measurable β_UV not measured, β_opt not measured at z_agn
Line in F410M: none 0 line-free optical band(s)
Line-ambiguous: no
Settling verdict: not evaluated

Literature

Published objects within 1″ of this position. A match is a positional recovery, not an adopted classification.

Barro et al. (2025)
Barro et al. (2026)
de Graaff et al. (2025)
Kocevski et al. (2024)
Leung et al. (2024)
Hviding+2025 broad-line AGN

Photometry

Circular 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.

Band	Instrument	Pivot (µm)	f (nJy)	σ (nJy)	AB mag	S/N	Ap. corr.
F090W	NIRCam wide	0.902	68.74	5.84	26.81	11.8	1.15
F115W	NIRCam wide	1.154	50.15	5.74	27.15	8.7	1.12
F150W	NIRCam wide	1.501	57.66	4.63	27.00	12.5	1.11
F200W	NIRCam wide	1.989	76.44	3.96	26.69	19.3	1.09
F277W	NIRCam wide	2.762	190.47	2.92	25.70	65.3	1.20
F356W	NIRCam wide	3.568	327.09	2.99	25.11	109.3	1.23
F410M	NIRCam medium	4.082	232.81	4.70	25.48	49.6	1.26
F444W	NIRCam wide	4.404	273.67	3.32	25.31	82.4	1.27
F1280W	MIRI	12.809	79.66	50.05	26.65	1.6	3.12
F1500W	MIRI	15.048	80.20	62.39	26.64	1.3	3.86

Provenance

Field: UDS (PRIMER UDS-2) (primeruds2)
Programmes: 01837, 07814 behind every mosaic the field measured
Pipeline rows merged: 1 all at one position
Detection pass: original
Release build: 33af9933d1cc 2026-10-17T14:29:44Z

Image sources

Band	Mosaic	Native pixel	Coverage
F090W	`jw01837-c1001_t000_nircam_clear-f090w_i2d.fits`	0.031″	1.00
F115W	`jw01837-c1001_t000_nircam_clear-f115w_i2d.fits`	0.031″	1.00
F150W	`jw01837-c1001_t000_nircam_clear-f150w_i2d.fits`	0.031″	1.00
F200W	`jw01837-c1001_t000_nircam_clear-f200w_i2d.fits`	0.031″	1.00
F277W	`jw01837-c1001_t000_nircam_clear-f277w_i2d.fits`	0.063″	1.00
F356W	`jw01837-c1001_t000_nircam_clear-f356w_i2d.fits`	0.063″	1.00
F410M	`jw01837-c1001_t000_nircam_clear-f410m_i2d.fits`	0.063″	1.00
F444W	`jw01837-c1001_t000_nircam_clear-f444w_i2d.fits`	0.063″	1.00

Cite

Anderson, 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 J021720.30-050636.9.

CC 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.