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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"

3039 results found.

  1. GRB 241112B: SVOM/GRM observation
  2. GRB 241112B : detection of a long GRB by SVOM/ECLAIRs
  3. Fermi trigger No 752990530: Global MASTER-Net observations report
  4. Fermi trigger No 752878030: Global MASTER-Net observations report
  5. EP241107a: AKO Optical Afterglow Follow-Up Observations
  6. GRB 240511A: LCO upper limits
  7. Fermi GRB 241105A: Global MASTER-Net observations report
  8. Fermi GRB 241104A: Global MASTER-Net observations report
  9. EP241101a: EP-FXT observations update
  10. Fermi trigger No 752365806: Global MASTER-Net observations report
  11. EP241103a: Swift XRT detection and improved X-ray position
  12. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  13. GRB 241101A: Swift detection of a burst
  14. Fermi trigger No 752083996: Global MASTER-Net observations report
  15. EP EP241030a: Global MASTER-Net observations report
  16. Fermi trigger No 752006065: Global MASTER-Net observations report
  17. GRB 241030B: Swift detection of a burst
  18. GRB 240912A: radio detection with the VLA
  19. Fermi GRB 241030A: Global MASTER-Net observations report
  20. GRB 241026A: SAO RAS observations of possible optical afterglow
  21. Fermi GRB 241026A: Global MASTER-Net observations report
  22. GRB 241026A: Prompt enhanced Swift-XRT position
  23. EP241021a: optical follow-up observations with Xinglong Observatory
  24. Fermi GRB 241025A: Global MASTER-Net observations report
  25. IPN triangulation of GRB 241021A (long)
  26. GRB241017A: 1.3m DFOT optical upper limit
  27. Fermi trigger No 750788395: Global MASTER-Net observations report
  28. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  29. Fermi GRB 241016A: Global MASTER-Net observations report
  30. GRB 240916A: radio detection with the VLA
  31. GRB241013A: REM observations
  32. Fermi trigger No 750211959: Global MASTER-Net observations report
  33. IceCube Alert 241006.94: Global MASTER-Net observations report
  34. EP EP240930a: Global MASTER-Net observations report
  35. Fermi GRB 240929A: Global MASTER-Net observations report
  36. LIGO/Virgo S240919bn: GOTO optical upper limits
  37. GRB 240918B: AstroSat CZTI detection
  38. EP240919a: EP-FXT follow-up observation update
  39. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  40. GRB 240918B: Fermi GBM Detection
  41. GRB 240912A: Swift-BAT refined analysis
  42. Fermi GRB 240908A: Global MASTER-Net observations report
  43. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  44. GRB 240902B: AstroSat CZTI detection of a long burst
  45. GRB 240825A: Montarrenti Observatory optical follow-up observations
  46. Fermi trigger No 746923430: Global MASTER-Net observations report
  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 240825A: AKO Optical Follow-Up Observations
  52. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  53. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  54. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  55. Fermi GRB 240821B: Global MASTER-Net observations report
  56. Fermi trigger No 745866488: Global MASTER-Net observations report
  57. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  58. EP240816a: EP detection of a fast X-ray transient and follow-up observation
  59. Fermi GRB 240814B: Global MASTER-Net observations report
  60. GRB 240808A: AstroSat CZTI detection
  61. GRB 240808A: SVOM/GRM observation
  62. EP EP240807a: Global MASTER-Net observations report
  63. EP EP240806a: Global MASTER-Net observations report
  64. GRB 240805B: Swift-BAT refined analysis
  65. Fermi trigger No 744629911: Global MASTER-Net observations report
  66. Fermi GRB 240805A: Global MASTER-Net observations report
  67. Fermi GRB 240804A: Global MASTER-Net observations report
  68. Fermi trigger No 744459130: Global MASTER-Net observations report
  69. Fermi trigger No 744128417: Global MASTER-Net observations report
  70. GRB240730A: BOOTES-5/JGT early optical upper limit
  71. GRB 240720A: Swift-BAT refined analysis
  72. Fermi trigger No 743219692: Global MASTER-Net observations report
  73. GRB 240721A: Fermi GBM Final Real-time Localization
  74. Fermi GRB 240720A: Global MASTER-Net observations report
  75. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  76. Fermi trigger No 742405878: Global MASTER-Net observations report
  77. Fermi trigger No 742317942: Global MASTER-Net observations report
  78. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  79. Fermi trigger No 741448122: Global MASTER-Net observations report
  80. Fermi trigger No 741356809: Global MASTER-Net observations report
  81. GRB 240624A: Swift-BAT refined analysis
  82. Fermi trigger No 740949590: Global MASTER-Net observations report
  83. EP240617a: tentative Swift/XRT detection of the afterglow
  84. EP240618a: GRANDMA Optical Upper Limits
  85. LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations
  86. Fermi trigger No 740430582: Global MASTER-Net observations report
  87. Fermi trigger No 740221779: Global MASTER-Net observations report
  88. Fermi GRB 240616A: Global MASTER-Net observations report
  89. Fermi trigger No 740166710: Global MASTER-Net observations report
  90. Fermi trigger No 739506569: Global MASTER-Net observations report
  91. Fermi GRB 240607A: Global MASTER-Net observations report
  92. GRB 240607A: AstroSat CZTI detection of bright long burst
  93. Fermi GRB 240604A: Global MASTER-Net observations report
  94. GRB 240603B: Swift detection of a possible burst
  95. Fermi GRB 240602A: Global MASTER-Net observations report
  96. GRB 240529A: AKO Optical Afterglow Detection
  97. Fermi trigger No 738348224: Global MASTER-Net observations report
  98. Fermi trigger No 738330463: Global MASTER-Net observations report
  99. Fermi trigger No 737996942: Global MASTER-Net observations report
  100. Fermi trigger No 737788024: Global MASTER-Net observations report

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