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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"

28126 results found.

  1. GRB 250506A: Swift-XRT observations
  2. Fermi-LAT Gamma-ray Observations of IceCube-250506A
  3. GRB 250507A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  4. EP-WXT trigger 01709175213: a new X-ray outburst of LMXB MAXI J1957+032
  5. GRB 250507A: SVOM detection of a long burst
  6. GRB 250506A: Mephisto optical upper limits
  7. GRB 250504A: EIRSAT-1 GMOD Detection
  8. GRB 250502A: Bassano Bresciano Observatory upper limit
  9. GRB 250506A: Xinglong 2.16m optical upper limit
  10. SVOM/sb25050601: EP-FXT observations
  11. GRB 250506A: SVOM improved position and MXT detection of a fading X-ray afterglow
  12. GRB 250506A: REM optical/NIR upper limits
  13. GRB 250506A: Fermi GBM Observation
  14. GRB 250506A: Swift XRT observations and possible counterpart detection
  15. GRB 250506A: TRT optical observations
  16. GRB 250506A: SVOM/COLIBRÍ (FM-GFT) Upper Limits on the Optical Counterpart
  17. GRB 250506A: SVOM detection of a burst
  18. GRB 250504A: Swift-BAT refined analysis
  19. GRB 250430A: Swift-BAT refined analysis
  20. GRB 250504A: Swift-XRT refined Analysis
  21. GRB 250504A: VLT/X-shooter upper limits
  22. GRB 250504A: REM optical/NIR observations
  23. GRB 250502A: REM optical/NIR observations
  24. GRB 250504A: MeerLICHT optical afterglow detection
  25. GRB 250504A: Fermi GBM Observation
  26. GRB 250504A: Enhanced Swift-XRT position
  27. Fermi GRB 250504A: Global MASTER-Net observations report
  28. GRB 250504A: Swift detection of a burst
  29. GRB 250502A: Swift/UVOT Follow up
  30. GRB 250502A: Mondy and Tien-Shan Optical Observations
  31. GRB 250502A: KAIT optical observations
  32. GRB 250502A: Montarrenti Observatory optical detection
  33. GRB 250502A: Swift-XRT afterglow detection
  34. GRB 250502A: NOT optical observations
  35. GRB 250502B: AstroSat CZTI detection
  36. GRB 250502A: AKO Optical Afterglow Detection
  37. GRB 250502A: LCO optical counterpart detection
  38. GRB 250502A: Redshift from OSIRIS+/GTC z = 2.163
  39. GRB 250407A: VZLUSAT-2 detection
  40. Fermi-LAT Gamma-ray Observations of IceCube-250429A
  41. GRB 250502B: DDOTI Optical Observations
  42. GRB 250430A: Swift-XRT refined Analysis
  43. GRB 250502A: Early optical counterpart detection by LCO.
  44. GRB 250430A: Swift/UVOT Detection
  45. GRB 250502A: TRT optical afterglow confirmation
  46. GRB 250430A: Enhanced Swift-XRT position
  47. GRB 250502A: SVOM/COLIBRÍ (FM-GFT) Detection of a Bright Optical Counterpart Candidate
  48. GRB 250502A: SVOM detection of a burst
  49. GRB 250430A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  50. GRB 250430A: KAIT optical observations
  51. GRB 250430A / EP250430a: J-band upper limits with WINTER
  52. GRB 250430A: NUTTelA-TAO Early Measurements
  53. GRB 250430A: DDOTI Optical Observations
  54. GRB 250430A: Leavitt Observatory optical upper limit
  55. GRB 250430A: Bassano Bresciano Observatory upper limit
  56. GRB 250430A : MITSuME Akeno optical upper limits
  57. SVOM/sb25043004: EP-FXT observations
  58. EP250430a/GRB 250430A: Einstein Probe WXT detection of the X-ray prompt emission
  59. GRB 250424A: CALET Gamma-Ray Burst Monitor detection
  60. IceCube-250429A: Upper limits from a search for additional neutrino events in IceCube
  61. IceCube-250426A: Upper limits from a search for additional neutrino events in IceCube
  62. GRB 250430A: AKO Optical Afterglow Detection
  63. GRB 250430A: Kanata optical upper limit
  64. EP 250427A: Optical counterpart detection by LCO.
  65. GRB 250430A: Swift detection of a burst with optical counterpart
  66. EP250427a/GRB250427A: HCT optical follow-up
  67. SVOM/sb25043004: SVOM detection of a X-ray transient
  68. EP250428b: GROWTH-India telescope optical upper limit
  69. EP250428b: SAO RAS optical upper limit
  70. EP250428b: LAST optical upper limit
  71. GRB 250427A: Swift/UVOT Detection
  72. EP250428b: Global MASTER-Net observations report
  73. EP250428b: Einstein Probe detection of a fast X-ray transient
  74. Fermi-LAT Gamma-ray Observations of IceCube-250426A
  75. EP250427a: Lesedi optical counterpart detection
  76. EP250427A: COLIBRÍ Continuing Optical Observations
  77. GRB250427A/EP250427a GIT optical afterglow detection:
  78. EP250427a: LT optical counterpart detection
  79. GRB 250427A: Swift-XRT refined Analysis
  80. EP250427a / GRB 250427A: LCO optical counterpart detection
  81. EP250427a: REM optical/NIR afterglow detection
  82. GRB 250424A: LCO optical observation
  83. GRB 250427A/ EP250427a: Fermi-GBM Sub-Threshold Detection
  84. EP250427A: COLIBRÍ Optical Detection
  85. EP250427a: TRT optical counterpart detection
  86. EP250427a: Einstein Probe detection of a fast X-ray transient
  87. GRB 250424A: Swift-BAT refined analysis
  88. GRB 250424A: SVOM/GRM observation of a long burst
  89. GRB 250424A: PRIME near-infrared detection
  90. GRB 250424A: WINTER J-band detection
  91. GRB 250424A: EIRSAT-1 GMOD Detection
  92. IceCube-250416A: Upper limits from a search for additional neutrino events in IceCube
  93. IceCube-250421A: Upper limits from a search for additional neutrino events in IceCube
  94. GRB 250419A: Mondy Optical Observations
  95. GRB 250424A: Swift/UVOT Detection
  96. Fermi-LAT gamma-ray observations of IceCube-250421A
  97. GRB 250424A: Skynet Optical Observations
  98. GRB 250424A: Kilonova-Catcher optical afterglow detection
  99. GRB 250330B: GRBAlpha detection
  100. GRB 250424A: Swift-XRT refined Analysis

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