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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

36192 results found.

  1. GRB 241026A: SVOM/GRM observation
  2. GRB 241025A: Swift/UVOT Detection
  3. GRB 241026A: GROWTH-India Telescope optical observations
  4. GRB 241026A Fermi GBM Analysis
  5. GRB 241026A: BTA redshift identification of z = 2.79
  6. GRB 241026A: J-band observations with WINTER
  7. GRB 241025A: SAO RAS optical observations
  8. GRB 241026A: Las Cumbres optical detection
  9. GRB 241025A: Mondy optical observations
  10. EP241021a: further SAO RAS optical observations
  11. EP241026a (GRB 241026A): EP on-board trigger and follow-up observation
  12. GRB 241026A: Swift-XRT refined Analysis
  13. GRB 241026A: Enhanced Swift-XRT position
  14. GRB 241026A: KAIT optical observations
  15. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  16. GRB 241026A: SAO RAS observations of possible optical afterglow
  17. Fermi GRB 241026A: Global MASTER-Net observations report
  18. GRB 241026A: Prompt enhanced Swift-XRT position
  19. GRB 241026A: Swift detection of a burst
  20. GRB 241026A: Fermi GBM Final Real-time Localization
  21. GRB241025A: 1.3m DFOT optical afterglow detection
  22. ​GRB 241025A: optical photometry from Konkoly
  23. GRB 241025A: GROWTH-India Telescope optical observations
  24. GRB 241025A: COLIBRÍ Detection of the Afterglow
  25. GRB 241025A: Swift-XRT refined Analysis
  26. GRB 241025C: Fermi GBM Detection
  27. GRB 241025A: Fermi GBM Observation
  28. IPN triangulation of GRB 241022A (short/hard)
  29. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  30. GRB 241025C: Fermi GBM Final Localization
  31. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  32. GRB 241025B: Fermi GBM Final Localization
  33. EP 241021a: Swift-XRT observations
  34. Fermi GRB 241025A: Global MASTER-Net observations report
  35. Swift GRB 241025A: Global MASTER-Net observations report
  36. EP241025a (GRB 241025A): EP observations update
  37. GRB 241025A : SVOM/VT optical afterglow observations
  38. GRB 241025A: Enhanced Swift-XRT position
  39. GRB 241001A: JWST spectroscopic identification of a supernova counterpart
  40. GRB 241025A: NOT spectroscopic redshift of z = 4.20
  41. GRB 241025A: DDOTI Afterglow detection
  42. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  43. GRB 241025A: SVOM/GRM observation
  44. GRB 241025A: TRT optical afterglow observation
  45. Fermi GRB 241024B: Global MASTER-Net observations report
  46. GRB 241025A: Fermi GBM Final Real-time Localization
  47. GRB 241025A: Swift detection of a burst with an optical counterpart
  48. GRB 241001A: ATCA radio observations
  49. GRB 241024B: Fermi GBM Final Localization
  50. EP241021a: No Detection in Fermi-GBM Observation
  51. GRB 241010A: VIRT Optical Upper Limit
  52. GRB 241024A: Fermi GBM Final Localisation
  53. EP241021a: VLT/FORS2 redshift z = 0.75
  54. EP241021a: SAO RAS optical observations
  55. EP241021a: KAIT optical observations
  56. IPN triangulation of GRB 241021A (long)
  57. GRB 241018A: SVOM/C-GFT optical observations
  58. GRB241017A: 1.3m DFOT optical upper limit
  59. GRB 241018A: 1.3m DFOT Optical upper limit
  60. GRB 241018A: EP-FXT afterglow detection
  61. Konus-Wind detection of GRB 241018A
  62. GRB 241018A: SVOM/GRM observation
  63. GRB 241018A/sb24101802: Mephisto optical upper limit
  64. GRB 241017A/sb24101702: Mephisto optical upper limit
  65. GRB 241018A: BOOTES-4/MET optical upper limit
  66. GRB 241018A: Mondy optical upper limit
  67. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  68. GRB 241018A: GROWTH-India telescope optical upper limit
  69. GRB 241018A: Swift-XRT observations
  70. GRB 241018A: REM optical/NIR upper limits
  71. GRB 241018A: NOT optical observations
  72. GRB 241017A: SVOM/VT follow-up and optical upper limit
  73. GRB 241018A: SVOM/VT follow-up and optical candidate
  74. GRB 241018A: LCO/0.4m optical upper limits
  75. GRB 241018A: Swift ToO observations
  76. GRB 241006A: VIRT Optical Upper Limit
  77. GRB 240727A: VIRT Optical Upper Limit
  78. GRB 241018A: X-ray afterglow candidate observed by MXT
  79. GRB 241016B: Fermi GBM Observations
  80. GRB 241018A: Detection of a bright long GRB by SVOM
  81. GRB 241017A: Swift-XRT observations
  82. GRB 241001A: EP-FXT afterglow detection
  83. GRB 241017A: GROWTH-India Telescope optical upper limit
  84. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  85. GRB 241017A: J-band upper limit from WINTER
  86. GRB 241016B: SVOM/GRM observation
  87. GRB241016C: Fermi GBM Final Localization
  88. Fermi Gamma-ray Burst Monitor trigger 750792698/241016730 is not a GRB
  89. GRB 241017A: Swift ToO observations
  90. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  91. Fermi GRB 241016B: Global MASTER-Net observations report
  92. GRB 241016B: Fermi GBM Final Localization
  93. Fermi GRB 241016A: Global MASTER-Net observations report
  94. GRB 241016A: Fermi GBM Final Real-time Localization
  95. GRB 241010A: Swift-BAT refined analysis
  96. GRB 241013B: Fermi GBM Observation
  97. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  98. GRB 241013A: Fermi GBM Observation
  99. GRB 240916A: radio detection with the VLA
  100. GRB241013A: REM observations

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