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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"

36784 results found.

  1. EP241021a: SAO RAS optical observations
  2. EP241021a: KAIT optical observations
  3. IPN triangulation of GRB 241021A (long)
  4. GRB 241018A: SVOM/C-GFT optical observations
  5. GRB241017A: 1.3m DFOT optical upper limit
  6. GRB 241018A: 1.3m DFOT Optical upper limit
  7. GRB 241018A: EP-FXT afterglow detection
  8. Konus-Wind detection of GRB 241018A
  9. GRB 241018A: SVOM/GRM observation
  10. GRB 241018A/sb24101802: Mephisto optical upper limit
  11. GRB 241017A/sb24101702: Mephisto optical upper limit
  12. GRB 241018A: BOOTES-4/MET optical upper limit
  13. GRB 241018A: Mondy optical upper limit
  14. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  15. GRB 241018A: GROWTH-India telescope optical upper limit
  16. GRB 241018A: Swift-XRT observations
  17. GRB 241018A: REM optical/NIR upper limits
  18. GRB 241018A: NOT optical observations
  19. GRB 241017A: SVOM/VT follow-up and optical upper limit
  20. GRB 241018A: SVOM/VT follow-up and optical candidate
  21. GRB 241018A: LCO/0.4m optical upper limits
  22. GRB 241018A: Swift ToO observations
  23. GRB 241006A: VIRT Optical Upper Limit
  24. GRB 240727A: VIRT Optical Upper Limit
  25. GRB 241018A: X-ray afterglow candidate observed by MXT
  26. GRB 241016B: Fermi GBM Observations
  27. GRB 241018A: Detection of a bright long GRB by SVOM
  28. GRB 241017A: Swift-XRT observations
  29. GRB 241001A: EP-FXT afterglow detection
  30. GRB 241017A: GROWTH-India Telescope optical upper limit
  31. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  32. GRB 241017A: J-band upper limit from WINTER
  33. Fermi trigger No 750788395: Global MASTER-Net observations report
  34. GRB 241016B: SVOM/GRM observation
  35. GRB241016C: Fermi GBM Final Localization
  36. Fermi Gamma-ray Burst Monitor trigger 750792698/241016730 is not a GRB
  37. GRB 241017A: Swift ToO observations
  38. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  39. Fermi GRB 241016B: Global MASTER-Net observations report
  40. GRB 241016B: Fermi GBM Final Localization
  41. Fermi GRB 241016A: Global MASTER-Net observations report
  42. GRB 241016A: Fermi GBM Final Real-time Localization
  43. GRB 241010A: Swift-BAT refined analysis
  44. GRB 241013B: Fermi GBM Observation
  45. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  46. GRB 241013A: Fermi GBM Observation
  47. GRB 240916A: radio detection with the VLA
  48. GRB241013A: REM observations
  49. GRB 241009A: LCO optical upper limits
  50. GRB 241013B: SVOM/GRM observation
  51. Fermi GRB 241013B: Global MASTER-Net observations report
  52. GRB 241013B: Fermi GBM Final Real-time Localization
  53. GRB 241013A: a long GRB detected by INTEGRAL
  54. GRB 241013A: Fermi GBM Final Real-time Localization
  55. Fermi Gamma-ray Burst Monitor GRB trigger 750372658/241011869 (GRB 241011A) is not a GRB
  56. GRB 241011A: Fermi GBM Final Real-time Localization
  57. GRB 241009A: GRANDMA optical upper limits
  58. GRB 241009A: Swift-XRT afterglow detection
  59. GRB 241010A: JinShan optical observations and potential host galaxy
  60. GRB 241006A: ATCA Radio Upper Limits
  61. GRB 241010A: Swift-XRT refined Analysis
  62. Fermi trigger No 750211959: Global MASTER-Net observations report
  63. Fermi Gamma-ray Burst Monitor trigger 750303285/241011066 is not a GRB
  64. Fermi Gamma-ray Burst Monitor trigger 750291012/241010924 is not a GRB
  65. Swift GRB 241010A: Global MASTER-Net observations report
  66. Fermi trigger No 750291012: Global MASTER-Net observations report
  67. GRB 241010A: J-band observations with WINTER
  68. Fermi GRB 241010B: Global MASTER-Net observations report
  69. GRB 241010B: Fermi GBM Final Real-time Localization
  70. GRB 241010A: Enhanced Swift-XRT position
  71. GRB 241010A: LCO optical observations
  72. GRB 241010A: Swift detection of a burst with an optical counterpart
  73. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  74. GRB 241006A: Swift-BAT refined analysis
  75. GRB 241009A: Swift ToO observations
  76. GRB 241009A : Detection of a long duration GRB by SVOM/ECLAIRs
  77. GRB 241008A: Fermi GBM Observation
  78. GRB 241008A: Fermi-LAT detection
  79. GRB 241002B: Swift-XRT afterglow detection
  80. GRB 241002A: NOT optical upper limits
  81. Fermi GRB 241008A: Global MASTER-Net observations report
  82. GRB 241008A: BALROG localization (Fermi Trigger 750117609 / GRB 241008917)
  83. GRB 241008A: Fermi GBM Final Real-time Localization
  84. GRB 241006A: GRANDMA optical upper limits
  85. EP240930a / GRB 240930B: CrAO ZTSH optical upper limit
  86. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  87. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  88. GRB 240910A: LBT optical observations
  89. EP trigger ID 01709065118: KAIT confirmation of the stellar flare
  90. GRB 241006A: Swift-XRT refined Analysis
  91. GRB 240821A: Host galaxy redshift from VLT/X-shooter
  92. GRB 241006A: PRIME near-infrared upper limits
  93. GRB 241006A: Swift/UVOT Upper Limits
  94. GRB 241006A: SVOM/VT follow-up and optical upper limit
  95. GRB 241001A: Swift-XRT afterglow detection
  96. GRB 241006A: Enhanced Swift-XRT position
  97. IceCube-241006A - IceCube observation of a high-energy neutrino candidate track-like event
  98. GRB 241006A: Swift detection of a burst
  99. GRB 240930B: SVOM/C-GFT optical upper limit
  100. Fermi trigger No 749721670: Global MASTER-Net observations report

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