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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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. LIGO/Virgo/KAGRA S240527fv: Identification of a GW compact binary merger candidate
  2. GRB 240527B: Fermi-LAT detection
  3. LAT GRB240527.59: Global MASTER-Net observations report
  4. LIGO/Virgo/KAGRA S240527en: Identification of a GW compact binary merger candidate
  5. Fermi GRB 240527B: Global MASTER-Net observations report
  6. GRB 240527B: Fermi GBM Final Localization
  7. GRB 240527B: BALROG localization (Fermi Trigger 738511436 / GRB 240527586)
  8. GRB 240527A: Fermi GBM Final Real-time Localization
  9. GRB 240523A: Swift-BAT refined analysis
  10. Fermi trigger No 738348224: Global MASTER-Net observations report
  11. Fermi trigger No 738330463: Global MASTER-Net observations report
  12. LIGO/Virgo/KAGRA S240525p: Updated Sky localization
  13. LIGO/Virgo/KAGRA S240525p: Identification of a GW compact binary merger candidate
  14. GRB 240523A: Swift-XRT refined Analysis
  15. GRB 240523A: Enhanced Swift-XRT position
  16. GRB 240523A: Swift detection of a burst
  17. GRB 240521B: Fermi GBM Observation
  18. Fermi GBM Sub-Threshold Detection of GRB 240516B
  19. GRB 240513A: Swift-XRT afterglow detection
  20. GRB 240521B: Swift/BAT-GUANO arcminute localization of a long burst
  21. Fermi trigger No 737996942: Global MASTER-Net observations report
  22. LIGO/Virgo/KAGRA S240520cv: Updated Sky localization and EM Bright Classification
  23. EP240518a: GSP optical upper limit
  24. GRB 240521A: GECAM-B detection of a long burst
  25. GRB 240516B: AstroSat CZTI detection
  26. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  27. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  28. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  29. LIGO/Virgo/KAGRA S240520cv: Identification of a GW compact binary merger candidate
  30. IceCube-Cascade 240518A: Upper limits from a search for additional neutrino events in IceCube
  31. GRB 240514B: VZLUSAT-2 detection
  32. GRB 240504A: VZLUSAT-2 detection
  33. GRB 240502A: VZLUSAT-2 detection
  34. GRB 240519A: GRBAlpha detection
  35. GRB 240516A: Swift/UVOT Upper Limits
  36. GRB 240519A: AstroSat CZTI detection
  37. Fermi trigger No 737788024: Global MASTER-Net observations report
  38. EP240518a: possibly identified with a flare star by EP-FXT
  39. GRB 240519A: BALROG localization (Fermi Trigger 737788024 / GRB 240519213)
  40. EP240518a: EP-WXT detection of a new X-ray transient
  41. LIGO/Virgo/KAGRA S240514c: Updated Sky localization
  42. GRB 240516A: Swift-BAT refined analysis
  43. Fermi GRB 240517A: Global MASTER-Net observations report
  44. GRB 240516A ATCA radio observations
  45. IPN triangulation of GRB 240514B (short)
  46. GRB 240513A: Swift ToO observations
  47. GRB 240517A: Fermi GBM Final Real-time Localization
  48. Konus-Wind detection of GRB 240513A
  49. GRB 240516A: AstroSat CZTI detection
  50. GRB 240516A: Swift-XRT refined Analysis
  51. GRB 240514E: A possible candidate BD-21 1074
  52. Fermi trigger No 737559855: Global MASTER-Net observations report
  53. GRB 240516A: Fermi GBM Observation
  54. GRB 240511A: Observations from GTC/OSIRIS+
  55. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  56. GRB 240516A: GOTO optical upper limit
  57. LIGO/Virgo/KAGRA S240422ed: GRID non-detection and upper limits
  58. Fermi trigger No 737523389: Global MASTER-Net observations report
  59. GRB 240516A: Swift detection of a burst
  60. Swift GRB240516.15: Global MASTER-Net observations report
  61. GRB 240514B: AT2024ixa/GOTO24bph is not consistent with the Fermi localisation
  62. Fermi trigger No 737476171: Global MASTER-Net observations report
  63. GRB 240511A: radio detection of afterglow candidate
  64. GRB 240514B: GOTO candidate optical counterpart
  65. MAXI GRB240514.78: Global MASTER-Net observations report
  66. Fermi Gamma-ray Burst Monitor list of triggers that are not a GRB
  67. GRB 240514E: MAXI/GSC detection of a probable afterglow
  68. GRB 240514B: GRBAlpha detection
  69. LIGO/Virgo/KAGRA S240514x: Updated Sky localization
  70. LIGO/Virgo/KAGRA S240515m: Identification of a GW compact binary merger candidate
  71. GRB 240514B: Fermi GBM Detection
  72. LIGO/Virgo/KAGRA S240422ed: Las Cumbres Observatory Follow-up Observations of the Localization Region
  73. GRB 240513A: Fermi GBM observation
  74. GRB 240513A: Swift-XRT observations
  75. LIGO/Virgo/KAGRA S240513ei: Updated Sky localization
  76. LIGO/Virgo/KAGRA S240514x: Identification of a GW compact binary merger candidate
  77. GRB 240514D: AstroSat CZTI detection
  78. GRB 240514C: Fermi GBM Final Real-time Localization
  79. LIGO/Virgo/KAGRA S240514c: Identification of a GW compact binary merger candidate
  80. Fermi GRB 240514B: Global MASTER-Net observations report
  81. transient: Xinglong Nearby Galaxy Supernova Survey detection of AT2024iss
  82. Fermi Gamma-ray Burst Monitor triggers 737345659/240514093 and GRB240514A are not GRBs
  83. GRB 240514B: Fermi GBM Final Real-time Localization
  84. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  85. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  86. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  87. GRB 240514A: Fermi GBM Final Real-time Localization
  88. GRB 240513A: Tiled Swift observations
  89. LAT GRB240513.31: Global MASTER-Net observations report
  90. GRB 240513A: Fermi-LAT detection
  91. LIGO/Virgo/KAGRA S240513ei: Identification of a GW compact binary merger candidate
  92. GRB 240511A: Fermi GBM Observation
  93. GRB 240511A: Swift-BAT refined analysis
  94. Fermi GRB 240513B: Global MASTER-Net observations report
  95. Fermi trigger No 737277727: Global MASTER-Net observations report
  96. GRB 240513B: Fermi GBM Final Real-time Localization
  97. GRB 240513A: AstroSat CZTI detection
  98. LIGO/Virgo/KAGRA S240513cx: Coverage and upper limits from MAXI/GSC observations
  99. Fermi trigger No 737258655: Global MASTER-Net observations report
  100. GRB 240511A: J-band observations with WINTER

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