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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"

32721 results found.

  1. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  2. GRB 241029A: Mephisto observations
  3. EP 241026b: LBT possible optical counterpart (brightening source)
  4. GRB 241029A: TRT optical afterglow candidate detection
  5. GRB 241029A: Swift ToO observations
  6. GRB 241029A: SVOM/GRM observation
  7. GRB 241029A : Detection and localization of a bright long GRB by SVOM/ECLAIRs
  8. GRB 240821A: Keck/LRIS spectroscopic observations
  9. EP241021a: Gemini-South detection of optical rebrightening
  10. GRB 241026A: the 100th GRB detected by GRBAlpha
  11. GRB 241026A: TNOT optical counterpart detection
  12. Konus-Wind detection of GRB 241025A
  13. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  14. GRB 241026A: LBT redshift confirmation
  15. GRB 241026A: GECAM detection
  16. GRB 241025A: further SAO RAS optical observations
  17. GRB 241026A: BTA and Zeiss-1000 optical observations
  18. GRB 241026A: SVOM/GRM observation
  19. EP241026B: GROWTH-India Telescope optical upper limit
  20. GRB 241025A: Swift/UVOT Detection
  21. GRB 241026A: GROWTH-India Telescope optical observations
  22. GRB 241026A Fermi GBM Analysis
  23. GRB 241026A: BTA redshift identification of z = 2.79
  24. GRB 241026A: J-band observations with WINTER
  25. GRB 241025A: SAO RAS optical observations
  26. GRB 241026A: Las Cumbres optical detection
  27. GRB 241025A: Mondy optical observations
  28. EP241021a: SOAR observations of the optical counterpart
  29. EP241021a: further SAO RAS optical observations
  30. EP241026a (GRB 241026A): EP on-board trigger and follow-up observation
  31. EP 241026b: LBT optical observations
  32. EP241021a: e-MERLIN radio observation
  33. EP EP241026b: Global MASTER-Net observations report
  34. GRB 241026A: KAIT optical observations
  35. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  36. GRB 241026A: SAO RAS observations of possible optical afterglow
  37. Fermi GRB 241026A: Global MASTER-Net observations report
  38. GRB241025A: 1.3m DFOT optical afterglow detection
  39. EP241021a: optical follow-up observations with Xinglong Observatory
  40. ​GRB 241025A: optical photometry from Konkoly
  41. GRB 241025A: GROWTH-India Telescope optical observations
  42. GRB 241025A: COLIBRÍ Detection of the Afterglow
  43. GRB 241025C: Fermi GBM Detection
  44. GRB 241025A: Fermi GBM Observation
  45. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  46. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  47. EP241021a: Optical and NIR observations of counterpart with the Fraunhofer Telescope at Wendelstein Observatory
  48. EP 241021a: Swift-XRT observations
  49. EP241021a: optical follow-up observations with the Liverpool Telescope
  50. Fermi GRB 241025A: Global MASTER-Net observations report
  51. Swift GRB 241025A: Global MASTER-Net observations report
  52. EP241025a (GRB 241025A): EP observations update
  53. GRB 241025A : SVOM/VT optical afterglow observations
  54. EP 241021A: Swift ToO 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. GRB 241025A: DDOTI Afterglow detection
  59. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  60. GRB 241025A: SVOM/GRM observation
  61. GRB 241025A: TRT optical afterglow observation
  62. Fermi GRB 241024B: Global MASTER-Net observations report
  63. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  64. GRB 241001A: ATCA radio observations
  65. EP241021a: No Detection in Fermi-GBM Observation
  66. GRB 241010A: VIRT Optical Upper Limit
  67. EP241021a: VLT/FORS2 redshift z = 0.75
  68. EP241021a: SAO RAS optical observations
  69. EP241021a: KAIT optical observations
  70. EP241021a: EP-FXT follow-up observation update
  71. IPN triangulation of GRB 241021A (long)
  72. EP241021a: Optical counterpart observations with the Liverpool Telescope
  73. EP241021a: 1.3m DFOT Optical observations
  74. EP241021a: GSP detects optical candidate counterpart
  75. EP241021a: Optical upper limits with Kinder observations
  76. EP241021a: TRT optical observations
  77. GRB 241018A: SVOM/C-GFT optical observations
  78. EP241021a: NOT likely optical counterpart
  79. EP EP241021a: Global MASTER-Net observations report
  80. GRB241017A: 1.3m DFOT optical upper limit
  81. GRB 241018A: 1.3m DFOT Optical upper limit
  82. GRB 241018A: EP-FXT afterglow detection
  83. EP241021a: GOTO optical upper limits
  84. Konus-Wind detection of GRB 241018A
  85. GRB 241018A: SVOM/GRM observation
  86. GRB 241018A/sb24101802: Mephisto optical upper limit
  87. GRB 241017A/sb24101702: Mephisto optical upper limit
  88. GRB 241018A: Mondy optical upper limit
  89. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  90. GRB 241018A: GROWTH-India telescope optical upper limit
  91. GRB241018A: XingLong Optical Upper Limit
  92. GRB 241018A: REM optical/NIR upper limits
  93. GRB 241018A: NOT optical observations
  94. GRB 241017A: SVOM/VT follow-up and optical upper limit
  95. GRB 241018A: SVOM/VT follow-up and optical candidate
  96. GRB 241018A: LCO/0.4m optical upper limits
  97. GRB 241018A: Swift ToO observations
  98. GRB 241006A: VIRT Optical Upper Limit
  99. GRB 240727A: VIRT Optical Upper Limit
  100. GRB 241018A: X-ray afterglow candidate observed by MXT

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