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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"

39175 results found.

  1. GRB 241006A: VIRT Optical Upper Limit
  2. GRB 240727A: VIRT Optical Upper Limit
  3. GRB 241018A: X-ray afterglow candidate observed by MXT
  4. GRB 241016B: Fermi GBM Observations
  5. GRB 241018A: Detection of a bright long GRB by SVOM
  6. GRB 241017A: Swift-XRT observations
  7. GRB 241001A: EP-FXT afterglow detection
  8. GRB 241017A: GROWTH-India Telescope optical upper limit
  9. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  10. GRB 241017A: J-band upper limit from WINTER
  11. Fermi trigger No 750788395: Global MASTER-Net observations report
  12. GRB 241016B: SVOM/GRM observation
  13. GRB241016C: Fermi GBM Final Localization
  14. Fermi Gamma-ray Burst Monitor trigger 750792698/241016730 is not a GRB
  15. GRB 241017A: Swift ToO observations
  16. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  17. Fermi GRB 241016B: Global MASTER-Net observations report
  18. GRB 241016B: Fermi GBM Final Localization
  19. Fermi GRB 241016A: Global MASTER-Net observations report
  20. GRB 241016A: Fermi GBM Final Real-time Localization
  21. IceCube Alert 241016.04: Global MASTER-Net observations report
  22. GRB 241010A: Swift-BAT refined analysis
  23. GRB 241013B: Fermi GBM Observation
  24. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  25. GRB 241013A: Fermi GBM Observation
  26. GRB 240916A: radio detection with the VLA
  27. GRB241013A: REM observations
  28. GRB 241009A: LCO optical upper limits
  29. GRB 241013B: SVOM/GRM observation
  30. Fermi GRB 241013B: Global MASTER-Net observations report
  31. Integral GRB241013.04: Global MASTER-Net observations report
  32. GRB 241013B: Fermi GBM Final Real-time Localization
  33. GRB 241013A: a long GRB detected by INTEGRAL
  34. GRB 241013A: Fermi GBM Final Real-time Localization
  35. Fermi Gamma-ray Burst Monitor GRB trigger 750372658/241011869 (GRB 241011A) is not a GRB
  36. GRB 241011A: Fermi GBM Final Real-time Localization
  37. GRB 241009A: GRANDMA optical upper limits
  38. GRB 241009A: Swift-XRT afterglow detection
  39. GRB 241010A: JinShan optical observations and potential host galaxy
  40. GRB 241006A: ATCA Radio Upper Limits
  41. GRB 241010A: Swift-XRT refined Analysis
  42. Fermi trigger No 750211959: Global MASTER-Net observations report
  43. Fermi Gamma-ray Burst Monitor trigger 750303285/241011066 is not a GRB
  44. Fermi Gamma-ray Burst Monitor trigger 750291012/241010924 is not a GRB
  45. Swift GRB 241010A: Global MASTER-Net observations report
  46. Fermi trigger No 750291012: Global MASTER-Net observations report
  47. GRB 241010A: J-band observations with WINTER
  48. Fermi GRB 241010B: Global MASTER-Net observations report
  49. GRB 241010B: Fermi GBM Final Real-time Localization
  50. GRB 241010A: Enhanced Swift-XRT position
  51. GRB 241010A: LCO optical observations
  52. GRB 241010A: Swift detection of a burst with an optical counterpart
  53. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  54. GRB 241006A: Swift-BAT refined analysis
  55. GRB 241009A: Swift ToO observations
  56. GRB 241009A : Detection of a long duration GRB by SVOM/ECLAIRs
  57. GRB 241008A: Fermi GBM Observation
  58. GRB 241008A: Fermi-LAT detection
  59. GRB 241002B: Swift-XRT afterglow detection
  60. GRB 241002A: NOT optical upper limits
  61. Fermi GRB 241008A: Global MASTER-Net observations report
  62. GRB 241008A: BALROG localization (Fermi Trigger 750117609 / GRB 241008917)
  63. GRB 241008A: Fermi GBM Final Real-time Localization
  64. GRB 241006A: GRANDMA optical upper limits
  65. EP240930a / GRB 240930B: CrAO ZTSH optical upper limit
  66. GRB 241002B: PRIME near-infrared detection in 3rd epoch
  67. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  68. GRB 240910A: LBT optical observations
  69. EP trigger ID 01709065118: KAIT confirmation of the stellar flare
  70. GRB 241006A: Swift-XRT refined Analysis
  71. GRB 240821A: Host galaxy redshift from VLT/X-shooter
  72. GRB 241006A: PRIME near-infrared upper limits
  73. GRB 241006A: Swift/UVOT Upper Limits
  74. GRB 241006A: SVOM/VT follow-up and optical upper limit
  75. IceCube Alert 241006.94: Global MASTER-Net observations report
  76. GRB 241001A: Swift-XRT afterglow detection
  77. GRB 241006A: Enhanced Swift-XRT position
  78. GRB 241006A: Swift detection of a burst
  79. Swift GRB241006.91: Global MASTER-Net observations report
  80. GRB 240930B: SVOM/C-GFT optical upper limit
  81. Fermi trigger No 749721670: Global MASTER-Net observations report
  82. GRB 241004A: SVOM/GRM observation
  83. EP trigger ID 01709065118: the X-ray transient is likely a stellar flare event
  84. GRB 240930B / EP 240930a: SVOM/GRM observation
  85. GRB 241001A : ECLAIRs spectral analysis and XRF classification
  86. GRB 241002B: PRIME near-infrared detection in 2nd epoch
  87. GRB 241002B: Fermi GBM Observation
  88. Fermi trigger No 749735279: Global MASTER-Net observations report
  89. Fermi trigger No 749630753: Global MASTER-Net observations report
  90. Fermi trigger No 749693019: Global MASTER-Net observations report
  91. GRB 241002B: Swift-XRT observations
  92. GRB 241002C: SVOM/C-GFT optical upper limit
  93. GRB 241002A: Swift-BAT refined analysis
  94. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  95. GRB 241002B: Swift ToO observations
  96. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  97. Konus-Wind detection of GRB 240926A
  98. GRB 241002B: PRIME near-infrared detection
  99. GRB 241002C: Swift ToO observations
  100. Fermi-GBM Sub-Threshold Detection of GRB 241002D

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