Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. See news and announcements

GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

45531 results found.

  1. EP260214a: COLIBRÍ optical upper limits
  2. EP260214b: OHP/T120 optical observations
  3. EP260214a: refined analysis of the EP-FXT observation
  4. EP260214b: LCO optical counterpart detection
  5. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  6. GRB 260211A: SVOM/VT optical counterpart
  7. EP260214b: COLIBRÍ optical observations
  8. EP260214a: SVOM/VT optical upper limits
  9. EP260214b: NOT optical counterpart detection
  10. EP260214b: Einstein Probe detection of a fast X-ray transient
  11. EP260214a: Global MASTER-Net observations report
  12. EP260214a: Einstein Probe detection of an X-ray transient
  13. GRB 260212A: AstroSat CZTI detection
  14. GRB 260212A: Fermi GBM Observation
  15. EP260213a: Liverpool Telescope optical upper limits
  16. EP260213a: Global MASTER-Net observations report
  17. EP260213a: COLIBRÍ optical upper limits
  18. GRB 260212A: GECAM-B observation
  19. EP260213a: Optical upper limits with Kinder observations
  20. EP260213a: SVOM/VT optical upper limit
  21. EP260213a: Mondy R-band optical upper limit
  22. EP260213a: NUTTelA-TAO Early Optical Limits
  23. EP260213a: SVOM/C-GFT upper limit
  24. EP260213a: refined analysis of the EP-FXT observation
  25. EP260213a: Einstein Probe detection of a fast X-ray transient
  26. EP/WXT 01709258378: NOT optical upper limits
  27. GRB 260212A: SVOM/GRM observation of a long burst
  28. GRB 260213B: Fermi GBM Final Localization
  29. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  30. GRB 260211A - SVOM/ECLAIRs refined analysis
  31. GRB 260204A: SVOM/ECLAIRs refined analysis
  32. GRB 260213A: Fermi GBM Final Localization
  33. GRB 260211A: EP-FXT follow-up observation
  34. GRB 260211A: SVOM/VT optical observation
  35. GRB 260212A: Glowbug gamma-ray detection
  36. GRB 260211A: GOTO optical upper limit
  37. Fermi GRB 260212A: Global MASTER-Net observations report
  38. GRB 260212A: Fermi GBM Final Real-time Localization
  39. GRB 260211A: LAST optical upper limit
  40. GRB 260210A: SVOM/GRM observation
  41. Fermi GBM Sub-Threshold Detection of GRB 260211A
  42. Konus-Wind detection of GRB 260207B
  43. GRB 260128B: SVOM/ECLAIRs refined analysis
  44. GRID detection of GRB 260207B
  45. GRB 260211A: LCO optical upper limits
  46. GRB260131A/B: 3.6m DOT Optical Observations
  47. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  48. Fermi trigger No 792537871: Global MASTER-Net observations report
  49. GRB 260211A: SVOM detection of a burst
  50. Swift Operations Update + Community Forum (Friday, February 13 @ 10:00 AM EST)
  51. Konus-Wind detection of GRB 260209B
  52. GRB 260208A: Swift UVOT detection
  53. Konus-Wind detection of GRB 260127B
  54. EP260209a: COLIBRÍ optical upper limit
  55. Fermi GRB 260210C: Global MASTER-Net observations report
  56. EP260209a: LCO optical upper limits
  57. EP260210a: Global MASTER-Net observations report
  58. EP260210a: refined analysis of the EP-FXT observation
  59. EP260209a: Global MASTER-Net observations report
  60. GRB 260208A: LCO detection of the optical counterpart
  61. EP260209a: Einstein Probe detection of a fast X-ray transient
  62. EP260210a: Optical upper limits with Kinder observations
  63. IPN triangulation of GRB 260207B (short/hard with EE)
  64. GRB 260210C: Fermi GBM Final Real-time Localization
  65. GRB 260210A: Glowbug gamma-ray detection
  66. GRB 260210B: Fermi GBM Final Real-time Localization
  67. EP260210a: SVOM/VT optical upper limit
  68. GRB 260210A: AstroSat CZTI detection
  69. GRB 260208C: AstroSat CZTI detection
  70. EP260210a: COLIBRÍ optical upper limit
  71. EP260210a: SVOM/C-GFT upper limit
  72. GRB 260208B: refined analysis of the EP-FXT observation
  73. EP260210a: Einstein Probe detection of an X-ray transient
  74. GRB 260207B: AstroSat CZTI detection
  75. GRB 260208C: SVOM/GRM observation
  76. GRB 260204A: Swift-XRT afterglow detection
  77. GRB 260208B: AstroSat CZTI detection of a bright long burst
  78. GRB260208A: Liverpool Telescope optical follow-up observations
  79. GRB 260208A: Glowbug gamma-ray detection
  80. GRB 260208A: NuSTAR detection of prompt emission
  81. GRB 260208A: Fermi GBM Observation
  82. Fermi GRB 260209A: Global MASTER-Net observations report
  83. GRB 260208B: Swift-XRT observations
  84. GRB 260131A/B: continued Mondy optical observations
  85. GRB 260204A: Swift/UVOT Upper Limits
  86. GRB 260208B: COLIBRÍ optical observations
  87. GRB 260208A: Mondy optical observations (duplicate submission)
  88. GRB 260208A: Mondy optical observations
  89. GRB 260208A: 1.3m DFOT optical detection
  90. GRB 260208A: COLIBRÍ optical observations
  91. GRB 260208B: EP-FXT observation
  92. GRB 260208A: NOT spectroscopic redshift z = 2.36
  93. GRB 260208A: Liverpool Telescope optical detection
  94. Fermi GRB 260208C: Global MASTER-Net observations report
  95. GRB 260208B: SVOM/VT optical candidate
  96. GRB 260208A: GECAM-B observation of a bright burst
  97. GRB 260208A: Zwicky Transient Facility Follow-Up of a Fermi GRB (Trigger 792220053)
  98. GRB 260209A: Fermi GBM Final Real-time Localization
  99. GRB 260208A: SVOM/VT optical observation
  100. Fermi GRB 260208D: Global MASTER-Net observations report

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov