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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"

5526 results found.

  1. GRB 240812D: Fermi GBM Final Real-time Localization
  2. EP240801a: Assy-Turgen optical observations
  3. Fermi trigger No 745057312: Global MASTER-Net observations report
  4. EP240807a: STEP/T80S optical limits
  5. EP EP240807a: Global MASTER-Net observations report
  6. EP EP240806a: Global MASTER-Net observations report
  7. GRB 240801A: GRBAlpha detection
  8. The EP-WXT trigger 01709018832 on August 7th is likely a flaring star
  9. Fermi trigger No 744629911: Global MASTER-Net observations report
  10. Improved IPN triangulation of GRB 240802A / EP 240802a
  11. GRB 240626B: VZLUSAT-2 detection
  12. Fermi trigger No 744544656: Global MASTER-Net observations report
  13. EP240801a: BTA BVRI photometry
  14. Fermi GRB 240805A: Global MASTER-Net observations report
  15. EP240801a: Continued optical observations at ZTSh (CraO)
  16. EP240804a: LCOGT optical counterpart detection
  17. Fermi GRB 240804A: Global MASTER-Net observations report
  18. EP240802a: Montarrenti Observatory optical upper limit
  19. EP240801a: Osservatorio Astronomico Nastro Verde upper limit
  20. Fermi trigger No 744278264: Global MASTER-Net observations report
  21. EP240801a: GRANDMA and Kilonova-Catcher optical observations
  22. EP240801a: Leavitt Observatory optical observations
  23. EP240801a: GMG observation
  24. EP240801a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
  25. Fermi GRB 240801A: Global MASTER-Net observations report
  26. GRB 240801A: Fermi GBM Final Real-time Localization
  27. Fermi trigger No 744128417: Global MASTER-Net observations report
  28. Fermi GRB 240730B: Global MASTER-Net observations report
  29. Fermi trigger No 743953682: Global MASTER-Net observations report
  30. Fermi GRB 240727A: Global MASTER-Net observations report
  31. Fermi trigger No 743868421: Global MASTER-Net observations report
  32. GRB 240627A: GRBAlpha detection
  33. Fermi GRB 240726A: Global MASTER-Net observations report
  34. GRB240727A: Skynet Optical Afterglow Observations
  35. GRB 240727A: Swift detection of a burst
  36. IceCube-240725A: Upper limits from a search for additional neutrino events in IceCube
  37. IceCube Alert 240725.22: Global MASTER-Net observations report
  38. Fermi trigger No 743219692: Global MASTER-Net observations report
  39. Fermi GRB 240718A: Global MASTER-Net observations report
  40. LIGO/Virgo/KAGRA S240716b: Identification of a GW compact binary merger candidate
  41. GRB 240715A: Fermi GBM Final Real-time Localization
  42. EP240708a: GSP optical upper limit
  43. GRB 240712A: Swift detection of a burst
  44. Fermi trigger No 742405878: Global MASTER-Net observations report
  45. EP240708a: NOT optical observations
  46. EP240702a: TRT optical upper limits
  47. EP240703a: BTA observations
  48. LIGO/Virgo/KAGRA S240703ad: Identification of a GW compact binary merger candidate
  49. EP240702a: Swift/XRT upper limit
  50. Fermi trigger No 741448122: Global MASTER-Net observations report
  51. Fermi trigger No 741356809: Global MASTER-Net observations report
  52. IPN triangulation of GRB 240619C
  53. Konus-Wind detection of GRB 240619A
  54. Fermi GRB 240625B: Global MASTER-Net observations report
  55. Fermi trigger No 740744838: Global MASTER-Net observations report
  56. GRB 240619A: GRBAlpha detection
  57. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  58. GRB 240619A: Fermi GBM Observation
  59. Fermi trigger No 740430582: Global MASTER-Net observations report
  60. GRB 240619A: BALROG localization (Fermi Trigger 740461416 / GRB 240619155)
  61. GRB 240619A: Fermi GBM Final Real-time Localization
  62. Fermi GRB 240616A: Global MASTER-Net observations report
  63. GRB 240615A: GOTO optical upper limits
  64. Fermi trigger No 740166710: Global MASTER-Net observations report
  65. GRB 240603A: VZLUSAT-2 detection
  66. GRB 240610A: Fermi GBM Final Real-time Localization
  67. IPN triangulation of GRB 240607A
  68. Fermi trigger No 739506569: Global MASTER-Net observations report
  69. GRB 240608A: Fermi GBM Final Real-time Localization
  70. Fermi GRB 240607A: Global MASTER-Net observations report
  71. Swift GRB240606.15: Global MASTER-Net observations report
  72. Swift Trigger 1235109: a possible GRB 240606A
  73. Fermi GRB 240604A: Global MASTER-Net observations report
  74. Fermi GRB 240603C: Global MASTER-Net observations report
  75. GRB 240603A: Fermi GBM Final Localization
  76. GRB 240603C: BALROG localization (Fermi Trigger 739102156 / GRB 240603423)
  77. GRB 240529A: MASTER prompt OT detection
  78. Fermi GRB 240602A: Global MASTER-Net observations report
  79. GRB 240602A: Fermi GBM Final Real-time Localization
  80. GRB 240529A: Skynet Optical Observations
  81. GRB240529A: BOOTES-6/DPRT optical detection
  82. GRB 240529A: Swift detection of a burst with an optical counterpart
  83. Swift GRB240529.12: Global MASTER-Net observations report
  84. GRB 240527B: Fermi GBM Observation
  85. GRB 240527B: Fermi-LAT detection
  86. LAT GRB240527.59: Global MASTER-Net observations report
  87. Fermi GRB 240527B: Global MASTER-Net observations report
  88. GRB 240527B: Fermi GBM Final Localization
  89. GRB 240527B: BALROG localization (Fermi Trigger 738511436 / GRB 240527586)
  90. GRB 240523A: Swift-BAT refined analysis
  91. Fermi trigger No 738348224: Global MASTER-Net observations report
  92. Fermi trigger No 738330463: Global MASTER-Net observations report
  93. LIGO/Virgo/KAGRA S240525p: Identification of a GW compact binary merger candidate
  94. Fermi GBM Sub-Threshold Detection of GRB 240516B
  95. Fermi trigger No 737996942: Global MASTER-Net observations report
  96. GRB 240516B: AstroSat CZTI detection
  97. GRB 240514B: VZLUSAT-2 detection
  98. GRB 240504A: VZLUSAT-2 detection
  99. Fermi trigger No 737788024: Global MASTER-Net observations report
  100. Fermi GRB 240517A: Global MASTER-Net observations report

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