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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"

38255 results found.

  1. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  2. IPN triangulation of GRB 240627A
  3. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  4. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  5. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  6. EP240702a: GSP optical upper limit
  7. The first three GRBs detected by SVOM: GRB 240627B, GRB 240629A and GRB 240702A
  8. GRB 240702A: BALROG localization (Fermi Trigger / GRB 240702885)
  9. Fermi GRB 240702A: Global MASTER-Net observations report
  10. GRB 240702A: Fermi GBM Final Real-time Localization
  11. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  12. Fermi Gamma-ray Burst Monitor trigger 741448122/240630575 is not a GRB
  13. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  14. Fermi trigger No 741448122: Global MASTER-Net observations report
  15. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  16. Fermi trigger No 741356809: Global MASTER-Net observations report
  17. Fermi GRB 240629A: Global MASTER-Net observations report
  18. Fermi Gamma-ray Burst Monitor trigger 741362867/240629589 is not a GRB
  19. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  20. GRB 240629A: BALROG localization (Fermi Trigger 741372837 / GRB 240629704)
  21. GRB 240629A: Fermi GBM Final Real-time Localization
  22. Fermi Gamma-ray Burst Monitor trigger 741356809/240629519 is not a GRB
  23. Fermi trigger No 741296200: Global MASTER-Net observations report
  24. Fermi trigger No 741251380: Global MASTER-Net observations report
  25. IPN triangulation of GRB 240619C
  26. GRB 240628A: BALROG localization (Fermi Trigger 741288821 / GRB 240628732)
  27. GRB 240627A: NuSTAR Detection of the long GRB
  28. GRB 240615A: SAI CMO J- band observations
  29. GRB 240627A: AstroSat CZTI detection
  30. Fermi trigger No 741211696: Global MASTER-Net observations report
  31. EP240626a: Montarrenti Observatory optical upper limit
  32. EP240626a: KAIT optical upper limit
  33. GRB 240624A: Swift-BAT refined analysis
  34. Konus-Wind detection of GRB 240619A
  35. Fermi GRB 240625B: Global MASTER-Net observations report
  36. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  37. GRB 240625B: Fermi GBM Final Real-time Localization
  38. GRB 240625A: Fermi GBM Observation
  39. GRB 240624B: GRBAlpha detection
  40. GRB 240625A: Fermi GBM Final Real-time Localization
  41. GRB240624A: Fermi GBM Observation
  42. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  43. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  44. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  45. Swift GRB 240624A: Global MASTER-Net observations report
  46. GRB240615A: Gemini-North observations of the BAT and XRT positions
  47. Fermi GRB 240624A: Global MASTER-Net observations report
  48. GRB 240624B: Fermi GBM Final Real-time Localization
  49. Fermi trigger No 740949590: Global MASTER-Net observations report
  50. GRB240615A: Gemini-North observations of the BAT and XRT positions
  51. GRB 240624A: Fermi GBM Final Real-time Localization
  52. GRB 240619A: detection of a radio counterpart with AMI-LA
  53. GRB 240624A: Swift detection of a burst
  54. GRB 240619A: J-band detection with WINTER (duplicate submission of GCN 36739)
  55. GRB 240619A: J-band detection with WINTER
  56. Fermi trigger No 740744838: Global MASTER-Net observations report
  57. EP240618a: NOT optical counterpart candidate
  58. GRB 240529A: JinShan optical observations
  59. EP240618a: GSP optical upper limit
  60. IPN triangulation of GRB 240615A (short)
  61. GRB 240619A: GRBAlpha detection
  62. GRB 240619A: Swift-XRT probable afterglow detection
  63. GRB 240619A: Swift ToO observations
  64. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  65. GRB 240619C: NuSTAR automated detection of the GRB
  66. GRB 240619A: Fermi GBM Observation
  67. Fermi GBM Sub-Threshold Detection of GRB 240619C
  68. GRB 240619A: GOTO candidate optical afterglow
  69. EP240618a: Abastumani optical observationsEP240618a
  70. GRB 240615A: NOT optical observations
  71. GRB 240619C: AstroSat CZTI detection
  72. EP240618a: TRT optical upper limit
  73. Fermi trigger No 740474239: Global MASTER-Net observations report
  74. Fermi GRB 240619A: Global MASTER-Net observations report
  75. GRB 240615A: possible transient detection from Wendelstein observations
  76. LIGO/Virgo S240615dg: GRANDMA/FRAM-CTA-N Observations
  77. EP240618a: OHP/T193 MISTRAL i' and Y band upper limits
  78. Fermi Gamma-ray Burst Monitor trigger 740474239/240619304 is not a GRB
  79. GRB 240619B: Fermi GBM Final Real-time Localization
  80. Fermi trigger No 740430582: Global MASTER-Net observations report
  81. GRB240615A: 1.3m DFOT optical upper limit
  82. GRB 240619A: BALROG localization (Fermi Trigger 740461416 / GRB 240619155)
  83. GRB 240619A: Fermi GBM Final Real-time Localization
  84. EP240617a: BOOTES-6/DPRT optical upper limit
  85. EP240617a is likely a GRB event
  86. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  87. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  88. GRB 240615A: J-band upper limits from WINTER
  89. GRB 240615A: Fermi GBM Observation
  90. GRB 240615A: Swift-XRT observations
  91. GRB 240615A: GECAM detection
  92. GRB 240615A: FLWO-1.2m optical upper limits
  93. Fermi trigger No 740221779: Global MASTER-Net observations report
  94. Fermi GRB 240616A: Global MASTER-Net observations report
  95. Konus-Wind detection of GRB 240615A (short/hard)
  96. GRB 240615A: GOTO optical upper limits
  97. Fermi trigger No 740166710: Global MASTER-Net observations report
  98. GRB 240616A: Fermi GBM Final Real-time Localization
  99. GRB 240615A: Swift ToO observations
  100. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst

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