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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"

28090 results found.

  1. GRB 260527A/EP260527a: VLT/X-shooter tentative redshift
  2. Fermi GRB 260529A: Global MASTER-Net observations report
  3. EP260526a: SVOM/VT optical upper limits
  4. EP260527a / GRB 260527A: VLT detection of the optical and nIR counterpart
  5. EP260527a/GRB 260527A: Infrared J upper limit with MDM/MIRAGE
  6. EP260527a/GRB 260527A: EP-FXT follow-up observation
  7. GRB 260527A: GECAM-B detection of a short burst probably associated with EP260527a
  8. EP260527a: SVOM/VT optical observation
  9. EP260527a: COLIBRÍ optical detection
  10. EP260527a: Einstein Probe detection of a fast X-ray transient
  11. Fermi trigger No 801580882: Global MASTER-Net observations report
  12. EP260526a: LCO optical upper limits
  13. EP260526a: Einstein Probe detection of a fast X-ray transient
  14. EP260526.405: COLIBRÍ optical upper limits
  15. The EP-WXT trigger 01709266106 is not a real source
  16. Fermi GRB 260526A: Global MASTER-Net observations report
  17. EP01709266106 (EP260526a?): Liverpool Telescope upper limits
  18. EP-WXT 01709266106: NOT optical upper limits
  19. Fermi GRB 260525A: Global MASTER-Net observations report
  20. GRB 260523B: AstroSat CZTI detection
  21. Fermi GRB 260523A: Global MASTER-Net observations report
  22. GRB 260522A: Fermi GBM Observation
  23. GRB 260522B: NuSTAR detection of prompt emission
  24. EP260518a (AT2026ndp): LCO observations and Gemini-South Redshift z = 2.28
  25. Fermi trigger No 801135305: Global MASTER-Net observations report
  26. Fermi GRB 260522A: Global MASTER-Net observations report
  27. EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
  28. GRB 260511A: iTelescope T-75 optical detection
  29. GRB 260520B: SVOM/GRM observation
  30. GRB 260411B: TERI Gamma-ray detection
  31. GRB 260407A: TERI Gamma-ray detection
  32. GRB 260307A: TERI Gamma-ray detection
  33. GRB 260225D: TERI Gamma-ray detection
  34. GRB 251118A: TERI Gamma-ray detection
  35. GRB 251113A: TERI Gamma-ray detection
  36. GRB 260428A: TERI Gamma-ray detection
  37. GRB 260519C: NuSTAR detection of prompt emission
  38. Konus-Wind detection of GRB 260518A
  39. GRB 260516D: SVOM/ECLAIRs refined analysis
  40. GRB 260421B: radio detection with the VLA
  41. GRB 260509A: CrAO ZTSh optical upper limit
  42. GRB 260516D: GOTO optical counterpart detection
  43. GRB 260516D: LCO optical observations
  44. GRB 260515A: further Liverpool Telescope observations
  45. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  46. GRB 260516D: GROWTH-India Telescope optical detection
  47. GRB 260516D: SVOM/VT optical bright candidate
  48. GRB 260515A: CrAO ZTSh BVRI optical observations
  49. Fermi GRB 260516C: Global MASTER-Net observations report
  50. SVOM GRB260516D: Global MASTER-Net observations report
  51. GRB 260516D: SVOM possible detection of a burst
  52. GRB 260515A: LCO optical counterpart detection
  53. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  54. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  55. EP260514a: NOT optical counterpart confirmation
  56. EP260514a: TRT optical counterpart candidate
  57. EP260514a: SVOM/VT optical candidate
  58. Fermi GRB 260516B: Global MASTER-Net observations report
  59. GRB 260515A: OHP/T193 optical observations
  60. EP260514a: COLIBRÍ optical upper limits
  61. GRB 260515A: LCO optical observations
  62. SVOM GRB 260515A: Global MASTER-Net observations report
  63. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  64. GRB 260515A: SVOM/VT optical candidate from VHF data
  65. GRB 260515A: JinShan optical counterpart candidate
  66. GRB 260515A: SVOM detection of a burst
  67. GRB 260510C: Glowbug gamma-ray detection
  68. EP260514a: GROWTH-India Telescope optical upper limit
  69. GRB 260511B: GMG Optical Upper Limit
  70. EP260514a: Global MASTER-Net observations report
  71. EP260514a: Einstein Probe detection of a fast X-ray transient
  72. EP260512a: LCO optical upper limits
  73. GRB 260511B: Mephisto multi-band optical followup
  74. Fermi GRB 260514A: Global MASTER-Net observations report
  75. GRB 260512A: AstroSat CZTI detection
  76. EP260512a: EP-FXT follow-up observation
  77. EP260507a: Xinglong Schmidt optical counterpart detection
  78. EP260512a: Global MASTER-Net observations report
  79. Fermi GRB 260513A: Global MASTER-Net observations report
  80. Fermi GRB 260512A: Global MASTER-Net observations report
  81. GRB 260511B: further SAO RAS optical observations
  82. GRB 260509A: SVOM/VT optical observations
  83. The EP-WXT trigger 01709262036 is likely a flaring star
  84. EP260512a: COLIBRÍ optical upper limits
  85. EP260512a: Einstein Probe detection of an X-ray transient
  86. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  87. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  88. GRB 260512A: NuSTAR detection of prompt emission
  89. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  90. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  91. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  92. GRB 260511A: Glowbug gamma-ray detection
  93. GRB 260511B: SAO RAS optical observations
  94. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  95. GRB 260511B: FRAM-ORM optical detection
  96. GRB 260511A: EP-FXT follow-up observation
  97. GRB 260511B: EP-FXT follow-up observation
  98. GRB 260511B: LCO optical counterpart detection
  99. GRB260511B: MAO/AZT-22 optical observations
  100. GRB 260511B: LCO optical observations

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