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"

2409 results found.

  1. GRB 260802A: LCO optical upper limits
  2. GRB 260802A / EP J223759.5+531421: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  3. GRB 260802A/EP J223759.5+531421: SVOM detection of a possible magnetar burst
  4. GRB 260727A: EP-FXT further follow-up observations and candidate afterglow
  5. GRB 260618B: SVOM/VT continued optical observations indicated a steeper and redder decay
  6. GRB 260731A: AstroSat CZTI detection of a long burst
  7. GRB 260730B: NuSTAR detection of prompt emission
  8. GRB 260727A: SVOM/ECLAIRs refined analysis
  9. GRB 260726A: SVOM/ECLAIRs refined analysis
  10. GRB 260727A: AbAO and SAO RAS optical observations
  11. GRB 260726A: EP-FXT follow-up observations
  12. GRB 260727A: SVOM/GRM observation
  13. GRB 260726A: Fermi GBM Observation
  14. Konus-Wind detection of GRB 260727A
  15. GRB 260727A: Liverpool Telescope optical upper limits
  16. GRB 260727A: EP/FXT follow-up observations
  17. GRB 260727A: Glowbug gamma-ray detection
  18. GRB 260726A: J-band upper limit with WINTER
  19. GRB 260727A: J-band upper limit with WINTER
  20. GRB 260726A: SVOM/VT optical candidate
  21. GRB 260726A: SVOM ECLAIRs improved position and MXT possible detection of a counterpart
  22. GRB 260727A / SVOM sb26072702: RAPAS optical non-detection
  23. EP260723a: SVOM/ECLAIRs Upper Limit
  24. GRB 260727A: GOTO early optical upper limit
  25. GRB 260727A: AstroSat CZTI detection
  26. GRB 260727A: Kilonova-Catcher optical upper limit
  27. GRB 260727A: LCO optical upper limits
  28. GRB 260727A: SVOM detection of a bright long burst
  29. GRB 260726A: SVOM detection of a burst
  30. EP260723a: further EP-FXT follow-up observation
  31. GRB 260616A: cubesat Avion detection
  32. GRB 260601A: cubesat Avion detection
  33. EP260723a: EP-FXT follow-up observation
  34. GRB 260718A: SVOM/ECLAIRs refined analysis
  35. EP260723a: SVOM/VT optical observation
  36. Konus-Wind detection of GRB 260714B
  37. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  38. GRB 260714B: Insight-HXMT/HE detection
  39. GRB 260718A: EP-FXT follow-up observation
  40. GRB 260718A: LCO optical upper limits
  41. GRB 260711A: SVOM/GRM observation
  42. GRB 260710A: SVOM/GRM observation
  43. GRB 260718A: Fermi GBM Observation
  44. GRB 260718A : GRANDMA and KNC upper limits
  45. GRB 260718A: SVOM/VT optical upper limits
  46. GRB 260718A: SVOM/VT optical upper limits from VHF data
  47. GRB 260718A: SVOM detection of a burst
  48. GRB 260714B: SVOM/GRM observation
  49. GRB 260618B: EP-FXT follow-up observation upper limit
  50. SVOM sb26071506: Global MASTER-Net observations report
  51. sb26071506: SVOM detection of a X-ray transient
  52. EP260703a: SVOM/ECLAIRs Upper Limit
  53. GRB 260709A: AstroSat CZTI detection
  54. GRB 260706A: ATCA detection of possible radio counterpart
  55. GRB 260705A: ATCA radio observations
  56. GRB 260619A: SVOM/VT continuous optical observations
  57. GRB 260618B: SVOM/VT optical observations indicate shallow decay and reddening
  58. GRB 260708A: GRANDMA Optical Observations
  59. GRB 260708A: LCO optical observations
  60. GRB 260709A: SVOM/GRM detection
  61. GRB 260704A: SVOM/ECLAIRs refined analysis
  62. GRB 260706A : GRANDMA Upper limits
  63. GRB 260705B: SVOM/GRM observation
  64. GRB 260706A: Further EP-FXT follow-up observation
  65. GRB 260706A: SVOM/VT optical upper limits
  66. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  67. GRB 260706A: SVOM/ECLAIRs refined analysis
  68. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  69. GRB 260706A: SVOM/GRM observation
  70. GRB 260706A: REM optical/NIR observations
  71. GRB 260706A: LCO optical upper limit
  72. GRB 260706A: EP-FXT follow-up observation
  73. GRB 260706A: Fermi GBM Observation
  74. GRB 260705A: SVOM/ECLAIRs refined analysis
  75. GRB 260706A: SVOM detection of a burst
  76. GRB 260705A: LCO optical upper limits
  77. GRB 260704A: NOT optical upper limits
  78. Fermi GBM Sub-Threshold Detection of GRB 260705A
  79. GRB 260705A: SVOM detection of a burst
  80. GRB 260704A: EP-FXT follow-up observation
  81. GRB 260629A: SVOM/GRM observation of a short burst
  82. GRB 260704A: SVOM detection of a possible GRB
  83. GRB 260614B: ATCA Radio Upper Limits
  84. MASS-Cube (GRID 2.0) detection of GRB 260616B
  85. GRB 260619A: SVOM/ECLAIRs refined analysis
  86. IPN triangulation of GRB 260605A
  87. EP260623a: SVOM/VT optical observations
  88. GRB 260616B/EP260616a: Insight-HXMT/HE detection
  89. GRB 260614B: EP-FXT follow-up observation
  90. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  91. GRB 260619A: NOT optical observations
  92. GRB 260618B: LCO optical observations
  93. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  94. GRB 260618B: Fermi GBM Observation
  95. GRB 260619A: TRT optical counterpart confirmation
  96. GRB 260610B: Further GRANDMA Optical Observations and re-brightening detection
  97. GRB 260604B: 239Alferov CubeSat detection
  98. GRB 260604A: 239Alferov CubeSat detection
  99. GRB 260610B: VLT/FORS2 spectroscopic observation suggests the non-thermal nature of the optical rebrightening
  100. GRB 260619A: SVOM/VT optical counterpart confirmation

Advanced

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