2026ApJ...997..250Z -
Astrophys. J., 997, 250 (2026/February-1)
Abundant Population of Broad Hα Emitters in the GOODS-N Field Revealed by CONGRESS, FRESCO, and JADES.
ZHANG J., EGAMI E., SUN F., LIN X., LYU J., ZHU Y., RINALDI P., SUN Y., BUNKER A.J., BHATAWDEKAR R., HELTON J.M., MAIOLINO R., MA Z., ROBERTSON B., TACCHELLA S., VENTURI G., WILLIAMS C.C. and WILLOTT C.
Abstract (from CDS):
We present a spectroscopic search for broad Hα emitters at z ≈ 3.7-6.5 in the GOODS-N field, utilizing JWST/NIRCam slitless spectroscopy from FRESCO and CONGRESS, complemented by JADES imaging. We identify 19 broad Hα emitters with FWHM > 1000 km s–1 at z ≈ 4-5.5, including nine new sources. The broad Hα luminosity function derived from our sample is consistent with those of other JWST-selected broad-line active galactic nuclei (AGN) reported in the literature. The black hole masses and AGN bolometric luminosities inferred from the broad Hα components indicate that most sources are accreting at ∼10% of the Eddington limit. We derive their host stellar masses via spectral energy distribution (SED) fitting and find higher MBH/M* ratios relative to the local MBH-M* relations, consistent with previous studies. We find that 42% of the sample do not satisfy the widely used color selection criteria for little red dots (LRDs), with the majority of these sources lacking the characteristic steep rest-optical red slope, indicating that the LRD selection is highly incomplete when selecting AGN galaxies. A comparison of the average SEDs between our sample and LRDs selected in the same field reveals that the steep red slopes observed in some LRDs are likely due to line-boosting effects as previously suggested. Furthermore, we find that 68% of color-selected LRDs with Hα detections in the NIRCam/grism spectra do not exhibit broad-line features. While the limited sensitivity of the grism spectra may hinder the detection of broad-line components in faint sources, our findings still highlight the enigmatic nature of the LRD population.
Abstract Copyright:
© 2026. The Author(s). Published by the American Astronomical Society.
Journal keyword(s):
AGN host galaxies - Active galactic nuclei - Supermassive black holes - High-redshift galaxies
Simbad objects:
22
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