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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"

35427 results found.

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

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