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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"

36144 results found.

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

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