---
res:
  bibo_abstract:
  - 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.@eng
  bibo_authorlist:
  - foaf_Person:
      foaf_givenName: Lukas J.
      foaf_name: Furtak, Lukas J.
      foaf_surname: Furtak
  - foaf_Person:
      foaf_givenName: Amy R.
      foaf_name: Secunda, Amy R.
      foaf_surname: Secunda
  - foaf_Person:
      foaf_givenName: Jenny E.
      foaf_name: Greene, Jenny E.
      foaf_surname: Greene
  - foaf_Person:
      foaf_givenName: Adi
      foaf_name: Zitrin, Adi
      foaf_surname: Zitrin
  - foaf_Person:
      foaf_givenName: Ivo
      foaf_name: Labbé, Ivo
      foaf_surname: Labbé
  - foaf_Person:
      foaf_givenName: Miriam
      foaf_name: Golubchik, Miriam
      foaf_surname: Golubchik
  - foaf_Person:
      foaf_givenName: Rachel
      foaf_name: Bezanson, Rachel
      foaf_surname: Bezanson
  - foaf_Person:
      foaf_givenName: Vasily
      foaf_name: Kokorev, Vasily
      foaf_surname: Kokorev
  - foaf_Person:
      foaf_givenName: Hakim
      foaf_name: Atek, Hakim
      foaf_surname: Atek
  - foaf_Person:
      foaf_givenName: Gabriel B.
      foaf_name: Brammer, Gabriel B.
      foaf_surname: Brammer
  - foaf_Person:
      foaf_givenName: Iryna
      foaf_name: Chemerynska, Iryna
      foaf_surname: Chemerynska
  - foaf_Person:
      foaf_givenName: Sam E.
      foaf_name: Cutler, Sam E.
      foaf_surname: Cutler
  - foaf_Person:
      foaf_givenName: Pratika
      foaf_name: Dayal, Pratika
      foaf_surname: Dayal
  - foaf_Person:
      foaf_givenName: Robert
      foaf_name: Feldmann, Robert
      foaf_surname: Feldmann
  - foaf_Person:
      foaf_givenName: Seiji
      foaf_name: Fujimoto, Seiji
      foaf_surname: Fujimoto
  - foaf_Person:
      foaf_givenName: Karl
      foaf_name: Glazebrook, Karl
      foaf_surname: Glazebrook
  - foaf_Person:
      foaf_givenName: Joel
      foaf_name: Leja, Joel
      foaf_surname: Leja
  - foaf_Person:
      foaf_givenName: Yilun
      foaf_name: Ma, Yilun
      foaf_surname: Ma
  - foaf_Person:
      foaf_givenName: Jorryt J
      foaf_name: Matthee, Jorryt J
      foaf_surname: Matthee
      foaf_workInfoHomepage: http://www.librecat.org/personId=7439a258-f3c0-11ec-9501-9df22fe06720
    orcid: 0000-0003-2871-127X
  - foaf_Person:
      foaf_givenName: Rohan P.
      foaf_name: Naidu, Rohan P.
      foaf_surname: Naidu
  - foaf_Person:
      foaf_givenName: Erica J.
      foaf_name: Nelson, Erica J.
      foaf_surname: Nelson
  - foaf_Person:
      foaf_givenName: Pascal A.
      foaf_name: Oesch, Pascal A.
      foaf_surname: Oesch
  - foaf_Person:
      foaf_givenName: Richard
      foaf_name: Pan, Richard
      foaf_surname: Pan
  - foaf_Person:
      foaf_givenName: Sedona H.
      foaf_name: Price, Sedona H.
      foaf_surname: Price
  - foaf_Person:
      foaf_givenName: Katherine A.
      foaf_name: Suess, Katherine A.
      foaf_surname: Suess
  - foaf_Person:
      foaf_givenName: Bingjie
      foaf_name: Wang, Bingjie
      foaf_surname: Wang
  - foaf_Person:
      foaf_givenName: John R.
      foaf_name: Weaver, John R.
      foaf_surname: Weaver
  - foaf_Person:
      foaf_givenName: Katherine E.
      foaf_name: Whitaker, Katherine E.
      foaf_surname: Whitaker
  bibo_doi: 10.1051/0004-6361/202554110
  bibo_volume: 698
  dct_date: 2025^xs_gYear
  dct_identifier:
  - UT:001510826300017
  dct_isPartOf:
  - http://id.crossref.org/issn/0004-6361
  - http://id.crossref.org/issn/1432-0746
  dct_language: eng
  dct_publisher: EDP Sciences@
  dct_title: Investigating photometric and spectroscopic variability in the multiply
    imaged little red dot A2744-QSO1@
...