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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"

37982 results found.

  1. GRB 260818A: Continued ATCA observations
  2. SVOM GRB260913.32: Global MASTER-Net observations report
  3. GRB 260913A: SVOM/C-GFT optical upper limit
  4. GRB 260913A: SVOM detection of a faint burst
  5. GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
  6. GRB 260907A: SVOM/GRM observation
  7. GRB 260909A: CrAO and AbAO optical upper limits
  8. GRB 260909A: SVOM/ECLAIRs refined analysis
  9. GRB 260910B: GOTO tentative optical counterpart candidates
  10. GRB 260909A: Swift ToO observations
  11. GRB 260910B: Fermi GBM Final Real-time Localization
  12. GRB 260909A: KAIT optical upper limit
  13. GRB 260903A: Swift-XRT observations
  14. GRB 260909A: OHP/T193 z-band upper limit
  15. GRB 260909A: VLT optical and near-infrared upper limits
  16. EP Alert 260909.53: Global MASTER-Net observations report
  17. GRB 260909A: EP-FXT follow-up observation
  18. GRB 260910A: Fermi GBM Final Real-time Localization
  19. GRB 260909A: SVOM/VT optical upper limits
  20. GRB 260909A: SVOM/GRM observation
  21. GRB 260909A: Mondy optical observations and afterglow candidate
  22. GRB 260909A: Xinglong 2.16m optical upper limit
  23. GRB 260909A: SVOM/C-GFT optical upper limit
  24. GRB 260909A: SVOM detection of a burst
  25. Fermi trigger No 810554827: Global MASTER-Net observations report
  26. EP Alert 260908.60: Global MASTER-Net observations report
  27. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  28. GRB 260903A: Swift ToO observations
  29. Fermi GRB 260907B: Global MASTER-Net observations report
  30. GRB 260903A: SAO RAS optical upper limit
  31. GRB 260907B: Fermi GBM Final Real-time Localization
  32. Fermi GRB 260907A: Global MASTER-Net observations report
  33. GRB 260907A: Fermi GBM Final Real-time Localization
  34. EP Alert 260905.11: Global MASTER-Net observations report
  35. GRB 260903A: J-band upper limit with WINTER
  36. EP Alert 260903.47: Global MASTER-Net observations report
  37. GRB 260903A: SVOM/ECLAIRs refined analysis
  38. GRB260903A: Liverpool Telescope optical observations
  39. GRB 260903A: SAO RAS optical observations
  40. GRB 260830A: GECAM-B detection of a burst
  41. EP Alert 260903.62: Global MASTER-Net observations report
  42. GRB 260830A: Insight-HXMT/HE detection
  43. GRB 260903A: EP-FXT follow-up observation
  44. GRB 260903A: OHP/T193 optical afterglow detection
  45. GRB 260903A: NOT optical observations and afterglow fading
  46. SVOM GRB260903A: Global MASTER-Net observations report
  47. GRB 260903A: LCO optical observations
  48. GRB 260903A: SVOM/VT optical candidate
  49. GRB 260903A: Retraction of optical counterpart of GCN 45501
  50. GRB 260831A: GECAM-B observation
  51. GRB 260903A: LCO optical counterpart detection
  52. GRB 260827A: Insight-HXMT/HE detection
  53. GRB 260903A: SVOM detection of a soft faint burst
  54. Konus-Wind detection of GRB 260829A
  55. GRB 260829A: SVOM/GRM observation
  56. GRB 260818A: ATCA detection of a candidate radio counterpart
  57. EP260901a: Global MASTER-Net observations report
  58. IceCube-260827A: No transient candidates from the Zwicky Transient Facility
  59. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  60. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  61. SVOM trigger sb26083106 is not a GRB
  62. GRB 260829A: AstroSat CZTI detection
  63. GRB 260831B: EP-FXT follow-up observation
  64. GRB 260830A: NuSTAR detection of prompt emission
  65. GRB 260831B: LCO optical upper limits
  66. EP260830a: Global MASTER-Net observations report
  67. GRB 260827A: SVOM/GRM observation
  68. GRB 260831B: SVOM detection of a possible burst
  69. IPN triangulation of GRB 260829A
  70. GRB 260827A: Glowbug gamma-ray detection
  71. GRB 260831A: Fermi GBM Final Real-time Localization
  72. GRB 260829A: GECAM-B observation of a long burst
  73. GRB 260825A: SVOM/GRM observation of a long burst
  74. GRB 260825A: GECAM-B observation
  75. GRB 260829A: Fermi GBM Detection
  76. GRB 260825A: AstroSat CZTI detection
  77. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  78. GRB 260829A: Fermi GBM Final Real-time Localization
  79. Fermi GBM trigger 809666623/260829141 is not a GRB
  80. GRB 260818B: Further EP-FXT observation
  81. GRB 260818B: VLT optical and nIR observations
  82. GRB 260818B: TNG NIR observations
  83. MAXI GRB260827.40: Global MASTER-Net observations report
  84. GRB 260827A: Fermi GBM Final Real-time Localization
  85. GRB 260818B: 6 GHz VLA observations
  86. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  87. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  88. GRB 260808B: SAO RAS observations of the optical rebrightening
  89. EP260822a: Global MASTER-Net observations report
  90. EP Alert 260820.31: Global MASTER-Net observations report
  91. IceCube-260825A: No transient candidates from the Zwicky Transient Facility
  92. GRB 260807A: EP-FXT follow-up observations
  93. GRB 260822A: SVOM/ECLAIRs refined analysis
  94. GRB 260809A: SVOM/ECLAIRs refined analysis
  95. GRB 260822A: SVOM/VT optical upper limits
  96. IceCube Alert 260825A: Global MASTER-Net observations report
  97. GRB 260825A: Fermi GBM Final Real-time Localization
  98. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  99. GRB 260822A: EP/FXT follow-up observations
  100. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN

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