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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"

36132 results found.

  1. GRB 240712A: Swift/UVOT Upper Limits
  2. GRB 240715A: Fermi GBM Final Real-time Localization
  3. GRB 240713A: Tiled Swift observations
  4. GRB 240713A: J-band upper limit from WINTER
  5. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  6. GRB 240713A: JinShan optical upper limits
  7. GRB 240713A: OHP/T120 optical upper limit
  8. GRB240713A: X-ray follow-up observation with EP-FXT
  9. GRB 240713B: AstroSat CZTI detection of a long burst
  10. Fermi Sub-threshold Observation of GRB240713A
  11. GRB240713A : The first probable GRB Located on-Board SVOM by ECLAIRs
  12. Fermi Gamma-ray Burst Monitor trigger 742413075/240711744 is not a GRB
  13. GRB 240712A: Swift detection of a burst
  14. GRB 240711A: Fermi GBM Final Real-time Localization
  15. EP240708a: KAIT optical upper limit
  16. Fermi GRB 240710A: Global MASTER-Net observations report
  17. GRB 240710A: Fermi GBM Final Real-time Localization
  18. EP240708a: SVOM/C-GFT optical upper limit
  19. Fermi Gamma-ray Burst Monitor trigger 741911057/240705933 is not a GRB
  20. GRB 240705A: Fermi GBM Final Real-time Localization
  21. Konus-Wind detection of GRB 240627A
  22. IPN triangulation of GRB 240628B (short)
  23. EP240703a: KAIT optical upper limit
  24. EP240703a: BTA observations
  25. EP240703a/GRB 240703A: TRT optical candidate likely not real
  26. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  27. IPN triangulation of GRB 240627A
  28. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  29. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  30. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  31. The first three GRBs detected by SVOM: GRB 240627B, GRB 240629A and GRB 240702A
  32. GRB 240702A: BALROG localization (Fermi Trigger / GRB 240702885)
  33. Fermi GRB 240702A: Global MASTER-Net observations report
  34. GRB 240702A: Fermi GBM Final Real-time Localization
  35. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  36. Fermi Gamma-ray Burst Monitor trigger 741448122/240630575 is not a GRB
  37. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  38. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  39. Fermi GRB 240629A: Global MASTER-Net observations report
  40. Fermi Gamma-ray Burst Monitor trigger 741362867/240629589 is not a GRB
  41. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  42. GRB 240629A: BALROG localization (Fermi Trigger 741372837 / GRB 240629704)
  43. GRB 240629A: Fermi GBM Final Real-time Localization
  44. Fermi Gamma-ray Burst Monitor trigger 741356809/240629519 is not a GRB
  45. IPN triangulation of GRB 240619C
  46. GRB 240628A: BALROG localization (Fermi Trigger 741288821 / GRB 240628732)
  47. GRB 240627A: NuSTAR Detection of the long GRB
  48. GRB 240615A: SAI CMO J- band observations
  49. GRB 240627A: AstroSat CZTI detection
  50. EP240626a: Montarrenti Observatory optical upper limit
  51. EP240626a: KAIT optical upper limit
  52. GRB 240624A: Swift-BAT refined analysis
  53. Konus-Wind detection of GRB 240619A
  54. Fermi GRB 240625B: Global MASTER-Net observations report
  55. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  56. GRB 240625B: Fermi GBM Final Real-time Localization
  57. GRB 240625A: Fermi GBM Observation
  58. GRB 240624B: GRBAlpha detection
  59. GRB 240625A: Fermi GBM Final Real-time Localization
  60. GRB240624A: Fermi GBM Observation
  61. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  62. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  63. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  64. Swift GRB 240624A: Global MASTER-Net observations report
  65. GRB240615A: Gemini-North observations of the BAT and XRT positions
  66. Fermi GRB 240624A: Global MASTER-Net observations report
  67. GRB 240624B: Fermi GBM Final Real-time Localization
  68. GRB240615A: Gemini-North observations of the BAT and XRT positions
  69. GRB 240624A: Fermi GBM Final Real-time Localization
  70. GRB 240619A: detection of a radio counterpart with AMI-LA
  71. GRB 240624A: Swift detection of a burst
  72. GRB 240619A: J-band detection with WINTER (duplicate submission of GCN 36739)
  73. GRB 240619A: J-band detection with WINTER
  74. EP240618a: NOT optical counterpart candidate
  75. GRB 240529A: JinShan optical observations
  76. IPN triangulation of GRB 240615A (short)
  77. GRB 240619A: GRBAlpha detection
  78. GRB 240619A: Swift-XRT probable afterglow detection
  79. GRB 240619A: Swift ToO observations
  80. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  81. GRB 240619C: NuSTAR automated detection of the GRB
  82. GRB 240619A: Fermi GBM Observation
  83. Fermi GBM Sub-Threshold Detection of GRB 240619C
  84. GRB 240619A: GOTO candidate optical afterglow
  85. EP240618a: Abastumani optical observationsEP240618a
  86. GRB 240615A: NOT optical observations
  87. GRB 240619C: AstroSat CZTI detection
  88. Fermi GRB 240619A: Global MASTER-Net observations report
  89. EP240617a: STEP/T80S optical limits
  90. GRB 240615A: possible transient detection from Wendelstein observations
  91. Fermi Gamma-ray Burst Monitor trigger 740474239/240619304 is not a GRB
  92. GRB 240619B: Fermi GBM Final Real-time Localization
  93. GRB240615A: 1.3m DFOT optical upper limit
  94. GRB 240619A: BALROG localization (Fermi Trigger 740461416 / GRB 240619155)
  95. GRB 240619A: Fermi GBM Final Real-time Localization
  96. EP240617a: BOOTES-6/DPRT optical upper limit
  97. EP240617a is likely a GRB event
  98. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
  99. LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
  100. GRB 240615A: J-band upper limits from WINTER

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