article published yes Lukas J. Furtak author Amy R. Secunda author Jenny E. Greene author Adi Zitrin author Ivo Labbé author Miriam Golubchik author Rachel Bezanson author Vasily Kokorev author Hakim Atek author Gabriel B. Brammer author Iryna Chemerynska author Sam E. Cutler author Pratika Dayal author Robert Feldmann author Seiji Fujimoto author Karl Glazebrook author Joel Leja author Yilun Ma author Jorryt J Matthee author 7439a258-f3c0-11ec-9501-9df22fe067200000-0003-2871-127X Rohan P. Naidu author Erica J. Nelson author Pascal A. Oesch author Richard Pan author Sedona H. Price author Katherine A. Suess author Bingjie Wang author John R. Weaver author Katherine E. Whitaker author JoMa department JWST observations have uncovered a new population of red, compact objects at high redshifts dubbed “little red dots” (LRDs), which typically show broad emission lines and are thought to be dusty active galactic nuclei (AGNs). Some of their other features, however, challenge the AGN explanation, such as prominent Balmer breaks and extremely faint or even missing metal high-ionization lines, X-ray, or radio emission, including in deep stacks. Time variability is another robust test of AGN activity. Here, we exploit the z = 7.045 multiply imaged LRD A2744-QSO1, which offers a particularly unique test of variability due to lensing-induced time delays between the three images spanning 22 yr (2.7 yr in the rest-frame), to investigate its photometric and spectroscopic variability. We find the equivalent widths (EWs) of the broad Hα and Hβ lines, which are independent of magnification and other systematics, to exhibit significant variations, of up to 18 ± 3% for Hα and up to 22 ± 8% in Hβ, on a timescale of 875 d (2.4 yr) in the rest-frame. This suggests that A2744-QSO1 is indeed an AGN. We find no significant photometric variability beyond the limiting systematic uncertainties, so it currently cannot be determined whether the EW variations are due to line-flux or continuum variability. These results are consistent with a typical damped random walk variability model for an AGN such as A2744-QSO1 (MBH = 4 × 107 M⊙) given the sparse sampling of the light curve with the available data. Our results therefore support the AGN interpretation of this LRD, and highlight the need for further photometric and spectroscopic monitoring in order to build a detailed and reliable light curve. https://research-explorer.ista.ac.at/download/19931/19934/2025_AstronomyAstrophysics_Furtak.pdf application/pdfno EDP Sciences2025 eng 0004-6361 1432-0746 2502.07875 00151082630001710.1051/0004-6361/202554110 698 L. J. Furtak <i>et al.</i>, “Investigating photometric and spectroscopic variability in the multiply imaged little red dot A2744-QSO1,” <i>Astronomy &#38; Astrophysics</i>, vol. 698. EDP Sciences, 2025. Furtak LJ, Secunda AR, Greene JE, et al. Investigating photometric and spectroscopic variability in the multiply imaged little red dot A2744-QSO1. <i>Astronomy &#38; Astrophysics</i>. 2025;698. doi:<a href="https://doi.org/10.1051/0004-6361/202554110">10.1051/0004-6361/202554110</a> Furtak LJ, Secunda AR, Greene JE, Zitrin A, Labbé I, Golubchik M, Bezanson R, Kokorev V, Atek H, Brammer GB, Chemerynska I, Cutler SE, Dayal P, Feldmann R, Fujimoto S, Glazebrook K, Leja J, Ma Y, Matthee JJ, Naidu RP, Nelson EJ, Oesch PA, Pan R, Price SH, Suess KA, Wang B, Weaver JR, Whitaker KE. 2025. Investigating photometric and spectroscopic variability in the multiply imaged little red dot A2744-QSO1. Astronomy &#38; Astrophysics. 698, A227. Furtak, Lukas J., Amy R. Secunda, Jenny E. Greene, Adi Zitrin, Ivo Labbé, Miriam Golubchik, Rachel Bezanson, et al. “Investigating Photometric and Spectroscopic Variability in the Multiply Imaged Little Red Dot A2744-QSO1.” <i>Astronomy &#38; Astrophysics</i>. EDP Sciences, 2025. <a href="https://doi.org/10.1051/0004-6361/202554110">https://doi.org/10.1051/0004-6361/202554110</a>. Furtak, L. J., Secunda, A. R., Greene, J. E., Zitrin, A., Labbé, I., Golubchik, M., … Whitaker, K. E. (2025). Investigating photometric and spectroscopic variability in the multiply imaged little red dot A2744-QSO1. <i>Astronomy &#38; Astrophysics</i>. EDP Sciences. <a href="https://doi.org/10.1051/0004-6361/202554110">https://doi.org/10.1051/0004-6361/202554110</a> L.J. Furtak, A.R. Secunda, J.E. Greene, A. Zitrin, I. Labbé, M. Golubchik, R. Bezanson, V. Kokorev, H. Atek, G.B. Brammer, I. Chemerynska, S.E. Cutler, P. Dayal, R. Feldmann, S. Fujimoto, K. Glazebrook, J. Leja, Y. Ma, J.J. Matthee, R.P. Naidu, E.J. Nelson, P.A. Oesch, R. Pan, S.H. Price, K.A. Suess, B. Wang, J.R. Weaver, K.E. Whitaker, Astronomy &#38; Astrophysics 698 (2025). Furtak, Lukas J., et al. “Investigating Photometric and Spectroscopic Variability in the Multiply Imaged Little Red Dot A2744-QSO1.” <i>Astronomy &#38; Astrophysics</i>, vol. 698, A227, EDP Sciences, 2025, doi:<a href="https://doi.org/10.1051/0004-6361/202554110">10.1051/0004-6361/202554110</a>. 199312025-06-29T22:01:16Z2026-02-16T12:11:22Z