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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"

28096 results found.

  1. AT2026nik: EP-FXT X-ray counterpart
  2. Fermi trigger No 801900520: Global MASTER-Net observations report
  3. GRB 260531A: MAXI/GSC detection
  4. AT 2026nuz: COLIBRÍ optical observations
  5. EP260527a/GRB 260527A: optical upper limit with Kinder observations
  6. GRB 260429B / EP260429a: COLIBRÍ optical counterpart candidate
  7. GRB 260527A/EP260527a: VLT/X-shooter tentative redshift
  8. Fermi GRB 260529A: Global MASTER-Net observations report
  9. EP260526a: SVOM/VT optical upper limits
  10. EP260527a / GRB 260527A: VLT detection of the optical and nIR counterpart
  11. EP260527a/GRB 260527A: Infrared J upper limit with MDM/MIRAGE
  12. EP260527a/GRB 260527A: EP-FXT follow-up observation
  13. GRB 260527A: GECAM-B detection of a short burst probably associated with EP260527a
  14. EP260527a: SVOM/VT optical observation
  15. EP260527a: COLIBRÍ optical detection
  16. EP260527a: Einstein Probe detection of a fast X-ray transient
  17. Fermi trigger No 801580882: Global MASTER-Net observations report
  18. EP260526a: LCO optical upper limits
  19. EP260526a: Einstein Probe detection of a fast X-ray transient
  20. EP260526.405: COLIBRÍ optical upper limits
  21. The EP-WXT trigger 01709266106 is not a real source
  22. Fermi GRB 260526A: Global MASTER-Net observations report
  23. EP01709266106 (EP260526a?): Liverpool Telescope upper limits
  24. EP-WXT 01709266106: NOT optical upper limits
  25. Fermi GRB 260525A: Global MASTER-Net observations report
  26. GRB 260523B: AstroSat CZTI detection
  27. Fermi GRB 260523A: Global MASTER-Net observations report
  28. GRB 260522A: Fermi GBM Observation
  29. GRB 260522B: NuSTAR detection of prompt emission
  30. EP260518a (AT2026ndp): LCO observations and Gemini-South Redshift z = 2.28
  31. Fermi trigger No 801135305: Global MASTER-Net observations report
  32. Fermi GRB 260522A: Global MASTER-Net observations report
  33. EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
  34. GRB 260511A: iTelescope T-75 optical detection
  35. GRB 260520B: SVOM/GRM observation
  36. GRB 260411B: TERI Gamma-ray detection
  37. GRB 260407A: TERI Gamma-ray detection
  38. GRB 260307A: TERI Gamma-ray detection
  39. GRB 260225D: TERI Gamma-ray detection
  40. GRB 251118A: TERI Gamma-ray detection
  41. GRB 251113A: TERI Gamma-ray detection
  42. GRB 260428A: TERI Gamma-ray detection
  43. GRB 260519C: NuSTAR detection of prompt emission
  44. Konus-Wind detection of GRB 260518A
  45. GRB 260516D: SVOM/ECLAIRs refined analysis
  46. GRB 260421B: radio detection with the VLA
  47. GRB 260509A: CrAO ZTSh optical upper limit
  48. GRB 260516D: GOTO optical counterpart detection
  49. GRB 260516D: LCO optical observations
  50. GRB 260515A: further Liverpool Telescope observations
  51. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  52. GRB 260516D: GROWTH-India Telescope optical detection
  53. GRB 260516D: SVOM/VT optical bright candidate
  54. GRB 260515A: CrAO ZTSh BVRI optical observations
  55. Fermi GRB 260516C: Global MASTER-Net observations report
  56. SVOM GRB260516D: Global MASTER-Net observations report
  57. GRB 260516D: SVOM possible detection of a burst
  58. GRB 260515A: LCO optical counterpart detection
  59. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  60. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  61. EP260514a: NOT optical counterpart confirmation
  62. EP260514a: TRT optical counterpart candidate
  63. EP260514a: SVOM/VT optical candidate
  64. Fermi GRB 260516B: Global MASTER-Net observations report
  65. GRB 260515A: OHP/T193 optical observations
  66. EP260514a: COLIBRÍ optical upper limits
  67. GRB 260515A: LCO optical observations
  68. SVOM GRB 260515A: Global MASTER-Net observations report
  69. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  70. GRB 260515A: SVOM/VT optical candidate from VHF data
  71. GRB 260515A: JinShan optical counterpart candidate
  72. GRB 260515A: SVOM detection of a burst
  73. GRB 260510C: Glowbug gamma-ray detection
  74. EP260514a: GROWTH-India Telescope optical upper limit
  75. GRB 260511B: GMG Optical Upper Limit
  76. EP260514a: Global MASTER-Net observations report
  77. EP260514a: Einstein Probe detection of a fast X-ray transient
  78. EP260512a: LCO optical upper limits
  79. GRB 260511B: Mephisto multi-band optical followup
  80. Fermi GRB 260514A: Global MASTER-Net observations report
  81. GRB 260512A: AstroSat CZTI detection
  82. EP260512a: EP-FXT follow-up observation
  83. EP260507a: Xinglong Schmidt optical counterpart detection
  84. EP260512a: Global MASTER-Net observations report
  85. Fermi GRB 260513A: Global MASTER-Net observations report
  86. Fermi GRB 260512A: Global MASTER-Net observations report
  87. GRB 260511B: further SAO RAS optical observations
  88. GRB 260509A: SVOM/VT optical observations
  89. The EP-WXT trigger 01709262036 is likely a flaring star
  90. EP260512a: COLIBRÍ optical upper limits
  91. EP260512a: Einstein Probe detection of an X-ray transient
  92. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  93. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  94. GRB 260512A: NuSTAR detection of prompt emission
  95. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  96. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  97. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  98. GRB 260511A: Glowbug gamma-ray detection
  99. GRB 260511B: SAO RAS optical observations
  100. GRB 260510D: Glowbug gamma-ray detection of a likely short burst

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