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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.

Advanced Search Examples (click to copy):

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

42786 results found.

  1. GRB 260519D: Fermi GBM Final Localization Correction
  2. GRB 260519C: NuSTAR detection of prompt emission
  3. Konus-Wind detection of GRB 260518A
  4. GRB 260519B: Fermi GBM Final Localization
  5. GRB 260519A: Fermi GBM Final Localization
  6. GRB 260518A: AstroSat CZTI detection of a long burst
  7. GRB 260516D: SVOM/ECLAIRs refined analysis
  8. GRB 260515A: SVOM/ECLAIRs refined analysis
  9. GRB 260421B: radio detection with the VLA
  10. GRID detection of GRB 260511A
  11. GRB 260509A: CrAO ZTSh optical upper limit
  12. GRB 260516D: EP-FXT follow-up observation
  13. GRB 260516D: GOTO optical counterpart detection
  14. GRB 260516D: LCO optical observations
  15. GRB 260515A: further Liverpool Telescope observations
  16. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  17. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  18. GRB 260516D: GROWTH-India Telescope optical detection
  19. GRB 260516D: SVOM/VT optical bright candidate
  20. GRB 260516D: FRAM-ORM optical limit
  21. GRB 260515A: CrAO ZTSh BVRI optical observations
  22. Fermi GRB 260516C: Global MASTER-Net observations report
  23. SVOM GRB260516D: Global MASTER-Net observations report
  24. GRB 260516D: SVOM possible detection of a burst
  25. GRB 260516C: Fermi GBM Final Real-time Localization
  26. Konus-Wind detection of GRB 260515A
  27. GRB 260515A: Liverpool Telescope optical detection
  28. GRB 260515A: LCO optical counterpart detection
  29. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  30. GRB 260515A: EP-FXT follow-up observation
  31. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  32. EP260514a: NOT optical counterpart confirmation
  33. EP260514a: TRT optical counterpart candidate
  34. EP260514a: SVOM/VT optical candidate
  35. Fermi GRB 260516B: Global MASTER-Net observations report
  36. GRB 260516B: Fermi GBM Final Real-time Localization
  37. GRB 260515A: SVOM/VT optical observations
  38. GRB 260515A: OHP/T193 optical observations
  39. EP260514a: COLIBRÍ optical upper limits
  40. GRB 260516A: Fermi GBM Final Real-time Localization
  41. GRID detection of GRB 260507A
  42. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  43. GRB 260515A: LCO optical observations
  44. SVOM GRB 260515A: Global MASTER-Net observations report
  45. GRB 260515A: NOT optical observations.
  46. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  47. GRB 260515A: SVOM/VT optical candidate from VHF data
  48. GRB 260515A: JinShan optical counterpart candidate
  49. GRB 260515A: SVOM detection of a burst
  50. GRB 260510C: Glowbug gamma-ray detection
  51. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  52. EP260514a: GROWTH-India Telescope optical upper limit
  53. GRB 260511B: NOT optical observations
  54. Konus-Wind detection of GRB 260512A
  55. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  56. GRB 260511B: GMG Optical Upper Limit
  57. EP260514a: Global MASTER-Net observations report
  58. EP260514a: Einstein Probe detection of a fast X-ray transient
  59. EP260512a: LCO optical upper limits
  60. IPN triangulation of GRB 260512A
  61. GRB 260511B: Mephisto multi-band optical followup
  62. Fermi GRB 260514A: Global MASTER-Net observations report
  63. GRB 260512A: AstroSat CZTI detection
  64. The EP-WXT trigger 01709262077 is likely a flaring star
  65. EP260512a: EP-FXT follow-up observation
  66. EP260507a: Xinglong Schmidt optical counterpart detection
  67. GRB 260514A: Fermi GBM Final Real-time Localization
  68. EP260512a: Global MASTER-Net observations report
  69. Fermi GRB 260513A: Global MASTER-Net observations report
  70. Fermi GRB 260512A: Global MASTER-Net observations report
  71. GRB 260511B: further SAO RAS optical observations
  72. GRB 260513A: Fermi GBM Final Real-time Localization
  73. GRB 260509A: SVOM/VT optical observations
  74. Konus-Wind detection of GRB 260511B
  75. The EP-WXT trigger 01709262036 is likely a flaring star
  76. EP260512a: COLIBRÍ optical upper limits
  77. EP260512a: Einstein Probe detection of an X-ray transient
  78. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  79. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  80. GRB 260512A: NuSTAR detection of prompt emission
  81. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  82. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  83. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  84. GRB 260512A: Fermi GBM Final Real-time Localization
  85. GRB 260511A: Glowbug gamma-ray detection
  86. Konus-Wind detection of GRB 260511A
  87. MASS-Cube (GRID 2.0) detection of GRB 260511A
  88. MASS-Cube (GRID 2.0) detection of GRB 260507A
  89. GRB 260511B: SAO RAS optical observations
  90. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  91. GRB 260511B: FRAM-ORM optical detection
  92. GRB 260511A: EP-FXT follow-up observation
  93. GRB 260511B: EP-FXT follow-up observation
  94. GRB 260511B: LCO optical counterpart detection
  95. GRB260511B: MAO/AZT-22 optical observations
  96. GRB 260511A: SVOM/VT optical observations
  97. GRB 260511B: LCO optical observations
  98. GRB 260511B: OHP/T193 spectroscopic observations
  99. GRB 260511B: GOTO optical counterpart detection
  100. GRB 260511B: Xinglong 2.16m/BEFOSC redshift confirmation

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