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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"

39198 results found.

  1. GRB 240529A: JinShan optical observations
  2. EP240618a: GSP optical upper limit
  3. IPN triangulation of GRB 240615A (short)
  4. GRB 240619A: GRBAlpha detection
  5. GRB 240619A: Swift-XRT probable afterglow detection
  6. GRB 240619A: Swift ToO observations
  7. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  8. GRB 240619C: NuSTAR automated detection of the GRB
  9. GRB 240619A: Fermi GBM Observation
  10. Fermi GBM Sub-Threshold Detection of GRB 240619C
  11. GRB 240619A: GOTO candidate optical afterglow
  12. EP240618a: Abastumani optical observationsEP240618a
  13. GRB 240615A: NOT optical observations
  14. GRB 240619C: AstroSat CZTI detection
  15. EP240618a: TRT optical upper limit
  16. Fermi trigger No 740474239: Global MASTER-Net observations report
  17. Fermi GRB 240619A: Global MASTER-Net observations report
  18. GRB 240615A: possible transient detection from Wendelstein observations
  19. LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations
  20. EP240618a: OHP/T193 MISTRAL i' and Y band upper limits
  21. Fermi Gamma-ray Burst Monitor trigger 740474239/240619304 is not a GRB
  22. GRB 240619B: Fermi GBM Final Real-time Localization
  23. Fermi trigger No 740430582: Global MASTER-Net observations report
  24. GRB240615A: 1.3m DFOT optical upper limit
  25. GRB 240619A: BALROG localization (Fermi Trigger 740461416 / GRB 240619155)
  26. GRB 240619A: Fermi GBM Final Real-time Localization
  27. EP240617a: BOOTES-6/DPRT optical upper limit
  28. EP240617a is likely a GRB event
  29. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  30. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  31. GRB 240615A: J-band upper limits from WINTER
  32. GRB 240615A: Fermi GBM Observation
  33. GRB 240615A: Swift-XRT observations
  34. GRB 240615A: GECAM detection
  35. GRB 240615A: FLWO-1.2m optical upper limits
  36. Fermi trigger No 740221779: Global MASTER-Net observations report
  37. Fermi GRB 240616A: Global MASTER-Net observations report
  38. Konus-Wind detection of GRB 240615A (short/hard)
  39. GRB 240615A: GOTO optical upper limits
  40. Fermi trigger No 740166710: Global MASTER-Net observations report
  41. GRB 240616A: Fermi GBM Final Real-time Localization
  42. GRB 240615A: Swift ToO observations
  43. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  44. GRB 240615A: Fermi GBM Final Real-time Localization
  45. GRB 240603A: VZLUSAT-2 detection
  46. GRB 240612A: GRBAlpha detection
  47. GRB 240613A: Fermi GBM Final Real-time Localization
  48. Fermi GRB 240612B: Global MASTER-Net observations report
  49. Fermi GRB 240612A: Global MASTER-Net observations report
  50. GRB 240612B: Fermi GBM Final Real-time Localization
  51. GRB 240612A: Fermi GBM Final Real-time Localization
  52. GRB 240607A: GECAM detection of a bright long burst
  53. Fermi GRB 240611A: Global MASTER-Net observations report
  54. Konus-Wind detection of GRB 240607A
  55. GRB 240611A: Fermi GBM Final Real-time Localization
  56. GRB 240529A: LBT optical detection and late temporal decay
  57. GRB 240529A : MITSuME Akeno optical afterglow detection
  58. Trigger 1236151: Swift detection of EXO 0748-676
  59. Fermi GRB 240610A: Global MASTER-Net observations report
  60. GRB 240610A: Fermi GBM Final Real-time Localization
  61. IPN triangulation of GRB 240607A
  62. Fermi Gamma-ray Burst Monitor trigger 739632045/240609556 is not a GRB
  63. Fermi trigger No 739632045: Global MASTER-Net observations report
  64. Fermi GRB 240608A: Global MASTER-Net observations report
  65. Konus-Wind detection of GRB 240606B
  66. Fermi trigger No 739506569: Global MASTER-Net observations report
  67. GRB 240608A: Fermi GBM Final Real-time Localization
  68. Fermi GRB 240607A: Global MASTER-Net observations report
  69. GRB 240529A: NOEMA detection
  70. GRB 240607A: Fermi GBM Observation
  71. GRB 240606B: Fermi GBM Observation
  72. Swift Trigger 1235109: consistent with noise and not astrophysical
  73. GRB 240607A: AstroSat CZTI detection of bright long burst
  74. GRB 240607A: Fermi GBM detection of a very bright burst
  75. GRB 240529A: radio detection with AMI-LA
  76. GRB 240607A: BALROG localization (Fermi Trigger 739450879 / GRB 240607459)
  77. GRB 240607A: Fermi GBM Final Real-time Localization
  78. GRB 240606B: GECAM-B detection a long burst
  79. Fermi trigger No 739373591: Global MASTER-Net observations report
  80. GRB 240606B: Swift-XRT afterglow detection
  81. Swift GRB240606.15: Global MASTER-Net observations report
  82. GRB 240606B: Swift ToO observations
  83. GRB 240606B: Swift/BAT-GUANO arcminute localization of a burst
  84. Konus-Wind detection of GRB 240603A
  85. Swift Trigger 1235109: a possible GRB 240606A
  86. Fermi GRB 240604A: Global MASTER-Net observations report
  87. IPN triangulation of GRB 240531A (short)
  88. Fermi GRB 240605A: Global MASTER-Net observations report
  89. Fermi GRB 240605C: Global MASTER-Net observations report
  90. Fermi Gamma-ray Burst Monitor trigger 739290883/240605607 is not a GRB
  91. GRB 240605C: Fermi GBM Final Real-time Localization
  92. IPN triangulation of GRB 240603A
  93. GRB 240605B: Fermi GBM Final Real-time Localization
  94. GRB 240604A: Fermi GBM Final Localization
  95. GRB 240605A: Fermi GBM Final Real-time Localization
  96. GRB 240604A: GECAM detection of a long burst
  97. GRB 240529A: SAO RAS optical observations
  98. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  99. Fermi GRB 240603C: Global MASTER-Net observations report
  100. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO

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