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"

32514 results found.

  1. GRB 260527A: CALET Gamma-Ray Burst Monitor detection
  2. EP260527a/GRB 260527A: EP-FXT follow-up observation
  3. GRB 260527A: GECAM-B detection of a short burst probably associated with EP260527a
  4. GRB 260526A: GECAM-B observation
  5. Konus-Wind detection of GRB 260527A (short/hard) ~4 min before EP260527a
  6. EP260526a: EP-FXT follow-up observation
  7. EP260527a: SVOM/VT optical observation
  8. EP260527a: COLIBRÍ optical detection
  9. EP260526a: LCO optical upper limits
  10. EP260526a: Einstein Probe detection of a fast X-ray transient
  11. GRB 260525A: AstroSat CZTI detection
  12. The EP-WXT trigger 01709266106 is not a real source
  13. Fermi GRB 260526A: Global MASTER-Net observations report
  14. Fermi GRB 260525A: Global MASTER-Net observations report
  15. GRB 260523B: AstroSat CZTI detection
  16. GRB 260523B: GECAM-B observation
  17. Fermi GRB 260523A: Global MASTER-Net observations report
  18. GRB 260522A: Fermi GBM Observation
  19. GRB 260522B: NuSTAR detection of prompt emission
  20. EP260518a (AT2026ndp): LCO observations and Gemini-South Redshift z = 2.28
  21. GRB 260522A: GOTO optical upper limit
  22. Fermi GRB 260522A: Global MASTER-Net observations report
  23. GRB 260522A: Fermi-LAT detection
  24. GRB 260519C: SVOM/GRM observation
  25. GRB 260511A: iTelescope T-75 optical detection
  26. GRB 260520B: SVOM/GRM observation
  27. GRB 260411B: TERI Gamma-ray detection
  28. GRB 260407A: TERI Gamma-ray detection
  29. GRB 260307A: TERI Gamma-ray detection
  30. GRB 260225D: TERI Gamma-ray detection
  31. GRB 251118A: TERI Gamma-ray detection
  32. GRB 251113A: TERI Gamma-ray detection
  33. GRB 260428A: TERI Gamma-ray detection
  34. Konus-Wind detection of GRB 260519C
  35. GRB 260509A: SVOM/ECLAIRs refined analysis
  36. GRB 260519C: NuSTAR detection of prompt emission
  37. Konus-Wind detection of GRB 260518A
  38. GRB 260516D: SVOM/ECLAIRs refined analysis
  39. GRB 260515A: SVOM/ECLAIRs refined analysis
  40. GRB 260421B: radio detection with the VLA
  41. GRID detection of GRB 260511A
  42. GRB 260509A: CrAO ZTSh optical upper limit (Duplicate Submission)
  43. GRB 260509A: CrAO ZTSh optical upper limit
  44. GRB 260516D: EP-FXT follow-up observation
  45. GRB 260516D: GOTO optical counterpart detection
  46. GRB 260516D: LCO optical observations
  47. GRB 260515A: further Liverpool Telescope observations
  48. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  49. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  50. GRB 260516D: GROWTH-India Telescope optical detection
  51. GRB 260516D: SVOM/VT optical bright candidate
  52. GRB 260515A: CrAO ZTSh BVRI optical observations
  53. Fermi GRB 260516C: Global MASTER-Net observations report
  54. Konus-Wind detection of GRB 260515A
  55. GRB 260515A: Liverpool Telescope optical detection
  56. GRB 260515A: LCO optical counterpart detection
  57. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  58. GRB 260515A: EP-FXT follow-up observation
  59. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  60. EP260514a: NOT optical counterpart confirmation
  61. EP260514a: TRT optical counterpart candidate
  62. EP260514a: SVOM/VT optical candidate
  63. Fermi GRB 260516B: Global MASTER-Net observations report
  64. GRB 260515A: SVOM/VT optical observations
  65. GRB 260515A: OHP/T193 optical observations
  66. EP260514a: COLIBRÍ optical upper limits
  67. GRID detection of GRB 260507A
  68. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  69. GRB 260515A: LCO optical observations
  70. SVOM GRB 260515A: Global MASTER-Net observations report
  71. GRB 260515A: NOT optical observations.
  72. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  73. GRB 260515A: SVOM/VT optical candidate from VHF data
  74. GRB 260515A: JinShan optical counterpart candidate
  75. GRB 260510C: Glowbug gamma-ray detection
  76. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  77. EP260514a: GROWTH-India Telescope optical upper limit
  78. GRB 260511B: NOT optical observations
  79. Konus-Wind detection of GRB 260512A
  80. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  81. GRB 260511B: GMG Optical Upper Limit
  82. EP260514a: Global MASTER-Net observations report
  83. EP260512a: LCO optical upper limits
  84. IPN triangulation of GRB 260512A
  85. GRB 260511B: Mephisto multi-band optical followup
  86. Fermi GRB 260514A: Global MASTER-Net observations report
  87. GRB 260512A: AstroSat CZTI detection
  88. EP260512a: EP-FXT follow-up observation
  89. EP260507a: Xinglong Schmidt optical counterpart detection
  90. EP260512a: Global MASTER-Net observations report
  91. Fermi GRB 260513A: Global MASTER-Net observations report
  92. Fermi GRB 260512A: Global MASTER-Net observations report
  93. GRB 260511B: further SAO RAS optical observations
  94. GRB 260509A: SVOM/VT optical observations
  95. Konus-Wind detection of GRB 260511B
  96. EP260512a: COLIBRÍ optical upper limits
  97. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  98. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  99. GRB 260512A: NuSTAR detection of prompt emission
  100. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE

Advanced

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