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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"

35987 results found.

  1. GRB 260909A: SVOM/VT optical upper limits
  2. GRB 260909A: SVOM/GRM observation
  3. GRB 260909A: Mondy optical observations and afterglow candidate
  4. GRB 260909A: Xinglong 2.16m optical upper limit
  5. GRB 260909A: SVOM/C-GFT optical upper limit
  6. GRB 260909A: SVOM detection of a burst
  7. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  8. GRB 260903A: Swift ToO observations
  9. Fermi GRB 260907B: Global MASTER-Net observations report
  10. GRB 260903A: SAO RAS optical upper limit
  11. GRB 260907B: Fermi GBM Final Real-time Localization
  12. Fermi GRB 260907A: Global MASTER-Net observations report
  13. GRB 260907A: Fermi GBM Final Real-time Localization
  14. GRB 260903A: J-band upper limit with WINTER
  15. GRB 260903A: SVOM/ECLAIRs refined analysis
  16. GRB260903A: Liverpool Telescope optical observations
  17. GRB 260903A: SAO RAS optical observations
  18. GRB 260830A: GECAM-B detection of a burst
  19. GRB 260830A: Insight-HXMT/HE detection
  20. GRB 260903A: EP-FXT follow-up observation
  21. GRB 260903A: OHP/T193 optical afterglow detection
  22. GRB 260903A: NOT optical observations and afterglow fading
  23. GRB 260903A: LCO optical observations
  24. GRB 260903A: SVOM/VT optical candidate
  25. GRB 260903A: Retraction of optical counterpart of GCN 45501
  26. GRB 260831A: GECAM-B observation
  27. GRB 260903A: LCO optical counterpart detection
  28. GRB 260827A: Insight-HXMT/HE detection
  29. GRB 260903A: SVOM detection of a soft faint burst
  30. Konus-Wind detection of GRB 260829A
  31. GRB 260829A: SVOM/GRM observation
  32. GRB 260818A: ATCA detection of a candidate radio counterpart
  33. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  34. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  35. SVOM trigger sb26083106 is not a GRB
  36. GRB 260829A: AstroSat CZTI detection
  37. GRB 260831B: EP-FXT follow-up observation
  38. GRB 260830A: NuSTAR detection of prompt emission
  39. GRB 260831B: LCO optical upper limits
  40. GRB 260827A: SVOM/GRM observation
  41. GRB 260831B: SVOM detection of a possible burst
  42. IPN triangulation of GRB 260829A
  43. GRB 260827A: Glowbug gamma-ray detection
  44. GRB 260831A: Fermi GBM Final Real-time Localization
  45. GRB 260829A: GECAM-B observation of a long burst
  46. GRB 260825A: SVOM/GRM observation of a long burst
  47. GRB 260825A: GECAM-B observation
  48. GRB 260829A: Fermi GBM Detection
  49. GRB 260825A: AstroSat CZTI detection
  50. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  51. GRB 260829A: Fermi GBM Final Real-time Localization
  52. Fermi GBM trigger 809666623/260829141 is not a GRB
  53. GRB 260818B: Further EP-FXT observation
  54. GRB 260818B: VLT optical and nIR observations
  55. GRB 260818B: TNG NIR observations
  56. GRB 260827A: Fermi GBM Final Real-time Localization
  57. GRB 260818B: 6 GHz VLA observations
  58. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  59. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  60. GRB 260808B: SAO RAS observations of the optical rebrightening
  61. GRB 260807A: EP-FXT follow-up observations
  62. GRB 260822A: SVOM/ECLAIRs refined analysis
  63. GRB 260809A: SVOM/ECLAIRs refined analysis
  64. GRB 260822A: SVOM/VT optical upper limits
  65. GRB 260825A: Fermi GBM Final Real-time Localization
  66. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  67. GRB 260822A: EP/FXT follow-up observations
  68. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  69. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  70. GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
  71. GRB 260822A: GOTO optical counterpart detection
  72. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  73. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  74. GRB 260822A: LCO optical upper limits
  75. GRB260822B: Fermi GBM Final Localization
  76. GRB 260822A: GROWTH-India Telescope Upper Limits
  77. GRB 260822A: GOTO optical upper limit
  78. GRB 260822A: SVOM detection of a short burst
  79. GRB 260818B: VLA radio observations
  80. GRB 260818B: SVOM/C-GFT optical upper limit
  81. GRB 260820A: Insight-HXMT/HE detection
  82. GRB 260818B: SVOM/GRM observation
  83. GRB260820A: Fermi GBM Final Real-Time Localization
  84. GRB 260818B: Insight-HXMT detection
  85. GRB 260818B: EP-FXT follow-up observation
  86. GRB 260818A: J-band observations with WINTER
  87. GRB 260818B: SVOM/ECLAIRs refined analysis
  88. GRB 260818A: SVOM/ECLAIRs refined analysis
  89. GRB 260818B: NOT optical upper limits
  90. GRB 260810A: SVOM/GRM observation
  91. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  92. GRB260818A: EP-FXT follow-up observation
  93. GRB 260818B: LCO optical upper limits
  94. GRB 260818B: SVOM detection of a short burst
  95. SVOM trigger sb26081806 is not a GRB
  96. EP260806a: SAO RAS multicolor optical observations
  97. GRB 260818A: LCO optical upper limits
  98. EP260812a: AbAO optical upper limit
  99. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  100. GRB 260810A: Insight-HXMT/HE detection

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