MAXI J1820+070

MAXI J1820+070

MAXI J1830+070 imaged by Neil Gehrels Swift Observatory
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Ophiuchus
Right ascension 18h 20m 21.942s[1]
Declination +07° 11′ 07.28″[1]
Apparent magnitude (V) 12±19[2]
Characteristics
Spectral type K3-K5[3]
Astrometry
Proper motion (μ) RA: −3.093 mas/yr[1]
Dec.: −6.286 mas/yr[1]
Parallax (π)0.3692±0.078 mas[1]
Distance9,700 ± 1,100 ly
(2,960±330[4] pc)
Orbit[2]
Period (P)0.68549 d
Eccentricity (e)0.026
Inclination (i)66–81°
Details
Primary
Mass5 to 10[5] M☉
Secondary
Mass0.49±0.10[5] M☉
Other designations
ASASSN-18ey, MAXI J1820+070, TIC 317984780, 2MASS J18202194+0711073, WISE J182021.94+071107.2[6]
Database references
SIMBADdata

MAXI J1820+070 is an X-ray binary system in the equatorial constellation of Ophiuchus. It was discovered in 2018, when it underwent a flare event,[7] becoming one of the brightest such objects ever observed (in both the visual and X-ray bands).[2] Based on parallax measurements, it is located at a distance of approximately 9.7 ± 1.1 kly (2.96 ± 0.33 kpc) from the Sun.[4]

Discovery

This target was discovered March 6, 2018 by the All Sky Automated Survey for SuperNovae at an apparent visual magnitude of 14.88. Previously it had been at magnitudes below 16.7. On March 11, X-ray emission from this source was detected by the MAXI telescope,[7] mounted on the International Space Station.[8] On March 13, the Swift Burst Alert Telescope was triggered by MAXI J1820+070.[9]

Subsequently, the source underwent three re-brightenings that were extensively monitored, before its final optical activity was observed in April 2021. It began fading rapidly in June 2023 and returned to quiescence at its pre-brightening level after five years.[10]

Observations

Optical observations of this transient source, combined with distance estimates, indicated it is consistent with a low-mass X-ray binary system containing a candidate black hole.[11] The spectra displayed hydrogen absorption lines with emission cores, suggesting an accretion disk undergoing outburst.[12] By April 4, 2018, quasi-periodic oscillations had been observed in both the X-ray and visual bands with variability on time scales of less than a second.[13] Optical variation of 0.03–0.10 in magnitude showed a periodicity of 3.4 hours, suggesting this may be the orbital period.[14]

In 2019, the presence of a black hole in the system was confirmed through measurements of the system dynamics.[3] The cool, evolved, low mass companion is transferring matter via its Roche lobe to an accretion disk orbiting the black hole.[2] This disk is truncated at around 51 times the gravitational radii, and has a high density of around 1020 cm−3.[5] Observations suggest the disk may be warped and is precessing.[2] The black hole has an estimated spin parameter of a ~ 0.77 ± 0.21.[5]

An accurate radio parallax measurement was made in 2020, providing a distance estimate of 9,700 ± 1,100 ly.[4] The detection of knots in the ejecta allowed the angle of the jet to be measured as 64°±5° to the plane of the sky relative to Earth. The ejecta is moving at ~0.97 c, where c is the speed of light.[15]

References

  1. ^ a b c d Vallenari, A.; et al. (Gaia collaboration) (2023), "Gaia Data Release 3. Summary of the content and survey properties", Astronomy and Astrophysics, 674: A1, arXiv:2208.00211, Bibcode:2023A&A...674A...1G, doi:10.1051/0004-6361/202243940, S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ a b c d e Thomas, Jessymol K.; et al. (January 2022), "Large optical modulations during 2018 outburst of MAXI J1820 + 070 reveal evolution of warped accretion disc through X-ray state change", Monthly Notices of the Royal Astronomical Society, 509 (1): 1062–1074, arXiv:2108.05447, Bibcode:2022MNRAS.509.1062T, doi:10.1093/mnras/stab3033.
  3. ^ a b Torres, M. A. P.; et al. (September 2019), "Dynamical Confirmation of a Black Hole in MAXI J1820+070", The Astrophysical Journal Letters, 882 (2), id. L21, arXiv:1907.00938, Bibcode:2019ApJ...882L..21T, doi:10.3847/2041-8213/ab39df.
  4. ^ a b c Atri, P.; et al. (March 2020), "A radio parallax to the black hole X-ray binary MAXI J1820+070", Monthly Notices of the Royal Astronomical Society: Letters, 493 (1): L81–L86, arXiv:1912.04525, Bibcode:2020MNRAS.493L..81A, doi:10.1093/mnrasl/slaa010.
  5. ^ a b c d Banerjee, Srimanta; et al. (April 2024), "A Multiwavelength Study of the Hard and Soft States of MAXI J1820+070 During Its 2018 Outburst", The Astrophysical Journal, 964 (2), id. 189, arXiv:2402.08237, Bibcode:2024ApJ...964..189B, doi:10.3847/1538-4357/ad24ef.
  6. ^ "MAXI J1820+070", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2025-12-05.
  7. ^ a b Tucker, M. A.; et al. (November 2018), "ASASSN-18ey: The Rise of a New Black Hole X-Ray Binary", The Astrophysical Journal Letters, 867 (1), id. L9, arXiv:1808.07875, Bibcode:2018ApJ...867L...9T, doi:10.3847/2041-8213/aae88a.
  8. ^ Matsuoka, Masaru; et al. (October 2009), "The MAXI Mission on the ISS: Science and Instruments for Monitoring All-Sky X-Ray Images", Publications of the Astronomical Society of Japan, 61 (5): 999–1010, arXiv:0906.0631, Bibcode:2009PASJ...61..999M, doi:10.1093/pasj/61.5.999.
  9. ^ Kennea, J. A.; et al. (March 2018), "Swift detection of MAXI J1820+070", GRB Coordinates Network, Circular Service, 22471: 1, Bibcode:2018GCN.22471....1K.
  10. ^ Baglio, M. Cristina; et al. (August 2023), "MAXI J1820+070 drops to its pre-outburst quiescent level after 5 years of activity", The Astronomer's Telegram, 16192, Bibcode:2023ATel16192....1B.
  11. ^ Baglio, M.; et al. (March 2018), "Optical observations of MAXI J1820+070 suggest it is a black hole X-ray binary", The Astronomer's Telegram, 11418, Bibcode:2018ATel11418....1B.
  12. ^ Garnavich, Peter; Littlefield, Colin (March 2018), "Optical Spectra of MAXI J1820+070 with Keck", The Astronomer's Telegram, 11425, Bibcode:2018ATel11425....1G.
  13. ^ Yu, Wenfei; et al. (April 2018), "Detection of optical and X-ray QPOs at similar frequencies in MAXI J1820+070", The Astronomer's Telegram, 11510, Bibcode:2018ATel11510....1Y.
  14. ^ Richmond, Michael (May 2018), "MAXI J1820+070 has optical period of 3.4 hours", The Astronomer's Telegram, 11596, Bibcode:2018ATel11596....1R.
  15. ^ Wood, C. M.; et al. (August 2021), "The varying kinematics of multiple ejecta from the black hole X-ray binary MAXI J1820 + 070", Monthly Notices of the Royal Astronomical Society, 505 (3): 3393–3403, arXiv:2105.09529, Bibcode:2021MNRAS.505.3393W, doi:10.1093/mnras/stab1479.

Further reading

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