Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! See news and announcements

GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

3138 results found.

  1. GRB 210420B: Optical observations
  2. GRB 210411C: LCO Optical Afterglow Candidate
  3. Fermi GRB 210411B: Global MASTER-Net observations report
  4. Fermi GRB 210411A: Global MASTER-Net observations report
  5. Fermi GRB 210410A: Global MASTER-Net observations report
  6. Fermi trigger No 639093861: Global MASTER-Net observations report
  7. Swift GRB210402.92: Global MASTER-Net observations report
  8. Fermi GRB 210324B: Global MASTER-Net observations report
  9. GRB 210320A: MAXI/GSC detection
  10. Fermi GRB 210317A: Global MASTER-Net observations report
  11. Fermi trigger No 637521056: Global MASTER-Net observations report
  12. Konus-Wind detection of GRB 210305A
  13. GRB 210307A: Swift detection of a burst
  14. GRB 210306A: iTelescope optical afterglow observations
  15. Fermi trigger No 636459103: Global MASTER-Net observations report
  16. Fermi trigger No 636168178: Global MASTER-Net observations report
  17. Integral GRB210227.19: Global MASTER-Net OT detection
  18. GRB 210222B: MASTER OT observation
  19. GRB 210222B: GOTO confirmation of afterglow detection
  20. Swift GRB210222.94: Global MASTER-Net observations report
  21. Fermi GBM Sub-Threshold Detection of GRB 210217A
  22. GRB 210217A: Swift-BAT refined analysis
  23. GRB 210217A: Swift detection of a burst with an optical counterpart
  24. GRB 210208A: 1.3m DFOT Optical upper limit
  25. GRB 210211A: ePESSTO+ NTT optical observations
  26. IceCube Alert 210213.78: Global MASTER-Net observations report
  27. GRB 210204A (ZTF21aagwbjr/AT2021buv): continued CrAO and AbAO optical observations
  28. GRB 210207B: AstroSat CZTI detection
  29. GRB 210207B: Swift-BAT refined analysis
  30. Konus-Wind detection of GRB 210204A (correction to GCN 29415)
  31. GRB 210207A: Fermi GBM Final Real-time Localization
  32. Fermi GRB 210204B: Global MASTER-Net observations report
  33. Fermi GRB 210204A: Global MASTER-Net observations report
  34. GRB 140320B: Swift-XRT refined Analysis
  35. GRB 210104A: DOAO optical afterglow observations
  36. Fermi GRB 210101A: Global MASTER-Net observations report
  37. Fermi trigger No 631118376: Global MASTER-Net observations report
  38. Fermi GRB 201229B: Global MASTER-Net observations report
  39. Fermi GRB 201228B: Global MASTER-Net observations report
  40. GRB 201228B: Fermi GBM Final Real-time Localization
  41. Fermi GRB 201222B: Global MASTER-Net observations report
  42. GRB 201221D: Archival PS1 Imaging of the Putative Host Galaxy
  43. GRB 201221D: candidate optical counterpart from the NOT
  44. GRB 201221A: Swift-BAT refined analysis
  45. GRB 201221D: Prompt enhanced Swift-XRT position
  46. GRB 201221A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 5.7
  47. GRB 201209A: Mondy optical observations, afterglow confirmation
  48. GRB 201214A: 1.3m DFOT, optical upper limits
  49. Baksan Neutrino Observatory Alert 201216.94: Global MASTER-Net observations report
  50. Fermi GRB 201214B: Global MASTER-Net observations report
  51. Fermi GRB 201208A: Global MASTER-Net observations report
  52. IceCube-201130A: No significant detection in HAWC
  53. Swift observations of the Fermi-LAT source 4FGL J0206.4-1151 in the error region of IceCube-201130A
  54. Swift-XRT observations of IceCube 201130A
  55. GRB 201128A: Swift-BAT refined analysis
  56. GRB 201120B: Fermi GBM Final Localization
  57. ZTF20acozryr/AT2020yxz (GRB 201103B): SAO RAS optical observations
  58. IceCube-201114A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  59. ZTF20acozryr/AT2020yxz (GRB 201103B): Mondy, Kitab, TSHAO optical observations
  60. Konus-Wind detection of GRB 201105A
  61. GRB 201104C: Fermi GBM Final Real-time Localization
  62. GRB 201104A: Fermi GBM Final Real-time Localization
  63. Swift GRB201027.05: Global MASTER-Net observations report
  64. IceCube-201021A: No neutrino counterpart candidates in ANTARES search
  65. IceCube-201021A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  66. Alert from the HAWC Burst Monitor HAWC-201019A
  67. Fermi GRB 201020B: Global MASTER-Net observations report
  68. GRB 201015A: Assy and Mondy optical observations
  69. IceCube-201014A: No neutrino counterpart candidates in ANTARES search
  70. GRB 201006A: Chandra upper limit on the X-ray afterglow
  71. Fermi GRB 201007A: Global MASTER-Net observations report
  72. Baksan Neutrino Observatory Alert 201006.88: Global MASTER-Net observations report
  73. GRB 201006A: Fermi GBM detection
  74. Fermi trigger No 623470566: Global MASTER-Net observations report
  75. Fermi GRB 200925A: Global MASTER-Net observations report
  76. Fermi GRB 200924A: Global MASTER-Net observations report
  77. Fermi GRB 200923A: Global MASTER-Net observations report
  78. IPN triangulation of GRB 200920B (short)
  79. GRB 200917A: GROWTH-India Telescope optical upper limit.
  80. IceCube-200916A: No neutrino counterpart candidates in ANTARES search
  81. GRB 200917A: Enhanced Swift-XRT position
  82. GRB 200917A: Swift detection of a burst
  83. Fermi GRB 200916A: Global MASTER-Net observations report
  84. GRB 200916A: Fermi GBM Final Real-time Localization
  85. IceCube Alert 200914.00: Global MASTER-Net observations report
  86. Fermi GRB 200907C: Global MASTER-Net observations report
  87. Fermi GRB 200903C: Global MASTER-Net observations report
  88. GRB 200903B: Insight-HXMT/HE detection
  89. AGILE detection of a burst (AGILE trigger no. 526185273)
  90. Fermi GRB 200903B: Global MASTER-Net observations report
  91. GRB 200903B: Fermi GBM Final Real-time Localization
  92. GRB 200901B: Swift-BAT refined analysis
  93. GRB 200901B: Enhanced Swift-XRT position
  94. GRB 200901B: Swift detection of a burst
  95. GRB 200829A: Liverpool Telescope observations
  96. GRB 200826B: Fermi GBM Final Real-time Localization
  97. GRB 200826A: AstroSat CZTI detection
  98. Fermi GRB 200826A: Global MASTER-Net observations report
  99. Fermi trigger No 619270776: Global MASTER-Net observations report
  100. HAWC alert 200815.26: MASTER optical observations

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov