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Arxiv: A SPectroscopic survey of biased halos In the Reionization Era (ASPIRE): Broad-line AGN at z=4-5 revealed by JWST/NIRCam WFSS Published: 7/24/2024 9:03:24 PM Updated: 7/24/2024 9:03:24 PM

Paper abstract: Low-luminosity AGNs with low-mass black holes (BHs) in the early universe arefundamental to understanding the BH growth and their co-evolution with the hostgalaxies. Utilizing JWST NIRCam Wide Field Slitless Spectroscopy (WFSS), weperform a systematic search for broad-line {\rm H\alpha} emitters (BHAEs) atz~ 4-5 in 25 fields of the ASPIRE (A SPectroscopic survey of biasedhalos In the Reionization Era) project, covering a total area of 275arcmin^2. We identify 16 BHAEs with FWHM of the broad components spanningfrom ~ 1000 km s^{-1} to 3000 km s^{-1}. Assuming the broad linewidthsarise due to Doppler broadening around BHs, the implied BH masses range from10^7 to 10^{8}~M_\odot, with broad {\rm H\alpha}-converted bolometricluminosity of 10^{44.5}-10^{45.5} erg s^{-1} and Eddington ratios of0.07-0.47. The spatially extended structure of the F200W stacked image maytrace the stellar light from the host galaxies. The {\rm H\alpha} luminosityfunction indicates an increasing AGN fraction towards the higher {\rmH\alpha} luminosities. We find possible evidence for clustering of BHAEs: twosources are at the same redshift with a projected separation of 519 kpc; oneBHAE appears as a composite system residing in an overdense region with threeclose companion {\rm H\alpha} emitters. Three BHAEs exhibit blueshiftedabsorption troughs indicative of the presence of high-column-density gas. Wefind the broad-line and photometrically selected BHAE samples exhibit differentdistributions in the optical continuum slopes, which can be attributed to theirdifferent selection methods. The ASPIRE broad-line {\rm H\alpha} sampleprovides a good database for future studies of faint AGN populations at highredshift.