J/A+A/712/A183 Hidden Monsters with SPHEREx. I. (Stepney+, 2026)
Hidden Monsters with SPHEREx.
I. A goldmine for heavily reddened quasars at cosmic noon.
Stepney M., Banerji M., Bauer F.E., Assef R.J., Li G.
<Astron. Astrophys. 712, A183 (2026)>
=2026A&A...712A.183S 2026A&A...712A.183S (SIMBAD/NED BibCode)
ADC_Keywords: QSOs ; Photometry ; Optical ; Infrared ; Redshifts
Keywords: galaxies: evolution - galaxies: photometry - quasars: general
Abstract:
Heavily reddened quasars (HRQs) are luminous, dust-obscured broad-line
quasars thought to trace a short-lived phase of intense black hole
growth and feedback. Previous studies have been limited by small
sample sizes, which restricted robust statistical analyses of their
properties. We expand the census of the most luminous HRQs to enable
population-level studies, aiming to connect their spectral energy
distributions (SEDs) to other luminous quasar populations and place
them in the context of an evolutionary sequence for massive galaxy and
black hole formation.
We assembled multi-wavelength broadband photometry for the brightest
(KAB<18mag) HRQ candidates and selected active galactic nucleus
(AGN) candidates with red near-IR colours of (J-K)AB>1.6. We
employed SPX spectrophotometry to confirm the HRQs and determine
redshifts. Detailed SED fitting allowed us to compare these HRQs to
other luminous quasar populations, including a control sample of
hyper-luminous, unobscured unWISE-Gaia (Quaia) quasars, as well as
luminous hot dust-obscured galaxies (hot DOGs).
We confirm 76 new HRQs with redshifts of 1.5<zsys<3.9,
dust-corrected optical continuum luminosities of
log10(λLλ(3000Å[erg/s])>47.0, and line-of-sight
extinctions of 0.4<E(B-V)<1.6 (AV∼1-5mag). This more than doubles
the number of confirmed HRQs at zsys>1.5 including the first 7 HRQs
ever identified at z>3. A UV excess consistent with scattered quasar
emission is detected in 76 per cent of SPX HRQs. We conclusively
demonstrate that HRQs are hot-dust poor compared to blue quasars of
similar luminosities and redshifts. We find that the 6um continuum
luminosities of HRQs are systematically lower at fixed 3000Å,
continuum luminosity relative to blue Quaia quasars, suggesting that
HRQs are deficient in both hot and warm dust components. This
combination of depleted torus-scale dust reservoirs and higher
luminosities compared to hot DOGs and blue quasars supports a scenario
in which HRQs represent a blow-out phase, when strong feedback has
begun to clear the central regions of obscuring material.
Description:
The table contains the WISE designation, coordinates, and redshifts
for the 76 newly confirmed heavily reddened quasars from this study.
In addition, the photometric data in the grizYJHKW1W2W3W4 photometric
bands, as well as their associated uncertainties, are published where
available. Optical bands using the column naming convention
'magautoXYZ' refer to DELVE photometry. Optical bands using the
column naming convention 'XYZmag' refer to SDSS photometry. Finally,
the best-fit parameters and their Monte Carlo uncertainties are
published (see paper for details), together with the 6um continuum
luminosities for each source.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 523 76 SED properties of 76 SPHEREx-confirmed heavily
reddened quasars (table B1 + photometric data)
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Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 19 A19 --- WISE WISE name (WISE_Designation)
