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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"

32495 results found.

  1. GRB 260522A: GOTO optical upper limit
  2. Fermi GRB 260522A: Global MASTER-Net observations report
  3. GRB 260522A: Fermi-LAT detection
  4. GRB 260519C: SVOM/GRM observation
  5. GRB 260511A: iTelescope T-75 optical detection
  6. GRB 260520B: SVOM/GRM observation
  7. GRB 260411B: TERI Gamma-ray detection
  8. GRB 260407A: TERI Gamma-ray detection
  9. GRB 260307A: TERI Gamma-ray detection
  10. GRB 260225D: TERI Gamma-ray detection
  11. GRB 251118A: TERI Gamma-ray detection
  12. GRB 251113A: TERI Gamma-ray detection
  13. GRB 260428A: TERI Gamma-ray detection
  14. Konus-Wind detection of GRB 260519C
  15. GRB 260509A: SVOM/ECLAIRs refined analysis
  16. GRB 260519C: NuSTAR detection of prompt emission
  17. Konus-Wind detection of GRB 260518A
  18. GRB 260516D: SVOM/ECLAIRs refined analysis
  19. GRB 260515A: SVOM/ECLAIRs refined analysis
  20. GRB 260421B: radio detection with the VLA
  21. GRID detection of GRB 260511A
  22. GRB 260509A: CrAO ZTSh optical upper limit (Duplicate Submission)
  23. GRB 260509A: CrAO ZTSh optical upper limit
  24. GRB 260516D: EP-FXT follow-up observation
  25. GRB 260516D: GOTO optical counterpart detection
  26. GRB 260516D: LCO optical observations
  27. GRB 260515A: further Liverpool Telescope observations
  28. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  29. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  30. GRB 260516D: GROWTH-India Telescope optical detection
  31. GRB 260516D: SVOM/VT optical bright candidate
  32. GRB 260515A: CrAO ZTSh BVRI optical observations
  33. Fermi GRB 260516C: Global MASTER-Net observations report
  34. Konus-Wind detection of GRB 260515A
  35. GRB 260515A: Liverpool Telescope optical detection
  36. GRB 260515A: LCO optical counterpart detection
  37. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  38. GRB 260515A: EP-FXT follow-up observation
  39. EP260514a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  40. EP260514a: NOT optical counterpart confirmation
  41. EP260514a: TRT optical counterpart candidate
  42. EP260514a: SVOM/VT optical candidate
  43. Fermi GRB 260516B: Global MASTER-Net observations report
  44. GRB 260515A: SVOM/VT optical observations
  45. GRB 260515A: OHP/T193 optical observations
  46. EP260514a: COLIBRÍ optical upper limits
  47. GRID detection of GRB 260507A
  48. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  49. GRB 260515A: LCO optical observations
  50. SVOM GRB 260515A: Global MASTER-Net observations report
  51. GRB 260515A: NOT optical observations.
  52. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  53. GRB 260515A: SVOM/VT optical candidate from VHF data
  54. GRB 260515A: JinShan optical counterpart candidate
  55. GRB 260510C: Glowbug gamma-ray detection
  56. IceCube-260504A: No Candidate Transients from the Zwicky Transient Facility
  57. EP260514a: GROWTH-India Telescope optical upper limit
  58. GRB 260511B: NOT optical observations
  59. Konus-Wind detection of GRB 260512A
  60. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  61. GRB 260511B: GMG Optical Upper Limit
  62. EP260514a: Global MASTER-Net observations report
  63. EP260512a: LCO optical upper limits
  64. IPN triangulation of GRB 260512A
  65. GRB 260511B: Mephisto multi-band optical followup
  66. Fermi GRB 260514A: Global MASTER-Net observations report
  67. GRB 260512A: AstroSat CZTI detection
  68. EP260512a: EP-FXT follow-up observation
  69. EP260507a: Xinglong Schmidt optical counterpart detection
  70. EP260512a: Global MASTER-Net observations report
  71. Fermi GRB 260513A: Global MASTER-Net observations report
  72. Fermi GRB 260512A: Global MASTER-Net observations report
  73. GRB 260511B: further SAO RAS optical observations
  74. GRB 260509A: SVOM/VT optical observations
  75. Konus-Wind detection of GRB 260511B
  76. EP260512a: COLIBRÍ optical upper limits
  77. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  78. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  79. GRB 260512A: NuSTAR detection of prompt emission
  80. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  81. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  82. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  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 260511B: SVOM/VT optical observations

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