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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

42650 results found.

  1. EP260526.405: COLIBRÍ optical upper limits
  2. The EP-WXT trigger 01709266106 is not a real source
  3. Fermi GRB 260526A: Global MASTER-Net observations report
  4. GRB 260526A: Fermi GBM Final Real-time Localization
  5. EP01709266106 (EP260526a?): Liverpool Telescope upper limits
  6. EP-WXT 01709266106: NOT optical upper limits
  7. Fermi GRB 260525A: Global MASTER-Net observations report
  8. GRB 260525A: Fermi GBM Final Real-time Localization
  9. GRB 260523B: AstroSat CZTI detection
  10. GRB 260523B: GECAM-B observation
  11. Fermi GRB 260523A: Global MASTER-Net observations report
  12. GRB 260523B: Fermi GBM Final Real-time Localization
  13. GRB 260523A: Fermi GBM Final Real-time Localization
  14. GRB 260522A: Fermi GBM Observation
  15. GRB 260522B: NuSTAR detection of prompt emission
  16. EP260518a (AT2026ndp): LCO observations and Gemini-South Redshift z = 2.28
  17. GRB 260522B: Fermi GBM Final Real-time Localization
  18. GRB 260522A: GOTO optical upper limit
  19. Fermi trigger No 801135305: Global MASTER-Net observations report
  20. Fermi GRB 260522A: Global MASTER-Net observations report
  21. EP260518a: Einstein Probe detection of an sub-threshold X-ray transient with counterpart AT 2026ndp
  22. GRB 260522A: Fermi-LAT detection
  23. GRB 260519C: SVOM/GRM observation
  24. GRB 260522A: Fermi GBM Final Real-time Localization
  25. GRB 260520B: SVOM/GRM observation
  26. GRB 260411B: TERI Gamma-ray detection
  27. GRB 260407A: TERI Gamma-ray detection
  28. GRB 260307A: TERI Gamma-ray detection
  29. GRB 260225D: TERI Gamma-ray detection
  30. GRB 251118A: TERI Gamma-ray detection
  31. GRB 251113A: TERI Gamma-ray detection
  32. GRB 260428A: TERI Gamma-ray detection
  33. Konus-Wind detection of GRB 260519C
  34. GRB 260520B: Fermi GBM Final Localization
  35. GRB 260509A: SVOM/ECLAIRs refined analysis
  36. GRB 260520A: Fermi GBM Final Localization
  37. GRB 260519D: Fermi GBM Final Localization Correction
  38. GRB 260519C: NuSTAR detection of prompt emission
  39. Konus-Wind detection of GRB 260518A
  40. GRB 260519B: Fermi GBM Final Localization
  41. GRB 260519A: Fermi GBM Final Localization
  42. GRB 260518A: AstroSat CZTI detection of a long burst
  43. GRB 260516D: SVOM/ECLAIRs refined analysis
  44. GRB 260515A: SVOM/ECLAIRs refined analysis
  45. GRB 260421B: radio detection with the VLA
  46. GRID detection of GRB 260511A
  47. GRB 260509A: CrAO ZTSh optical upper limit (Duplicate Submission)
  48. GRB 260509A: CrAO ZTSh optical upper limit
  49. GRB 260516D: EP-FXT follow-up observation
  50. GRB 260516D: GOTO optical counterpart detection
  51. GRB 260516D: LCO optical observations
  52. GRB 260515A: further Liverpool Telescope observations
  53. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  54. GRB 260516D: GROWTH-India Telescope optical detection
  55. GRB 260516D: SVOM/VT optical bright candidate
  56. GRB 260516D: FRAM-ORM optical limit
  57. GRB 260515A: CrAO ZTSh BVRI optical observations
  58. Fermi GRB 260516C: Global MASTER-Net observations report
  59. SVOM GRB260516D: Global MASTER-Net observations report
  60. GRB 260516D: SVOM possible detection of a burst
  61. GRB 260516C: Fermi GBM Final Real-time Localization
  62. Konus-Wind detection of GRB 260515A
  63. GRB 260515A: Liverpool Telescope optical detection
  64. GRB 260515A: LCO optical counterpart detection
  65. Fermi Gamma-ray Burst Monitor trigger 800627191/260516518 is not a GRB
  66. GRB 260515A: EP-FXT follow-up observation
  67. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  68. EP260514a: NOT optical counterpart confirmation
  69. EP260514a: TRT optical counterpart candidate
  70. EP260514a: SVOM/VT optical candidate
  71. Fermi GRB 260516B: Global MASTER-Net observations report
  72. GRB 260516B: Fermi GBM Final Real-time Localization
  73. Fermi Gamma-ray Burst Monitor trigger 800592653/260516119 is not a GRB
  74. GRB 260515A: SVOM/VT optical observations
  75. GRB 260515A: OHP/T193 optical observations
  76. GRB 260516A: Fermi GBM Final Real-time Localization
  77. GRID detection of GRB 260507A
  78. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  79. GRB 260515A: LCO optical observations
  80. SVOM GRB 260515A: Global MASTER-Net observations report
  81. GRB 260515A: NOT optical observations.
  82. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  83. GRB 260515A: SVOM/VT optical candidate from VHF data
  84. GRB 260515A: JinShan optical counterpart candidate
  85. GRB 260515A: SVOM detection of a burst
  86. GRB 260510C: Glowbug gamma-ray detection
  87. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  88. EP260514a: GROWTH-India Telescope optical upper limit
  89. GRB 260511B: NOT optical observations
  90. Konus-Wind detection of GRB 260512A
  91. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  92. EP260514a: Global MASTER-Net observations report
  93. EP260514a: Einstein Probe detection of a fast X-ray transient
  94. EP260512a: LCO optical upper limits
  95. IPN triangulation of GRB 260512A
  96. GRB 260511B: Mephisto multi-band optical followup
  97. Fermi GRB 260514A: Global MASTER-Net observations report
  98. GRB 260512A: AstroSat CZTI detection
  99. The EP-WXT trigger 01709262077 is likely a flaring star
  100. EP260512a: EP-FXT follow-up observation

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