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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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
  1. GRB 260518A: AstroSat CZTI detection of a long burst
  2. GRB 260516D: SVOM/ECLAIRs refined analysis
  3. GRB 260515A: SVOM/ECLAIRs refined analysis
  4. GRB 260421B: radio detection with the VLA
  5. GRID detection of GRB 260511A
  6. GRB 260509A: CrAO ZTSh optical upper limit (Duplicate Submission)
  7. GRB 260509A: CrAO ZTSh optical upper limit
  8. GRB 260516D: EP-FXT follow-up observation
  9. GRB 260516D: GOTO optical counterpart detection
  10. GRB 260516D: LCO optical observations
  11. GRB 260515A: further Liverpool Telescope observations
  12. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  13. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  14. GRB 260516D: GROWTH-India Telescope optical detection
  15. GRB 260516D: SVOM/VT optical bright candidate
  16. GRB 260516D: FRAM-ORM optical limit
  17. GRB 260515A: CrAO ZTSh BVRI optical observations
  18. Fermi GRB 260516C: Global MASTER-Net observations report
  19. SVOM GRB260516D: Global MASTER-Net observations report
  20. GRB 260516D: SVOM possible detection of a burst
  21. GRB 260516C: Fermi GBM Final Real-time Localization
  22. Konus-Wind detection of GRB 260515A
  23. GRB 260515A: Liverpool Telescope optical detection
  24. GRB 260515A: LCO optical counterpart detection
  25. Fermi Gamma-ray Burst Monitor trigger 800627191/260516518 is not a GRB
  26. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  27. GRB 260515A: EP-FXT follow-up observation
  28. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  29. EP260514a: NOT optical counterpart confirmation
  30. EP260514a: TRT optical counterpart candidate
  31. EP260514a: SVOM/VT optical candidate
  32. Fermi GRB 260516B: Global MASTER-Net observations report
  33. GRB 260516B: Fermi GBM Final Real-time Localization
  34. Fermi Gamma-ray Burst Monitor trigger 800592653/260516119 is not a GRB
  35. GRB 260515A: SVOM/VT optical observations
  36. GRB 260515A: OHP/T193 optical observations
  37. EP260514a: COLIBRÍ optical upper limits
  38. GRB 260516A: Fermi GBM Final Real-time Localization
  39. GRID detection of GRB 260507A
  40. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  41. GRB 260515A: LCO optical observations
  42. SVOM GRB 260515A: Global MASTER-Net observations report
  43. GRB 260515A: NOT optical observations.
  44. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  45. GRB 260515A: SVOM/VT optical candidate from VHF data
  46. GRB 260515A: JinShan optical counterpart candidate
  47. GRB 260515A: SVOM detection of a burst
  48. GRB 260510C: Glowbug gamma-ray detection
  49. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  50. EP260514a: GROWTH-India Telescope optical upper limit
  51. GRB 260511B: NOT optical observations
  52. Konus-Wind detection of GRB 260512A
  53. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  54. GRB 260511B: GMG Optical Upper Limit
  55. EP260514a: Global MASTER-Net observations report
  56. EP260514a: Einstein Probe detection of a fast X-ray transient
  57. EP260512a: LCO optical upper limits
  58. IPN triangulation of GRB 260512A
  59. GRB 260511B: Mephisto multi-band optical followup
  60. Fermi GRB 260514A: Global MASTER-Net observations report
  61. GRB 260512A: AstroSat CZTI detection
  62. The EP-WXT trigger 01709262077 is likely a flaring star
  63. EP260512a: EP-FXT follow-up observation
  64. EP260507a: Xinglong Schmidt optical counterpart detection
  65. GRB 260514A: Fermi GBM Final Real-time Localization
  66. EP260512a: Global MASTER-Net observations report
  67. Fermi GRB 260513A: Global MASTER-Net observations report
  68. Fermi GRB 260512A: Global MASTER-Net observations report
  69. GRB 260511B: further SAO RAS optical observations
  70. GRB 260513A: Fermi GBM Final Real-time Localization
  71. GRB 260509A: SVOM/VT optical observations
  72. Konus-Wind detection of GRB 260511B
  73. The EP-WXT trigger 01709262036 is likely a flaring star
  74. EP260512a: COLIBRÍ optical upper limits
  75. EP260512a: Einstein Probe detection of an X-ray transient
  76. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  77. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  78. GRB 260512A: NuSTAR detection of prompt emission
  79. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  80. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  81. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  82. GRB 260512A: Fermi GBM Final Real-time Localization
  83. GRB 260511A: Glowbug gamma-ray detection
  84. Konus-Wind detection of GRB 260511A
  85. MASS-Cube (GRID 2.0) detection of GRB 260511A
  86. MASS-Cube (GRID 2.0) detection of GRB 260507A
  87. GRB 260511B: SAO RAS optical observations
  88. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  89. GRB 260511B: FRAM-ORM optical detection
  90. GRB 260511A: EP-FXT follow-up observation
  91. GRB 260511B: EP-FXT follow-up observation
  92. GRB 260511B: LCO optical counterpart detection
  93. GRB260511B: MAO/AZT-22 optical observations
  94. GRB 260511A: SVOM/VT optical observations
  95. GRB 260511B: LCO optical observations
  96. GRB 260511B: OHP/T193 spectroscopic observations
  97. GRB 260511B: GOTO optical counterpart detection
  98. GRB 260511B: Xinglong 2.16m/BEFOSC redshift confirmation
  99. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  100. GRB 260510A: AstroSat CZTI detection (Erroneous Submission)

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