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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"

19810 results found.

  1. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  2. GRB 260515A: SVOM/VT optical candidate from VHF data
  3. GRB 260515A: JinShan optical counterpart candidate
  4. GRB 260515A: SVOM detection of a burst
  5. EP260514a: GROWTH-India Telescope optical upper limit
  6. GRB 260511B: GMG Optical Upper Limit
  7. EP260514a: Einstein Probe detection of a fast X-ray transient
  8. EP260512a: LCO optical upper limits
  9. GRB 260511B: Mephisto multi-band optical followup
  10. EP260512a: EP-FXT follow-up observation
  11. EP260507a: Xinglong Schmidt optical counterpart detection
  12. GRB 260511B: further SAO RAS optical observations
  13. EP260512a: COLIBRÍ optical upper limits
  14. EP260512a: Einstein Probe detection of an X-ray transient
  15. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  16. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  17. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  18. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  19. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  20. MASS-Cube (GRID 2.0) detection of GRB 260511A
  21. MASS-Cube (GRID 2.0) detection of GRB 260507A
  22. GRB 260511B: SAO RAS optical observations
  23. GRB 260511B: FRAM-ORM optical detection
  24. GRB 260511B: LCO optical counterpart detection
  25. GRB260511B: MAO/AZT-22 optical observations
  26. GRB 260511B: LCO optical observations
  27. GRB 260511B: OHP/T193 spectroscopic 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: AstroSat CZTI detection
  34. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  35. GRB 260511B: SVOM/VT optical observation with VHF data
  36. GRB 260511B: TRT optical observation
  37. GRB 260510B: SVOM/ECLAIRs refined analysis
  38. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  39. GRB 260511B SVOM/C-GFT optical counterpart detection
  40. EP260509a: LCO optical upper limits
  41. GRB 260511A: UTGO H50 optical afterglow observation
  42. GRB 260511B: SVOM detection of a burst
  43. EP260509a: EP-FXT non-detection and upper limit
  44. GRB 260511A: SVOM/VT optical observation with VHF data
  45. GRB 260511A: KAIT optical afterglow observations
  46. GRB 260511A: LCO optical afterglow detection
  47. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  48. GRB 260511A: TRT optical counterpart detection
  49. GRB 260511A: SVOM detection of a bright burst
  50. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  51. GRB 260510B: GOTO early upper limit
  52. GRB 260510C: SVOM detection of a burst
  53. GRB 260510B: LCO optical upper limits
  54. EP260509a: Einstein Probe detection of an X-ray transient
  55. GRB 260509A: Liverpool Telescope optical observations
  56. GRB 260510B: SVOM detection of a burst
  57. GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
  58. GRB 260509A: LCO optical observations
  59. SVOM GRB 260509A: MASTER-OAFA optical observation
  60. GRB 260509A: KAIT optical observations
  61. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  62. GRB 260509A: SVOM/VT optical candidate with VHF data
  63. GRB 260509A: LCO optical counterpart detection
  64. GRB 260509A: SVOM detection of a burst
  65. GRB 260506B: AstroSat CZTI detection
  66. IceCube-260504A: Upper limits from a search for additional neutrino events in IceCube
  67. EP260507a: REM optical/NIR observations
  68. EP260507a: refined analysis of the EP-WXT and EP-FXT observations
  69. GRB 260507B / EP260507a: Fermi-GBM Sub-Threshold Detection
  70. EP260507a: COLIBRÍ optical observations
  71. EP260507a: NOT optical observations
  72. EP260507a: further Liverpool Telescope observations
  73. EP260507a: Liverpool Telescope optical upper limits
  74. EP260507a: TRT optical counterpart detection
  75. EP260507a: Kinder optical counterpart candidate
  76. EP260507a: LCO optical counterpart
  77. EP260507a: Einstein Probe detection of an X-ray transient
  78. GRB 260504B: SVOM/ECLAIRs refined analysis
  79. EP260502a is likely a flaring star
  80. GRB 260503A: GECAM-B observation of a burst
  81. GRB 260421B: radio observation with the VLA
  82. Konus-Wind detection of a burst from SGR 1E1841-045 on 2026 May 2
  83. Fermi-LAT Gamma-ray Observations of IceCube-260504A
  84. GRB 260430B: AstroSat CZTI detection of a long burst
  85. GRB 260502A: SVOM/GRM observation of a short GRB
  86. GRB 260503A: SVOM/GRM observation of a GRB
  87. GRB 260504B: REM optical/NIR observations
  88. GRB 260504B: LCO z-band upper limit
  89. SVOM GRB 260504B: MASTER-OAFA optical observations
  90. GRB 260504B: SVOM detection of a short burst
  91. GRB 260504A: Fermi GBM Final Real-time Localization
  92. SVOM/GRM observation of a bright burst from SGR 1E1841-045
  93. EP260502a: Einstein Probe detection of an X-ray transient
  94. GRB 260429A: SVOM/GRM observation of a short burst
  95. SN 2026kid: Optical follow-up with small-aperture telescopes in Spain and China
  96. EP260430a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  97. GRB 260429B / EP260429a: COLIBRÍ optical upper limit
  98. EP260429a: LCO optical upper limits
  99. EP260430a: LCO optical upper limits
  100. GRB 260430A / EP260430a: COLIBRÍ optical upper limit

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