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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

32766 results found.

  1. Fermi GRB 250621A: Global MASTER-Net observations report
  2. GRB 250619B: Fermi GBM Observation
  3. GRB 250620B: Swift/BAT-GUANO localization skymap of a burst
  4. GRB 250506A - SVOM/ECLAIRs Refined analysis
  5. GRB 250620A: Swift/BAT-GUANO subthreshold detection of a possibly short burst
  6. GRB 250619B: Swift/BAT-GUANO localization skymap of a burst
  7. GRB 250617B: Nickel telescope optical observations
  8. GRB 250615A: Kilonova-Catcher optical upper limits
  9. GRB 250617B: Assy AZT-20 Optical Observations
  10. GRB 250612A / Swift J1643.6−3854: Swift-BAT refined analysis
  11. Fermi GRB 250617A: Global MASTER-Net observations report
  12. GRB 250615A/EP250615a: FTW optical and NIR observations
  13. sb25061218/SVOM: OHP/T120 and OHP/T193 optical imaging and spectroscopic observations
  14. GRB 250617B: Swift/UVOT Detection
  15. GRB 250617B: Kilonova-Catcher optical afterglow detection
  16. GRB 250617B: VLT/X-shooter spectroscopic redshift z = 1.396
  17. GRB 250617B: COLIBRÍ optical observations
  18. GRB 250617B: NOT NIR observations of the afterglow
  19. GRB 250617B: SVOM/VT optical observation
  20. GRB 250617B: NUTTelA-TAO early time optical observations
  21. Swift GRB 250617B: Global MASTER-Net observations report
  22. GRB 250617B: GOTO optical upper limit
  23. GRB 250617B: Fermi GBM Observation
  24. GRB 250615A: Swift-BAT refined analysis
  25. GRB 250617B: Fermi GBM Final Localization
  26. GRB 250617B: Ondrejov D50 optical afterglow detection
  27. GRB 250617B: SAO RAS optical observations
  28. GRB 250615A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  29. IPN triangulation of GRB 250612C (short/hard)
  30. Konus-Wind detection of GRB 250615A / EP250615a
  31. GRB 250615A / EP250615a: AstroSat CZTI detection
  32. SVOM sb25061207: AbAO AS-32 Optical Upper Limit
  33. GRB 250615A: COLIBRÍ optical upper limit
  34. GRB 250615A: DDOTI Optical Upper Limit
  35. GRB 250615A: Swift/UVOT Upper Limits
  36. Konus-Wind detection of GRB 250612C (short/hard with extended emission)
  37. sb25061207/SVOM: T120 OHP optical upper limit
  38. EP250615a/GRB 250615A: EP-WXT detection of a fast X-ray transient
  39. EP-WXT trigger 01709178875: confirmation of a stellar flare by BOOTES-6
  40. GRID detection of GRB 250612C
  41. sb25061207: Mephisto optical upper limits
  42. EP250612a / GRB 250612B: NOT optical observations of the afterglow candidate
  43. sb25061218: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  44. sb25061207: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  45. EP250612a: refined analysis of the EP-WXT and EP-FXT observations
  46. GRB 250610B: J band upper limit by SYSU 80cm infrared telescope
  47. sb25061207: EP-FXT follow-up observation and afterglow candidate
  48. GRB 250612B: Fermi GBM Observation
  49. EP250612a / GRB 250612B: SVOM/VT optical candidate
  50. EP250612a: Global MASTER-Net observations report
  51. GRB 250612C: Fermi GBM Observation
  52. sb25061207: Swift-XRT observations
  53. EP250612a/GRB 250612B: JinShan optical upper limit
  54. EP 250612a: AST3-3 Yaoan Optical Observation
  55. GRB 250612C: SVOM/GRM observation an intermedium duration burst
  56. sb25061207: SVOM/VT optical counterpart
  57. EP250610a: Upper limit from Fermi-GBM Observations
  58. GRB 250612B: BALROG localization (Fermi Trigger 771424081 / GRB 250612519)
  59. GRB 250610B: Liverpool Telescope continued monitoring
  60. GRB 250610B: MISTRAL/T193 and T120 OHP further observations
  61. EP250610a: continuous follow-up observations with EP-FXT
  62. GRB 250610B - SVOM/ECLAIRs refined analysis
  63. Fermi GBM Sub-Threshold Detection of GRB 250610B
  64. GRB 250610B: Swift/UVOT Detection
  65. EP250610A: Swift/UVOT Upper limits
  66. GRB 250610B: SVOM/COLIBRÍ (FM-GFT) optical observations
  67. EP250610a: TNG NIR upper limit
  68. GRB 250610B: REM optical/NIR observations
  69. EP250610a: Liverpool Telescope optical upper limits
  70. GRB 250610B: SVOM/VT optical shallow decay
  71. GRB 250610B: additional Liverpool Telescope optical observations
  72. GRB 250610B: SVOM/GRM analysis
  73. GRB 250610B: Fermi/GBM sub-threshold detection of a possibly hard burst
  74. GRB 250610B: EP-FXT follow-up observation and afterglow counterpart
  75. GRB 250610B: Swift-XRT counterpart detection
  76. GRB 250610B: SVOM/VT optical counterpart
  77. GRB 250610B: LT detection of the optical counterpart
  78. GRB 250610B: OHP/T120 optical counterpart candidate
  79. GRB 250610B: GOTO optical upper limit
  80. EP250610a: Global MASTER-Net observations report
  81. GRB 250610B : SVOM/GWAC-F60A and F50 observations
  82. EP250610a: refined analysis of the EP-WXT and EP-FXT observations
  83. GRB 250605A: Swift-BAT refined analysis
  84. EP250610a: SVOM/VT optical upper limit
  85. EP250610a: REM optical/NIR observations
  86. GRB 250609A: Fermi GBM Observation
  87. EP250610a: COLIBRÍ optical upper limit
  88. GRB 250609A: Swift/BAT-GUANO localization skymap of a likely short burst
  89. GRB 250605A: Swift/UVOT Upper Limits
  90. GRB 250529A: GOTO optical counterpart candidate (GOTO25dea/AT 2025ndt)
  91. GRB 250527C: CrAO Optical Upper Limit
  92. GRB 250607A: SVOM/GRM observation of a long burst
  93. EP-WXT trigger 01709178244: confirmation of a stellar flare by BOOTES-5 & BOOTES-7
  94. EP-WXT trigger 01709178069: confirmation of a stellar flare by BOOTES-6 & BOOTES-7
  95. GRB 250605A: SVOM/VT optical upper limit
  96. Fermi GRB 250606A: Global MASTER-Net observations report
  97. GRB 250602A: GECAM detection
  98. GRB 250605A: LT optical observations
  99. Konus-Wind detection of GRB 250601A
  100. IPN triangulation of GRB 250404B

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