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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"

43155 results found.

  1. Fermi trigger No 751861204: Global MASTER-Net observations report
  2. GRB 241029A: Fermi GBM Final Real-time Localization
  3. GRB 240821A: Keck/LRIS spectroscopic observations
  4. EP241021a: Gemini-South detection of optical rebrightening
  5. GRB 241026A: the 100th GRB detected by GRBAlpha
  6. GRB 241026A: TNOT optical counterpart detection
  7. Konus-Wind detection of GRB 241025A
  8. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  9. GRB 241026A: LBT redshift confirmation
  10. GRB 241026A: GECAM detection
  11. GRB 241025A: further SAO RAS optical observations
  12. GRB 241026A: BTA and Zeiss-1000 optical observations
  13. GRB 241026A: SVOM/GRM observation
  14. EP241026B: GROWTH-India Telescope optical upper limit
  15. GRB 241025A: Swift/UVOT Detection
  16. GRB 241026A: GROWTH-India Telescope optical observations
  17. GRB 241026A Fermi GBM Analysis
  18. GRB 241026A: J-band observations with WINTER
  19. GRB 241025A: SAO RAS optical observations
  20. GRB 241026A: Las Cumbres optical detection
  21. EP241021a: SOAR observations of the optical counterpart
  22. EP241021a: further SAO RAS optical observations
  23. EP241026a (GRB 241026A): EP on-board trigger and follow-up observation
  24. GRB 241026A: Swift-XRT refined Analysis
  25. EP 241026b: LBT optical observations
  26. EP241021a: e-MERLIN radio observation
  27. EP EP241026b: Global MASTER-Net observations report
  28. GRB 241026A: Enhanced Swift-XRT position
  29. GRB 241026A: KAIT optical observations
  30. EP241026b: EP detection of a fast X-ray transient
  31. Fermi trigger No 751616906: Global MASTER-Net observations report
  32. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  33. GRB 241026A: SAO RAS observations of possible optical afterglow
  34. Fermi GRB 241026A: Global MASTER-Net observations report
  35. GRB 241026A: Prompt enhanced Swift-XRT position
  36. GRB 241026A: Swift detection of a burst
  37. Swift GRB241026.95: Global MASTER-Net observations report
  38. GRB 241026A: Fermi GBM Final Real-time Localization
  39. GRB241025A: 1.3m DFOT optical afterglow detection
  40. EP241021a: optical follow-up observations with Xinglong Observatory
  41. ​GRB 241025A: optical photometry from Konkoly
  42. GRB 241025A: GROWTH-India Telescope optical observations
  43. GRB 241025A: COLIBRÍ Detection of the Afterglow
  44. GRB 241025A: Swift-XRT refined Analysis
  45. GRB 241025C: Fermi GBM Detection
  46. GRB 241025A: Fermi GBM Observation
  47. IPN triangulation of GRB 241022A (short/hard)
  48. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  49. GRB 241025C: Fermi GBM Final Localization
  50. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  51. GRB 241025B: Fermi GBM Final Localization
  52. Fermi trigger No 751563375: Global MASTER-Net observations report
  53. Fermi trigger No 751554401: Global MASTER-Net observations report
  54. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  55. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  56. EP 241021a: Swift-XRT observations
  57. EP241021a: optical follow-up observations with the Liverpool Telescope
  58. Fermi GRB 241025A: Global MASTER-Net observations report
  59. Swift GRB 241025A: Global MASTER-Net observations report
  60. EP241025a (GRB 241025A): EP observations update
  61. GRB 241025A : SVOM/VT optical afterglow observations
  62. EP 241021A: Swift ToO observations
  63. EP241021a: Liverpool Telescope optical follow-up observations
  64. GRB 241025A: Enhanced Swift-XRT position
  65. GRB 241001A: JWST spectroscopic identification of a supernova counterpart
  66. GRB 241025A: NOT spectroscopic redshift of z = 4.20
  67. GRB 241025A: DDOTI Afterglow detection
  68. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  69. GRB 241025A: SVOM/GRM observation
  70. GRB 241025A: TRT optical afterglow observation
  71. Fermi GRB 241024B: Global MASTER-Net observations report
  72. GRB 241025A: Fermi GBM Final Real-time Localization
  73. GRB 241025A: Swift detection of a burst with an optical counterpart
  74. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  75. GRB 241001A: ATCA radio observations
  76. GRB 241024B: Fermi GBM Final Localization
  77. EP241021a: No Detection in Fermi-GBM Observation
  78. GRB 241010A: VIRT Optical Upper Limit
  79. GRB 241024A: Fermi GBM Final Localisation
  80. EP241021a: VLT/FORS2 redshift z = 0.75
  81. Fermi trigger No 751449953: Global MASTER-Net observations report
  82. EP241021a: SAO RAS optical observations
  83. EP241021a: KAIT optical observations
  84. EP241021a: EP-FXT follow-up observation update
  85. IPN triangulation of GRB 241021A (long)
  86. EP241021a: Optical counterpart observations with the Liverpool Telescope
  87. EP241021a: 1.3m DFOT Optical observations
  88. EP241021a: GSP detects optical candidate counterpart
  89. EP241021a: Optical upper limits with Kinder observations
  90. EP241021a: TRT optical observations
  91. GRB 241018A: SVOM/C-GFT optical observations
  92. EP241021a: NOT likely optical counterpart
  93. EP EP241021a: Global MASTER-Net observations report
  94. GRB241017A: 1.3m DFOT optical upper limit
  95. GRB 241018A: 1.3m DFOT Optical upper limit
  96. GRB 241018A: EP-FXT afterglow detection
  97. EP241021a: GOTO optical upper limits
  98. EP241021a: EP detection of a fast X-ray transient
  99. IceCube-Cascade 241019A: Upper limits from a search for additional neutrino events in IceCube
  100. Konus-Wind detection of GRB 241018A

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