---
OA_place: publisher
OA_type: hybrid
_id: '19439'
abstract:
- lang: eng
  text: "White dwarfs (WDs) are the most abundant compact objects, and recent surveys
    have suggested that over a third of WDs in accreting binaries host a strong (B
    \ ≳ 1 MG) magnetic field. However, the origin and evolution of WD magnetism remain
    under debate. Two WD pulsars, AR Sco and J191213.72–441045.1 (J1912), have been
    found, which are non-accreting binaries hosting rapidly spinning (1.97 minutes
    and 5.30 minutes, respectively) magnetic WDs. The WD in AR Sco is slowing down
    on a (math formular) yr timescale. It is believed they will eventually become
    polars, accreting systems in which a magnetic WD (B  ≈ 10−240 MG) accretes from
    a Roche lobe-filling donor spinning in sync with the orbit (≳78 minutes). Here,
    we present multiwavelength data and analysis of Gaia22ayj, which outbursted in
    2022 March. We find that Gaia22ayj is a magnetic accreting WD that is rapidly
    spinning down (math formular\r\n yr) like WD pulsars, but shows clear evidence
    of accretion, like polars. Strong linear polarization (40%) is detected in Gaia22ayj;
    such high levels have only been seen in the WD pulsar AR Sco and demonstrate the
    WD is magnetic. High speed photometry reveals a 9.36 minutes period accompanying
    a high amplitude (∼2 mag) modulation. We associate this with a WD spin or spin–orbit
    beat period, not an orbital period as was previously suggested. Fast (60 s) optical
    spectroscopy reveals a broad \"hump,\" reminiscent of cyclotron emission in polars,
    between 4000 and 8000 Å. We find an X-ray luminosity of (math formular) in the
    0.3–8 keV energy range, while two very large array radio campaigns resulted in
    a non-detection with a Fr < 15.8 μJy 3σ upper limit. The shared properties of
    both WD pulsars and polars suggest that Gaia22ayj is a missing link between the
    two classes of magnetic WD binaries."
acknowledgement: "We wish to dedicate this work to the memory of our colleague and
  friend Tom Marsh. Tom's enthusiasm to work on this object and rapid efforts to facilitate
  data collection truly made this project possible.\r\n\r\nA.C.R. acknowledges support
  from an NSF Graduate Fellowship. A.C.R. thanks the LSST-DA Data Science Fellowship
  Program, which is funded by LSST-DA, the Brinson Foundation, and the Moore Foundation;
  his participation in the program has benefited this work. P.R.-G. acknowledges support
  by the Spanish Agencia Estatal de Investigación del Ministerio de Ciencia e Innovación
  (MCIN/AEI) and the European Regional Development Fund (ERDF) under grant PID2021–124879NB–I00.
  M.R.S. is supported by FONDECYT (grant No. 1221059) and eRO-STEP (SA 2131/15-2 project
  number 414059771). I.P. acknowledges support from a Royal Society University Research
  Fellowship (URF/R1/231496). We thank the referee for feedback that improved the
  clarity of this paper.\r\n\r\nBased on observations made with the Gran Telescopio
  Canarias (GTC), installed at the Spanish Observatorio del Roque de los Muchachos
  of the Instituto de Astrofìsica de Canarias, on the island of La Palma. Based on
  observations obtained with the Samuel Oschin Telescope 48 inch and the 60 inch Telescope
  at the Palomar Observatory as part of the ZTF project. ZTF is supported by the National
  Science Foundation under grants No. AST-1440341 and AST-2034437 and a collaboration
  including current partners Caltech, IPAC, the Weizmann Institute of Science, the
  Oskar Klein Center at Stockholm University, the University of Maryland, Deutsches
  Elektronen-Synchrotron and Humboldt University, the TANGO Consortium of Taiwan,
  the University of Wisconsin at Milwaukee, Trinity College Dublin, Lawrence Livermore
  National Laboratories, IN2P3, University of Warwick, Ruhr University Bochum, Northwestern
  University and former partners the University of Washington, Los Alamos National
  Laboratories, and Lawrence Berkeley National Laboratories. Operations are conducted
  by COO, IPAC, and UW.\r\n\r\nSome of the data presented herein were obtained at
  Keck Observatory, which is a private 501(c)3 non-profit organization operated as
  a scientific partnership among the California Institute of Technology, the University
  of California, and the National Aeronautics and Space Administration. The Observatory
  was made possible by the generous financial support of the W. M. Keck Foundation.
  The authors wish to recognize and acknowledge the very significant cultural role
  and reverence that the summit of Maunakea has always had within the Native Hawaiian
  community. We are most fortunate to have the opportunity to conduct observations
  from this mountain. We are also grateful to the staff of Palomar Observatory for
  their assistance in carrying out observations used in this work.\r\n\r\nPartly based
  on observations made with the NOT, owned in collaboration by the University of Turku
  and Aarhus University, and operated jointly by Aarhus University, the University
  of Turku and the University of Oslo, representing Denmark, Finland and Norway, the
  University of Iceland and Stockholm University at the Observatorio del Roque de
  los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias. The
  data presented here were obtained with ALFOSC, which is provided by the Instituto
  de Astrofisica de Andalucia (IAA) under a joint agreement with the University of
  Copenhagen and NOT. The observation with the SALT was obtained under program 2021-2-LSP-001
  (PI: D. Buckley). Polish participation in SALT is funded by grant No. MEiN nr 2021/WK/01.
