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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"

44307 results found.

  1. GRB 260516C: Fermi GBM Final Real-time Localization
  2. Konus-Wind detection of GRB 260515A
  3. GRB 260515A: Liverpool Telescope optical detection
  4. GRB 260515A: LCO optical counterpart detection
  5. Fermi Gamma-ray Burst Monitor trigger 800627191/260516518 is not a GRB
  6. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) further optical observations
  7. GRB 260515A: EP-FXT follow-up observation
  8. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  9. EP260514a: NOT optical counterpart confirmation
  10. EP260514a: TRT optical counterpart candidate
  11. EP260514a: SVOM/VT optical candidate
  12. Fermi GRB 260516B: Global MASTER-Net observations report
  13. GRB 260516B: Fermi GBM Final Real-time Localization
  14. Fermi Gamma-ray Burst Monitor trigger 800592653/260516119 is not a GRB
  15. GRB 260515A: SVOM/VT optical observations
  16. GRB 260515A: OHP/T193 optical observations
  17. EP260514a: COLIBRÍ optical upper limits
  18. GRB 260516A: Fermi GBM Final Real-time Localization
  19. GRID detection of GRB 260507A
  20. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  21. GRB 260515A: LCO optical observations
  22. SVOM GRB 260515A: Global MASTER-Net observations report
  23. GRB 260515A: NOT optical observations.
  24. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  25. GRB 260515A: SVOM/VT optical candidate from VHF data
  26. GRB 260515A: JinShan optical counterpart candidate
  27. GRB 260515A: SVOM detection of a burst
  28. GRB 260510C: Glowbug gamma-ray detection
  29. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  30. EP260514a: GROWTH-India Telescope optical upper limit
  31. GRB 260511B: NOT optical observations
  32. Konus-Wind detection of GRB 260512A
  33. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  34. GRB 260511B: GMG Optical Upper Limit
  35. EP260514a: Global MASTER-Net observations report
  36. EP260514a: Einstein Probe detection of a fast X-ray transient
  37. EP260512a: LCO optical upper limits
  38. IPN triangulation of GRB 260512A
  39. GRB 260511B: Mephisto multi-band optical followup
  40. Fermi GRB 260514A: Global MASTER-Net observations report
  41. GRB 260512A: AstroSat CZTI detection
  42. The EP-WXT trigger 01709262077 is likely a flaring star
  43. EP260512a: EP-FXT follow-up observation
  44. EP260507a: Xinglong Schmidt optical counterpart detection
  45. GRB 260514A: Fermi GBM Final Real-time Localization
  46. EP260512a: Global MASTER-Net observations report
  47. Fermi GRB 260513A: Global MASTER-Net observations report
  48. Fermi GRB 260512A: Global MASTER-Net observations report
  49. GRB 260511B: further SAO RAS optical observations
  50. GRB 260513A: Fermi GBM Final Real-time Localization
  51. GRB 260509A: SVOM/VT optical observations
  52. Konus-Wind detection of GRB 260511B
  53. The EP-WXT trigger 01709262036 is likely a flaring star
  54. EP260512a: COLIBRÍ optical upper limits
  55. EP260512a: Einstein Probe detection of an X-ray transient
  56. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  57. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  58. GRB 260512A: NuSTAR detection of prompt emission
  59. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  60. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  61. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  62. GRB 260512A: Fermi GBM Final Real-time Localization
  63. GRB 260511A: Glowbug gamma-ray detection
  64. Konus-Wind detection of GRB 260511A
  65. MASS-Cube (GRID 2.0) detection of GRB 260511A
  66. MASS-Cube (GRID 2.0) detection of GRB 260507A
  67. GRB 260511B: SAO RAS optical observations
  68. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  69. GRB 260511B: FRAM-ORM optical detection
  70. GRB 260511A: EP-FXT follow-up observation
  71. GRB 260511B: EP-FXT follow-up observation
  72. GRB 260511B: LCO optical counterpart detection
  73. GRB260511B: MAO/AZT-22 optical observations
  74. GRB 260511A: SVOM/VT optical observations
  75. GRB 260511B: LCO optical observations
  76. GRB 260511B: OHP/T193 spectroscopic observations
  77. GRB 260511B: GOTO optical counterpart detection
  78. GRB 260511B: Xinglong 2.16m/BEFOSC redshift confirmation
  79. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  80. GRB 260511B: SVOM/VT optical observations
  81. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  82. GRB 260510B: EP-FXT follow-up observation
  83. GRB 260511B: OSIRIS+/GTC redshift z=2.006
  84. GRB 260510C: Fermi GBM Observation
  85. GRB 260509A: SAO RAS optical observations
  86. GRB 260511A: REM near-infrared detection
  87. GRB 260511B: GROWTH-India Telescope optical observations
  88. GRB 260511B: AstroSat CZTI detection
  89. GRB 260506B: Glowbug gamma-ray detection
  90. GRB 260506A: Glowbug gamma-ray detection of a short burst
  91. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  92. GRB 260511B: NuSTAR detection of prompt emission
  93. GRB 260511A: NuSTAR detection of prompt emission
  94. GRB 260511B: Fermi GBM Detection
  95. GRB 260511C: Fermi GBM Final Real-time Localization
  96. GRB 260511B: SVOM/VT optical observation with VHF data
  97. GRB 260511B: TRT optical observation
  98. GRB 260510B: SVOM/ECLAIRs refined analysis
  99. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  100. GRB 260511A: Fermi GBM Detection

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