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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"

27783 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. Fermi trigger No 801580882: Global MASTER-Net observations report
  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. Fermi GRB 260526A: Global MASTER-Net observations report
  10. EP01709266106 (EP260526a?): Liverpool Telescope upper limits
  11. EP-WXT 01709266106: NOT optical upper limits
  12. Fermi GRB 260525A: Global MASTER-Net observations report
  13. GRB 260523B: AstroSat CZTI detection
  14. Fermi GRB 260523A: Global MASTER-Net observations report
  15. GRB 260522A: Fermi GBM Observation
  16. GRB 260522B: NuSTAR detection of prompt emission
  17. EP260518a (AT2026ndp): LCO observations and Gemini-South Redshift z = 2.28
  18. Fermi trigger No 801135305: Global MASTER-Net observations report
  19. Fermi GRB 260522A: Global MASTER-Net observations report
  20. EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
  21. GRB 260511A: iTelescope T-75 optical detection
  22. GRB 260520B: SVOM/GRM observation
  23. GRB 260411B: TERI Gamma-ray detection
  24. GRB 260407A: TERI Gamma-ray detection
  25. GRB 260307A: TERI Gamma-ray detection
  26. GRB 260225D: TERI Gamma-ray detection
  27. GRB 251118A: TERI Gamma-ray detection
  28. GRB 251113A: TERI Gamma-ray detection
  29. GRB 260428A: TERI Gamma-ray detection
  30. GRB 260519C: NuSTAR detection of prompt emission
  31. Konus-Wind detection of GRB 260518A
  32. GRB 260516D: 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. Fermi GRB 260516C: Global MASTER-Net observations report
  43. SVOM GRB260516D: Global MASTER-Net observations report
  44. GRB 260516D: SVOM possible detection of a burst
  45. GRB 260515A: LCO optical counterpart detection
  46. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  47. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  48. EP260514a: NOT optical counterpart confirmation
  49. EP260514a: TRT optical counterpart candidate
  50. EP260514a: SVOM/VT optical candidate
  51. Fermi GRB 260516B: Global MASTER-Net observations report
  52. GRB 260515A: OHP/T193 optical observations
  53. EP260514a: COLIBRÍ optical upper limits
  54. GRB 260515A: LCO optical observations
  55. SVOM GRB 260515A: Global MASTER-Net observations report
  56. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  57. GRB 260515A: SVOM/VT optical candidate from VHF data
  58. GRB 260515A: JinShan optical counterpart candidate
  59. GRB 260515A: SVOM detection of a burst
  60. GRB 260510C: Glowbug gamma-ray detection
  61. EP260514a: GROWTH-India Telescope optical upper limit
  62. GRB 260511B: GMG Optical Upper Limit
  63. EP260514a: Global MASTER-Net observations report
  64. EP260514a: Einstein Probe detection of a fast X-ray transient
  65. EP260512a: LCO optical upper limits
  66. GRB 260511B: Mephisto multi-band optical followup
  67. Fermi GRB 260514A: Global MASTER-Net observations report
  68. GRB 260512A: AstroSat CZTI detection
  69. EP260512a: EP-FXT follow-up observation
  70. EP260507a: Xinglong Schmidt optical counterpart detection
  71. EP260512a: Global MASTER-Net observations report
  72. Fermi GRB 260513A: Global MASTER-Net observations report
  73. Fermi GRB 260512A: Global MASTER-Net observations report
  74. GRB 260511B: further SAO RAS optical observations
  75. GRB 260509A: SVOM/VT optical observations
  76. The EP-WXT trigger 01709262036 is likely a flaring star
  77. EP260512a: COLIBRÍ optical upper limits
  78. EP260512a: Einstein Probe detection of an X-ray transient
  79. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  80. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  81. GRB 260512A: NuSTAR detection of prompt emission
  82. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  83. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  84. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  85. GRB 260511A: Glowbug gamma-ray detection
  86. GRB 260511B: SAO RAS optical observations
  87. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  88. GRB 260511B: FRAM-ORM optical detection
  89. GRB 260511A: EP-FXT follow-up observation
  90. GRB 260511B: EP-FXT follow-up observation
  91. GRB 260511B: LCO optical counterpart detection
  92. GRB260511B: MAO/AZT-22 optical observations
  93. GRB 260511B: LCO optical observations
  94. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  95. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  96. GRB 260510B: EP-FXT follow-up observation
  97. GRB 260510C: Fermi GBM Observation
  98. GRB 260509A: SAO RAS optical observations
  99. GRB 260511A: REM near-infrared detection
  100. GRB 260511B: GROWTH-India Telescope optical observations

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