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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. Konus-Wind detection of GRB 240615A (short/hard)
  2. GRB 240615A: GOTO optical upper limits
  3. Fermi trigger No 740166710: Global MASTER-Net observations report
  4. GRB 240616A: Fermi GBM Final Real-time Localization
  5. GRB 240615A: Swift ToO observations
  6. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  7. GRB 240615A: Fermi GBM Final Real-time Localization
  8. LIGO/Virgo/KAGRA S240615ea: Identification of a GW compact binary merger candidate
  9. LIGO/Virgo/KAGRA S240615dg: Identification of a GW compact binary merger candidate
  10. GRB 240603A: VZLUSAT-2 detection
  11. GRB 240612A: GRBAlpha detection
  12. GRB 240613A: Fermi GBM Final Real-time Localization
  13. Fermi GRB 240612B: Global MASTER-Net observations report
  14. Fermi GRB 240612A: Global MASTER-Net observations report
  15. GRB 240612B: Fermi GBM Final Real-time Localization
  16. GRB 240612A: Fermi GBM Final Real-time Localization
  17. GRB 240607A: GECAM detection of a bright long burst
  18. Fermi GRB 240611A: Global MASTER-Net observations report
  19. Konus-Wind detection of GRB 240607A
  20. GRB 240611A: Fermi GBM Final Real-time Localization
  21. EXO 0748-676: Swift-BAT refined analysis
  22. GRB240529A: 3.6m TNG NIR detection 8d after the burst
  23. GRB 240529A: LBT optical detection and late temporal decay
  24. GRB 240529A : MITSuME Akeno optical afterglow detection
  25. Trigger 1236151: Swift detection of EXO 0748-676
  26. Fermi GRB 240610A: Global MASTER-Net observations report
  27. GRB 240610A: Fermi GBM Final Real-time Localization
  28. IPN triangulation of GRB 240607A
  29. Fermi Gamma-ray Burst Monitor trigger 739632045/240609556 is not a GRB
  30. Fermi trigger No 739632045: Global MASTER-Net observations report
  31. Fermi GRB 240608A: Global MASTER-Net observations report
  32. Konus-Wind detection of GRB 240606B
  33. Fermi trigger No 739506569: Global MASTER-Net observations report
  34. GRB 240608A: Fermi GBM Final Real-time Localization
  35. Fermi GRB 240607A: Global MASTER-Net observations report
  36. GRB 240529A: NOEMA detection
  37. GRB 240607A: Fermi GBM Observation
  38. GRB 240606B: Fermi GBM Observation
  39. Swift Trigger 1235109: consistent with noise and not astrophysical
  40. GRB 240607A: AstroSat CZTI detection of bright long burst
  41. GRB 240607A: Fermi GBM detection of a very bright burst
  42. GRB 240529A: radio detection with AMI-LA
  43. GRB 240607A: BALROG localization (Fermi Trigger 739450879 / GRB 240607459)
  44. GRB 240607A: Fermi GBM Final Real-time Localization
  45. GRB 240606B: GECAM-B detection a long burst
  46. Fermi trigger No 739373591: Global MASTER-Net observations report
  47. GRB 240606B: Swift-XRT afterglow detection
  48. Swift GRB240606.15: Global MASTER-Net observations report
  49. GRB 240606B: Swift ToO observations
  50. GRB 240606B: Swift/BAT-GUANO arcminute localization of a burst
  51. Konus-Wind detection of GRB 240603A
  52. Swift Trigger 1235109: a possible GRB 240606A
  53. Fermi GRB 240604A: Global MASTER-Net observations report
  54. IPN triangulation of GRB 240531A (short)
  55. Fermi GRB 240605A: Global MASTER-Net observations report
  56. Fermi GRB 240605C: Global MASTER-Net observations report
  57. Fermi Gamma-ray Burst Monitor trigger 739290883/240605607 is not a GRB
  58. LIGO/Virgo/KAGRA S240601co: Updated Sky localization
  59. GRB 240605C: Fermi GBM Final Real-time Localization
  60. IPN triangulation of GRB 240603A
  61. GRB 240605B: Fermi GBM Final Real-time Localization
  62. GRB 240604A: Fermi GBM Final Localization
  63. GRB 240605A: Fermi GBM Final Real-time Localization
  64. GRB 240604A: GECAM detection of a long burst
  65. GRB 240529A: SAO RAS optical observations
  66. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  67. Fermi GRB 240603C: Global MASTER-Net observations report
  68. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
  69. LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
  70. GRB 240603A: Fermi GBM Final Localization
  71. GRB 240603C: BALROG localization (Fermi Trigger 739102156 / GRB 240603423)
  72. GRB 240603C: Fermi GBM Final Real-time Localization
  73. Swift Trigger 1232465: consistent with noise
  74. GRB 240603B: Swift detection of a possible burst
  75. GRB 240529A: MASTER prompt OT detection
  76. GRB 240603A: GECAM detection of a short burst
  77. GRB 240529A: continued SAO RAS optical observations
  78. Fermi GRB 240602A: Global MASTER-Net observations report
  79. GRB 240529A: OSN optical detection
  80. The EP-WXT source triggered on June 1st is likely a flaring star
  81. GRB 240529A: further SAO RAS optical observations
  82. LIGO/Virgo/KAGRA S240601aj: Updated Sky localization
  83. GRB 240602A: Fermi GBM Final Real-time Localization
  84. LIGO/Virgo/KAGRA S240601co: Identification of a GW compact binary merger candidate
  85. Swift Trigger 1232465 is not a GRB
  86. GRB 240529A: AKO Optical Afterglow Follow-Up Observations
  87. LIGO/Virgo/KAGRA S240530a: Updated Sky localization
  88. LXT 240528A: GSP optical upper limit
  89. GRB 240529A: 1.3m DFOT Optical observations
  90. LIGO/Virgo/KAGRA S240527en: Updated Sky localization
  91. LIGO/Virgo/KAGRA S240601aj: Identification of a GW compact binary merger candidate
  92. GRB 240531A: AstroSat CZTI detection of a short burst
  93. GRB 240529A : Mondy optical observations
  94. Konus-Wind detection of GRB 240529A
  95. IPN triangulation of the initial episode of GRB 240529A
  96. GRB 240529A: SAO RAS optical observations
  97. LIGO/Virgo/KAGRA S240531bp: Updated Sky localization
  98. LIGO/Virgo/KAGRA S240531bp: Identification of a GW compact binary merger candidate
  99. GRB 240529A: MAAO 0.7m telescope optical afterglow detection
  100. GRB 240529A: Insight-HXMT/HE detection

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