More Like this

1. The Large-scale Environments of Low-luminosity AGNs at 3.9 < z < 6 and Implications for Their Host Dark Matter Halos from a Complete NIRCam Grism Redshift Survey

   https://doi.org/10.3847/1538-4357/ae1eef  

   Lin, Xiaojing; Fan, Xiaohui; Sun, Fengwu; Zhang, Junyu; Egami, Eiichi; Helton, Jakob M; Wang, Feige; Zhang, Haowen; Bunker, Andrew J; Cai, Zheng; et al (January 2026, The Astrophysical Journal)

   Abstract We study the large-scale environments and clustering properties of 28 low-luminosity active galactic nuclei (AGNs) atz = 3.9–6 in the GOODS-N field. Our sample, identified from the JWST NIRCam Imaging and WFSS data in Complete NIRCam Grism Redshift Survey and First Reionization Epoch Spectroscopically Complete Observations surveys with either broad Hαemission lines or V-shaped continua, are compared to 782 Hαemitters (HAEs) selected from the same data. These AGNs are located in diverse large-scale environments and do not preferentially reside in denser environments compared to HAEs. Their overdensity field,δ, averaged over (15h⁻¹cMpc)³, ranges from −0.56 to 10.56, and shows no clear correlation with broad-line luminosity, black hole (BH) masses, or the AGN fraction. It suggests that >10 cMpc structures do not significantly influence BH growth. We measure the two-point cross-correlation function of AGNs with HAEs, finding a comparable amplitude to that of the HAE autocorrelation. This indicates similar bias parameters and host dark matter halo masses for AGNs and HAEs. The correlation length of field AGNs is 4.26h⁻¹cMpc and 7.66h⁻¹cMpc at 3.9 < z < 5 and 5 < z < 6, respectively. We infer a median host dark matter halo mass of $\log (M_h/M_{\odot })\approx 11.0-11.2$ and host stellar masses of $\log \left(M_{\star }/M_{\odot }\right)\approx 8.4\text{–}8.6$ by comparing with the UniverseMachinesimulation. Our clustering analysis suggests that low-luminosity AGNs at high redshift reside in normal star-forming galaxies with overmassive BHs. They represent an intrinsically distinct population from luminous quasars and could be a common phase in galaxy evolution. 

   more » « less
2. A Quasar-anchored Protocluster at z = 6.6 in the ASPIRE Survey. II. An Environmental Analysis of Galaxy Properties in an Overdense Structure

   https://doi.org/10.3847/1538-4357/adb1bc  

   Champagne, Jaclyn B; Wang, Feige; Yang, Jinyi; Fan, Xiaohui; Hennawi, Joseph F; Sun, Fengwu; Bañados, Eduardo; Bosman, Sarah_E I; Costa, Tiago; Habouzit, Melanie; et al (March 2025, The Astrophysical Journal)

   Abstract We present in this paper (Paper II of the series) a 35 arcmin²JWST/NIRCam imaging and wide-field slitless spectroscopy mosaic centered on J0305–3150, a luminous quasar atz= 6.61. The F356W grism data reveal 124 [Oiii]+Hβemitters at 5.3 < z < 7, 53 of which constitute a protocluster spanning (10 cMpc)²across 6.5 < z < 6.8. We find no evidence of any broad-line active galactic nucleus (AGN) in individual galaxies or stacking, reporting a median HβFWHM of 585 ± 152 km s⁻¹; however, the mass–excitation diagram and “little red dot” color and compactness criteria suggest that there are a few AGN candidates on the outskirts of the protocluster. We fit the spectral energy distributions (SEDs) of the [Oiii] emitters withProspectorandBagpipesand find that none of the SED-derived properties (stellar mass, age, or star formation rate) correlate with proximity to the quasar. While there is no correlation between galaxy age and local galaxy density, we find modest correlations of local galaxy density with increasing stellar mass, decreasing 10–100 Myr star formation rate ratios, and decreasing nebular line equivalent widths. We further find that the protocluster galaxies are consistent with being more massive, being older, and hosting higher star formation rates than the field sample at the 3σlevel, distributed in a filamentary structure that supports inside-out formation of the protocluster. There is modest evidence that galaxy evolution proceeds differently as a function of the density of local environment within protoclusters during the epoch of reionization, and the central quasar has little effect on the galaxy properties of the surrounding structure. 

   more » « less
3. A Quasar-anchored Protocluster at z = 6.6 in the ASPIRE Survey. I. Properties of [O iii ] Emitters in a 10 Mpc Overdensity Structure

   https://doi.org/10.3847/1538-4357/adb1bd  

   Champagne, Jaclyn B; Wang, Feige; Zhang_张, Haowen 昊文; Yang, Jinyi; Fan, Xiaohui; Hennawi, Joseph F; Sun, Fengwu; Bañados, Eduardo; Bosman, Sarah_E I; Costa, Tiago; et al (March 2025, The Astrophysical Journal)

