The Astrophysical Journal Letters (Jan 2024)
Discovery of the Optical and Radio Counterpart to the Fast X-Ray Transient EP 240315a
- J. H. Gillanders,
- L. Rhodes,
- S. Srivastav,
- F. Carotenuto,
- J. Bright,
- M. E. Huber,
- H. F. Stevance,
- S. J. Smartt,
- K. C. Chambers,
- T.-W. Chen,
- R. Fender,
- A. Andersson,
- A. J. Cooper,
- P. G. Jonker,
- F. J. Cowie,
- T. de Boer,
- N. Erasmus,
- M. D. Fulton,
- H. Gao,
- J. Herman,
- C.-C. Lin,
- T. Lowe,
- E. A. Magnier,
- H.-Y. Miao,
- P. Minguez,
- T. Moore,
- C.-C. Ngeow,
- M. Nicholl,
- Y.-C. Pan,
- G. Pignata,
- A. Rest,
- X. Sheng,
- I. A. Smith,
- K. W. Smith,
- J. L. Tonry,
- R. J. Wainscoat,
- J. Weston,
- S. Yang,
- D. R. Young
Affiliations
- J. H. Gillanders
- ORCiD
- Astrophysics sub-Department, Department of Physics, University of Oxford , Keble Road, Oxford, OX1 3RH, UK ; [email protected], [email protected], [email protected]
- L. Rhodes
- ORCiD
- Astrophysics sub-Department, Department of Physics, University of Oxford , Keble Road, Oxford, OX1 3RH, UK ; [email protected], [email protected], [email protected]
- S. Srivastav
- ORCiD
- Astrophysics sub-Department, Department of Physics, University of Oxford , Keble Road, Oxford, OX1 3RH, UK ; [email protected], [email protected], [email protected]
- F. Carotenuto
- ORCiD
- Astrophysics sub-Department, Department of Physics, University of Oxford , Keble Road, Oxford, OX1 3RH, UK ; [email protected], [email protected], [email protected]
- J. Bright
- ORCiD
- Astrophysics sub-Department, Department of Physics, University of Oxford , Keble Road, Oxford, OX1 3RH, UK ; [email protected], [email protected], [email protected]
- M. E. Huber
- ORCiD
- Institute for Astronomy, University of Hawai’i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA
- H. F. Stevance
- ORCiD
- Astrophysics sub-Department, Department of Physics, University of Oxford , Keble Road, Oxford, OX1 3RH, UK ; [email protected], [email protected], [email protected]; Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast , BT7 1NN, UK
- S. J. Smartt
- ORCiD
- Astrophysics sub-Department, Department of Physics, University of Oxford , Keble Road, Oxford, OX1 3RH, UK ; [email protected], [email protected], [email protected]; Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast , BT7 1NN, UK
- K. C. Chambers
- ORCiD
- Institute for Astronomy, University of Hawai’i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA
- T.-W. Chen
- ORCiD
- Graduate Institute of Astronomy, National Central University , 300 Jhongda Road, 32001 Jhongli, Taiwan
- R. Fender
- Astrophysics sub-Department, Department of Physics, University of Oxford , Keble Road, Oxford, OX1 3RH, UK ; [email protected], [email protected], [email protected]; Department of Astronomy, University of Cape Town , Private Bag X3, Rondebosch 7701, South Africa
- A. Andersson
- ORCiD
- Astrophysics sub-Department, Department of Physics, University of Oxford , Keble Road, Oxford, OX1 3RH, UK ; [email protected], [email protected], [email protected]
- A. J. Cooper
- ORCiD
- Astrophysics sub-Department, Department of Physics, University of Oxford , Keble Road, Oxford, OX1 3RH, UK ; [email protected], [email protected], [email protected]
- P. G. Jonker
- ORCiD
- Department of Astrophysics/IMAPP, Radboud University , P.O. Box 9010, 6500 GL, Nijmegen, The Netherlands
- F. J. Cowie
- ORCiD
- Astrophysics sub-Department, Department of Physics, University of Oxford , Keble Road, Oxford, OX1 3RH, UK ; [email protected], [email protected], [email protected]
- T. de Boer
- Institute for Astronomy, University of Hawai’i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA
- N. Erasmus
- ORCiD
- South African Astronomical Observatory , PO Box 9, Observatory 7935, Cape Town, South Africa
- M. D. Fulton
- ORCiD
- Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast , BT7 1NN, UK
- H. Gao
- ORCiD
- Institute for Astronomy, University of Hawai’i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA
