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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"

37579 results found.

  1. GRB 241029A: GROWTH-India Telescope optical follow up
  2. GRB 241030A: TRT optical observations
  3. GRB 241030A: Keck/LRIS spectroscopic redshift z = 1.411
  4. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  5. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  6. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  7. GRB 241030A: Fermi GBM Final Real-time Localization
  8. GRB 241029A: SAO RAS optical observations
  9. GRB 241026A: SAO RAS optical observations
  10. EP240919a / GRB 240919A: ATCA Detection of Radio Counterpart
  11. EP241021a: SAO RAS observations of rebrightening
  12. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  13. MISTRAL@OHP photometric and spectroscopic observations of GRB 241029A
  14. GRB 241026A: Swift/UVOT Upper Limits
  15. GRB 241029A: Swift-XRT observations
  16. GRB 241029A: Fermi GBM Observation
  17. GRB 241029A: AKO Optical Afterglow Detection
  18. GRB 241029A: GOTO optical afterglow detection
  19. GRB 241029A: MASTER early optical counterpart detection
  20. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  21. GRB 241029A: Mephisto observations
  22. EP 241026b: LBT possible optical counterpart (brightening source)
  23. GRB 241029A: TRT optical afterglow candidate detection
  24. GRB 241029A: Swift ToO observations
  25. GRB 241029A: SVOM/GRM observation
  26. GRB 241029A : Detection and localization of a bright long GRB by SVOM/ECLAIRs
  27. Fermi trigger No 751861204: Global MASTER-Net observations report
  28. GRB 241029A: Fermi GBM Final Real-time Localization
  29. GRB 240821A: Keck/LRIS spectroscopic observations
  30. GRB 241026A: the 100th GRB detected by GRBAlpha
  31. GRB 241026A: TNOT optical counterpart detection
  32. Konus-Wind detection of GRB 241025A
  33. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  34. GRB 241026A: LBT redshift confirmation
  35. GRB 241026A: GECAM detection
  36. GRB 241025A: further SAO RAS optical observations
  37. GRB 241026A: BTA and Zeiss-1000 optical observations
  38. GRB 241026A: SVOM/GRM observation
  39. GRB 241025A: Swift/UVOT Detection
  40. GRB 241026A: GROWTH-India Telescope optical observations
  41. GRB 241026A Fermi GBM Analysis
  42. GRB 241026A: BTA redshift identification of z = 2.79
  43. GRB 241026A: J-band observations with WINTER
  44. GRB 241025A: SAO RAS optical observations
  45. GRB 241026A: Las Cumbres optical detection
  46. GRB 241025A: Mondy optical observations
  47. EP241021a: further SAO RAS optical observations
  48. EP241026a (GRB 241026A): EP on-board trigger and follow-up observation
  49. GRB 241026A: Swift-XRT refined Analysis
  50. GRB 241026A: Enhanced Swift-XRT position
  51. GRB 241026A: KAIT optical observations
  52. Fermi trigger No 751616906: Global MASTER-Net observations report
  53. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  54. GRB 241026A: SAO RAS observations of possible optical afterglow
  55. Fermi GRB 241026A: Global MASTER-Net observations report
  56. GRB 241026A: Prompt enhanced Swift-XRT position
  57. GRB 241026A: Swift detection of a burst
  58. GRB 241026A: Fermi GBM Final Real-time Localization
  59. GRB241025A: 1.3m DFOT optical afterglow detection
  60. ​GRB 241025A: optical photometry from Konkoly
  61. GRB 241025A: GROWTH-India Telescope optical observations
  62. GRB 241025A: COLIBRÍ Detection of the Afterglow
  63. GRB 241025A: Swift-XRT refined Analysis
  64. GRB 241025C: Fermi GBM Detection
  65. GRB 241025A: Fermi GBM Observation
  66. IPN triangulation of GRB 241022A (short/hard)
  67. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  68. GRB 241025C: Fermi GBM Final Localization
  69. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  70. GRB 241025B: Fermi GBM Final Localization
  71. Fermi trigger No 751563375: Global MASTER-Net observations report
  72. Fermi trigger No 751554401: Global MASTER-Net observations report
  73. EP 241021a: Swift-XRT observations
  74. Fermi GRB 241025A: Global MASTER-Net observations report
  75. Swift GRB 241025A: Global MASTER-Net observations report
  76. EP241025a (GRB 241025A): EP observations update
  77. GRB 241025A : SVOM/VT optical afterglow observations
  78. GRB 241025A: Enhanced Swift-XRT position
  79. GRB 241001A: JWST spectroscopic identification of a supernova counterpart
  80. GRB 241025A: NOT spectroscopic redshift of z = 4.20
  81. GRB 241025A: DDOTI Afterglow detection
  82. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  83. GRB 241025A: SVOM/GRM observation
  84. GRB 241025A: TRT optical afterglow observation
  85. Fermi GRB 241024B: Global MASTER-Net observations report
  86. GRB 241025A: Fermi GBM Final Real-time Localization
  87. GRB 241025A: Swift detection of a burst with an optical counterpart
  88. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  89. GRB 241001A: ATCA radio observations
  90. GRB 241024B: Fermi GBM Final Localization
  91. EP241021a: No Detection in Fermi-GBM Observation
  92. GRB 241010A: VIRT Optical Upper Limit
  93. GRB 241024A: Fermi GBM Final Localisation
  94. EP241021a: VLT/FORS2 redshift z = 0.75
  95. Fermi trigger No 751449953: Global MASTER-Net observations report
  96. EP241021a: SAO RAS optical observations
  97. EP241021a: KAIT optical observations
  98. IPN triangulation of GRB 241021A (long)
  99. GRB 241018A: SVOM/C-GFT optical observations
  100. GRB241017A: 1.3m DFOT optical upper limit

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