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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"

39205 results found.

  1. GRID detection of GRB 260511A
  2. GRB 260509A: CrAO ZTSh optical upper limit (Duplicate Submission)
  3. GRB 260509A: CrAO ZTSh optical upper limit
  4. GRB 260516D: EP-FXT follow-up observation
  5. GRB 260516D: GOTO optical counterpart detection
  6. GRB 260516D: LCO optical observations
  7. GRB 260515A: further Liverpool Telescope observations
  8. GRB 260516D: SVOM/COLIBRÍ (FM-GFT) optical observations
  9. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  10. GRB 260516D: GROWTH-India Telescope optical detection
  11. GRB 260516D: SVOM/VT optical bright candidate
  12. GRB 260516D: FRAM-ORM optical limit
  13. GRB 260515A: CrAO ZTSh BVRI optical observations
  14. Fermi GRB 260516C: Global MASTER-Net observations report
  15. SVOM GRB260516D: Global MASTER-Net observations report
  16. GRB 260516D: SVOM possible detection of a burst
  17. GRB 260516C: Fermi GBM Final Real-time Localization
  18. Konus-Wind detection of GRB 260515A
  19. GRB 260515A: Liverpool Telescope optical detection
  20. GRB 260515A: LCO optical counterpart detection
  21. Fermi Gamma-ray Burst Monitor trigger 800627191/260516518 is not a GRB
  22. GRB 260515A: SVOM/COLIBRÍ (FM-GFT) optical observations
  23. GRB 260515A: EP-FXT follow-up observation
  24. EP260514a: TRT optical counterpart candidate
  25. Fermi GRB 260516B: Global MASTER-Net observations report
  26. GRB 260516B: Fermi GBM Final Real-time Localization
  27. Fermi Gamma-ray Burst Monitor trigger 800592653/260516119 is not a GRB
  28. GRB 260515A: SVOM/VT optical observations
  29. GRB 260515A: OHP/T193 optical observations
  30. EP260514a: COLIBRÍ optical upper limits
  31. GRB 260516A: Fermi GBM Final Real-time Localization
  32. GRID detection of GRB 260507A
  33. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  34. GRB 260515A: LCO optical observations
  35. SVOM GRB 260515A: Global MASTER-Net observations report
  36. GRB 260515A: NOT optical observations.
  37. SVOM GRB 260515A: MASTER OT J151044.43+243321.7 optical counterpart detection
  38. GRB 260515A: SVOM/VT optical candidate from VHF data
  39. GRB 260515A: JinShan optical counterpart candidate
  40. GRB 260515A: SVOM detection of a burst
  41. GRB 260510C: Glowbug gamma-ray detection
  42. EP260514a: GROWTH-India Telescope optical upper limit
  43. GRB 260511B: NOT optical observations
  44. Konus-Wind detection of GRB 260512A
  45. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  46. GRB 260511B: GMG Optical Upper Limit
  47. EP260514a: Global MASTER-Net observations report
  48. EP260512a: LCO optical upper limits
  49. IPN triangulation of GRB 260512A
  50. GRB 260511B: Mephisto multi-band optical followup
  51. Fermi GRB 260514A: Global MASTER-Net observations report
  52. GRB 260512A: AstroSat CZTI detection
  53. GRB 260514A: Fermi GBM Final Real-time Localization
  54. EP260512a: Global MASTER-Net observations report
  55. Fermi GRB 260513A: Global MASTER-Net observations report
  56. Fermi GRB 260512A: Global MASTER-Net observations report
  57. GRB 260511B: further SAO RAS optical observations
  58. GRB 260513A: Fermi GBM Final Real-time Localization
  59. GRB 260509A: SVOM/VT optical observations
  60. Konus-Wind detection of GRB 260511B
  61. EP260512a: COLIBRÍ optical upper limits
  62. GRB 260511B: further J-band observations by the SYSU 80 cm infrared telescope
  63. GRB 260511B: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  64. GRB 260512A: NuSTAR detection of prompt emission
  65. GRB 260509A: Infrared J and Hs observations with MDM/MIRAGE
  66. GRB 260510C: Infrared J and Hs detections with MDM/MIRAGE
  67. EP260507a: Infrared J and Hs upper limits with MDM/MIRAGE
  68. GRB 260512A: Fermi GBM Final Real-time Localization
  69. GRB 260511A: Glowbug gamma-ray detection
  70. Konus-Wind detection of GRB 260511A
  71. MASS-Cube (GRID 2.0) detection of GRB 260511A
  72. MASS-Cube (GRID 2.0) detection of GRB 260507A
  73. GRB 260511B: SAO RAS optical observations
  74. GRB 260510D: Glowbug gamma-ray detection of a likely short burst
  75. GRB 260511B: FRAM-ORM optical detection
  76. GRB 260511A: EP-FXT follow-up observation
  77. GRB 260511B: EP-FXT follow-up observation
  78. GRB 260511B: LCO optical counterpart detection
  79. GRB260511B: MAO/AZT-22 optical observations
  80. GRB 260511A: SVOM/VT optical observations
  81. GRB 260511B: LCO optical observations
  82. GRB 260511B: OHP/T193 spectroscopic observations
  83. GRB 260511B: GOTO optical counterpart detection
  84. GRB 260511B: Xinglong 2.16m/BEFOSC redshift confirmation
  85. GRB 260510C: SVOM/COLIBRÍ (FM-GFT) further optical observations
  86. GRB 260510A: AstroSat CZTI detection (Erroneous Submission)
  87. GRB 260511B: SVOM/VT optical observations
  88. GRB 260511B: SVOM/COLIBRÍ (FM-GFT) optical observations
  89. GRB 260510B: EP-FXT follow-up observation
  90. GRB 260511B: OSIRIS+/GTC redshift z=2.006
  91. GRB 260510C: Fermi GBM Observation
  92. GRB 260509A: SAO RAS optical observations
  93. GRB 260511A: REM near-infrared detection
  94. GRB 260511B: GROWTH-India Telescope optical observations
  95. GRB 260511B: AstroSat CZTI detection
  96. GRB 260506B: Glowbug gamma-ray detection
  97. GRB 260506A: Glowbug gamma-ray detection of a short burst
  98. GRB 260511B: J-band observations by the SYSU 80 cm infrared telescope
  99. GRB 260511B: NuSTAR detection of prompt emission
  100. GRB 260511A: NuSTAR detection of prompt emission

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