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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"

12108 results found.

  1. Fermi trigger No 740474239: Global MASTER-Net observations report
  2. EP240618a: BOOTES-6/DPRT optical upper limit
  3. LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
  4. Fermi trigger No 740430582: Global MASTER-Net observations report
  5. GRB240615A: 1.3m DFOT optical upper limit
  6. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  7. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  8. Konus-Wind detection of GRB 240615A (short/hard)
  9. Fermi trigger No 740166710: Global MASTER-Net observations report
  10. Konus-Wind detection of GRB 240607A
  11. Fermi GRB 240610A: Global MASTER-Net observations report
  12. Fermi Gamma-ray Burst Monitor trigger 739632045/240609556 is not a GRB
  13. Konus-Wind detection of GRB 240606B
  14. Fermi trigger No 739506569: Global MASTER-Net observations report
  15. GRB 240607A: AstroSat CZTI detection of bright long burst
  16. GRB 240606B: GECAM-B detection a long burst
  17. Fermi trigger No 739373591: Global MASTER-Net observations report
  18. GRB 240606B: Swift-XRT afterglow detection
  19. Konus-Wind detection of GRB 240603A
  20. Fermi GRB 240604A: Global MASTER-Net observations report
  21. GRB 240604A: GECAM detection of a long burst
  22. Fermi GRB 240603C: Global MASTER-Net observations report
  23. LIGO/Virgo/KAGRA S240601co: Upper limits from Swift/BAT-GUANO
  24. LIGO/Virgo/KAGRA S240530a: Upper limits from Swift/BAT-GUANO
  25. GRB 240529A: MASTER prompt OT detection
  26. GRB 240603A: GECAM detection of a short burst
  27. Fermi GRB 240602A: Global MASTER-Net observations report
  28. GRB 240529A: further SAO RAS optical observations
  29. Swift Trigger 1232465 is not a GRB
  30. GRB 240529A: 1.3m DFOT Optical observations
  31. GRB 240531A: AstroSat CZTI detection of a short burst
  32. Konus-Wind detection of GRB 240529A
  33. LIGO/Virgo/KAGRA S240527fv: Upper limits from Swift/BAT-GUANO
  34. LIGO/Virgo/KAGRA S240525p: Upper limits from Swift/BAT-GUANO
  35. GRB 240529A: Skynet Optical Observations
  36. LXT 240528A: LEIA detection of a fast X-ray transient
  37. LIGO/Virgo S240527fv: GRANDMA/FRAM-Auger Optical Observations
  38. GRB 240529A: AstroSat CZTI detection
  39. GRB 240527B: Swift-XRT afterglow detection
  40. GRB 240529A: Swift detection of a burst with an optical counterpart
  41. Swift GRB240529.12: Global MASTER-Net observations report
  42. GRB 240527B: Fermi GBM Observation
  43. GRB 240527B: Fermi-LAT detection
  44. Fermi trigger No 738348224: Global MASTER-Net observations report
  45. Fermi trigger No 738330463: Global MASTER-Net observations report
  46. GRB 240523A: Swift-XRT refined Analysis
  47. Fermi trigger No 737996942: Global MASTER-Net observations report
  48. GRB 240521A: GECAM-B detection of a long burst
  49. GRB 240516B: AstroSat CZTI detection
  50. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  51. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  52. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  53. LIGO/Virgo/KAGRA S240520cv: Identification of a GW compact binary merger candidate
  54. GRB 240519A: AstroSat CZTI detection
  55. Fermi GRB 240517A: Global MASTER-Net observations report
  56. Konus-Wind detection of GRB 240513A
  57. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  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. MAXI GRB240514.78: Global MASTER-Net observations report
  62. GRB 240514E: MAXI/GSC detection of a probable afterglow
  63. GRB 240514D: AstroSat CZTI detection
  64. GRB 240514C: Fermi GBM Final Real-time Localization
  65. Fermi GRB 240514B: Global MASTER-Net observations report
  66. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  67. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  68. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  69. LAT GRB240513.31: Global MASTER-Net observations report
  70. GRB 240513A: Fermi-LAT detection
  71. GRB 240511A: Fermi GBM Observation
  72. GRB 240511A: Swift-BAT refined analysis
  73. Fermi trigger No 737277727: Global MASTER-Net observations report
  74. GRB 240513A: AstroSat CZTI detection
  75. LIGO/Virgo/KAGRA S240513cx: Coverage and upper limits from MAXI/GSC observations
  76. Fermi trigger No 737196587: Global MASTER-Net observations report
  77. Fermi trigger No 737168073: Global MASTER-Net observations report
  78. GRB 240511A: Swift-XRT refined Analysis
  79. Fermi trigger No 737152719: Global MASTER-Net observations report
  80. GRB 240511A: Swift detection of a burst
  81. GRB 240511A: Fermi GBM Final Real-time Localization
  82. Fermi trigger No 737111207: Global MASTER-Net observations report
  83. LIGO/Virgo/KAGRA S240422ed: GMOS-S photometry of J-GEM24a
  84. EP240506a: CrAO ZTSH optical upper limit
  85. EP240506a: EP-WXT detection of a new fast X-ray transient
  86. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  87. Fermi trigger No 736564880: Global MASTER-Net observations report
  88. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  89. IPN triangulation of GRB 240501B and GRB 240501A - possible episodes of ultra long GRB
  90. Fermi GRB 240504A: Global MASTER-Net observations report
  91. Fermi trigger No 736472503: Global MASTER-Net observations report
  92. GRB 240503A: AstroSat CZTI detection
  93. LXT 240402A / GRB 240402B: VLT X-shooter redshift of host
  94. GRB 240502C: GOTO possible optical counterpart candidates
  95. GRB 240502A long GRB detected by INTEGRAL
  96. Fermi GRB 240501A: Global MASTER-Net observations report
  97. Fermi trigger No 736197684: Global MASTER-Net observations report
  98. MeerKAT Discovery of a Probable Radio Counterpart to EP240414a
  99. GRB 240501B: AstroSat CZTI detection
  100. LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations

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