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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').
  1. Fermi trigger No 740430582: Global MASTER-Net observations report
  2. GRB240615A: 1.3m DFOT optical upper limit
  3. GRB 240619A: BALROG localization (Fermi Trigger 740461416 / GRB 240619155)
  4. GRB 240619A: Fermi GBM Final Real-time Localization
  5. EP240617a: BOOTES-6/DPRT optical upper limit
  6. EP240617a is likely a GRB event
  7. EP240617a: EP-WXT detection of a fast X-ray transient
  8. EP240618a: EP-WXT detection of a fast X-ray transient and EP-FXT quick follow-up
  9. LIGO/Virgo/KAGRA S240618ah: Identification of a GW compact binary merger candidate
  10. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  11. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  12. GRB 240615A: J-band upper limits from WINTER
  13. GRB 240615A: Fermi GBM Observation
  14. LIGO/Virgo/KAGRA S240615ea: Updated Sky localization
  15. GRB 240615A: Swift-XRT observations
  16. GRB 240615A: GECAM detection
  17. X-ray transient EP240414a: Chandra late time observation
  18. GRB 240615A: FLWO-1.2m optical upper limits
  19. Fermi trigger No 740221779: Global MASTER-Net observations report
  20. Fermi GRB 240616A: Global MASTER-Net observations report
  21. Konus-Wind detection of GRB 240615A (short/hard)
  22. GRB 240615A: GOTO optical upper limits
  23. Fermi trigger No 740166710: Global MASTER-Net observations report
  24. GRB 240616A: Fermi GBM Final Real-time Localization
  25. GRB 240615A: Swift ToO observations
  26. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  27. GRB 240615A: Fermi GBM Final Real-time Localization
  28. LIGO/Virgo/KAGRA S240615ea: Identification of a GW compact binary merger candidate
  29. LIGO/Virgo/KAGRA S240615dg: Identification of a GW compact binary merger candidate
  30. GRB 240603A: VZLUSAT-2 detection
  31. GRB 240612A: GRBAlpha detection
  32. GRB 240613A: Fermi GBM Final Real-time Localization
  33. Fermi GRB 240612B: Global MASTER-Net observations report
  34. Fermi GRB 240612A: Global MASTER-Net observations report
  35. GRB 240612B: Fermi GBM Final Real-time Localization
  36. GRB 240612A: Fermi GBM Final Real-time Localization
  37. GRB 240607A: GECAM detection of a bright long burst
  38. Fermi GRB 240611A: Global MASTER-Net observations report
  39. Konus-Wind detection of GRB 240607A
  40. GRB 240611A: Fermi GBM Final Real-time Localization
  41. EXO 0748-676: Swift-BAT refined analysis
  42. GRB240529A: 3.6m TNG NIR detection 8d after the burst
  43. GRB 240529A: LBT optical detection and late temporal decay
  44. GRB 240529A : MITSuME Akeno optical afterglow detection
  45. Trigger 1236151: Swift detection of EXO 0748-676
  46. Fermi GRB 240610A: Global MASTER-Net observations report
  47. GRB 240610A: Fermi GBM Final Real-time Localization
  48. IPN triangulation of GRB 240607A
  49. Fermi Gamma-ray Burst Monitor trigger 739632045/240609556 is not a GRB
  50. Fermi trigger No 739632045: Global MASTER-Net observations report
  51. Fermi GRB 240608A: Global MASTER-Net observations report
  52. Konus-Wind detection of GRB 240606B
  53. Fermi trigger No 739506569: Global MASTER-Net observations report
  54. GRB 240608A: Fermi GBM Final Real-time Localization
  55. Fermi GRB 240607A: Global MASTER-Net observations report
  56. GRB 240529A: NOEMA detection
  57. GRB 240607A: Fermi GBM Observation
  58. GRB 240606B: Fermi GBM Observation
  59. Swift Trigger 1235109: consistent with noise and not astrophysical
  60. GRB 240607A: AstroSat CZTI detection of bright long burst
  61. GRB 240607A: Fermi GBM detection of a very bright burst
  62. GRB 240529A: radio detection with AMI-LA
  63. GRB 240607A: BALROG localization (Fermi Trigger 739450879 / GRB 240607459)
  64. GRB 240607A: Fermi GBM Final Real-time Localization
  65. GRB 240606B: GECAM-B detection a long burst
  66. Fermi trigger No 739373591: Global MASTER-Net observations report
  67. GRB 240606B: Swift-XRT afterglow detection
  68. Swift GRB240606.15: Global MASTER-Net observations report
  69. GRB 240606B: Swift ToO observations
  70. GRB 240606B: Swift/BAT-GUANO arcminute localization of a burst
  71. Konus-Wind detection of GRB 240603A
  72. Swift Trigger 1235109: a possible GRB 240606A
  73. Fermi GRB 240604A: Global MASTER-Net observations report
  74. IPN triangulation of GRB 240531A (short)
  75. Fermi GRB 240605A: Global MASTER-Net observations report
  76. Fermi GRB 240605C: Global MASTER-Net observations report
  77. Fermi Gamma-ray Burst Monitor trigger 739290883/240605607 is not a GRB
  78. LIGO/Virgo/KAGRA S240601co: Updated Sky localization
  79. GRB 240605C: Fermi GBM Final Real-time Localization
  80. IPN triangulation of GRB 240603A
  81. GRB 240605B: Fermi GBM Final Real-time Localization
  82. GRB 240604A: Fermi GBM Final Localization
  83. GRB 240605A: Fermi GBM Final Real-time Localization
  84. GRB 240604A: GECAM detection of a long burst
  85. GRB 240529A: SAO RAS optical observations
  86. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  87. Fermi GRB 240603C: Global MASTER-Net observations report
  88. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
  89. LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
  90. GRB 240603A: Fermi GBM Final Localization
  91. GRB 240603C: BALROG localization (Fermi Trigger 739102156 / GRB 240603423)
  92. GRB 240603C: Fermi GBM Final Real-time Localization
  93. Swift Trigger 1232465: consistent with noise
  94. GRB 240603B: Swift detection of a possible burst
  95. GRB 240529A: MASTER prompt OT detection
  96. GRB 240603A: GECAM detection of a short burst
  97. GRB 240529A: continued SAO RAS optical observations
  98. Fermi GRB 240602A: Global MASTER-Net observations report
  99. GRB 240529A: OSN optical detection
  100. The EP-WXT source triggered on June 1st is likely a flaring star

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