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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"

38927 results found.

  1. GRB 241025B: Fermi GBM Final Localization
  2. Fermi trigger No 751563375: Global MASTER-Net observations report
  3. Fermi trigger No 751554401: Global MASTER-Net observations report
  4. EP 241021a: Swift-XRT observations
  5. Fermi GRB 241025A: Global MASTER-Net observations report
  6. Swift GRB 241025A: Global MASTER-Net observations report
  7. EP241025a (GRB 241025A): EP observations update
  8. GRB 241025A : SVOM/VT optical afterglow observations
  9. EP 241021A: Swift ToO observations
  10. GRB 241025A: Enhanced Swift-XRT position
  11. GRB 241001A: JWST spectroscopic identification of a supernova counterpart
  12. GRB 241025A: NOT spectroscopic redshift of z = 4.20
  13. GRB 241025A: DDOTI Afterglow detection
  14. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  15. GRB 241025A: SVOM/GRM observation
  16. GRB 241025A: TRT optical afterglow observation
  17. Fermi GRB 241024B: Global MASTER-Net observations report
  18. GRB 241025A: Fermi GBM Final Real-time Localization
  19. GRB 241025A: Swift detection of a burst with an optical counterpart
  20. GRB 241001A: ATCA radio observations
  21. GRB 241024B: Fermi GBM Final Localization
  22. EP241021a: No Detection in Fermi-GBM Observation
  23. GRB 241010A: VIRT Optical Upper Limit
  24. GRB 241024A: Fermi GBM Final Localisation
  25. EP241021a: VLT/FORS2 redshift z = 0.75
  26. Fermi trigger No 751449953: Global MASTER-Net observations report
  27. EP241021a: SAO RAS optical observations
  28. EP241021a: KAIT optical observations
  29. IPN triangulation of GRB 241021A (long)
  30. EP241021a: 1.3m DFOT Optical observations
  31. EP241021a: GSP detects optical candidate counterpart
  32. EP241021a: TRT optical observations
  33. GRB 241018A: SVOM/C-GFT optical observations
  34. EP EP241021a: Global MASTER-Net observations report
  35. GRB241017A: 1.3m DFOT optical upper limit
  36. GRB 241018A: 1.3m DFOT Optical upper limit
  37. GRB 241018A: EP-FXT afterglow detection
  38. Konus-Wind detection of GRB 241018A
  39. GRB 241018A: SVOM/GRM observation
  40. GRB 241018A/sb24101802: Mephisto optical upper limit
  41. GRB 241017A/sb24101702: Mephisto optical upper limit
  42. GRB 241018A: BOOTES-4/MET optical upper limit
  43. GRB 241018A: Mondy optical upper limit
  44. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  45. GRB 241018A: GROWTH-India telescope optical upper limit
  46. GRB 241018A: Swift-XRT observations
  47. GRB 241018A: REM optical/NIR upper limits
  48. GRB 241018A: NOT optical observations
  49. GRB 241017A: SVOM/VT follow-up and optical upper limit
  50. GRB 241018A: SVOM/VT follow-up and optical candidate
  51. GRB 241018A: LCO/0.4m optical upper limits
  52. GRB 241018A: Swift ToO observations
  53. GRB 241006A: VIRT Optical Upper Limit
  54. GRB 240727A: VIRT Optical Upper Limit
  55. GRB 241018A: X-ray afterglow candidate observed by MXT
  56. GRB 241016B: Fermi GBM Observations
  57. GRB 241018A: Detection of a bright long GRB by SVOM
  58. GRB 241017A: Swift-XRT observations
  59. GRB 241001A: EP-FXT afterglow detection
  60. GRB 241017A: GROWTH-India Telescope optical upper limit
  61. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  62. GRB 241017A: J-band upper limit from WINTER
  63. Fermi trigger No 750788395: Global MASTER-Net observations report
  64. GRB 241016B: SVOM/GRM observation
  65. GRB241016C: Fermi GBM Final Localization
  66. Fermi Gamma-ray Burst Monitor trigger 750792698/241016730 is not a GRB
  67. GRB 241017A: Swift ToO observations
  68. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  69. Fermi GRB 241016B: Global MASTER-Net observations report
  70. GRB 241016B: Fermi GBM Final Localization
  71. Fermi GRB 241016A: Global MASTER-Net observations report
  72. GRB 241016A: Fermi GBM Final Real-time Localization
  73. IceCube Alert 241016.04: Global MASTER-Net observations report
  74. GRB 241010A: Swift-BAT refined analysis
  75. GRB 241013B: Fermi GBM Observation
  76. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  77. GRB 241013A: Fermi GBM Observation
  78. GRB 240916A: radio detection with the VLA
  79. GRB241013A: REM observations
  80. GRB 241009A: LCO optical upper limits
  81. GRB 241013B: SVOM/GRM observation
  82. Fermi GRB 241013B: Global MASTER-Net observations report
  83. Integral GRB241013.04: Global MASTER-Net observations report
  84. GRB 241013B: Fermi GBM Final Real-time Localization
  85. GRB 241013A: a long GRB detected by INTEGRAL
  86. GRB 241013A: Fermi GBM Final Real-time Localization
  87. Fermi Gamma-ray Burst Monitor GRB trigger 750372658/241011869 (GRB 241011A) is not a GRB
  88. GRB 241011A: Fermi GBM Final Real-time Localization
  89. GRB 241009A: GRANDMA optical upper limits
  90. GRB 241009A: Swift-XRT afterglow detection
  91. GRB 241010A: JinShan optical observations and potential host galaxy
  92. GRB 241006A: ATCA Radio Upper Limits
  93. GRB 241010A: Swift-XRT refined Analysis
  94. Fermi trigger No 750211959: Global MASTER-Net observations report
  95. Fermi Gamma-ray Burst Monitor trigger 750303285/241011066 is not a GRB
  96. Fermi Gamma-ray Burst Monitor trigger 750291012/241010924 is not a GRB
  97. Swift GRB 241010A: Global MASTER-Net observations report
  98. Fermi trigger No 750291012: Global MASTER-Net observations report
  99. GRB 241010A: J-band observations with WINTER
  100. Fermi GRB 241010B: Global MASTER-Net observations report

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