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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"

27250 results found.

  1. GRB 241029A: Fermi GBM Observation
  2. GRB 241029A: AKO Optical Afterglow Detection
  3. GRB 241029A: GOTO optical afterglow detection
  4. GRB 241029A: MASTER early optical counterpart detection
  5. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  6. EP 241026b: LBT possible optical counterpart (brightening source)
  7. GRB 241029A: TRT optical afterglow candidate detection
  8. GRB 241029A: SVOM/GRM observation
  9. GRB 241029A : Detection and localization of a bright long GRB by SVOM/ECLAIRs
  10. Fermi trigger No 751861204: Global MASTER-Net observations report
  11. GRB 241029A: Fermi GBM Final Real-time Localization
  12. EP241021a: Gemini-South detection of optical rebrightening
  13. GRB 241026A: LBT redshift confirmation
  14. GRB 241026A: GECAM detection
  15. GRB 241026A: SVOM/GRM observation
  16. EP241026B: GROWTH-India Telescope optical upper limit
  17. GRB 241025A: Swift/UVOT Detection
  18. GRB 241026A: GROWTH-India Telescope optical observations
  19. GRB 241026A Fermi GBM Analysis
  20. GRB 241026A: Las Cumbres optical detection
  21. EP241026a (GRB 241026A): EP on-board trigger and follow-up observation
  22. GRB 241026A: Swift-XRT refined Analysis
  23. EP 241026b: LBT optical observations
  24. EP241021a: e-MERLIN radio observation
  25. EP EP241026b: Global MASTER-Net observations report
  26. EP241026b: EP detection of a fast X-ray transient
  27. Fermi trigger No 751616906: Global MASTER-Net observations report
  28. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  29. GRB 241026A: SAO RAS observations of possible optical afterglow
  30. Fermi GRB 241026A: Global MASTER-Net observations report
  31. GRB 241026A: Swift detection of a burst
  32. Swift GRB241026.95: Global MASTER-Net observations report
  33. GRB 241026A: Fermi GBM Final Real-time Localization
  34. GRB241025A: 1.3m DFOT optical afterglow detection
  35. EP241021a: optical follow-up observations with Xinglong Observatory
  36. ​GRB 241025A: optical photometry from Konkoly
  37. GRB 241025A: GROWTH-India Telescope optical observations
  38. GRB 241025A: COLIBRÍ Detection of the Afterglow
  39. GRB 241025A: Swift-XRT refined Analysis
  40. GRB 241025C: Fermi GBM Detection
  41. GRB 241025A: Fermi GBM Observation
  42. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  43. GRB 241025C: Fermi GBM Final Localization
  44. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  45. GRB 241025B: Fermi GBM Final Localization
  46. Fermi trigger No 751563375: Global MASTER-Net observations report
  47. Fermi trigger No 751554401: Global MASTER-Net observations report
  48. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  49. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  50. EP241021a: optical follow-up observations with the Liverpool Telescope
  51. Fermi GRB 241025A: Global MASTER-Net observations report
  52. Swift GRB 241025A: Global MASTER-Net observations report
  53. EP241025a (GRB 241025A): EP observations update
  54. GRB 241025A : SVOM/VT optical afterglow observations
  55. EP241021a: Liverpool Telescope optical follow-up observations
  56. GRB 241001A: JWST spectroscopic identification of a supernova counterpart
  57. GRB 241025A: NOT spectroscopic redshift of z = 4.20
  58. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  59. GRB 241025A: SVOM/GRM observation
  60. GRB 241025A: TRT optical afterglow observation
  61. Fermi GRB 241024B: Global MASTER-Net observations report
  62. GRB 241025A: Fermi GBM Final Real-time Localization
  63. GRB 241025A: Swift detection of a burst with an optical counterpart
  64. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  65. GRB 241024B: Fermi GBM Final Localization
  66. EP241021a: No Detection in Fermi-GBM Observation
  67. GRB 241024A: Fermi GBM Final Localisation
  68. EP241021a: VLT/FORS2 redshift z = 0.75
  69. Fermi trigger No 751449953: Global MASTER-Net observations report
  70. EP241021a: KAIT optical observations
  71. EP241021a: EP-FXT follow-up observation update
  72. EP241021a: 1.3m DFOT Optical observations
  73. EP241021a: Optical upper limits with Kinder observations
  74. EP241021a: TRT optical observations
  75. GRB 241018A: SVOM/C-GFT optical observations
  76. EP241021a: NOT likely optical counterpart
  77. EP EP241021a: Global MASTER-Net observations report
  78. GRB241017A: 1.3m DFOT optical upper limit
  79. GRB 241018A: 1.3m DFOT Optical upper limit
  80. GRB 241018A: EP-FXT afterglow detection
  81. EP241021a: GOTO optical upper limits
  82. EP241021a: EP detection of a fast X-ray transient
  83. GRB 241018A: SVOM/GRM observation
  84. GRB 241018A/sb24101802: Mephisto optical upper limit
  85. GRB 241017A/sb24101702: Mephisto optical upper limit
  86. GRB 241018A: BOOTES-4/MET optical upper limit
  87. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  88. GRB 241018A: GROWTH-India telescope optical upper limit
  89. GRB241018A: XingLong Optical Upper Limit
  90. GRB 241018A: REM optical/NIR upper limits
  91. GRB 241018A: NOT optical observations
  92. GRB 241017A: SVOM/VT follow-up and optical upper limit
  93. GRB 241018A: SVOM/VT follow-up and optical candidate
  94. GRB 241018A: X-ray afterglow candidate observed by MXT
  95. GRB 241016B: Fermi GBM Observations
  96. GRB 241018A: Detection of a bright long GRB by SVOM
  97. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  98. GRB 241001A: EP-FXT afterglow detection
  99. GRB 241017A: GROWTH-India Telescope optical upper limit
  100. GRB241017A: TOO Observations by SVOM/MXT

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