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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.

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

32548 results found.

  1. GRB 260601A: GECAM-B observation of a short burst
  2. GRB 260601B/EP260601a: J-band upper limit with WINTER
  3. EP260530a/AT 2026nwl: COLIBRÍ optical follow up
  4. EP260530a/AT 2026nwl: KAIT optical observations
  5. GRB 260601B: CALET Gamma-Ray Burst Monitor detection
  6. EP260602a: Optical upper limits with Kinder observations
  7. GRB 260601B / EP260601a: NuSTAR detection of prompt emission
  8. GRB 260601B/EP260601a: SVOM/VT optical observations
  9. GRB 260601B/EP260601a: GECAM-B analysis suggests a possible long duration Type I burst
  10. GRB 260601B: GECAM-B detection of a burst probably associated with EP260601a
  11. EP-WXT trigger 01709266307 (EP260601a): COLIBRÍ optical observations
  12. GRB 260601A: Glowbug gamma-ray detection of a short burst
  13. GRB 260531B: Glowbug gamma-ray detection
  14. GRB 260516D: VLA radio detection
  15. GRB 260527A/EP260527a: Glowbug gamma-ray detection
  16. Fermi GRB 260601A: Global MASTER-Net observations report
  17. GRB 260531B: GECAM-B observation
  18. GRB 260518B: SVOM/ECLAIRs detection of a soft burst possibly associated with EP 260518a and AT 2026ndp
  19. AT 2026nuz: COLIBRÍ optical observations
  20. IPN triangulation of GRB 260527A / EP260527a
  21. EP260527a/GRB 260527A: further FTW optical and NIR observations
  22. GRB 260527A / EP260527a: VLA radio detection
  23. EP260527a/GRB 260527A: optical upper limit with Kinder observations
  24. GRB 260429B / EP260429a: COLIBRÍ optical counterpart candidate
  25. GRB 260529A: GOTO tentative optical afterglow candidate
  26. GRB 260527A/EP260527a: VLT/X-shooter tentative redshift
  27. GRB 260527A/EP260527a: Insight-HXMT detection
  28. Fermi GRB 260529A: Global MASTER-Net observations report
  29. EP260526a: SVOM/VT optical upper limits
  30. GRB 260527A/EP260527a: Gemini GMOS-S Optical Observations
  31. EP260527a / GRB 260527A: VLT detection of the optical and nIR counterpart
  32. EP260527a / GRB 260527A: NOT optical observations
  33. GRB 260527A/EP260527a: FTW optical and NIR observations
  34. EP260527a/GRB 260527A: Infrared J upper limit with MDM/MIRAGE
  35. GRB 260527A: CALET Gamma-Ray Burst Monitor detection
  36. EP260527a/GRB 260527A: EP-FXT follow-up observation
  37. GRB 260527A: GECAM-B detection of a short burst probably associated with EP260527a
  38. GRB 260526A: GECAM-B observation
  39. Konus-Wind detection of GRB 260527A (short/hard) ~4 min before EP260527a
  40. EP260526a: EP-FXT follow-up observation
  41. EP260527a: SVOM/VT optical observation
  42. EP260527a: COLIBRÍ optical detection
  43. EP260526a: LCO optical upper limits
  44. EP260526a: Einstein Probe detection of a fast X-ray transient
  45. GRB 260525A: AstroSat CZTI detection
  46. The EP-WXT trigger 01709266106 is not a real source
  47. Fermi GRB 260526A: Global MASTER-Net observations report
  48. Fermi GRB 260525A: Global MASTER-Net observations report
  49. GRB 260523B: AstroSat CZTI detection
  50. GRB 260523B: GECAM-B observation
  51. Fermi GRB 260523A: Global MASTER-Net observations report
  52. GRB 260522A: Fermi GBM Observation
  53. GRB 260522B: NuSTAR detection of prompt emission
  54. EP260518a (AT2026ndp): LCO observations and Gemini-South Redshift z = 2.28
  55. GRB 260522A: GOTO optical upper limit
  56. Fermi GRB 260522A: Global MASTER-Net observations report
  57. GRB 260522A: Fermi-LAT detection
  58. GRB 260519C: SVOM/GRM observation
  59. GRB 260511A: iTelescope T-75 optical detection
  60. GRB 260520B: SVOM/GRM observation
  61. GRB 260411B: TERI Gamma-ray detection
  62. GRB 260407A: TERI Gamma-ray detection
  63. GRB 260307A: TERI Gamma-ray detection
  64. GRB 260225D: TERI Gamma-ray detection
  65. GRB 251118A: TERI Gamma-ray detection
  66. GRB 251113A: TERI Gamma-ray detection
  67. GRB 260428A: TERI Gamma-ray detection
  68. Konus-Wind detection of GRB 260519C
  69. GRB 260509A: SVOM/ECLAIRs refined analysis
  70. GRB 260519C: NuSTAR detection of prompt emission
  71. Konus-Wind detection of GRB 260518A
  72. GRB 260516D: SVOM/ECLAIRs refined analysis
  73. GRB 260515A: SVOM/ECLAIRs refined analysis
  74. GRB 260421B: radio detection with the VLA
  75. GRID detection of GRB 260511A
  76. GRB 260509A: CrAO ZTSh optical upper limit (Duplicate Submission)
  77. GRB 260509A: CrAO ZTSh optical upper limit
  78. GRB 260516D: EP-FXT follow-up observation
  79. GRB 260516D: GOTO optical counterpart detection
  80. GRB 260516D: LCO optical observations
  81. GRB 260515A: further Liverpool Telescope observations
  82. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  83. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  84. GRB 260516D: GROWTH-India Telescope optical detection
  85. GRB 260516D: SVOM/VT optical bright candidate
  86. GRB 260515A: CrAO ZTSh BVRI optical observations
  87. Fermi GRB 260516C: Global MASTER-Net observations report
  88. Konus-Wind detection of GRB 260515A
  89. GRB 260515A: Liverpool Telescope optical detection
  90. GRB 260515A: LCO optical counterpart detection
  91. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  92. GRB 260515A: EP-FXT follow-up observation
  93. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  94. EP260514a: NOT optical counterpart confirmation
  95. EP260514a: TRT optical counterpart candidate
  96. EP260514a: SVOM/VT optical candidate
  97. Fermi GRB 260516B: Global MASTER-Net observations report
  98. GRB 260515A: SVOM/VT optical observations
  99. GRB 260515A: OHP/T193 optical observations
  100. EP260514a: COLIBRÍ optical upper limits

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