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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"

19549 results found.

  1. GRB 260515A: LCO optical observations
  2. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  3. GRB 260515A: SVOM/VT optical candidate from VHF data
  4. GRB 260515A: JinShan optical counterpart candidate
  5. GRB 260515A: SVOM detection of a burst
  6. EP260514a: GROWTH-India Telescope optical upper limit
  7. GRB 260511B: GMG Optical Upper Limit
  8. EP260514a: Einstein Probe detection of a fast X-ray transient
  9. EP260512a: LCO optical upper limits
  10. GRB 260511B: Mephisto multi-band optical followup
  11. EP260512a: EP-FXT follow-up observation
  12. EP260507a: Xinglong Schmidt optical counterpart detection
  13. Fermi GRB 260513A: Global MASTER-Net observations report
  14. GRB 260511B: further SAO RAS optical observations
  15. EP260512a: COLIBRÍ optical upper limits
  16. EP260512a: Einstein Probe detection of an X-ray transient
  17. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  18. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  19. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  20. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  21. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  22. Konus-Wind detection of GRB 260511A
  23. GRB 260511B: SAO RAS optical observations
  24. GRB 260511B: FRAM-ORM optical detection
  25. GRB 260511B: LCO optical counterpart detection
  26. GRB260511B: MAO/AZT-22 optical observations
  27. GRB 260511B: LCO optical observations
  28. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  29. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  30. GRB 260509A: SAO RAS optical observations
  31. GRB 260511A: REM near-infrared detection
  32. GRB 260511B: GROWTH-India Telescope optical observations
  33. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  34. GRB 260511B: SVOM/VT optical observation with VHF data
  35. GRB 260511B: TRT optical observation
  36. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  37. GRB 260511B SVOM/C-GFT optical counterpart detection
  38. EP260509a: LCO optical upper limits
  39. GRB 260511A: UTGO H50 optical afterglow observation
  40. GRB 260511B: SVOM detection of a burst
  41. EP260509a: EP-FXT non-detection and upper limit
  42. GRB 260511A: SVOM/VT optical observation with VHF data
  43. GRB 260511A: KAIT optical afterglow observations
  44. GRB 260511A: LCO optical afterglow detection
  45. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  46. GRB 260511A: TRT optical counterpart detection
  47. GRB 260511A: SVOM detection of a bright burst
  48. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  49. Fermi GBM Sub-Threshold Detection of GRB 260510B
  50. GRB 260510C: SVOM detection of a burst
  51. GRB 260510B: LCO optical upper limits
  52. EP260509a: Einstein Probe detection of an X-ray transient
  53. GRB 260509A: Liverpool Telescope optical observations
  54. GRB 260510B: SVOM detection of a burst
  55. GRB 260509A: LCO optical observations
  56. SVOM GRB 260509A: MASTER-OAFA optical observation
  57. GRB 260509A: KAIT optical observations
  58. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  59. GRB 260509A: SVOM/VT optical candidate with VHF data
  60. GRB 260509A: LCO optical counterpart detection
  61. GRB 260509A: SVOM detection of a burst
  62. EP260507a: REM optical/NIR observations
  63. EP260507a: refined analysis of the EP-WXT and EP-FXT observations
  64. EP260507a: COLIBRÍ optical observations
  65. EP260507a: NOT optical observations
  66. EP260507a: further Liverpool Telescope observations
  67. EP260507a: Liverpool Telescope optical upper limits
  68. EP260507a: TRT optical counterpart detection
  69. EP260507a: Kinder optical counterpart candidate
  70. EP260507a: LCO optical counterpart
  71. EP260507a: Einstein Probe detection of an X-ray transient
  72. GRB 260504B: SVOM/VT optical upper limits
  73. GRB 260421B: radio observation with the VLA
  74. GRB 260504B: SVOM/MXT refined analysis and potential detection
  75. GRB 260502A: SVOM/GRM observation of a short GRB
  76. GRB 260503A: SVOM/GRM observation of a GRB
  77. Konus-Wind detection of GRB 260411C
  78. GRB 260504B: REM optical/NIR observations
  79. GRB 260504B: LCO z-band upper limit
  80. SVOM GRB 260504B: MASTER-OAFA optical observations
  81. GRB 260504B: SVOM detection of a short burst
  82. SVOM/GRM observation of a bright burst from SGR 1E1841-045
  83. EP260502a: Einstein Probe detection of an X-ray transient
  84. GRB 260429A: SVOM/GRM observation of a short burst
  85. SN 2026kid: Optical follow-up with small-aperture telescopes in Spain and China
  86. EP260430a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  87. GRB 260429B / EP260429a: COLIBRÍ optical upper limit
  88. EP260429a: LCO optical upper limits
  89. EP260430a: LCO optical upper limits
  90. GRB 260430A / EP260430a: COLIBRÍ optical upper limit
  91. EP260430a: Einstein Probe detection of an X-ray transient
  92. EP260429a: EP-WXT detection of a fast X-ray transient
  93. GRB 260428A: SVOM/GRM observation of a possible short burst with extended emission
  94. EP260416a: Mondy and Terskol optical upper limits
  95. GRB 260424B: COLIBRÍ optical upper limit
  96. GRB 260401A: cubesat Avion detection
  97. EP260321a: Upper limits from ATCA radio observations
  98. GRB 260421B: Kilonova-Catcher optical afterglow detection
  99. The EP-WXT trigger 01709258652: Mondy optical observations
  100. EP260416a: Mondy optical observations

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