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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"

28097 results found.

  1. GRB 260601A: Fermi GBM Final Real-time Localization
  2. The EP-WXT trigger 01709266272 is likely a flaring star
  3. AT2026nik: EP-FXT X-ray counterpart
  4. Fermi trigger No 801900520: Global MASTER-Net observations report
  5. GRB 260531A: MAXI/GSC detection
  6. AT 2026nuz: COLIBRÍ optical observations
  7. EP260527a/GRB 260527A: optical upper limit with Kinder observations
  8. GRB 260429B / EP260429a: COLIBRÍ optical counterpart candidate
  9. GRB 260527A/EP260527a: VLT/X-shooter tentative redshift
  10. Fermi GRB 260529A: Global MASTER-Net observations report
  11. EP260526a: SVOM/VT optical upper limits
  12. EP260527a / GRB 260527A: VLT detection of the optical and nIR counterpart
  13. EP260527a/GRB 260527A: Infrared J upper limit with MDM/MIRAGE
  14. EP260527a/GRB 260527A: EP-FXT follow-up observation
  15. GRB 260527A: GECAM-B detection of a short burst probably associated with EP260527a
  16. EP260527a: SVOM/VT optical observation
  17. EP260527a: COLIBRÍ optical detection
  18. EP260527a: Einstein Probe detection of a fast X-ray transient
  19. Fermi trigger No 801580882: Global MASTER-Net observations report
  20. EP260526a: LCO optical upper limits
  21. EP260526a: Einstein Probe detection of a fast X-ray transient
  22. EP260526.405: COLIBRÍ optical upper limits
  23. The EP-WXT trigger 01709266106 is not a real source
  24. Fermi GRB 260526A: Global MASTER-Net observations report
  25. EP01709266106 (EP260526a?): Liverpool Telescope upper limits
  26. EP-WXT 01709266106: NOT optical upper limits
  27. Fermi GRB 260525A: Global MASTER-Net observations report
  28. GRB 260523B: AstroSat CZTI detection
  29. Fermi GRB 260523A: Global MASTER-Net observations report
  30. GRB 260522A: Fermi GBM Observation
  31. GRB 260522B: NuSTAR detection of prompt emission
  32. EP260518a (AT2026ndp): LCO observations and Gemini-South Redshift z = 2.28
  33. Fermi trigger No 801135305: Global MASTER-Net observations report
  34. Fermi GRB 260522A: Global MASTER-Net observations report
  35. EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
  36. GRB 260511A: iTelescope T-75 optical detection
  37. GRB 260520B: SVOM/GRM observation
  38. GRB 260411B: TERI Gamma-ray detection
  39. GRB 260407A: TERI Gamma-ray detection
  40. GRB 260307A: TERI Gamma-ray detection
  41. GRB 260225D: TERI Gamma-ray detection
  42. GRB 251118A: TERI Gamma-ray detection
  43. GRB 251113A: TERI Gamma-ray detection
  44. GRB 260428A: TERI Gamma-ray detection
  45. GRB 260519C: NuSTAR detection of prompt emission
  46. Konus-Wind detection of GRB 260518A
  47. GRB 260516D: SVOM/ECLAIRs refined analysis
  48. GRB 260421B: radio detection with the VLA
  49. GRB 260509A: CrAO ZTSh optical upper limit
  50. GRB 260516D: GOTO optical counterpart detection
  51. GRB 260516D: LCO optical observations
  52. GRB 260515A: further Liverpool Telescope observations
  53. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  54. GRB 260516D: GROWTH-India Telescope optical detection
  55. GRB 260516D: SVOM/VT optical bright candidate
  56. GRB 260515A: CrAO ZTSh BVRI optical observations
  57. Fermi GRB 260516C: Global MASTER-Net observations report
  58. SVOM GRB260516D: Global MASTER-Net observations report
  59. GRB 260516D: SVOM possible detection of a burst
  60. GRB 260515A: LCO optical counterpart detection
  61. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  62. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  63. EP260514a: NOT optical counterpart confirmation
  64. EP260514a: TRT optical counterpart candidate
  65. EP260514a: SVOM/VT optical candidate
  66. Fermi GRB 260516B: Global MASTER-Net observations report
  67. GRB 260515A: OHP/T193 optical observations
  68. EP260514a: COLIBRÍ optical upper limits
  69. GRB 260515A: LCO optical observations
  70. SVOM GRB 260515A: Global MASTER-Net observations report
  71. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  72. GRB 260515A: SVOM/VT optical candidate from VHF data
  73. GRB 260515A: JinShan optical counterpart candidate
  74. GRB 260515A: SVOM detection of a burst
  75. GRB 260510C: Glowbug gamma-ray detection
  76. EP260514a: GROWTH-India Telescope optical upper limit
  77. GRB 260511B: GMG Optical Upper Limit
  78. EP260514a: Global MASTER-Net observations report
  79. EP260514a: Einstein Probe detection of a fast X-ray transient
  80. EP260512a: LCO optical upper limits
  81. GRB 260511B: Mephisto multi-band optical followup
  82. Fermi GRB 260514A: Global MASTER-Net observations report
  83. GRB 260512A: AstroSat CZTI detection
  84. EP260512a: EP-FXT follow-up observation
  85. EP260507a: Xinglong Schmidt optical counterpart detection
  86. EP260512a: Global MASTER-Net observations report
  87. Fermi GRB 260513A: Global MASTER-Net observations report
  88. Fermi GRB 260512A: Global MASTER-Net observations report
  89. GRB 260511B: further SAO RAS optical observations
  90. GRB 260509A: SVOM/VT optical observations
  91. The EP-WXT trigger 01709262036 is likely a flaring star
  92. EP260512a: COLIBRÍ optical upper limits
  93. EP260512a: Einstein Probe detection of an X-ray transient
  94. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  95. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  96. GRB 260512A: NuSTAR detection of prompt emission
  97. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  98. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  99. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  100. GRB 260511A: Glowbug gamma-ray detection

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