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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"

18503 results found.

  1. GRB 250713A: JinShan optical upper limits
  2. GRB 250713A: SVOM detection of a long burst
  3. GRB 250711A: DDOTI Optical Upper Limit
  4. EP250711a: COLIBRÍ refined photometry and optical confirmation of the candidate
  5. GRB 250711A: SVOM/GRM observation
  6. EP250711a: NOT optical counterpart candidate
  7. EP250711a: EP-WXT detection and FXT follow-up observation of a fast X-ray transient
  8. EP candidate (ID=08500000365): COLIBRÍ optical Upper limit
  9. EP250702a: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
  10. GRB 250704A: GRANDMA observations
  11. GRB 250702B,D,E / EP250702a: ALMA detection
  12. IceCube-250708A: No Candidates from WINTER
  13. IceCube-250708A: No Candidate Transients from the Zwicky Transient Facility
  14. EP250704a/GRB 250704B: 10 GHz VLA detection
  15. The EP-WXT trigger 01709181970 is likely a flaring star
  16. IceCube-250706A: No Candidates from WINTER
  17. IceCube-250706A: No Candidates from the Zwicky Transient Facility
  18. EP250704a/GRB250704B : HCT optical and NIR upper limits
  19. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  20. GRB 250702F: radio detection with the VLA
  21. IceCube-250706A: EP-FXT follow-up observations
  22. GRB 250706B/C: Fermi-LAT detection
  23. GRB 250704A: SVOM/COLIBRÍ (FM-GFT) optical observations
  24. EP250702a/GRB250702 B,D,E: GRANDMA Upper Limit
  25. GRB 250706B: Swift/UVOT Detection
  26. GRB 250704A: Swift/BAT-GUANO localization skymap of a burst
  27. GRB 250702F: GRANDMA observations
  28. GRB 250706A: Swift/UVOT Upper Limits
  29. GRB 250706B: REM optical observations
  30. GRB 250706A: REM optical/NIR observations
  31. EP250706a/GRB 250706A: EP-WXT detection of a fast X-ray transient
  32. IceCube-250416A: DDOTI Optical Upper Limit
  33. IceCube-250706A: COLIBRÍ optical upper limits
  34. GRB 250706A: JinShan optical upper limits
  35. GRB 250706A: SAO RAS optical observations
  36. EP250704A: NOWT Detection
  37. GRB 250706A: SVOM/C-GFT upper limit in eary phase
  38. The EP-WXT trigger 01709181580 is likely a flaring star
  39. GRB 250706B: iTelescope optical observations
  40. EP250704a / GRB 250704B: end of optical plateau phase and rapid fading of the counterpart
  41. GRB 250706B: SVOM/VT optical observation
  42. GRB 250706B: TRT bright optical counterpart detection
  43. GRB 250706A: GROWTH-India Telescope optical upper limit
  44. GRB 250706B: SVOM detection of a long burst
  45. GRB 250706A: Swift detection of a burst
  46. GRB 250704B: Swift-XRT refined Analysis
  47. GRBs 250702B,C,D,E / EP250702a: J band upper limit by SYSU 80cm infrared telescope
  48. EP250702a/GRB250702 B,E,D: MeerKAT radio counterpart
  49. EP250702a/GRB 250702B,C,D,E: Archival radio observations from ASKAP VAST
  50. GRB 250704B: Swift/UVOT Upper Limits
  51. GRB 250704A: Swift/UVOT Detection
  52. Radio observation of GRBs 250702B,C,E / EP250702a with the Allen Telescope Array
  53. GRB 250702F: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  54. EP250704a / GRB 250704B: NOT observations of the optical afterglow
  55. EP250704a/GRB 250704B VLT/HAWK-I NIR afterglow detection
  56. GRB 250702F: Kilonova-Catcher optical afterglow detection
  57. GRB 250702F: Monte Agliale Observatory optical observations
  58. GRB250702F: afterglow detected by joint EP-ZTF shadowing program
  59. EP250704a / GRB 250704B: JinShan optical observations
  60. EP250704a / GRB 250704B: SAO RAS optical observations
  61. EP250704a / GRB 250704B : GROWTH-India Telescope optical observations
  62. EP250704a: refined analysis of the EP-WXT and FXT follow-up observations
  63. GRB 250704A: VLT/X-shooter afterglow discovery and spectroscopic redshift z = 1.091
  64. GRB 250704A: Swift-XRT afterglow detection
  65. EP250704a / GRB 250704B - REM observations
  66. GRB 250702F: GROWTH-India Telescope optical observations
  67. EP250704a / GRB 250704B: VLT/FORS2 optical afterglow detection
  68. GRB 250704A: REM retraction of optical afterglow detection and updated limit
  69. EP250702a: WFST optical observations
  70. EP250704a: COLIBRÍ optical counterpart candidate
  71. EP250704a: Einstein Probe detection of an X-ray transient
  72. GRB 250704A: REM detection of the optical afterglow
  73. GRB 250704A: SVOM detection of a burst
  74. GRB 250702F: Swift/UVOT Detection
  75. GRB 250702F: Leavitt Observatory optical observations
  76. GRB 250702F: AKO Optical Afterglow Detection
  77. GRBs 250702B,C,D,E / EP250702a: VLT/HAWK-I NIR candidate
  78. GRBs 250702B,C,D,E / EP250702a: SVOM/GRM observation
  79. GRB 250702F: Skynet Optical Observations
  80. GRB 250424A: VIRT Optical Upper Limit
  81. GRB 250702B,C,D,E/EP250702a: COLIBRÍ optical upper limit
  82. EP250702a/GRB 250702B, C, D, E: EP-FXT follow-up observation
  83. GRB 250702F: TRT Optical Observation
  84. GRB 250703A: DDOTI Optical Upper Limit
  85. GRB 250702F: REM optical afterglow detection
  86. GRB 250702F: DDOTI Optical Observation
  87. GRB 250702F: COLIBRÍ Observations of the Afterglow
  88. EP250702a : an X-ray transient detected by Einstein Probe likely associated with GRB 250702B,C,D,E
  89. GRB 250702D, C, E: Swift/BAT-GUANO localization skymap of a burst or galactic transient
  90. GRB 250702F: Enhanced Swift-XRT position
  91. GRB 250702F: NOT observations of the optical afterglow
  92. GRB 250702F: Swift detection of a burst with an optical counterpart
  93. GRB 250702A: Fermi GBM Detection
  94. LIGO/Virgo/KAGRA S250702n: Identification of a GW compact binary merger candidate
  95. GRB 250628B: EP-FXT counterpart detection
  96. GRB 250628A: REM optical/NIR upper limits
  97. GRB 250628A: VLT/X-shooter upper limits
  98. GRB 250628A: Swift/UVOT Upper Limits
  99. GRB 250628A: Enhanced Swift-XRT position
  100. GRB 250628A: Swift detection of a burst

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