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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"

3400 results found.

  1. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations
  2. EP241107a: AKO Optical Afterglow Follow-Up Observations
  3. GRB 240511A: LCO upper limits
  4. Fermi GRB 241105A: Global MASTER-Net observations report
  5. Fermi GRB 241104A: Global MASTER-Net observations report
  6. EP241101a: EP-FXT observations update
  7. Fermi trigger No 752365806: Global MASTER-Net observations report
  8. EP241103a: Swift XRT detection and improved X-ray position
  9. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  10. GRB 241101A: Swift detection of a burst
  11. Fermi trigger No 752083996: Global MASTER-Net observations report
  12. EP EP241030a: Global MASTER-Net observations report
  13. Fermi trigger No 752006065: Global MASTER-Net observations report
  14. GRB 241030B: Swift detection of a burst
  15. GRB 240912A: radio detection with the VLA
  16. Fermi GRB 241030A: Global MASTER-Net observations report
  17. GRB 241026A: SAO RAS observations of possible optical afterglow
  18. Fermi GRB 241026A: Global MASTER-Net observations report
  19. GRB 241026A: Prompt enhanced Swift-XRT position
  20. EP241021a: optical follow-up observations with Xinglong Observatory
  21. Fermi GRB 241025A: Global MASTER-Net observations report
  22. IPN triangulation of GRB 241021A (long)
  23. GRB241017A: 1.3m DFOT optical upper limit
  24. Fermi trigger No 750788395: Global MASTER-Net observations report
  25. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  26. Fermi GRB 241016A: Global MASTER-Net observations report
  27. GRB 240916A: radio detection with the VLA
  28. GRB241013A: REM observations
  29. Fermi trigger No 750211959: Global MASTER-Net observations report
  30. IceCube Alert 241006.94: Global MASTER-Net observations report
  31. EP EP240930a: Global MASTER-Net observations report
  32. Fermi GRB 240929A: Global MASTER-Net observations report
  33. LIGO/Virgo S240919bn: GOTO optical upper limits
  34. GRB 240918B: AstroSat CZTI detection
  35. EP240919a: EP-FXT follow-up observation update
  36. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  37. GRB 240918B: Fermi GBM Detection
  38. GRB 240912A: Swift-BAT refined analysis
  39. LIGO/Virgo/KAGRA S240915b: Coverage and upper limits from MAXI/GSC observations
  40. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  41. Fermi GRB 240908A: Global MASTER-Net observations report
  42. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  43. GRB 240902B: AstroSat CZTI detection of a long burst
  44. GRB 240825A: Montarrenti Observatory optical follow-up observations
  45. Fermi trigger No 746923430: Global MASTER-Net observations report
  46. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  47. Fermi trigger No 746587425: Global MASTER-Net observations report
  48. Swift GRB240829.16: Global MASTER-Net observations report
  49. Fermi trigger No 746438824: Global MASTER-Net observations report
  50. GRB 240824A: GIT optical upper limit
  51. GRB 240824B: Ondrejov D50 optical limit
  52. GRB 240825A: AKO Optical Follow-Up Observations
  53. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  54. GRB 240824B: Fermi GBM Observation
  55. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  56. GRB 240824B: Swift-XRT afterglow detection
  57. GRB 240824B: Swift/BAT arcminute localization of a burst
  58. GRB 240824B: MAXI/GSC detection
  59. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  60. Fermi GRB 240821B: Global MASTER-Net observations report
  61. Fermi trigger No 745866488: Global MASTER-Net observations report
  62. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  63. EP240816a: EP detection of a fast X-ray transient and follow-up observation
  64. Fermi GRB 240814B: Global MASTER-Net observations report
  65. GRB 240808A: AstroSat CZTI detection
  66. GRB 240809B: MAXI/GSC detection
  67. GRB 240808A: SVOM/GRM observation
  68. EP EP240807a: Global MASTER-Net observations report
  69. EP EP240806a: Global MASTER-Net observations report
  70. GRB 240805B: Swift-BAT refined analysis
  71. Fermi trigger No 744629911: Global MASTER-Net observations report
  72. Fermi GRB 240805A: Global MASTER-Net observations report
  73. Fermi GRB 240804A: Global MASTER-Net observations report
  74. Fermi trigger No 744459130: Global MASTER-Net observations report
  75. Fermi trigger No 744128417: Global MASTER-Net observations report
  76. GRB240730A: BOOTES-5/JGT early optical upper limit
  77. GRB 240720A: Swift-BAT refined analysis
  78. Fermi trigger No 743219692: Global MASTER-Net observations report
  79. GRB 240721A: Fermi GBM Final Real-time Localization
  80. Fermi GRB 240720A: Global MASTER-Net observations report
  81. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  82. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  83. Fermi trigger No 742405878: Global MASTER-Net observations report
  84. Fermi trigger No 742317942: Global MASTER-Net observations report
  85. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  86. Fermi trigger No 741448122: Global MASTER-Net observations report
  87. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  88. Fermi trigger No 741356809: Global MASTER-Net observations report
  89. GRB 240624A: Swift-BAT refined analysis
  90. Fermi trigger No 740949590: Global MASTER-Net observations report
  91. EP240617a: tentative Swift/XRT detection of the afterglow
  92. EP240618a: GRANDMA Optical Upper Limits
  93. LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations
  94. Fermi trigger No 740430582: Global MASTER-Net observations report
  95. Fermi trigger No 740221779: Global MASTER-Net observations report
  96. Fermi GRB 240616A: Global MASTER-Net observations report
  97. Fermi trigger No 740166710: Global MASTER-Net observations report
  98. Fermi trigger No 739506569: Global MASTER-Net observations report
  99. Fermi GRB 240607A: Global MASTER-Net observations report
  100. GRB 240607A: AstroSat CZTI detection of bright long burst

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