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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"
  1. GRB 240615A: GECAM detection
  2. X-ray transient EP240414a: Chandra late time observation
  3. GRB 240615A: FLWO-1.2m optical upper limits
  4. Fermi trigger No 740221779: Global MASTER-Net observations report
  5. Fermi GRB 240616A: Global MASTER-Net observations report
  6. Konus-Wind detection of GRB 240615A (short/hard)
  7. GRB 240615A: GOTO optical upper limits
  8. Fermi trigger No 740166710: Global MASTER-Net observations report
  9. GRB 240616A: Fermi GBM Final Real-time Localization
  10. GRB 240615A: Swift ToO observations
  11. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  12. GRB 240615A: Fermi GBM Final Real-time Localization
  13. LIGO/Virgo/KAGRA S240615ea: Identification of a GW compact binary merger candidate
  14. LIGO/Virgo/KAGRA S240615dg: Identification of a GW compact binary merger candidate
  15. GRB 240603A: VZLUSAT-2 detection
  16. GRB 240612A: GRBAlpha detection
  17. GRB 240613A: Fermi GBM Final Real-time Localization
  18. Fermi GRB 240612B: Global MASTER-Net observations report
  19. Fermi GRB 240612A: Global MASTER-Net observations report
  20. GRB 240612B: Fermi GBM Final Real-time Localization
  21. GRB 240612A: Fermi GBM Final Real-time Localization
  22. GRB 240607A: GECAM detection of a bright long burst
  23. Fermi GRB 240611A: Global MASTER-Net observations report
  24. Konus-Wind detection of GRB 240607A
  25. GRB 240611A: Fermi GBM Final Real-time Localization
  26. EXO 0748-676: Swift-BAT refined analysis
  27. GRB240529A: 3.6m TNG NIR detection 8d after the burst
  28. GRB 240529A: LBT optical detection and late temporal decay
  29. GRB 240529A : MITSuME Akeno optical afterglow detection
  30. Trigger 1236151: Swift detection of EXO 0748-676
  31. Fermi GRB 240610A: Global MASTER-Net observations report
  32. GRB 240610A: Fermi GBM Final Real-time Localization
  33. IPN triangulation of GRB 240607A
  34. Fermi Gamma-ray Burst Monitor trigger 739632045/240609556 is not a GRB
  35. Fermi trigger No 739632045: Global MASTER-Net observations report
  36. Fermi GRB 240608A: Global MASTER-Net observations report
  37. Konus-Wind detection of GRB 240606B
  38. Fermi trigger No 739506569: Global MASTER-Net observations report
  39. GRB 240608A: Fermi GBM Final Real-time Localization
  40. Fermi GRB 240607A: Global MASTER-Net observations report
  41. GRB 240529A: NOEMA detection
  42. GRB 240607A: Fermi GBM Observation
  43. GRB 240606B: Fermi GBM Observation
  44. Swift Trigger 1235109: consistent with noise and not astrophysical
  45. GRB 240607A: AstroSat CZTI detection of bright long burst
  46. GRB 240607A: Fermi GBM detection of a very bright burst
  47. GRB 240529A: radio detection with AMI-LA
  48. GRB 240607A: BALROG localization (Fermi Trigger 739450879 / GRB 240607459)
  49. GRB 240607A: Fermi GBM Final Real-time Localization
  50. GRB 240606B: GECAM-B detection a long burst
  51. Fermi trigger No 739373591: Global MASTER-Net observations report
  52. GRB 240606B: Swift-XRT afterglow detection
  53. Swift GRB240606.15: Global MASTER-Net observations report
  54. GRB 240606B: Swift ToO observations
  55. GRB 240606B: Swift/BAT-GUANO arcminute localization of a burst
  56. Konus-Wind detection of GRB 240603A
  57. Swift Trigger 1235109: a possible GRB 240606A
  58. Fermi GRB 240604A: Global MASTER-Net observations report
  59. IPN triangulation of GRB 240531A (short)
  60. Fermi GRB 240605A: Global MASTER-Net observations report
  61. Fermi GRB 240605C: Global MASTER-Net observations report
  62. Fermi Gamma-ray Burst Monitor trigger 739290883/240605607 is not a GRB
  63. LIGO/Virgo/KAGRA S240601co: Updated Sky localization
  64. GRB 240605C: Fermi GBM Final Real-time Localization
  65. IPN triangulation of GRB 240603A
  66. GRB 240605B: Fermi GBM Final Real-time Localization
  67. GRB 240604A: Fermi GBM Final Localization
  68. GRB 240605A: Fermi GBM Final Real-time Localization
  69. GRB 240604A: GECAM detection of a long burst
  70. GRB 240529A: SAO RAS optical observations
  71. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  72. Fermi GRB 240603C: Global MASTER-Net observations report
  73. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
  74. LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
  75. GRB 240603A: Fermi GBM Final Localization
  76. GRB 240603C: BALROG localization (Fermi Trigger 739102156 / GRB 240603423)
  77. GRB 240603C: Fermi GBM Final Real-time Localization
  78. Swift Trigger 1232465: consistent with noise
  79. GRB 240603B: Swift detection of a possible burst
  80. GRB 240529A: MASTER prompt OT detection
  81. GRB 240603A: GECAM detection of a short burst
  82. GRB 240529A: continued SAO RAS optical observations
  83. Fermi GRB 240602A: Global MASTER-Net observations report
  84. GRB 240529A: OSN optical detection
  85. The EP-WXT source triggered on June 1st is likely a flaring star
  86. GRB 240529A: further SAO RAS optical observations
  87. LIGO/Virgo/KAGRA S240601aj: Updated Sky localization
  88. GRB 240602A: Fermi GBM Final Real-time Localization
  89. LIGO/Virgo/KAGRA S240601co: Identification of a GW compact binary merger candidate
  90. Swift Trigger 1232465 is not a GRB
  91. GRB 240529A: AKO Optical Afterglow Follow-Up Observations
  92. LIGO/Virgo/KAGRA S240530a: Updated Sky localization
  93. LXT 240528A: GSP optical upper limit
  94. GRB 240529A: 1.3m DFOT Optical observations
  95. LIGO/Virgo/KAGRA S240527en: Updated Sky localization
  96. LIGO/Virgo/KAGRA S240601aj: Identification of a GW compact binary merger candidate
  97. GRB 240531A: AstroSat CZTI detection of a short burst
  98. GRB 240529A : Mondy optical observations
  99. Konus-Wind detection of GRB 240529A
  100. IPN triangulation of the initial episode of GRB 240529A

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