   Abstract A SPectroscopic survey of bIased halos in the Reionization Era is a quasar legacy survey primarily using JWST to target a sample of 25z > 6 quasars with NIRCam slitless spectroscopy and imaging. The first study in this series found evidence of a strong overdensity of galaxies around J0305−3150, a luminous quasar atz= 6.61, within a single NIRCam pointing obtained in JWST Cycle 1. Here we present the first results of a JWST Cycle 2 mosaic that covers 35 arcmin²with NIRCam imaging/wide-field slitless spectroscopy of the same field to investigate the spatial extent of the putative protocluster. The F356W grism data target [Oiii]+Hβat 5.3 < z < 7 and reveal a population of 124 line emitters down to a flux limit of 1.2 × 10⁻¹⁸erg s⁻¹cm⁻². Fifty-three of these galaxies lie at 6.5 < z < 6.8 spanning 10 cMpc on the sky, corresponding to an overdensity within a 2500 cMpc³volume of 12.5 ± 2.6, anchored by the quasar. Comparing to the [Oiii] luminosity function from the Emission line galaxies and Intergalactic Gas in the Epoch of Reionization project, we find a dearth of faint [Oiii] emitters at log(L/erg s⁻¹) < 42.3, which we suggest is consistent with either bursty star formation causing galaxies to scatter around the grism detection limit or modest suppression from quasar feedback. While we find a strong filamentary overdensity of [Oiii] emitters consistent with a protocluster, we suggest that we could be insensitive to a population of older, more massive Lyman break galaxies with weak nebular emission on scales >​​​​​​10 cMpc. 

   more » « less
4. New Insight from the James Webb Space Telescope on Variable Active Galactic Nuclei

   https://doi.org/10.3847/1538-4357/ae3fa0  

   Sun, Bangzheng; Yan, Haojing; Tee, Wei Leong; Wang, Feige (March 2026, The Astrophysical Journal)

   Abstract Variability detected in galaxies is usually attributed to their active galactic nuclei (AGNs). While all AGNs are intrinsically variable, the AGN unification model predicts that Type 2 AGNs rarely vary because their engines are blocked by dust tori. Previous UV to near-IR variability studies largely support this expectation. Here, we present a variability study with the James Webb Space Telescope (JWST) that reveals a more subtle picture. Using NIRCam imaging data from three surveys over ∼140 arcmin²in the COSMOS field, we found 117 galaxies with ≥4σvariability in the F356W band across an ∼2 yr baseline. Crossmatching with existing JWST spectroscopic data, we identified five of them atz= 0.19–3.69 (F356W corresponding to rest-frameλ ≈ 0.76–2.97 μm), which were all coincidentally observed by an NIRSpec program almost contemporaneously with the last imaging epoch. One additional variable was identified atz= 0.90 using archival Keck telescope data. These six objects form our spectroscopic subsample. Interestingly, two reside in close-pair environments, while two others form a close pair themselves. Most of their light curves can hardly be explained by nuclear transients, and AGN variability is a more plausible cause. However, among these six objects (1) only one shows broad Bracket and Pfund series permitted lines (Δv > 1000 km s⁻¹) indicative of a Type 1 AGN; (2) two show narrow permitted lines (Hαand/or He Iλ10830) consistent with Type 2 AGNs, with another one likely Type 2 based on the host galaxy properties; and (3) two others, which form a pair, show no emission lines. Our results add more challenges to the unification model. 

   more » « less
5. An Excess of Active Galactic Nuclei Triggered by Galaxy Mergers in MaNGA Galaxies of Stellar Mass ∼10 ¹¹ M _⊙

   https://doi.org/10.3847/1538-4357/ad1a15  

   Comerford, Julia M; Nevin, Rebecca; Negus, James; Barrows, R Scott; Eracleous, Michael; Müller-Sánchez, Francisco; Roy, Namrata; Stemo, Aaron; Storchi-Bergmann, Thaisa; Wylezalek, Dominika (February 2024, The Astrophysical Journal)

   Abstract To facilitate new studies of galaxy-merger-driven fueling of active galactic nuclei (AGNs), we present a catalog of 387 AGNs that we have identified in the final population of over 10,000z< 0.15 galaxies observed by the Sloan Digital Sky Survey-IV (SDSS-IV) integral field spectroscopy survey Mapping Nearby Galaxies at Apache Point Observatory (MaNGA). We selected the AGNs via mid-infrared Wide-field Infrared Survey Explorer colors, Swift/Burst Alert Telescope ultra-hard X-ray detections, NRAO Very Large Array Sky Survey and Faint Images of the Radio Sky at Twenty centimeters radio observations, and broad emission lines in SDSS spectra. By combining the MaNGA AGN catalog with a new SDSS catalog of galaxy mergers that were identified based on a suite of hydrodynamical simulations of merging galaxies, we study the link between galaxy mergers and nuclear activity for AGNs above a limiting bolometric luminosity of 10^44.4erg s⁻¹. We find an excess of AGNs in mergers, relative to nonmergers, for galaxies with stellar mass ∼10¹¹M_⊙, where the AGN excess is somewhat stronger in major mergers than in minor mergers. Further, when we combine minor and major mergers and sort by merger stage, we find that the highest AGN excess occurs in post-coalescence mergers in the highest-mass galaxies. However, we find no evidence of a correlation between galaxy mergers and AGN luminosity or accretion rate. In summary, while galaxy mergers overall do appear to trigger or enhance AGN activity more than nonmergers, they do not seem to induce higher levels of accretion or higher luminosities. We provide the MaNGA AGN Catalog and the MaNGA Galaxy Merger Catalog for the community here. 

   more » « less