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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"

32155 results found.

  1. Fermi Gamma-ray Burst Monitor trigger 745220784/240813240 is not a GRB
  2. GRB 240809A: Correction to the VLA source position in GCN 37158
  3. GRB 240810A: SVOM/GRM observation
  4. Fermi Gamma-ray Burst Monitor trigger 240812940/745194848 is not a GRB
  5. Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
  6. Fermi Gamma-ray Burst Monitor trigger 240812917/745192855 is not a GRB
  7. GRB 240809A: ATA radio non-detection
  8. GRB 240812D: Fermi GBM Final Real-time Localization
  9. GRB 240812C: Fermi GBM Final Real-time Localization
  10. GRB 240809A : RAPAS follow-up observations
  11. GRB 240809A: VLA detection
  12. GRB 240809A: ALMA detection
  13. IPN triangulation of GRB 240810A (short)
  14. GRB 240811A: Swift-BAT refined analysis
  15. GRB 240809A: Swift-BAT refined analysis
  16. GRB 240812B: AstroSat CZTI detection of a long burst
  17. GRB 240811A: Bassano Bresciano Observatory upper limit
  18. GRB 240811A: Swift-XRT refined Analysis
  19. Fermi Gamma-ray Burst Monitor trigger 745135620/240812255 is not a GRB
  20. GRB 240811A: Swift/UVOT Upper Limits
  21. EP240801a: Assy-Turgen optical observations
  22. Fermi GRB 240810A: Global MASTER-Net observations report
  23. Fermi Gamma-ray Burst Monitor trigger 240812094/745121685 is not a GRB
  24. GRB 240812A: Fermi GBM Final Real-time Localization
  25. GRB 240811A: LCOGT Optical Upper Limit
  26. GRB 240811A: Enhanced Swift-XRT position
  27. GRB 240811A: Upper limits with Mephisto
  28. Konus-Wind detection of GRB 240809A
  29. Swift GRB 240811A: Global MASTER-Net observations report
  30. GRB 240811A: Swift detection of a burst
  31. Fermi Gamma-ray Burst Monitor trigger 745050426/240811269 is not a GRB
  32. GRB 240810A: Fermi GBM Final Real-time Localization
  33. GRB 240809A: REM detection of the optical afterglow
  34. GRB 240809A: Bassano Bresciano Observatory optical observations
  35. Konus-Wind detection of GRB 240807A (a counterpart of EP240807a)
  36. GRB 240809A: Conclusive redshift from VLT
  37. GRB 240809A: KAIT optical observations
  38. GRB 240808A: AstroSat CZTI detection
  39. GRB 240809A: GIT afterglow observations
  40. GRB 240809B: MAXI/GSC detection
  41. GRB 240809A: Swift/UVOT Detection
  42. GRB 240809A: Tentative redshift from NOT
  43. GRB 240809A: Swift-XRT refined Analysis
  44. IPN triangulation of GRB 240807A / EP 240807a
  45. Swift GRB 240809A: Global MASTER-Net observations report
  46. GRB 240809A: JinShan optical observations
  47. GRB 240809A: Enhanced Swift-XRT position
  48. GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
  49. GRB 240809A: SVOM/GRM observation
  50. GRB 240808A: SVOM/GRM observation
  51. GRB 240807A: SVOM/GRM observation
  52. GRB 240809A: Swift detection of a burst with a bright optical counterpart
  53. EP-WXT trigger 01709018832: SVOM/C-GFT observations of the star flare
  54. GRB 240807B: AstroSat CZTI detection of a short burst
  55. GRB 240801A: GRBAlpha detection
  56. GRB 240807B: Fermi GBM Final Localization
  57. GRB 240710B: VZLUSAT-2 detection
  58. GRB 240805A: ATCA Radio Upper Limits
  59. EP240807a/GRB 240807A: EP-FXT detection of the X-ray emission
  60. EP-WXT trigger 01709018832: KAIT optical observations of the star flare
  61. EP240802a/GRB240802A: KAIT optical upper limit
  62. GRB 240720B: VZLUSAT-2 detection
  63. GRB 240710A: VZLUSAT-2 detection
  64. GRB 240807A: Fermi GBM Final Localization
  65. GRB 240805B: GIT optical upper limit
  66. EP240806a: KAIT optical observations
  67. GRB 240805B: Swift-BAT refined analysis
  68. GRB 240805A: Swift-BAT refined analysis
  69. EP240804a (GRB 240804B): NOT optical observations
  70. Konus-Wind detection of GRB 240802A (EP240802a)
  71. Improved IPN triangulation of GRB 240802A / EP 240802a
  72. Konus-Wind detection of GRB 240805A
  73. GRB 240805B Bassano Bresciano Observatory upper limit
  74. GRB240805A: Fermi GBM Observation
  75. GRB 240805B: JinShan optical afterglow detection
  76. GRB 240804B/EP240804a: Correction to the GRB name in GCN 37071
  77. GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
  78. Konus-Wind detection of GRB 240804B (a counterpart of EP240804a)
  79. Fermi Gamma-ray Burst Monitor trigger 240806402/744629911 is not a GRB
  80. GRB 240626B: VZLUSAT-2 detection
  81. GRB 240624B: VZLUSAT-2 detection
  82. GRB 240619C: VZLUSAT-2 detection
  83. EP 240806A: LCO optical observations
  84. GRB 240805B: Optical detection with 1.6m Mephisto
  85. GRB 240805B: NUTTelA-TAO / BSTI Optical Limits
  86. GRB 240805B: Swift-XRT refined Analysis
  87. GRB 240805B: Swift/UVOT Upper Limits
  88. GRB 240805A: Swift/UVOT Upper Limits
  89. GRB 240805B: BTA optical afterglow candidate
  90. GRB 240805A: SVOM/GRM observation
  91. GRB 240805B: Enhanced Swift-XRT position
  92. GRB 240805B: LCOGT Optical Upper Limits
  93. Swift GRB 240805B: Global MASTER-Net observations report
  94. GRB 240805B: JinShan optical upper limits
  95. Fermi GRB 240805A: Global MASTER-Net observations report
  96. Swift GRB 240805A: Global MASTER-Net observations report
  97. Fermi Gamma-ray Burst Monitor trigger 744558410/240805574 is not a GRB
  98. GRB 240805A: Swift-XRT refined Analysis
  99. GRB 240805B: Swift detection of a burst
  100. GRB 240805A: Fermi-LAT detection

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