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			<titleStmt><title level='a'>New Insight from the James Webb Space Telescope on Variable Active Galactic Nuclei</title></titleStmt>
			<publicationStmt>
				<publisher>IOP Science</publisher>
				<date>03/02/2026</date>
			</publicationStmt>
			<sourceDesc>
				<bibl> 
					<idno type="par_id">10704038</idno>
					<idno type="doi">10.3847/1538-4357/ae3fa0</idno>
					<title level='j'>The Astrophysical Journal</title>
<idno>0004-637X</idno>
<biblScope unit="volume">999</biblScope>
<biblScope unit="issue">2</biblScope>					

					<author>Bangzheng Sun</author><author>Haojing Yan</author><author>Wei Leong Tee</author><author>Feige Wang</author>
				</bibl>
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			<abstract><ab><![CDATA[<title>Abstract</title> <p>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 ∼140arcmin<sup>2</sup>in the COSMOS field, we found 117 galaxies with ≥4<italic>σ</italic>variability in the F356W band across an ∼2 yr baseline. Crossmatching with existing JWST spectroscopic data, we identified five of them at<italic>z</italic>= 0.19–3.69 (F356W corresponding to rest-frame<italic>λ</italic>≈0.76–2.97<italic>μ</italic>m), which were all coincidentally observed by an NIRSpec program almost contemporaneously with the last imaging epoch. One additional variable was identified at<italic>z</italic>= 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 (Δ<italic>v</italic>>1000kms<sup>−1</sup>) indicative of a Type 1 AGN; (2) two show narrow permitted lines (H<italic>α</italic>and/or He<sc>I</sc><italic>λ</italic>10830) 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.</p>]]></ab></abstract>
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