- J. Herman
- Institute for Astronomy, University of Hawai’i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA
- C.-C. Lin
- ORCiD
- Institute for Astronomy, University of Hawai’i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA
- T. Lowe
- Institute for Astronomy, University of Hawai’i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA
- E. A. Magnier
- ORCiD
- Institute for Astronomy, University of Hawai’i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA
- H.-Y. Miao
- ORCiD
- Graduate Institute of Astronomy, National Central University , 300 Jhongda Road, 32001 Jhongli, Taiwan
- P. Minguez
- Institute for Astronomy, University of Hawai’i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA
- T. Moore
- ORCiD
- Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast , BT7 1NN, UK
- C.-C. Ngeow
- ORCiD
- Graduate Institute of Astronomy, National Central University , 300 Jhongda Road, 32001 Jhongli, Taiwan
- M. Nicholl
- ORCiD
- Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast , BT7 1NN, UK
- Y.-C. Pan
- ORCiD
- Graduate Institute of Astronomy, National Central University , 300 Jhongda Road, 32001 Jhongli, Taiwan
- G. Pignata
- ORCiD
- Instituto de Alta Investigación, Universidad de Tarapacá , Arica, Casilla 7D, Chile
- A. Rest
- Space Telescope Science Institute , 3700 San Martin Drive, Baltimore, MD 21218, USA; Department of Physics and Astronomy, Johns Hopkins University , Baltimore, MD 21218, USA
- X. Sheng
- ORCiD
- Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast , BT7 1NN, UK
- I. A. Smith
- ORCiD
- Institute for Astronomy, University of Hawai’i , 34 Ohia Ku St., Pukalani, HI 96768-8288, USA
- K. W. Smith
- ORCiD
- Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast , BT7 1NN, UK
- J. L. Tonry
- ORCiD
- Institute for Astronomy, University of Hawai’i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA
- R. J. Wainscoat
- ORCiD
- Institute for Astronomy, University of Hawai’i , 2680 Woodlawn Drive, Honolulu, HI 96822, USA
- J. Weston
- Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast , BT7 1NN, UK
- S. Yang
- Henan Academy of Sciences , Zhengzhou 450046, Henan, People’s Republic of China
- D. R. Young
- ORCiD
- Astrophysics Research Centre, School of Mathematics and Physics, Queen’s University Belfast , BT7 1NN, UK
- DOI
- https://doi.org/10.3847/2041-8213/ad55cd
- Journal volume & issue
-
Vol. 969,
no. 1
p. L14
Abstract
Fast X-ray Transients (FXTs) are extragalactic bursts of soft X-rays first identified ≳10 yr ago. Since then, nearly 40 events have been discovered, although almost all of these have been recovered from archival Chandra and XMM-Newton data. To date, optical sky surveys and follow-up searches have not revealed any multiwavelength counterparts. The Einstein Probe, launched in 2024 January, has started surveying the sky in the soft X-ray regime (0.5–4 keV) and will rapidly increase the sample of FXTs discovered in real time. Here we report the first discovery of both an optical and radio counterpart to a distant FXT, the fourth source publicly released by the Einstein Probe. We discovered a fast-fading optical transient within the 3′ localization radius of EP 240315a with the all-sky optical survey ATLAS, and our follow-up Gemini spectrum provides a redshift, z = 4.859 ± 0.002. Furthermore, we uncovered a radio counterpart in the S band (3.0 GHz) with the MeerKAT radio interferometer. The optical (rest-frame UV) and radio luminosities indicate that the FXT most likely originates from either a long gamma-ray burst or a relativistic tidal disruption event. This may be a fortuitous early mission detection by the Einstein Probe or may signpost a mode of discovery for high-redshift, high-energy transients through soft X-ray surveys, combined with locating multiwavelength counterparts.
Keywords
- Transient sources
- Relativistic jets
- High energy astrophysics
- X-ray transient sources
- Optical identification
- Radio interferometry
