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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"

36141 results found.

  1. GRB 240529A: J-band detections with WINTER
  2. GRB 240529A: Skynet Optical Observations
  3. GRB 240529A: Swift-BAT refined analysis
  4. GRB 240529A: Swift-XRT refined Analysis
  5. GRB240529A: BOOTES-6/DPRT optical detection
  6. GRB 240529A: Swift/UVOT Detection
  7. GRB 240529A: NOT optical observations
  8. GRB 240529A: AstroSat CZTI detection
  9. GRB 240529A: GOTO optical afterglow detection
  10. GRB 240527B: Swift-XRT afterglow detection
  11. GRB 240529A: Enhanced Swift-XRT position
  12. GRB 240529A: Swift detection of a burst with an optical counterpart
  13. GRB 240527B: Fermi GBM Observation
  14. Fermi GRB 240527A: Global MASTER-Net observations report
  15. GRB 240527B: Fermi-LAT detection
  16. Fermi GRB 240527B: Global MASTER-Net observations report
  17. GRB 240527B: Fermi GBM Final Localization
  18. GRB 240527B: BALROG localization (Fermi Trigger 738511436 / GRB 240527586)
  19. GRB 240527A: Fermi GBM Final Real-time Localization
  20. GRB 240523A: Swift-BAT refined analysis
  21. GRB 240523A: Swift-XRT refined Analysis
  22. GRB 240523A: Enhanced Swift-XRT position
  23. GRB 240523A: Swift detection of a burst
  24. GRB 240521B: Fermi GBM Observation
  25. Fermi GBM Sub-Threshold Detection of GRB 240516B
  26. GRB 240513A: Swift-XRT afterglow detection
  27. GRB 240521B: Swift/BAT-GUANO arcminute localization of a long burst
  28. GRB 240521A: GECAM-B detection of a long burst
  29. GRB 240516B: AstroSat CZTI detection
  30. LIGO/Virgo/KAGRA S240515m: Upper limits from Swift/BAT-GUANO
  31. LIGO/Virgo/KAGRA S240514x: Upper limits from Swift/BAT-GUANO
  32. LIGO/Virgo/KAGRA S240513ei: Upper limits from Swift/BAT-GUANO
  33. GRB 240514B: VZLUSAT-2 detection
  34. GRB 240504A: VZLUSAT-2 detection
  35. GRB 240502A: VZLUSAT-2 detection
  36. GRB 240519A: GRBAlpha detection
  37. GRB 240516A: Swift/UVOT Upper Limits
  38. GRB 240519A: AstroSat CZTI detection
  39. GRB 240519A: BALROG localization (Fermi Trigger 737788024 / GRB 240519213)
  40. GRB 240516A: Swift-BAT refined analysis
  41. Fermi GRB 240517A: Global MASTER-Net observations report
  42. GRB 240516A ATCA radio observations
  43. IPN triangulation of GRB 240514B (short)
  44. GRB 240513A: Swift ToO observations
  45. GRB 240517A: Fermi GBM Final Real-time Localization
  46. Konus-Wind detection of GRB 240513A
  47. GRB 240516A: AstroSat CZTI detection
  48. GRB 240516A: Swift-XRT refined Analysis
  49. GRB 240514E: A possible candidate BD-21 1074
  50. GRB 240516A: Fermi GBM Observation
  51. GRB 240511A: Observations from GTC/OSIRIS+
  52. GRB 240502C: Zeiss-1000 at Koshka observations of GOTO24bao optical counterpart candidate
  53. GRB 240516A: GOTO optical upper limit
  54. LIGO/Virgo/KAGRA S240422ed: GRID non-detection and upper limits
  55. GRB 240516A: Swift detection of a burst
  56. GRB 240514B: AT2024ixa/GOTO24bph is not consistent with the Fermi localisation
  57. GRB 240511A: radio detection of afterglow candidate
  58. GRB 240514B: GOTO candidate optical counterpart
  59. Fermi Gamma-ray Burst Monitor list of triggers that are not a GRB
  60. GRB 240514E: MAXI/GSC detection of a probable afterglow
  61. GRB 240514B: GRBAlpha detection
  62. GRB 240514B: Fermi GBM Detection
  63. GRB 240513A: Fermi GBM observation
  64. GRB 240513A: Swift-XRT observations
  65. GRB 240514D: AstroSat CZTI detection
  66. GRB 240514C: Fermi GBM Final Real-time Localization
  67. Fermi GRB 240514B: Global MASTER-Net observations report
  68. GRB 240514B: Fermi GBM Final Real-time Localization
  69. LIGO/Virgo/KAGRA S240507p: Upper limits from Swift/BAT-GUANO
  70. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  71. LIGO/Virgo/KAGRA S240505av: Upper limits from Swift/BAT-GUANO
  72. GRB 240514A: Fermi GBM Final Real-time Localization
  73. GRB 240513A: Tiled Swift observations
  74. GRB 240513A: Fermi-LAT detection
  75. GRB 240511A: Fermi GBM Observation
  76. GRB 240511A: Swift-BAT refined analysis
  77. Fermi GRB 240513B: Global MASTER-Net observations report
  78. GRB 240513B: Fermi GBM Final Real-time Localization
  79. GRB 240513A: AstroSat CZTI detection
  80. GRB 240511A: J-band observations with WINTER
  81. GRB 240511A: Enhanced Swift-XRT position
  82. GRB 240511A : MITSuME Akeno optical upper limits
  83. GRB 240511A: Swift-XRT refined Analysis
  84. GRB 240511A: optical afterglow detection from the NOT
  85. Fermi Gamma-ray Burst Monitor trigger 737102480/240511279 is not a GRB
  86. Fermi Gamma-ray Burst Monitor trigger 737111207/240511380 is not a GRB
  87. Fermi GBM trigger 737105243/240511311 is not a GRB
  88. Fermi GRB 240511A: Global MASTER-Net observations report
  89. Swift GRB 240511A: Global MASTER-Net observations report
  90. Fermi Gamma-ray Burst Monitor trigger 737133200/240511634 is not a GRB
  91. GRB 240511A: Prompt enhanced Swift-XRT position
  92. GRB 240511A: Swift detection of a burst
  93. GRB 240511A: Fermi GBM Final Real-time Localization
  94. Fermi Gamma-ray Burst Monitor trigger 737076431/240510977 is not a GRB
  95. Fermi Gamma-ray Burst Monitor trigger 230925241/717313591 is not a GRB
  96. EP240506a: CrAO ZTSH optical upper limit
  97. GRB 240504A: Fermi GBM Observation
  98. Fermi Gamma-ray Burst Monitor trigger 736837160/240508208 is not a GRB
  99. IPN triangulation of GRB 240504A
  100. GRB 240502A: 1.3m DFOT Optical upper limit

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