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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"

2409 results found.

  1. GRB 260208B: SVOM/GRM observation of a bright burst
  2. GRB 260204A: SVOM/VT confirms fading of the optical afterglow
  3. GRB 260204A: Swift-XRT observations
  4. GRB 260204A: LCO optical afterglow detection
  5. GRB 260204A: SVOM/VT optical candidate
  6. GRB 260204A : MASTER Global robotic net optical observations
  7. Fermi GBM Sub-Threshold Detection of GRB 260204A
  8. GRB 260204A: GOTO optical upper limit
  9. GRB 260204A: LCO optical upper limits
  10. GRB 260204A: SVOM detection of a burst
  11. EP260131a: SVOM/VT optical observation
  12. GRB 260128B: LCO optical upper limits
  13. GRB 260128B: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  14. GRB 260128B: SVOM detection of a burst through offline search
  15. EP260126a: SVOM/VT optical upperlimit
  16. GRB 260127A: SVOM/C-GFT optical observations
  17. GRB 260127A: LCO optical afterglow discovery
  18. GRB 251222A: SVOM/ECLAIRs refined analysis
  19. GRB 260114A: SVOM/VT optical upper limits
  20. GRB 260120B: SVOM/GRM observation
  21. GRB 260120B: AstroSat CZTI detection
  22. GRB 260114A: Insight-HXMT/HE detection
  23. GRB 260120B: Fermi GBM Observation
  24. SVOM GRB260121.06: Global MASTER-Net observations report
  25. GRB 260120B: SVOM/C-GFT optical counterpart detection
  26. GRB 260101A: 239Alferov CubeSat detection
  27. GRB 251202A: further radio observations with the VLA
  28. EP260119a: SVOM/VT optical observation
  29. SVOM GRB260119.92: Global MASTER-Net observations report
  30. SVOM GRB260119.92: Global MASTER-Net observations report
  31. SVOM GRB260119.90: Global MASTER-Net observations report
  32. GRB 251208D: SVOM/ECLAIRs refined analysis
  33. GRB 251208D: SVOM/ECLAIRs refined analysis
  34. GRB 260117A: Swift-XRT afterglow detection
  35. GRB 260117A: ZTSh optical upper limit
  36. GRB 260110A: SVOM detection of a burst through offline search
  37. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  38. SVOM GRB260117.82: Global MASTER-Net observations report
  39. GRB 260117A: SVOM/VT optical candidate
  40. GRB 260117A: SVOM/C-GFT upper limit
  41. GRB 260117A: Swift-XRT observations
  42. GRB 260117A: Swift ToO observations
  43. GRB 260117A: SVOM detection of a long faint burst
  44. GRB 251222A: radio detection with the VLA
  45. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  46. Konus-Wind detection of GRB 260114A
  47. GRB 260114A: 6 GHz VLA observations
  48. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  49. GRB 260114A: COLIBRÍ optical upper limits
  50. GRB 260114A: TNG NIR upper limit
  51. GRB 260114A: NOT optical observations
  52. GRB 260114A: SVOM/GRM observation of a short burst
  53. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  54. Konus-Wind detection of GRB 260101A
  55. EP260110a: SVOM/VT optical upper limits
  56. EP260110a: SVOM/C-GFT upper limit
  57. GRB 260109C: LCO optical upper limits
  58. GRB 260102A: Swift-XRT afterglow detection
  59. GRB 260105A: SVOM/GRM observation
  60. GRB 260105B: SVOM/GRM observation
  61. EP260105a: SVOM/VT optical upperlimit
  62. GRB 260101A: COLIBRÍ optical upper limits
  63. GRB 260103A: Insight-HXMT/HE detection
  64. GRB 260103A: GECAM-B observation of a burst
  65. GRB 260103A: SVOM/GRM observation of a possible GRB
  66. GRB 260101A: COLIBRÍ optical observations
  67. SVOM GRB260103.08: Global MASTER-Net observations report
  68. SVOM GRB260102A: Global MASTER-Net observations report
  69. Fermi GBM Sub-Threshold Detection of GRB 260102A
  70. GRB 260102A: EP-FXT follow-up observation
  71. GRB 260102A: LCO optical upper limits
  72. GRB 260102A: Swift-XRT observations
  73. GRB 260102A: SVOM/COLIBRÍ (FM-GFT) optical observations
  74. GRB 260102A: SVOM/VT optical counterpart
  75. GRB 260102A: Swift ToO observations
  76. GRB 260101A: Fermi GBM Observation
  77. GRB 260102A: SVOM detection of a burst
  78. GRB 260101A: GECAM-B detection
  79. GRB 260101A: NOT spectroscopic observations
  80. GRB 260101A: SVOM/GRM observation
  81. SVOM GRB251231.57: Global MASTER-Net observations report
  82. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  83. GRB 251230A / EP251230a: SVOM/VT optical observation
  84. GRB 251226A: Glowbug gamma-ray detection
  85. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  86. GRB 251226A: SVOM/GRM observation
  87. GRB 251226A: GECAM-B detection
  88. SVOM GRB251227.07: Global MASTER-Net observations report
  89. GRB 251222A: NUTTelA-TAO Early Measurements
  90. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  91. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  92. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  93. GRB 251222A: Continued 1.3m DFOT optical observation
  94. GRB 251222A: Fermi GBM Observation
  95. GRB 251222A / EP251222b: GECAM-B observation
  96. Konus-Wind detection of GRB 251222A / EP251222b
  97. GRB 251222A: Swift-XRT afterglow detection
  98. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  99. GRB 251222A / EP251222b: GOTO optical counterpart detection
  100. GRB 251222A / EP251222b: LCO optical observations

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