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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').
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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"

17797 results found.

  1. GRB 260511B: Mephisto multi-band optical followup
  2. The EP-WXT trigger 01709262077 is likely a flaring star
  3. EP260512a: EP-FXT follow-up observation
  4. EP260507a: Xinglong Schmidt optical counterpart detection
  5. GRB 260511B: further SAO RAS optical observations
  6. The EP-WXT trigger 01709262036 is likely a flaring star
  7. EP260512a: COLIBRÍ optical upper limits
  8. EP260512a: Einstein Probe detection of an X-ray transient
  9. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  10. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  11. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  12. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  13. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  14. GRB 260511B: SAO RAS optical observations
  15. GRB 260511B: FRAM-ORM optical detection
  16. GRB 260511A: EP-FXT follow-up observation
  17. GRB 260511B: EP-FXT follow-up observation
  18. GRB 260511B: LCO optical counterpart detection
  19. GRB260511B: MAO/AZT-22 optical observations
  20. GRB 260511B: LCO optical observations
  21. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  22. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  23. GRB 260510B: EP-FXT follow-up observation
  24. GRB 260509A: SAO RAS optical observations
  25. GRB 260511A: REM near-infrared detection
  26. GRB 260511B: GROWTH-India Telescope optical observations
  27. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  28. GRB 260511B: SVOM/VT optical observation with VHF data
  29. GRB 260511B: TRT optical observation
  30. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  31. GRB 260511A: Fermi GBM Detection
  32. GRB 260511B SVOM/C-GFT optical counterpart detection
  33. EP260509a: LCO optical upper limits
  34. GRB 260511A: UTGO H50 optical afterglow observation
  35. GRB 260511B: SVOM detection of a burst
  36. GRB 260510C: EP-FXT follow-up observation
  37. GRB 260510C: SVOM/VT optical counterpart confirmation
  38. EP260509a: EP-FXT non-detection and upper limit
  39. GRB 260511A: SVOM/VT optical observation with VHF data
  40. GRB 260511A: KAIT optical afterglow observations
  41. GRB 260511A: LCO optical afterglow detection
  42. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  43. GRB 260511A: TRT optical counterpart detection
  44. GRB 260511A: SVOM detection of a bright burst
  45. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  46. GRB 260510C: SVOM detection of a burst
  47. GRB 260510B: LCO optical upper limits
  48. EP260509a: Einstein Probe detection of an X-ray transient
  49. GRB 260509A: Liverpool Telescope optical observations
  50. GRB 260510B: SVOM detection of a burst
  51. GRB 260509A: LCO optical observations
  52. GRB 260509A: KAIT optical observations
  53. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  54. GRB 260509A: SVOM/VT optical candidate with VHF data
  55. GRB 260509A: LCO optical counterpart detection
  56. GRB 260509A: SVOM detection of a burst
  57. EP260507a: REM optical/NIR observations
  58. EP260507a: refined analysis of the EP-WXT and EP-FXT observations
  59. EP260507a: COLIBRÍ optical observations
  60. EP260507a: NOT optical observations
  61. EP260507a: further Liverpool Telescope observations
  62. EP260507a: Liverpool Telescope optical upper limits
  63. EP260507a: TRT optical counterpart detection
  64. EP260507a: Kinder optical counterpart candidate
  65. EP260507a: LCO optical counterpart
  66. EP260507a: Einstein Probe detection of an X-ray transient
  67. GRB 260504B: AstroSat CZTI detection
  68. EP260502a is likely a flaring star
  69. GRB 260421B: radio observation with the VLA
  70. GRB 260504B: EP-FXT upper limit
  71. GRB 260502A: SVOM/GRM observation of a short GRB
  72. GRB 260503A: SVOM/GRM observation of a GRB
  73. GRB 260504B: REM optical/NIR observations
  74. GRB 260504B: LCO z-band upper limit
  75. GRB 260504B: SVOM detection of a short burst
  76. SVOM/GRM observation of a bright burst from SGR 1E1841-045
  77. The EP-WXT trigger 01709261576 is likely a flaring star
  78. GRB 260429B / EP260429a: EP-FXT follow-up observation
  79. EP260502a: BOOTES-7 observations of a fading catalogued source close to the X-ray position
  80. GRB 260429B / EP260429a: AstroSat CZTI detection
  81. EP260502a: Einstein Probe detection of an X-ray transient
  82. GRB 260429A: SVOM/GRM observation of a short burst
  83. SN 2026kid: Optical follow-up with small-aperture telescopes in Spain and China
  84. EP260430a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  85. GRB 260429B / EP260429a: COLIBRÍ optical upper limit
  86. EP260429a: LCO optical upper limits
  87. EP260430a: LCO optical upper limits
  88. GRB 260430A / EP260430a: COLIBRÍ optical upper limit
  89. EP260430a: Einstein Probe detection of an X-ray transient
  90. EP260429a: EP-WXT detection of a fast X-ray transient
  91. GRB 260428A: SVOM/GRM observation of a possible short burst with extended emission
  92. EP260416a: Mondy and Terskol optical upper limits
  93. GRB 260424B: COLIBRÍ optical upper limit
  94. EP260321a: Upper limits from ATCA radio observations
  95. GRB 260421B: Kilonova-Catcher optical afterglow detection
  96. EP260416a: Mondy optical observations
  97. GRB 260421B: 3.6m DOT optical observation
  98. EP260416a: ZTSh R band observations
  99. EP-WXT trigger 01709260362: FRAM-ORM optical observations confirm flaring star G 151-9
  100. GRB 260421B: SVOM/GRM observation

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