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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"

35320 results found.

  1. GRB 240712A: Swift detection of a burst
  2. GRB 240711A: Fermi GBM Final Real-time Localization
  3. EP240708a: KAIT optical upper limit
  4. Fermi GRB 240710A: Global MASTER-Net observations report
  5. GRB 240710A: Fermi GBM Final Real-time Localization
  6. EP240708a: SVOM/C-GFT optical upper limit
  7. Fermi Gamma-ray Burst Monitor trigger 741911057/240705933 is not a GRB
  8. GRB 240705A: Fermi GBM Final Real-time Localization
  9. Konus-Wind detection of GRB 240627A
  10. IPN triangulation of GRB 240628B (short)
  11. EP240703a: KAIT optical upper limit
  12. EP240703a: BTA observations
  13. EP240703a/GRB 240703A: TRT optical candidate likely not real
  14. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  15. IPN triangulation of GRB 240627A
  16. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  17. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  18. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  19. The first three GRBs detected by SVOM: GRB 240627B, GRB 240629A and GRB 240702A
  20. GRB 240702A: BALROG localization (Fermi Trigger / GRB 240702885)
  21. Fermi GRB 240702A: Global MASTER-Net observations report
  22. GRB 240702A: Fermi GBM Final Real-time Localization
  23. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  24. Fermi Gamma-ray Burst Monitor trigger 741448122/240630575 is not a GRB
  25. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  26. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  27. Fermi GRB 240629A: Global MASTER-Net observations report
  28. Fermi Gamma-ray Burst Monitor trigger 741362867/240629589 is not a GRB
  29. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  30. GRB 240629A: BALROG localization (Fermi Trigger 741372837 / GRB 240629704)
  31. GRB 240629A: Fermi GBM Final Real-time Localization
  32. Fermi Gamma-ray Burst Monitor trigger 741356809/240629519 is not a GRB
  33. IPN triangulation of GRB 240619C
  34. GRB 240628A: BALROG localization (Fermi Trigger 741288821 / GRB 240628732)
  35. GRB 240627A: NuSTAR Detection of the long GRB
  36. GRB 240615A: SAI CMO J- band observations
  37. GRB 240627A: AstroSat CZTI detection
  38. EP240626a: Montarrenti Observatory optical upper limit
  39. EP240626a: KAIT optical upper limit
  40. GRB 240624A: Swift-BAT refined analysis
  41. Konus-Wind detection of GRB 240619A
  42. Fermi GRB 240625B: Global MASTER-Net observations report
  43. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  44. GRB 240625B: Fermi GBM Final Real-time Localization
  45. GRB 240625A: Fermi GBM Observation
  46. GRB 240624B: GRBAlpha detection
  47. GRB 240625A: Fermi GBM Final Real-time Localization
  48. GRB240624A: Fermi GBM Observation
  49. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  50. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  51. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  52. Swift GRB 240624A: Global MASTER-Net observations report
  53. GRB240615A: Gemini-North observations of the BAT and XRT positions
  54. Fermi GRB 240624A: Global MASTER-Net observations report
  55. GRB 240624B: Fermi GBM Final Real-time Localization
  56. GRB240615A: Gemini-North observations of the BAT and XRT positions
  57. GRB 240624A: Fermi GBM Final Real-time Localization
  58. GRB 240619A: detection of a radio counterpart with AMI-LA
  59. GRB 240624A: Swift detection of a burst
  60. GRB 240619A: J-band detection with WINTER (duplicate submission of GCN 36739)
  61. GRB 240619A: J-band detection with WINTER
  62. EP240618a: NOT optical counterpart candidate
  63. GRB 240529A: JinShan optical observations
  64. IPN triangulation of GRB 240615A (short)
  65. GRB 240619A: GRBAlpha detection
  66. GRB 240619A: Swift-XRT probable afterglow detection
  67. GRB 240619A: Swift ToO observations
  68. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  69. GRB 240619C: NuSTAR automated detection of the GRB
  70. GRB 240619A: Fermi GBM Observation
  71. Fermi GBM Sub-Threshold Detection of GRB 240619C
  72. GRB 240619A: GOTO candidate optical afterglow
  73. EP240618a: Abastumani optical observationsEP240618a
  74. GRB 240615A: NOT optical observations
  75. GRB 240619C: AstroSat CZTI detection
  76. Fermi GRB 240619A: Global MASTER-Net observations report
  77. EP240617a: STEP/T80S optical limits
  78. GRB 240615A: possible transient detection from Wendelstein observations
  79. Fermi Gamma-ray Burst Monitor trigger 740474239/240619304 is not a GRB
  80. GRB 240619B: Fermi GBM Final Real-time Localization
  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 GRB 240616A: Global MASTER-Net observations report
  94. Konus-Wind detection of GRB 240615A (short/hard)
  95. GRB 240615A: GOTO optical upper limits
  96. GRB 240616A: Fermi GBM Final Real-time Localization
  97. GRB 240615A: Swift ToO observations
  98. GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
  99. GRB 240615A: Fermi GBM Final Real-time Localization
  100. GRB 240603A: VZLUSAT-2 detection

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