  D.A.H.B. acknowledges support from the National Research Foundation.\r\n\r\nThis
  work presents results from the European Space Agency (ESA) space mission Gaia. Gaia
  data are being processed by the Gaia Data Processing and Analysis Consortium (DPAC).
  Funding for the DPAC is provided by national institutions, in particular the institutions
  participating in the Gaia MultiLateral Agreement (MLA). The Gaia mission website
  is https://www.cosmos.esa.int/gaia. The Gaia archive website is https://archives.esac.esa.int/gaia.
  This work made use of data supplied by the UK Swift Science Data Centre at the University
  of Leicester\r\n\r\nE.C.B. and J.K. acknowledge support from the DIRAC Institute
  in the Department of Astronomy at the University of Washington. The DIRAC Institute
  is supported through generous gifts from the Charles and Lisa Simonyi Fund for Arts
  and Sciences, and the Washington Research Foundation."
article_number: '024202'
article_processing_charge: Yes (in subscription journal)
article_type: original
arxiv: 1
author:
- first_name: Antonio C.
  full_name: Rodriguez, Antonio C.
  last_name: Rodriguez
- first_name: Kareem
  full_name: El-Badry, Kareem
  last_name: El-Badry
- first_name: Pasi
  full_name: Hakala, Pasi
  last_name: Hakala
- first_name: Pablo
  full_name: Rodríguez-Gil, Pablo
  last_name: Rodríguez-Gil
- first_name: Tong
  full_name: Bao, Tong
  last_name: Bao
- first_name: Ilkham
  full_name: Galiullin, Ilkham
  last_name: Galiullin
- first_name: Jacob A.
  full_name: Kurlander, Jacob A.
  last_name: Kurlander
- first_name: Casey J.
  full_name: Law, Casey J.
  last_name: Law
- first_name: Ingrid
  full_name: Pelisoli, Ingrid
  last_name: Pelisoli
- first_name: Matthias R.
  full_name: Schreiber, Matthias R.
  last_name: Schreiber
- first_name: Kevin
  full_name: Burdge, Kevin
  last_name: Burdge
- first_name: Ilaria
  full_name: Caiazzo, Ilaria
  id: 8ae5b6e7-2a03-11ee-914d-b58ed7a3b47d
  last_name: Caiazzo
  orcid: 0000-0002-4770-5388
- first_name: Jan Van
  full_name: Roestel, Jan Van
  last_name: Roestel
- first_name: Paula
  full_name: Szkody, Paula
  last_name: Szkody
- first_name: Andrew J.
  full_name: Drake, Andrew J.
  last_name: Drake
- first_name: David A.H.
  full_name: Buckley, David A.H.
  last_name: Buckley
- first_name: Stephen B.
  full_name: Potter, Stephen B.
  last_name: Potter
- first_name: Boris
  full_name: Gaensicke, Boris
  last_name: Gaensicke
- first_name: Kaya
  full_name: Mori, Kaya
  last_name: Mori
- first_name: Eric C.
  full_name: Bellm, Eric C.
  last_name: Bellm
- first_name: Shrinivas R.
  full_name: Kulkarni, Shrinivas R.
  last_name: Kulkarni
- first_name: Thomas A.
  full_name: Prince, Thomas A.
  last_name: Prince
- first_name: Matthew
  full_name: Graham, Matthew
  last_name: Graham
- first_name: Mansi M.
  full_name: Kasliwal, Mansi M.
  last_name: Kasliwal
- first_name: Sam
  full_name: Rose, Sam
  last_name: Rose
- first_name: Yashvi
  full_name: Sharma, Yashvi
  last_name: Sharma
- first_name: Tomás
  full_name: Ahumada, Tomás
  last_name: Ahumada
- first_name: Shreya
  full_name: Anand, Shreya
  last_name: Anand
- first_name: Akke
  full_name: Viitanen, Akke
  last_name: Viitanen
- first_name: Avery
  full_name: Wold, Avery
  last_name: Wold
- first_name: Tracy X.
  full_name: Chen, Tracy X.
  last_name: Chen
- first_name: Reed
  full_name: Riddle, Reed
  last_name: Riddle
- first_name: Roger
  full_name: Smith, Roger
  last_name: Smith
citation:
  ama: 'Rodriguez AC, El-Badry K, Hakala P, et al. A link between White Dwarf pulsars
    and polars: Multiwavelength observations of the 9.36-minute period variable Gaia22ayj.
