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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"

32140 results found.

  1. GRB 240712A ATCA radio observations
  2. GRB240715A: GRANDMA Optical Upper Limits
  3. IPN triangulation of GRB 240715A (short)
  4. GRB 240712A: Swift/UVOT Upper Limits
  5. GRB 240715A: Fermi GBM Final Real-time Localization
  6. GRB 240713A: Tiled Swift observations
  7. GRB 240713A: J-band upper limit from WINTER
  8. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  9. GRB 240713A: JinShan optical upper limits
  10. GRB 240713A: OHP/T120 optical upper limit
  11. GRB240713A: X-ray follow-up observation with EP-FXT
  12. GRB 240713B: AstroSat CZTI detection of a long burst
  13. Fermi Sub-threshold Observation of GRB240713A
  14. GRB240713A : The first probable GRB Located on-Board SVOM by ECLAIRs
  15. Fermi Gamma-ray Burst Monitor trigger 742413075/240711744 is not a GRB
  16. GRB 240712A: Swift detection of a burst
  17. GRB 240711A: Fermi GBM Final Real-time Localization
  18. EP240708a: KAIT optical upper limit
  19. Fermi GRB 240710A: Global MASTER-Net observations report
  20. GRB 240710A: Fermi GBM Final Real-time Localization
  21. EP240708a: SVOM/C-GFT optical upper limit
  22. Fermi Gamma-ray Burst Monitor trigger 741911057/240705933 is not a GRB
  23. GRB 240705A: Fermi GBM Final Real-time Localization
  24. Konus-Wind detection of GRB 240627A
  25. IPN triangulation of GRB 240628B (short)
  26. EP240703a: KAIT optical upper limit
  27. EP240703a: BTA observations
  28. EP240703a/GRB 240703A: TRT optical candidate likely not real
  29. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  30. IPN triangulation of GRB 240627A
  31. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  32. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  33. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  34. The first three GRBs detected by SVOM: GRB 240627B, GRB 240629A and GRB 240702A
  35. GRB 240702A: BALROG localization (Fermi Trigger / GRB 240702885)
  36. Fermi GRB 240702A: Global MASTER-Net observations report
  37. GRB 240702A: Fermi GBM Final Real-time Localization
  38. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  39. Fermi Gamma-ray Burst Monitor trigger 741448122/240630575 is not a GRB
  40. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  41. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  42. Fermi GRB 240629A: Global MASTER-Net observations report
  43. Fermi Gamma-ray Burst Monitor trigger 741362867/240629589 is not a GRB
  44. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  45. GRB 240629A: BALROG localization (Fermi Trigger 741372837 / GRB 240629704)
  46. GRB 240629A: Fermi GBM Final Real-time Localization
  47. Fermi Gamma-ray Burst Monitor trigger 741356809/240629519 is not a GRB
  48. IPN triangulation of GRB 240619C
  49. GRB 240628A: BALROG localization (Fermi Trigger 741288821 / GRB 240628732)
  50. GRB 240627A: NuSTAR Detection of the long GRB
  51. GRB 240615A: SAI CMO J- band observations
  52. GRB 240627A: AstroSat CZTI detection
  53. EP240626a: Montarrenti Observatory optical upper limit
  54. EP240626a: KAIT optical upper limit
  55. GRB 240624A: Swift-BAT refined analysis
  56. Konus-Wind detection of GRB 240619A
  57. Fermi GRB 240625B: Global MASTER-Net observations report
  58. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  59. GRB 240625B: Fermi GBM Final Real-time Localization
  60. GRB 240625A: Fermi GBM Observation
  61. GRB 240624B: GRBAlpha detection
  62. GRB 240625A: Fermi GBM Final Real-time Localization
  63. GRB240624A: Fermi GBM Observation
  64. LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
  65. LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
  66. LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
  67. Swift GRB 240624A: Global MASTER-Net observations report
  68. GRB240615A: Gemini-North observations of the BAT and XRT positions
  69. Fermi GRB 240624A: Global MASTER-Net observations report
  70. GRB 240624B: Fermi GBM Final Real-time Localization
  71. GRB240615A: Gemini-North observations of the BAT and XRT positions
  72. GRB 240624A: Fermi GBM Final Real-time Localization
  73. GRB 240619A: detection of a radio counterpart with AMI-LA
  74. GRB 240624A: Swift detection of a burst
  75. GRB 240619A: J-band detection with WINTER (duplicate submission of GCN 36739)
  76. GRB 240619A: J-band detection with WINTER
  77. EP240618a: NOT optical counterpart candidate
  78. GRB 240529A: JinShan optical observations
  79. IPN triangulation of GRB 240615A (short)
  80. GRB 240619A: GRBAlpha detection
  81. GRB 240619A: Swift-XRT probable afterglow detection
  82. GRB 240619A: Swift ToO observations
  83. GRB 240619A: CALET Gamma-Ray Burst Monitor detection
  84. GRB 240619C: NuSTAR automated detection of the GRB
  85. GRB 240619A: Fermi GBM Observation
  86. Fermi GBM Sub-Threshold Detection of GRB 240619C
  87. GRB 240619A: GOTO candidate optical afterglow
  88. EP240618a: Abastumani optical observationsEP240618a
  89. GRB 240615A: NOT optical observations
  90. GRB 240619C: AstroSat CZTI detection
  91. Fermi GRB 240619A: Global MASTER-Net observations report
  92. GRB 240615A: possible transient detection from Wendelstein observations
  93. Fermi Gamma-ray Burst Monitor trigger 740474239/240619304 is not a GRB
  94. GRB 240619B: Fermi GBM Final Real-time Localization
  95. GRB240615A: 1.3m DFOT optical upper limit
  96. GRB 240619A: BALROG localization (Fermi Trigger 740461416 / GRB 240619155)
  97. GRB 240619A: Fermi GBM Final Real-time Localization
  98. EP240617a: BOOTES-6/DPRT optical upper limit
  99. EP240617a is likely a GRB event
  100. LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO

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