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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"

35326 results found.

  1. GRB 240713A: JinShan optical upper limits
  2. GRB 240713A: OHP/T120 optical upper limit
  3. GRB240713A: X-ray follow-up observation with EP-FXT
  4. GRB 240713B: AstroSat CZTI detection of a long burst
  5. Fermi Sub-threshold Observation of GRB240713A
  6. GRB240713A : The first probable GRB Located on-Board SVOM by ECLAIRs
  7. Fermi Gamma-ray Burst Monitor trigger 742413075/240711744 is not a GRB
  8. GRB 240712A: Swift detection of a burst
  9. GRB 240711A: Fermi GBM Final Real-time Localization
  10. EP240708a: KAIT optical upper limit
  11. Fermi GRB 240710A: Global MASTER-Net observations report
  12. GRB 240710A: Fermi GBM Final Real-time Localization
  13. EP240708a: SVOM/C-GFT optical upper limit
  14. Fermi Gamma-ray Burst Monitor trigger 741911057/240705933 is not a GRB
  15. GRB 240705A: Fermi GBM Final Real-time Localization
  16. Konus-Wind detection of GRB 240627A
  17. IPN triangulation of GRB 240628B (short)
  18. EP240703a: KAIT optical upper limit
  19. EP240703a: BTA observations
  20. EP240703a/GRB 240703A: TRT optical candidate likely not real
  21. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  22. IPN triangulation of GRB 240627A
  23. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  24. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  25. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  26. The first three GRBs detected by SVOM: GRB 240627B, GRB 240629A and GRB 240702A
  27. GRB 240702A: BALROG localization (Fermi Trigger / GRB 240702885)
  28. Fermi GRB 240702A: Global MASTER-Net observations report
  29. GRB 240702A: Fermi GBM Final Real-time Localization
  30. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  31. Fermi Gamma-ray Burst Monitor trigger 741448122/240630575 is not a GRB
  32. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  33. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  34. Fermi GRB 240629A: Global MASTER-Net observations report
  35. Fermi Gamma-ray Burst Monitor trigger 741362867/240629589 is not a GRB
  36. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  37. GRB 240629A: BALROG localization (Fermi Trigger 741372837 / GRB 240629704)
  38. GRB 240629A: Fermi GBM Final Real-time Localization
  39. Fermi Gamma-ray Burst Monitor trigger 741356809/240629519 is not a GRB
  40. IPN triangulation of GRB 240619C
  41. GRB 240628A: BALROG localization (Fermi Trigger 741288821 / GRB 240628732)
  42. GRB 240627A: NuSTAR Detection of the long GRB
  43. GRB 240615A: SAI CMO J- band observations
  44. GRB 240627A: AstroSat CZTI detection
  45. EP240626a: Montarrenti Observatory optical upper limit
  46. EP240626a: KAIT optical upper limit
  47. GRB 240624A: Swift-BAT refined analysis
  48. Konus-Wind detection of GRB 240619A
  49. Fermi GRB 240625B: Global MASTER-Net observations report
  50. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  51. GRB 240625B: Fermi GBM Final Real-time Localization
  52. GRB 240625A: Fermi GBM Observation
  53. GRB 240624B: GRBAlpha detection
  54. GRB 240625A: Fermi GBM Final Real-time Localization
  55. GRB240624A: Fermi GBM Observation
  56. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  57. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  58. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  59. Swift GRB 240624A: Global MASTER-Net observations report
  60. GRB240615A: Gemini-North observations of the BAT and XRT positions
  61. Fermi GRB 240624A: Global MASTER-Net observations report
  62. GRB 240624B: Fermi GBM Final Real-time Localization
  63. GRB240615A: Gemini-North observations of the BAT and XRT positions
  64. GRB 240624A: Fermi GBM Final Real-time Localization
  65. GRB 240619A: detection of a radio counterpart with AMI-LA
  66. GRB 240624A: Swift detection of a burst
  67. GRB 240619A: J-band detection with WINTER (duplicate submission of GCN 36739)
  68. GRB 240619A: J-band detection with WINTER
  69. EP240618a: NOT optical counterpart candidate
  70. GRB 240529A: JinShan optical observations
  71. IPN triangulation of GRB 240615A (short)
  72. GRB 240619A: GRBAlpha detection
  73. GRB 240619A: Swift-XRT probable afterglow detection
  74. GRB 240619A: Swift ToO observations
  75. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  76. GRB 240619C: NuSTAR automated detection of the GRB
  77. GRB 240619A: Fermi GBM Observation
  78. Fermi GBM Sub-Threshold Detection of GRB 240619C
  79. GRB 240619A: GOTO candidate optical afterglow
  80. EP240618a: Abastumani optical observationsEP240618a
  81. GRB 240615A: NOT optical observations
  82. GRB 240619C: AstroSat CZTI detection
  83. Fermi GRB 240619A: Global MASTER-Net observations report
  84. EP240617a: STEP/T80S optical limits
  85. GRB 240615A: possible transient detection from Wendelstein observations
  86. Fermi Gamma-ray Burst Monitor trigger 740474239/240619304 is not a GRB
  87. GRB 240619B: Fermi GBM Final Real-time Localization
  88. GRB240615A: 1.3m DFOT optical upper limit
  89. GRB 240619A: BALROG localization (Fermi Trigger 740461416 / GRB 240619155)
  90. GRB 240619A: Fermi GBM Final Real-time Localization
  91. EP240617a: BOOTES-6/DPRT optical upper limit
  92. EP240617a is likely a GRB event
  93. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  94. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  95. GRB 240615A: J-band upper limits from WINTER
  96. GRB 240615A: Fermi GBM Observation
  97. GRB 240615A: Swift-XRT observations
  98. GRB 240615A: GECAM detection
  99. GRB 240615A: FLWO-1.2m optical upper limits
  100. Fermi GRB 240616A: Global MASTER-Net observations report

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