    <i>Publications of the Astronomical Society of the Pacific</i>. 2025;137(2). doi:<a
    href="https://doi.org/10.1088/1538-3873/adb0f1">10.1088/1538-3873/adb0f1</a>'
  apa: 'Rodriguez, A. C., El-Badry, K., Hakala, P., Rodríguez-Gil, P., Bao, T., Galiullin,
    I., … Smith, R. (2025). A link between White Dwarf pulsars and polars: Multiwavelength
    observations of the 9.36-minute period variable Gaia22ayj. <i>Publications of
    the Astronomical Society of the Pacific</i>. IOP Publishing. <a href="https://doi.org/10.1088/1538-3873/adb0f1">https://doi.org/10.1088/1538-3873/adb0f1</a>'
  chicago: 'Rodriguez, Antonio C., Kareem El-Badry, Pasi Hakala, Pablo Rodríguez-Gil,
    Tong Bao, Ilkham Galiullin, Jacob A. Kurlander, et al. “A Link between White Dwarf
    Pulsars and Polars: Multiwavelength Observations of the 9.36-Minute Period Variable
    Gaia22ayj.” <i>Publications of the Astronomical Society of the Pacific</i>. IOP
    Publishing, 2025. <a href="https://doi.org/10.1088/1538-3873/adb0f1">https://doi.org/10.1088/1538-3873/adb0f1</a>.'
  ieee: 'A. C. Rodriguez <i>et al.</i>, “A link between White Dwarf pulsars and polars:
    Multiwavelength observations of the 9.36-minute period variable Gaia22ayj,” <i>Publications
    of the Astronomical Society of the Pacific</i>, vol. 137, no. 2. IOP Publishing,
    2025.'
  ista: 'Rodriguez AC, El-Badry K, Hakala P, Rodríguez-Gil P, Bao T, Galiullin I,
    Kurlander JA, Law CJ, Pelisoli I, Schreiber MR, Burdge K, Caiazzo I, Roestel JV,
    Szkody P, Drake AJ, Buckley DAH, Potter SB, Gaensicke B, Mori K, Bellm EC, Kulkarni
    SR, Prince TA, Graham M, Kasliwal MM, Rose S, Sharma Y, Ahumada T, Anand S, Viitanen
    A, Wold A, Chen TX, Riddle R, Smith R. 2025. A link between White Dwarf pulsars
    and polars: Multiwavelength observations of the 9.36-minute period variable Gaia22ayj.
    Publications of the Astronomical Society of the Pacific. 137(2), 024202.'
  mla: 'Rodriguez, Antonio C., et al. “A Link between White Dwarf Pulsars and Polars:
    Multiwavelength Observations of the 9.36-Minute Period Variable Gaia22ayj.” <i>Publications
    of the Astronomical Society of the Pacific</i>, vol. 137, no. 2, 024202, IOP Publishing,
    2025, doi:<a href="https://doi.org/10.1088/1538-3873/adb0f1">10.1088/1538-3873/adb0f1</a>.'
  short: A.C. Rodriguez, K. El-Badry, P. Hakala, P. Rodríguez-Gil, T. Bao, I. Galiullin,
    J.A. Kurlander, C.J. Law, I. Pelisoli, M.R. Schreiber, K. Burdge, I. Caiazzo,
    J.V. Roestel, P. Szkody, A.J. Drake, D.A.H. Buckley, S.B. Potter, B. Gaensicke,
    K. Mori, E.C. Bellm, S.R. Kulkarni, T.A. Prince, M. Graham, M.M. Kasliwal, S.
    Rose, Y. Sharma, T. Ahumada, S. Anand, A. Viitanen, A. Wold, T.X. Chen, R. Riddle,
    R. Smith, Publications of the Astronomical Society of the Pacific 137 (2025).
date_created: 2025-03-23T23:01:26Z
date_published: 2025-02-01T00:00:00Z
date_updated: 2025-09-30T11:15:10Z
day: '01'
ddc:
- '520'
department:
- _id: IlCa
doi: 10.1088/1538-3873/adb0f1
external_id:
  arxiv:
  - '2501.01490'
  isi:
  - '001427877700001'
file:
- access_level: open_access
  checksum: 42d5aa504479c3fdf2a10165a9e3319f
  content_type: application/pdf
  creator: dernst
  date_created: 2025-03-25T10:01:24Z
  date_updated: 2025-03-25T10:01:24Z
  file_id: '19455'
  file_name: 2025_PubAstronomSocPacific_Rodriguez.pdf
  file_size: 3291933
  relation: main_file
  success: 1
file_date_updated: 2025-03-25T10:01:24Z
has_accepted_license: '1'
intvolume: '       137'
isi: 1
issue: '2'
language:
- iso: eng
month: '02'
oa: 1
oa_version: Published Version
publication: Publications of the Astronomical Society of the Pacific
publication_identifier:
  issn:
  - 0004-6280
publication_status: published
publisher: IOP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'A link between White Dwarf pulsars and polars: Multiwavelength observations
  of the 9.36-minute period variable Gaia22ayj'
tmp:
  image: /images/cc_by.png
  legal_code_url: https://creativecommons.org/licenses/by/4.0/legalcode
  name: Creative Commons Attribution 4.0 International Public License (CC-BY 4.0)
  short: CC BY (4.0)
type: journal_article
user_id: 317138e5-6ab7-11ef-aa6d-ffef3953e345
volume: 137
year: '2025'
...