21- 31 F11.7 deg RAdeg Right ascension (J2000) (RA)
33- 43 F11.7 deg DEdeg Declination (J2000) (Dec)
45- 50 F6.4 --- zsys Redshift (Zsys)
52- 57 F6.3 mag W1mag Wise W1 magnitude (w1mpro)
59- 63 F5.3 mag e_W1mag Wise W1 magnitude error (w1sigmpro)
65- 70 F6.3 mag W2mag Wise W2 magnitude (w2mpro)
72- 76 F5.3 mag e_W2mag Wise W2 magnitude error (w2sigmpro)
78- 83 F6.3 mag W3mag Wise W3 magnitude (w3mpro)
85- 89 F5.3 mag e_W3mag Wise W3 magnitude error (w3sigmpro)
91- 95 F5.3 mag W4mag Wise W4 magnitude (w4mpro)
97-101 F5.3 mag e_W4mag Wise W1 magnitude error (w4sigmpro)
103-117 E15.7 mag Yapmag3 ?=- Y aperture corrected magnitude
(yAperMag3)
119-133 E15.7 mag e_Yapmag3 ?=- Y aperture corrected magnitude error
(yAperMag3Err)
135-143 F9.6 mag Japmag3 J aperture corrected magnitude
(j_1AperMag3)
145-155 F11.9 mag e_Japmag3 ?=- J aperture corrected magnitude error
(j_1AperMag3Err) error
157-171 E15.7 mag Hapmag3 ?=- H aperture corrected magnitude
(hAperMag3)
173-187 E15.7 mag e_Hapmag3 ?=- H aperture corrected magnitude error
(hAperMag3Err)
189-198 F10.7 mag Kapmag3 K aperture corrected magnitude
(kAperMag3)
200-211 F12.10 mag e_Kapmag3 K aperture corrected magnitude error
(kAperMag3Err)
213-214 I2 --- KClass Classification (kClass)
216-224 F9.6 mag gmagauto ?=- SDSS g AUTO magnitude (magautog)
226-234 F9.6 mag e_gmagauto ?=- SDSS g AUTO magnitude error
(magerrautog)
236-244 F9.6 mag rmagauto ?=- SDSS r AUTO magnitude (magautor)
246-254 F9.6 mag e_rmagauto ?=- SDSS r AUTO magnitude error
(magerrautor)
256-264 F9.6 mag imagauto ?=- SDSS i AUTO magnitude (magautoi)
266-274 F9.6 mag e_imagauto ?=- SDSS i AUTO magnitude error
(magerrautoi)
276-284 F9.6 mag zmagauto ?=- SDSS z AUTO magnitude (magautoz)
286-294 F9.6 mag e_zmagauto ?=- SDSS z AUTO magnitude error
(magerrautoz)
296-315 F20.18 --- Sep1 Angular separation to nearest K-band
neighbour(Separation_1)
317-322 F6.3 mag umag ?=- SDSS u magnitude (umag)
324-329 F6.3 mag gmag ?=- SDSS g magnitude (gmag)
331-336 F6.3 mag rmag ?=- SDSS r magnitude (rmag)
338-343 F6.3 mag imag ?=- SDSS i magnitude (imag)
345-350 F6.3 mag zmag ?=- SDSS z magnitude (zmag)
352-356 F5.3 mag e_umag ?=- SDSS u magnitude error (e_umag)
358-362 F5.3 mag e_gmag ?=- SDSS g magnitude error (e_gmag)
364-369 F6.3 mag e_rmag ?=- SDSS r magnitude error (e_rmag)
371-375 F5.3 mag e_imag ?=- SDSS i magnitude error (e_imag)
377-381 F5.3 mag e_zmag ?=- SDSS z magnitude error (e_zmag)
383-391 F9.6 [10-7W] logL3000 Dust-corrected optical continuum
luminosity (LogL3000)
393-403 F11.9 [10-7W] e_logL3000 Dust-corrected optical continuum
luminosity error (LogL3000_Err)
405-414 F10.8 mag E(B-V) line-of-sight dust extinction (EBV)
416-426 F11.9 mag e_E(B-V) line-of-sight dust extinction error
(EBV_Err)
428-438 F11.9 --- BBnorm Normalisation of blackbody component
(BBnorm)
440-454 E15.7 --- e_BBnorm Normalisation of blackbody component
error (BBnorm_Err)
456-470 E15.7 % FUV Scattering fraction (Fuv)
472-487 E16.8 % e_FUV Scattering fraction error (Fuv_Err)
489-491 F3.1 --- UVxsFlag [0/1]?=- UV-excess flag (UVExcessFlag)
493-503 F11.8 --- rchisq Reduced chi2 (rchisq)
505-513 F9.6 [10-7W] L6um ?=- 6um continuum luminosity (L6um)
515-523 F9.6 [10-7W] logL2um-Dust Dust luminosity at 2um
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Acknowledgements:
Matthew Stepney, mstepney(at)cata.cl
License: CC-BY-4.0
(End) Patricia Vannier [CDS] 27-Jul-2026