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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"

20348 results found.

  1. EP260527a: SVOM/VT optical observation
  2. EP260527a: COLIBRÍ optical detection
  3. EP260527a: Einstein Probe detection of a fast X-ray transient
  4. GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
  5. EP260526a: LCO optical upper limits
  6. EP260526a: Einstein Probe detection of a fast X-ray transient
  7. EP260526.405: COLIBRÍ optical upper limits
  8. The EP-WXT trigger 01709266106 is not a real source
  9. EP01709266106 (EP260526a?): Liverpool Telescope upper limits
  10. EP-WXT 01709266106: NOT optical upper limits
  11. Fermi GRB 260525A: Global MASTER-Net observations report
  12. GRB 260523B: AstroSat CZTI detection
  13. EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
  14. GRB 260511A: iTelescope T-75 optical detection
  15. GRB 260520B: SVOM/GRM observation
  16. GRB 260509A: SVOM/ECLAIRs refined analysis
  17. GRB 260516D: SVOM/ECLAIRs refined analysis
  18. GRB 260515A: SVOM/ECLAIRs refined analysis
  19. GRB 260421B: radio detection with the VLA
  20. GRID detection of GRB 260511A
  21. GRB 260509A: CrAO ZTSh optical upper limit
  22. GRB 260516D: GOTO optical counterpart detection
  23. GRB 260516D: LCO optical observations
  24. GRB 260515A: further Liverpool Telescope observations
  25. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  26. GRB 260516D: GROWTH-India Telescope optical detection
  27. GRB 260516D: SVOM/VT optical bright candidate
  28. GRB 260515A: CrAO ZTSh BVRI optical observations
  29. GRB 260515A: LCO optical counterpart detection
  30. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  31. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  32. EP260514a: NOT optical counterpart confirmation
  33. EP260514a: TRT optical counterpart candidate
  34. EP260514a: SVOM/VT optical candidate
  35. GRB 260515A: OHP/T193 optical observations
  36. EP260514a: COLIBRÍ optical upper limits
  37. GRID detection of GRB 260507A
  38. GRB 260515A: LCO optical observations
  39. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  40. GRB 260515A: SVOM/VT optical candidate from VHF data
  41. GRB 260515A: JinShan optical counterpart candidate
  42. GRB 260515A: SVOM detection of a burst
  43. EP260514a: GROWTH-India Telescope optical upper limit
  44. GRB 260511B: GMG Optical Upper Limit
  45. EP260514a: Einstein Probe detection of a fast X-ray transient
  46. EP260512a: LCO optical upper limits
  47. GRB 260511B: Mephisto multi-band optical followup
  48. EP260512a: EP-FXT follow-up observation
  49. EP260507a: Xinglong Schmidt optical counterpart detection
  50. GRB 260511B: further SAO RAS optical observations
  51. EP260512a: COLIBRÍ optical upper limits
  52. EP260512a: Einstein Probe detection of an X-ray transient
  53. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  54. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  55. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  56. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  57. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  58. MASS-Cube (GRID 2.0) detection of GRB 260511A
  59. MASS-Cube (GRID 2.0) detection of GRB 260507A
  60. GRB 260511B: SAO RAS optical observations
  61. GRB 260511B: FRAM-ORM optical detection
  62. GRB 260511B: LCO optical counterpart detection
  63. GRB260511B: MAO/AZT-22 optical observations
  64. GRB 260511B: LCO optical observations
  65. GRB 260511B: OHP/T193 spectroscopic observations
  66. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  67. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  68. GRB 260509A: SAO RAS optical observations
  69. GRB 260511A: REM near-infrared detection
  70. GRB 260511B: GROWTH-India Telescope optical observations
  71. GRB 260511B: AstroSat CZTI detection
  72. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  73. GRB 260511B: SVOM/VT optical observation with VHF data
  74. GRB 260511B: TRT optical observation
  75. GRB 260510B: SVOM/ECLAIRs refined analysis
  76. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  77. GRB 260511B SVOM/C-GFT optical counterpart detection
  78. EP260509a: LCO optical upper limits
  79. GRB 260511A: UTGO H50 optical afterglow observation
  80. GRB 260511B: SVOM detection of a burst
  81. EP260509a: EP-FXT non-detection and upper limit
  82. GRB 260511A: SVOM/VT optical observation with VHF data
  83. GRB 260511A: KAIT optical afterglow observations
  84. GRB 260511A: LCO optical afterglow detection
  85. GRB 260511A: SVOM/COLIBRÍ (FM-GFT) optical counterpart
  86. GRB 260511A: TRT optical counterpart detection
  87. GRB 260511A: SVOM detection of a bright burst
  88. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  89. GRB 260510B: GOTO early upper limit
  90. GRB 260510C: SVOM detection of a burst
  91. GRB 260510B: LCO optical upper limits
  92. EP260509a: Einstein Probe detection of an X-ray transient
  93. GRB 260509A: Liverpool Telescope optical observations
  94. GRB 260510B: SVOM detection of a burst
  95. GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
  96. GRB 260509A: LCO optical observations
  97. SVOM GRB 260509A: MASTER-OAFA optical observation
  98. GRB 260509A: KAIT optical observations
  99. GRB 260509A: SVOM/COLIBRÍ (FM-GFT) observations
  100. GRB 260509A: SVOM/VT optical candidate with VHF data

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