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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"

32571 results found.

  1. EP260602a: GTC and Liverpool Telescope optical observations
  2. Konus-Wind detection of GRB 260601B/EP260601a
  3. GRB 260603A: EP-FXT follow-up observation
  4. EP260601a/GRB 260601B: EP-FXT follow-up observation
  5. GRB 260601B / EP260601a: Mondy optical upper limit
  6. EP260602b: EP-FXT follow-up observation
  7. GRB 260601B/EP260601a: Glowbug gamma-ray detection
  8. GRB 260603A: Kilonova-Catcher optical upper limit
  9. GRB 260603A: SVOM/VT optical observations
  10. EP260602a: NOT NIR J-band observations
  11. GRB 260603A: SVOM/COLIBRÍ (FM-GFT) photometric redshift z = 3.57
  12. EP260602d: Einstein Probe detection of a fast X-ray transient
  13. EP260602a: SVOM/VT optical magnitudes correction
  14. GRB 260601A: SVOM/GRM observation of a short burst
  15. EP260602c: Einstein Probe detection of a fast X-ray transient
  16. GRB 260603A: SVOM/COLIBRÍ (GFT-FM) optical counterpart candidate
  17. EP260602a: COLIBRÍ optical observations
  18. GRB260601B/EP260601a: NOT near-infrared observations
  19. EP260602b: Einstein Probe detection of a fast X-ray transient
  20. GRB 260601B/EP260601a: Insight-HXMT detection
  21. Fermi GRB 260602B: Global MASTER-Net observations report
  22. Fermi GRB 260602B: Global MASTER-Net observations report
  23. EP260602a: SVOM/VT optical candidate
  24. GRB 260601A: GECAM-B observation of a short burst
  25. GRB 260601B/EP260601a: J-band upper limit with WINTER
  26. EP260530a/AT 2026nwl: COLIBRÍ optical follow up
  27. EP260530a/AT 2026nwl: KAIT optical observations
  28. GRB 260601B: CALET Gamma-Ray Burst Monitor detection
  29. EP260602a: Optical upper limits with Kinder observations
  30. GRB 260601B / EP260601a: NuSTAR detection of prompt emission
  31. GRB 260601B/EP260601a: SVOM/VT optical observations
  32. GRB 260601B/EP260601a: GECAM-B analysis suggests a possible long duration Type I burst
  33. GRB 260601B: GECAM-B detection of a burst probably associated with EP260601a
  34. EP-WXT trigger 01709266307 (EP260601a): COLIBRÍ optical observations
  35. GRB 260601A: Glowbug gamma-ray detection of a short burst
  36. GRB 260531B: Glowbug gamma-ray detection
  37. GRB 260516D: VLA radio detection
  38. GRB 260527A/EP260527a: Glowbug gamma-ray detection
  39. Fermi GRB 260601A: Global MASTER-Net observations report
  40. GRB 260531B: GECAM-B observation
  41. GRB 260518B: SVOM/ECLAIRs detection of a soft burst possibly associated with EP 260518a and AT 2026ndp
  42. AT 2026nuz: COLIBRÍ optical observations
  43. IPN triangulation of GRB 260527A / EP260527a
  44. EP260527a/GRB 260527A: further FTW optical and NIR observations
  45. GRB 260527A / EP260527a: VLA radio detection
  46. EP260527a/GRB 260527A: optical upper limit with Kinder observations
  47. GRB 260429B / EP260429a: COLIBRÍ optical counterpart candidate
  48. GRB 260529A: GOTO tentative optical afterglow candidate
  49. GRB 260527A/EP260527a: VLT/X-shooter tentative redshift
  50. GRB 260527A/EP260527a: Insight-HXMT detection
  51. Fermi GRB 260529A: Global MASTER-Net observations report
  52. EP260526a: SVOM/VT optical upper limits
  53. GRB 260527A/EP260527a: Gemini GMOS-S Optical Observations
  54. EP260527a / GRB 260527A: VLT detection of the optical and nIR counterpart
  55. EP260527a / GRB 260527A: NOT optical observations
  56. GRB 260527A/EP260527a: FTW optical and NIR observations
  57. EP260527a/GRB 260527A: Infrared J upper limit with MDM/MIRAGE
  58. GRB 260527A: CALET Gamma-Ray Burst Monitor detection
  59. EP260527a/GRB 260527A: EP-FXT follow-up observation
  60. GRB 260527A: GECAM-B detection of a short burst probably associated with EP260527a
  61. GRB 260526A: GECAM-B observation
  62. Konus-Wind detection of GRB 260527A (short/hard) ~4 min before EP260527a
  63. EP260526a: EP-FXT follow-up observation
  64. EP260527a: SVOM/VT optical observation
  65. EP260527a: COLIBRÍ optical detection
  66. EP260526a: LCO optical upper limits
  67. EP260526a: Einstein Probe detection of a fast X-ray transient
  68. GRB 260525A: AstroSat CZTI detection
  69. The EP-WXT trigger 01709266106 is not a real source
  70. Fermi GRB 260526A: Global MASTER-Net observations report
  71. Fermi GRB 260525A: Global MASTER-Net observations report
  72. GRB 260523B: AstroSat CZTI detection
  73. GRB 260523B: GECAM-B observation
  74. Fermi GRB 260523A: Global MASTER-Net observations report
  75. GRB 260522A: Fermi GBM Observation
  76. GRB 260522B: NuSTAR detection of prompt emission
  77. EP260518a (AT2026ndp): LCO observations and Gemini-South Redshift z = 2.28
  78. GRB 260522A: GOTO optical upper limit
  79. Fermi GRB 260522A: Global MASTER-Net observations report
  80. GRB 260522A: Fermi-LAT detection
  81. GRB 260519C: SVOM/GRM observation
  82. GRB 260511A: iTelescope T-75 optical detection
  83. GRB 260520B: SVOM/GRM observation
  84. GRB 260411B: TERI Gamma-ray detection
  85. GRB 260407A: TERI Gamma-ray detection
  86. GRB 260307A: TERI Gamma-ray detection
  87. GRB 260225D: TERI Gamma-ray detection
  88. GRB 251118A: TERI Gamma-ray detection
  89. GRB 251113A: TERI Gamma-ray detection
  90. GRB 260428A: TERI Gamma-ray detection
  91. Konus-Wind detection of GRB 260519C
  92. GRB 260509A: SVOM/ECLAIRs refined analysis
  93. GRB 260519C: NuSTAR detection of prompt emission
  94. Konus-Wind detection of GRB 260518A
  95. GRB 260516D: SVOM/ECLAIRs refined analysis
  96. GRB 260515A: SVOM/ECLAIRs refined analysis
  97. GRB 260421B: radio detection with the VLA
  98. GRID detection of GRB 260511A
  99. GRB 260509A: CrAO ZTSh optical upper limit (Duplicate Submission)
  100. GRB 260509A: CrAO ZTSh optical upper limit

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