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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

26042 results found.

  1. GRB 241105A: Swift/BAT-GUANO arcminute localization of a short burst
  2. GRB 241104A: Swift ToO observations
  3. GRB 241104A: SVOM/VT optical candidate
  4. GRB 241010A: host galaxy redshift z = 0.977
  5. GRB 241030A: GRBAlpha detection
  6. EP241103a: GIT optical upper limit
  7. EP241103a: GOTO optical upper limit
  8. EP241103a: Swift XRT detection and improved X-ray position
  9. GRB 241030A: Swift-UVOT observations of the optical prompt flare
  10. GRB 241030A: Rapid release of TESS data.
  11. EP241030a: Futher EP-FXT observation of the X-ray Afterglow of GRB 241030A
  12. Swift GRB 241101A: Global MASTER-Net observations report
  13. GRB 241101A: FRAM-ORM optical limit
  14. GRB 241101A: Swift-BAT refined analysis
  15. GRB 241030B: Swift-XRT refined Analysis
  16. GRB 241030A / EP241030a: GMG possible spectroscopic redshift at z ~ 1.4
  17. EP241030a: EP/FXT observation of GRB 241030A X-ray Afterglow
  18. GRB 241101A: Swift detection of a burst
  19. GRB 241030B: NUTTelA-TAO / BSTI Optical Limits
  20. GRB 241030B: Montarrenti Observatory optical upper limit
  21. GRB 241030A / EP241030a: FTW Optical and NIR observations of the optical counterpart
  22. GRB 241030A: Fermi GBM Observation
  23. GRB 241030B: LCOGT Optical Upper Limits
  24. GRB 241030B: Swift-BAT refined analysis
  25. GRB 241030A: Swift-BAT refined analysis
  26. GRB 241030B: Swift/UVOT Detection
  27. GRB 241029A: LCO optical detection
  28. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  29. Swift GRB241030.77: Global MASTER-Net observations report
  30. GRB 241030B: SVOM/GRM observation
  31. GRB 241030B : MITSuME Akeno optical upper limits
  32. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  33. GRB 241030B: SVOM/VT optical afterglow observations
  34. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  35. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  36. GRB241030B: Fermi GBM Observation
  37. GRB 241029A: SVOM/VT optical afterglow observations
  38. GRB 241030A: detection of the bright optical counterpart in ATLAS forced photometry
  39. GRB 241030B: Enhanced Swift-XRT position
  40. GRB 241030B: optical observations from the INAF Asiago Observatory
  41. EP241021a: Swift-UVOT detection
  42. GRB241030B: GRANDMA/TAROT Upper Limit
  43. GRB 241030A: Swift-XRT refined Analysis
  44. GRB 241030B: AKO Optical Afterglow Detection
  45. GRB 241030B: Nanshan/HMT optical afterglow detection
  46. GRB 241030B: SVOM/ECLAIRs detection of a burst
  47. GRB 241030B: Prompt enhanced Swift-XRT position
  48. Konus-Wind detection of GRB 241030A
  49. GRB 241030B: Swift detection of a burst
  50. GRB 241030A: Fermi-LAT detection
  51. GRB 241030A: AKO Optical Afterglow Detection
  52. Swift GRB 241030A: Global MASTER-Net observations report
  53. GRB 241030A: Swift/UVOT Detection
  54. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  55. GRB 241030A: SVOM/GRM observation
  56. GRB 241026A: Swift-BAT refined analysis
  57. GRB 241030A: SVOM/C-GFT optical observations
  58. GRB 241026A: LBT optical observations
  59. GRB 241030A: Multiband optical detection with Mephisto
  60. GRB 241030A: SVOM/VT optical afterglow observations
  61. GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
  62. GRB 241030A : MITSuME Akeno optical afterglow detection
  63. GRB 241030A: Enhanced Swift-XRT position
  64. GRB 241029A: GROWTH-India Telescope optical follow up
  65. GRB 241030A: TRT optical observations
  66. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  67. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  68. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  69. EP240919a / GRB 240919A: ATCA Detection of Radio Counterpart
  70. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  71. GRB 241026A: Swift/UVOT Upper Limits
  72. GRB 241029A: Swift-XRT observations
  73. GRB 241029A: AKO Optical Afterglow Detection
  74. GRB 241029A: GOTO optical afterglow detection
  75. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  76. GRB 241029A: TRT optical afterglow candidate detection
  77. GRB 241029A: Swift ToO observations
  78. GRB 240821A: Keck/LRIS spectroscopic observations
  79. GRB 241026A: the 100th GRB detected by GRBAlpha
  80. GRB 241026A: TNOT optical counterpart detection
  81. Konus-Wind detection of GRB 241025A
  82. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  83. GRB 241026A: GECAM detection
  84. GRB 241026A: SVOM/GRM observation
  85. GRB 241025A: Swift/UVOT Detection
  86. GRB 241026A: GROWTH-India Telescope optical observations
  87. GRB 241026A Fermi GBM Analysis
  88. GRB 241026A: BTA redshift identification of z = 2.79
  89. GRB 241026A: J-band observations with WINTER
  90. GRB 241025A: SAO RAS optical observations
  91. GRB 241026A: Las Cumbres optical detection
  92. GRB 241025A: Mondy optical observations
  93. GRB 241026A: Swift-XRT refined Analysis
  94. GRB 241026A: Enhanced Swift-XRT position
  95. GRB 241026A: KAIT optical observations
  96. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  97. GRB 241026A: SAO RAS observations of possible optical afterglow
  98. GRB 241026A: Prompt enhanced Swift-XRT position
  99. GRB 241026A: Swift detection of a burst
  100. Swift GRB241026.95: Global MASTER-Net observations report

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