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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"

35321 results found.

  1. GRB240713A : The first probable GRB Located on-Board SVOM by ECLAIRs
  2. Fermi Gamma-ray Burst Monitor trigger 742413075/240711744 is not a GRB
  3. GRB 240712A: Swift detection of a burst
  4. GRB 240711A: Fermi GBM Final Real-time Localization
  5. EP240708a: KAIT optical upper limit
  6. Fermi GRB 240710A: Global MASTER-Net observations report
  7. GRB 240710A: Fermi GBM Final Real-time Localization
  8. EP240708a: SVOM/C-GFT optical upper limit
  9. Fermi Gamma-ray Burst Monitor trigger 741911057/240705933 is not a GRB
  10. GRB 240705A: Fermi GBM Final Real-time Localization
  11. Konus-Wind detection of GRB 240627A
  12. IPN triangulation of GRB 240628B (short)
  13. EP240703a: KAIT optical upper limit
  14. EP240703a: BTA observations
  15. EP240703a/GRB 240703A: TRT optical candidate likely not real
  16. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  17. IPN triangulation of GRB 240627A
  18. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  19. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  20. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  21. The first three GRBs detected by SVOM: GRB 240627B, GRB 240629A and GRB 240702A
  22. GRB 240702A: BALROG localization (Fermi Trigger / GRB 240702885)
  23. Fermi GRB 240702A: Global MASTER-Net observations report
  24. GRB 240702A: Fermi GBM Final Real-time Localization
  25. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  26. Fermi Gamma-ray Burst Monitor trigger 741448122/240630575 is not a GRB
  27. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  28. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  29. Fermi GRB 240629A: Global MASTER-Net observations report
  30. Fermi Gamma-ray Burst Monitor trigger 741362867/240629589 is not a GRB
  31. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  32. GRB 240629A: BALROG localization (Fermi Trigger 741372837 / GRB 240629704)
  33. GRB 240629A: Fermi GBM Final Real-time Localization
  34. Fermi Gamma-ray Burst Monitor trigger 741356809/240629519 is not a GRB
  35. IPN triangulation of GRB 240619C
  36. GRB 240628A: BALROG localization (Fermi Trigger 741288821 / GRB 240628732)
  37. GRB 240627A: NuSTAR Detection of the long GRB
  38. GRB 240615A: SAI CMO J- band observations
  39. GRB 240627A: AstroSat CZTI detection
  40. EP240626a: Montarrenti Observatory optical upper limit
  41. EP240626a: KAIT optical upper limit
  42. GRB 240624A: Swift-BAT refined analysis
  43. Konus-Wind detection of GRB 240619A
  44. Fermi GRB 240625B: Global MASTER-Net observations report
  45. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  46. GRB 240625B: Fermi GBM Final Real-time Localization
  47. GRB 240625A: Fermi GBM Observation
  48. GRB 240624B: GRBAlpha detection
  49. GRB 240625A: Fermi GBM Final Real-time Localization
  50. GRB240624A: Fermi GBM Observation
  51. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  52. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  53. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  54. Swift GRB 240624A: Global MASTER-Net observations report
  55. GRB240615A: Gemini-North observations of the BAT and XRT positions
  56. Fermi GRB 240624A: Global MASTER-Net observations report
  57. GRB 240624B: Fermi GBM Final Real-time Localization
  58. GRB240615A: Gemini-North observations of the BAT and XRT positions
  59. GRB 240624A: Fermi GBM Final Real-time Localization
  60. GRB 240619A: detection of a radio counterpart with AMI-LA
  61. GRB 240624A: Swift detection of a burst
  62. GRB 240619A: J-band detection with WINTER (duplicate submission of GCN 36739)
  63. GRB 240619A: J-band detection with WINTER
  64. EP240618a: NOT optical counterpart candidate
  65. GRB 240529A: JinShan optical observations
  66. IPN triangulation of GRB 240615A (short)
  67. GRB 240619A: GRBAlpha detection
  68. GRB 240619A: Swift-XRT probable afterglow detection
  69. GRB 240619A: Swift ToO observations
  70. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  71. GRB 240619C: NuSTAR automated detection of the GRB
  72. GRB 240619A: Fermi GBM Observation
  73. Fermi GBM Sub-Threshold Detection of GRB 240619C
  74. GRB 240619A: GOTO candidate optical afterglow
  75. EP240618a: Abastumani optical observationsEP240618a
  76. GRB 240615A: NOT optical observations
  77. GRB 240619C: AstroSat CZTI detection
  78. Fermi GRB 240619A: Global MASTER-Net observations report
  79. EP240617a: STEP/T80S optical limits
  80. GRB 240615A: possible transient detection from Wendelstein observations
  81. Fermi Gamma-ray Burst Monitor trigger 740474239/240619304 is not a GRB
  82. GRB 240619B: Fermi GBM Final Real-time Localization
  83. GRB240615A: 1.3m DFOT optical upper limit
  84. GRB 240619A: BALROG localization (Fermi Trigger 740461416 / GRB 240619155)
  85. GRB 240619A: Fermi GBM Final Real-time Localization
  86. EP240617a: BOOTES-6/DPRT optical upper limit
  87. EP240617a is likely a GRB event
  88. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  89. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  90. GRB 240615A: J-band upper limits from WINTER
  91. GRB 240615A: Fermi GBM Observation
  92. GRB 240615A: Swift-XRT observations
  93. GRB 240615A: GECAM detection
  94. GRB 240615A: FLWO-1.2m optical upper limits
  95. Fermi GRB 240616A: Global MASTER-Net observations report
  96. Konus-Wind detection of GRB 240615A (short/hard)
  97. GRB 240615A: GOTO optical upper limits
  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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