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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"

3798 results found.

  1. GRB 240511A: LCO upper limits
  2. Fermi GRB 241105A: Global MASTER-Net observations report
  3. Fermi GRB 241104A: Global MASTER-Net observations report
  4. EP241101a: EP-FXT observations update
  5. Fermi trigger No 752365806: Global MASTER-Net observations report
  6. EP241103a: Swift XRT detection and improved X-ray position
  7. LIGO/Virgo/KAGRA S241102br: MASTER observations and OT detection
  8. GRB 241101A: Swift detection of a burst
  9. Fermi trigger No 752083996: Global MASTER-Net observations report
  10. EP EP241030a: Global MASTER-Net observations report
  11. Fermi trigger No 752006065: Global MASTER-Net observations report
  12. GRB 241030B: Swift detection of a burst
  13. GRB 240912A: radio detection with the VLA
  14. Fermi GRB 241030A: Global MASTER-Net observations report
  15. GRB 241026A: SAO RAS observations of possible optical afterglow
  16. Fermi GRB 241026A: Global MASTER-Net observations report
  17. GRB 241026A: Prompt enhanced Swift-XRT position
  18. EP241021a: optical follow-up observations with Xinglong Observatory
  19. Fermi GRB 241025A: Global MASTER-Net observations report
  20. IPN triangulation of GRB 241021A (long)
  21. GRB241017A: 1.3m DFOT optical upper limit
  22. Fermi trigger No 750788395: Global MASTER-Net observations report
  23. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  24. Fermi GRB 241016A: Global MASTER-Net observations report
  25. GRB 240916A: radio detection with the VLA
  26. GRB241013A: REM observations
  27. Fermi trigger No 750211959: Global MASTER-Net observations report
  28. IceCube Alert 241006.94: Global MASTER-Net observations report
  29. EP EP240930a: Global MASTER-Net observations report
  30. Fermi GRB 240929A: Global MASTER-Net observations report
  31. LIGO/Virgo S240919bn: GOTO optical upper limits
  32. GRB 240918B: AstroSat CZTI detection
  33. EP240919a: EP-FXT follow-up observation update
  34. EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
  35. GRB 240918B: Fermi GBM Detection
  36. GRB 240912A: Swift-BAT refined analysis
  37. LIGO/Virgo/KAGRA S240915b: Coverage and upper limits from MAXI/GSC observations
  38. LIGO/Virgo/KAGRA S240910ci: Coverage and upper limits from MAXI/GSC observations
  39. Fermi GRB 240908A: Global MASTER-Net observations report
  40. GRB 240905E: NUTTelA-TAO / BSTI Optical Limits
  41. GRB 240902B: AstroSat CZTI detection of a long burst
  42. GRB 240825A: Montarrenti Observatory optical follow-up observations
  43. Fermi trigger No 746923430: Global MASTER-Net observations report
  44. LIGO/Virgo/KAGRA S240830gn: Coverage and upper limits from MAXI/GSC observations
  45. Fermi trigger No 746587425: Global MASTER-Net observations report
  46. Swift GRB240829.16: Global MASTER-Net observations report
  47. Fermi trigger No 746438824: Global MASTER-Net observations report
  48. GRB 240824A: GIT optical upper limit
  49. GRB 240824B: Ondrejov D50 optical limit
  50. GRB 240825A: AKO Optical Follow-Up Observations
  51. SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
  52. GRB 240824B: Fermi GBM Observation
  53. SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
  54. GRB 240824B: Swift-XRT afterglow detection
  55. GRB 240824B: Swift/BAT arcminute localization of a burst
  56. GRB 240824B: MAXI/GSC detection
  57. SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
  58. Fermi GRB 240821B: Global MASTER-Net observations report
  59. Fermi trigger No 745866488: Global MASTER-Net observations report
  60. Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
  61. EP240816a: EP detection of a fast X-ray transient and follow-up observation
  62. Fermi GRB 240814B: Global MASTER-Net observations report
  63. GRB 240808A: AstroSat CZTI detection
  64. GRB 240809B: MAXI/GSC detection
  65. GRB 240808A: SVOM/GRM observation
  66. EP EP240807a: Global MASTER-Net observations report
  67. EP EP240806a: Global MASTER-Net observations report
  68. GRB 240805B: Swift-BAT refined analysis
  69. Fermi trigger No 744629911: Global MASTER-Net observations report
  70. Fermi GRB 240805A: Global MASTER-Net observations report
  71. Fermi GRB 240804A: Global MASTER-Net observations report
  72. Fermi trigger No 744459130: Global MASTER-Net observations report
  73. Fermi trigger No 744128417: Global MASTER-Net observations report
  74. GRB240730A: BOOTES-5/JGT early optical upper limit
  75. GRB 240720A: Swift-BAT refined analysis
  76. Fermi trigger No 743219692: Global MASTER-Net observations report
  77. GRB 240721A: Fermi GBM Final Real-time Localization
  78. Fermi GRB 240720A: Global MASTER-Net observations report
  79. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  80. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  81. Fermi trigger No 742405878: Global MASTER-Net observations report
  82. Fermi trigger No 742317942: Global MASTER-Net observations report
  83. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  84. Fermi trigger No 741448122: Global MASTER-Net observations report
  85. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  86. Fermi trigger No 741356809: Global MASTER-Net observations report
  87. GRB 240624A: Swift-BAT refined analysis
  88. Fermi trigger No 740949590: Global MASTER-Net observations report
  89. EP240617a: tentative Swift/XRT detection of the afterglow
  90. EP240618a: GRANDMA Optical Upper Limits
  91. LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations
  92. Fermi trigger No 740430582: Global MASTER-Net observations report
  93. Fermi trigger No 740221779: Global MASTER-Net observations report
  94. Fermi GRB 240616A: Global MASTER-Net observations report
  95. Fermi trigger No 740166710: Global MASTER-Net observations report
  96. Fermi trigger No 739506569: Global MASTER-Net observations report
  97. Fermi GRB 240607A: Global MASTER-Net observations report
  98. GRB 240607A: AstroSat CZTI detection of bright long burst
  99. Fermi GRB 240604A: Global MASTER-Net observations report
  100. GRB 240603B: Swift detection of a possible burst

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