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"

38427 results found.

  1. EP260605a: EP-FXT follow-up observation
  2. GRB 260604C: GRANDMA further observations
  3. GRB 260607A: GOTO tentative optical counterpart candidate GOTO26fqf / AT2026ong
  4. GRB 260604A: SVOM/GRM detection
  5. GRB 260604C: Mondy optical observations: evidence of a possible brightening
  6. GRB 260607B: Fermi GBM Observation
  7. GRB 260607B: Fermi-LAT detection
  8. GRB 260607B: Fermi GBM Final Localization Correction
  9. GRB 260604C: Simeiz Zeiss-1000 optical observations of the afterglow
  10. GRB 260604C: OPD1.6m - GRANDMA observations - detection
  11. GRB 260607A: Fermi GBM Final Real-time Localization
  12. GRB 260604C: GECAM-B observation
  13. GRB 260604C: 6 GHz VLA observations
  14. GRB 260604C: SAO RAS optical observations
  15. GRB 260604C: GRANDMA observations
  16. GRB 260604B: SVOM/GRM detection
  17. GRB 260605A: Insight-HXMT/HE detection
  18. GRB260603A: SVOM/ECLAIRs refined analysis
  19. EP260605a: Einstein Probe detection of a fast X-ray transient
  20. EP260603a: COLIBRÍ optical upper limit
  21. GRB 260604A: Glowbug gamma-ray detection
  22. GRB 260604C: LCO optical upper limit
  23. GRB 260604C: Liverpool Telescope optical detection
  24. The EP-WXT trigger 01709267001 is likely a flaring star
  25. EP260602d: EP-FXT follow-up observation
  26. EP260602c: EP-FXT follow-up observation
  27. GRB 260601B / EP260601a: AstroSat CZTI detection
  28. GRB 260527A/EP260527a: 6 GHz VLA observations
  29. GRB 260604C: GOTO detections of the optical afterglow
  30. GRB 260604C: Correction to GCN 44828
  31. GRB 260604C: Kilonova-Catcher optical afterglow detection
  32. GRB 260604C: SVOM/COLIBRÍ (FM-GFT) optical observations
  33. The EP-WXT trigger 01709266798 is likely a flaring star
  34. GRB 260604C: Jinshan optical observations
  35. GRB 260604C: Fermi GBM Observation
  36. GRB 260604C: LAST detection of optical counterpart candidate
  37. GRB 260604C: MASTER OT J145749.59+284903.0 optical counterpart discovery
  38. SVOM GRB260604.85: Global MASTER-Net observations report
  39. GRB 260604C: SVOM detection of a long burst
  40. GRB 260604C: Fermi GBM Final Real-time Localization
  41. GRB 260515A: SVOM/VT optical detection at about 18 days post trigger
  42. GRB 260603A: NOT optical observations
  43. GRB 260603A: Simeiz Zeiss-1000 optical upper limit
  44. GRB 260604B: Fermi GBM Final Real-time Localization
  45. GRB 260601A: CALET Gamma-Ray Burst Monitor detection
  46. EP260602a: EP-FXT follow-up observation
  47. EP260603a: Einstein Probe detection of a fast X-ray transient
  48. EP260602d: Optical Upper limits with kinder observations
  49. GRB 260604A: Fermi GBM Final Real-time Localization
  50. EP260602b: Liverpool Telescope observations
  51. EP260602a: Liverpool Telescope optical upper limits
  52. EP260602b: Liverpool Telescope and LCO observations
  53. GRB 260603B: Fermi GBM Final Localization
  54. EP260602a: GTC and Liverpool Telescope optical observations
  55. Konus-Wind detection of GRB 260601B/EP260601a
  56. GRB 260603A: EP-FXT follow-up observation
  57. EP260601a/GRB 260601B: EP-FXT follow-up observation
  58. GRB 260601B / EP260601a: Mondy optical upper limit
  59. EP260602b: EP-FXT follow-up observation
  60. GRB 260601B/EP260601a: Glowbug gamma-ray detection
  61. GRB 260603A: Kilonova-Catcher optical upper limit
  62. GRB 260603A: SVOM/VT optical observations
  63. GRB 260603A: SVOM/COLIBRÍ (FM-GFT) photometric redshift z = 3.57
  64. EP260602d: Einstein Probe detection of a fast X-ray transient
  65. EP260602a: SVOM/VT optical magnitudes correction
  66. GRB 260601A: SVOM/GRM observation of a short burst
  67. EP260602c: Einstein Probe detection of a fast X-ray transient
  68. GRB 260603A: SVOM/COLIBRÍ (GFT-FM) optical counterpart candidate
  69. EP260602a: COLIBRÍ optical observations
  70. SVOM GRB260603.23: Global MASTER-Net observations report
  71. GRB 260603A: SVOM detection of a burst
  72. EP260602b: Einstein Probe detection of a fast X-ray transient
  73. GRB 260601B/EP260601a: Insight-HXMT detection
  74. EP260530a: Xinglong optical spectroscopy of EP260530a / AT 2026nwl
  75. EP260602a: SVOM/VT optical candidate
  76. GRB 260602B: Fermi GBM Final Localization
  77. GRB 260601A: GECAM-B observation of a short burst
  78. EP260530a/AT 2026nwl: COLIBRÍ optical follow up
  79. EP260530a/AT 2026nwl: KAIT optical observations
  80. GRB 260602A: Fermi GBM Final Real-time Localization
  81. GRB 260601B: CALET Gamma-Ray Burst Monitor detection
  82. EP260602a: Optical upper limits with Kinder observations
  83. GRB 260601B / EP260601a: NuSTAR detection of prompt emission
  84. EP260602a: Einstein Probe detection of a fast X-ray transient
  85. GRB 260601B/EP260601a: SVOM/VT optical observations
  86. GRB 260601B/EP260601a: GECAM-B analysis suggests a possible long duration Type I burst
  87. GRB 260601B: GECAM-B detection of a burst probably associated with EP260601a
  88. EP260601a: Einstein Probe detection of an X-ray transient
  89. EP-WXT trigger 01709266307 (EP260601a): COLIBRÍ optical observations
  90. GRB 260601A: Glowbug gamma-ray detection of a short burst
  91. GRB 260531B: Glowbug gamma-ray detection
  92. GRB 260516D: VLA radio detection
  93. GRB 260601A: Fermi GBM Observation
  94. EP260530a/AT 2026nwl: COLIBRÍ optical observations
  95. GRB 260530C: SVOM/ECLAIRs detection of a burst through on-ground search
  96. GRB 260527A/EP260527a: Glowbug gamma-ray detection
  97. GRB 260601A: Fermi GBM Final Real-time Localization
  98. GRB 260531B: GECAM-B observation
  99. GRB 260518B: SVOM/ECLAIRs detection of a soft burst possibly associated with EP 260518a and AT 2026ndp
  100. The EP-WXT trigger 01709266272 is likely a flaring star

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