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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

21766 results found.

  1. GRB 260518B: SVOM/ECLAIRs detection of a soft burst possibly associated with EP 260518a and AT 2026ndp
  2. AT2026nik: EP-FXT X-ray counterpart
  3. AT 2026nuz: COLIBRÍ optical observations
  4. EP260527a/GRB 260527A: optical upper limit with Kinder observations
  5. GRB 260429B / EP260429a: COLIBRÍ optical counterpart candidate
  6. GRB 260527A/EP260527a: VLT/X-shooter tentative redshift
  7. EP260526a: SVOM/VT optical upper limits
  8. EP260527a / GRB 260527A: VLT detection of the optical and nIR counterpart
  9. EP260527a/GRB 260527A: Infrared J upper limit with MDM/MIRAGE
  10. EP260527a/GRB 260527A: EP-FXT follow-up observation
  11. Konus-Wind detection of GRB 260527A (short/hard) ~4 min before EP260527a
  12. EP260527a: SVOM/VT optical observation
  13. EP260527a: COLIBRÍ optical detection
  14. EP260527a: Einstein Probe detection of a fast X-ray transient
  15. GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
  16. EP260526a: LCO optical upper limits
  17. EP260526a: Einstein Probe detection of a fast X-ray transient
  18. EP260526.405: COLIBRÍ optical upper limits
  19. The EP-WXT trigger 01709266106 is not a real source
  20. EP01709266106 (EP260526a?): Liverpool Telescope upper limits
  21. EP-WXT 01709266106: NOT optical upper limits
  22. GRB 260522A: GOTO optical upper limit
  23. EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
  24. GRB 260522A: Fermi-LAT detection
  25. GRB 260519C: SVOM/GRM observation
  26. GRB 260511A: iTelescope T-75 optical detection
  27. GRB 260520B: SVOM/GRM observation
  28. Konus-Wind detection of GRB 260519C
  29. GRB 260509A: SVOM/ECLAIRs refined analysis
  30. GRB 260518A: AstroSat CZTI detection of a long burst
  31. GRB 260516D: SVOM/ECLAIRs refined analysis
  32. GRB 260515A: SVOM/ECLAIRs refined analysis
  33. GRB 260421B: radio detection with the VLA
  34. GRB 260509A: CrAO ZTSh optical upper limit
  35. GRB 260516D: GOTO optical counterpart detection
  36. GRB 260516D: LCO optical observations
  37. GRB 260515A: further Liverpool Telescope observations
  38. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  39. GRB 260516D: GROWTH-India Telescope optical detection
  40. GRB 260516D: SVOM/VT optical bright candidate
  41. GRB 260515A: CrAO ZTSh BVRI optical observations
  42. GRB 260516D: SVOM possible detection of a burst
  43. GRB 260515A: Liverpool Telescope optical detection
  44. GRB 260515A: LCO optical counterpart detection
  45. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  46. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  47. EP260514a: NOT optical counterpart confirmation
  48. EP260514a: TRT optical counterpart candidate
  49. EP260514a: SVOM/VT optical candidate
  50. GRB 260515A: OHP/T193 optical observations
  51. EP260514a: COLIBRÍ optical upper limits
  52. GRB 260515A: LCO optical observations
  53. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  54. GRB 260515A: SVOM/VT optical candidate from VHF data
  55. GRB 260515A: JinShan optical counterpart candidate
  56. GRB 260515A: SVOM detection of a burst
  57. EP260514a: GROWTH-India Telescope optical upper limit
  58. Konus-Wind detection of GRB 260512A
  59. GRB 260511B: GMG Optical Upper Limit
  60. EP260514a: Einstein Probe detection of a fast X-ray transient
  61. EP260512a: LCO optical upper limits
  62. GRB 260511B: Mephisto multi-band optical followup
  63. GRB 260512A: AstroSat CZTI detection
  64. EP260512a: EP-FXT follow-up observation
  65. EP260507a: Xinglong Schmidt optical counterpart detection
  66. GRB 260511B: further SAO RAS optical observations
  67. Konus-Wind detection of GRB 260511B
  68. EP260512a: COLIBRÍ optical upper limits
  69. EP260512a: Einstein Probe detection of an X-ray transient
  70. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  71. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  72. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  73. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  74. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  75. Konus-Wind detection of GRB 260511A
  76. GRB 260511B: SAO RAS optical observations
  77. GRB 260511B: FRAM-ORM optical detection
  78. GRB 260511B: LCO optical counterpart detection
  79. GRB260511B: MAO/AZT-22 optical observations
  80. GRB 260511B: LCO optical observations
  81. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  82. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  83. GRB 260509A: SAO RAS optical observations
  84. GRB 260511A: REM near-infrared detection
  85. GRB 260511B: GROWTH-India Telescope optical observations
  86. GRB 260511B: AstroSat CZTI detection
  87. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  88. GRB 260511B: SVOM/VT optical observation with VHF data
  89. GRB 260511B: TRT optical observation
  90. GRB 260510B: SVOM/ECLAIRs refined analysis
  91. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  92. GRB 260511B SVOM/C-GFT optical counterpart detection
  93. EP260509a: LCO optical upper limits
  94. GRB 260511A: UTGO H50 optical afterglow observation
  95. GRB 260510C: AstroSat CZTI detection
  96. GRB 260511B: SVOM detection of a burst
  97. EP260509a: EP-FXT non-detection and upper limit
  98. GRB 260511A: SVOM/VT optical observation with VHF data
  99. GRB 260511A: KAIT optical afterglow observations
  100. GRB 260511A: LCO optical afterglow detection

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