Skip to main content
New! Super-Kamiokande JSON Notices and Schema v4.5.0. 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"

34169 results found.

  1. GRB 220101A: Tautenburg observations
  2. GRB 220101A: Swift-BAT refined analysis
  3. GRB 220101A: GMG observation (2nd epoch)
  4. GRB 211231A: AstroSat CZTI detection
  5. GRB 220101A: OASDG optical observations
  6. GRB 220101A : Eiso equals the maximum isotropic GRB energy
  7. GRB 220101A: GMG observation
  8. GRB 220101A: Asiago spectroscopic and photometric detection
  9. GRB 220101A: Fermi GBM Detection
  10. GRB 220101A: NOT redshift confirmation
  11. GRB 220101A: CAHA 2.2m/CAFOS detection
  12. GRB 220101A: Liverpool telescope imaging of a high-redshift afterglow
  13. GRB 220101A: THO optical observations
  14. GRB 220101A: Swift-XRT refined Analysis
  15. GRB 220101A: AGILE detection
  16. GRB 220101A: Xinglong-2.16m photometry and spectroscopy
  17. GRB 220101: Swift/UVOT Detection
  18. GRB 220101A: Fermi-LAT detection
  19. GRB 220101A: Enhanced Swift-XRT position
  20. GRB 220101A: Correction to GCN 31347
  21. GRB 220101A: Swift detection of a burst with a bright optical counterpart
  22. IPN triangulation of GRB 211219A
  23. GRB 211231A: GECAM detection
  24. GRB 211229B: AGILE detection
  25. GRB 211231A: Fermi GBM Final Real-time Localization
  26. GRB 211229A: Swift-XRT and UVOT observations
  27. GRB 211227A: Deep early CAHA 2.2m/CAFOS observation
  28. GRB 211229A: Fermi GBM observation
  29. GRB 211229B: GECAM detection
  30. GRB 211229C: Swift/BAT-GUANO detection likely outside the coded FOV
  31. Fermi GRB 211229B: Global MASTER-Net observations report
  32. GRB 211229B: Fermi GBM Final Real-time Localization
  33. GRB 211229A: Swift ToO observations
  34. GRB 211229A: Swift/BAT-GUANO arcminute localization
  35. GRB 211227A: CALET Gamma-Ray Burst Monitor detection
  36. GRB 211225B: CALET Gamma-Ray Burst Monitor detection
  37. GRB 211229A: GECAM detection
  38. Fermi GRB 211229A: Global MASTER-Net observations report
  39. GRB 211229A: Fermi GBM Final Real-time Localization
  40. GRB 211227A: Swift/UVOT Upper Limits
  41. GRB 211227A: Swift-XRT refined Analysis
  42. GRB 211227A: Swift-BAT refined analysis
  43. GRB 211227A: A possible short GRB with extended emission at z = 0.228?
  44. GRB 211227A: Liverpool Telescope upper limits
  45. GRB 211227A: Enhanced Swift-XRT position
  46. GRB 211227A: LCO Optical Observations
  47. GRB 211227A: Nanshan/NEXT optical observations and host galaxy candidate
  48. GRB 211227A: MAXI/GSC detection
  49. GRB 211227A: BOOTES-2/TELMA optical upper limit
  50. GRB 211221A: Swift/UVOT Upper Limits
  51. GRB 211227A: Swift detection of a burst
  52. GRB 211226A: Swift/BAT-GUANO detection outside the coded FOV
  53. GRB 211225B: Swift-BAT refined analysis
  54. GRB 211225A: MITSuME Akeno optical upper limits
  55. GRB 211226A: AGILE/MCAL detection of a burst
  56. Swift GRB 211225B: Global MASTER-Net observations report
  57. Fermi GRB 211225C: Global MASTER-Net observations report
  58. GRB 211225C: Fermi GBM Final Real-time Localization
  59. GRB 211225B: Swift detection of a burst
  60. GRB 211225A/MAXI J0827-071: MAXI/GSC detection
  61. GRB 211224A: Fermi GBM Final Real-time Localization
  62. GRB 211106A: Third HST Observation
  63. GRB 211211A: observations with the 3.6m Devasthal Optical Telescope
  64. GRB 211223C: Swift-BAT refined analysis
  65. GRB 211223C: BOOTES-4/MET optical upper limit
  66. Swift GRB 211223C: Global MASTER-Net observations report
  67. GRB 211223A: Insight-HXMT/HE detection
  68. Fermi GRB 211223B: Global MASTER-Net observations report
  69. Fermi GBM Sub-Threshold Detection of GRB 211221A
  70. Fermi GBM Sub-Threshold Detection of GRB 211207A
  71. GRB 211221A: Swift-BAT refined analysis
  72. GRB 211223C: Swift detection of a burst
  73. GRB 211223B: Fermi GBM Final Real-time Localization
  74. GRB 211223A: GECAM detection
  75. GRB 211221A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  76. GRB 211219B: AstroSat CZTI detection
  77. GRB 211219A: AstroSat CZTI detection
  78. Fermi GRB 211222A: Global MASTER-Net observations report
  79. GRB 211221A: Swift-XRT refined Analysis
  80. GRB 211222A: Fermi GBM Final Real-time Localization
  81. GRB 211221A: BOOTES-4/MET optical upper limit
  82. GRB 211218A: MITSuME Akeno optical upper limits
  83. GRB 211221A: MeerLICHT optical limits
  84. GRB 211221A: NOT optical limits
  85. GRB 211221A: Enhanced Swift-XRT position
  86. Swift GRB 211221A: Global MASTER-Net observations report
  87. GRB 211221A: Swift detection of a burst
  88. GRB 211219A: AGILE detection
  89. GRB 211219A: Swift/BAT-GUANO detection outside the coded FOV
  90. Fermi GRB 211219B: Global MASTER-Net observations report
  91. GRB 211219B: Fermi GBM Final Real-time Localization
  92. Fermi GRB 211219A: Global MASTER-Net observations report
  93. GRB 211219A: Fermi GBM Final Real-time Localization
  94. GRB 211211A: MMT/MMIRS Observations Indicate Fading of K-band Source
  95. GRB 211216A: Fermi GBM observation
  96. GRB 211218A, MAXI J0909-041: MAXI/GSC detection
  97. GRB 211106A: XMM-Newton monitoring campaign detections
  98. IceCube-211216B: Upper limits from Fermi-GBM Observations
  99. IceCube-211216A: Upper limits from Fermi-GBM Observations
  100. GRB 211217A: GECAM detection

Advanced

Download all Circulars as a .tar.gz archive:
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