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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"

37943 results found.

  1. GRB 260830A: GECAM-B detection of a burst
  2. EP Alert 260903.62: Global MASTER-Net observations report
  3. GRB 260830A: Insight-HXMT/HE detection
  4. GRB 260903A: EP-FXT follow-up observation
  5. GRB 260903A: OHP/T193 optical afterglow detection
  6. GRB 260903A: NOT optical observations and afterglow fading
  7. SVOM GRB260903A: Global MASTER-Net observations report
  8. GRB 260903A: LCO optical observations
  9. GRB 260903A: SVOM/VT optical candidate
  10. GRB 260903A: Retraction of optical counterpart of GCN 45501
  11. GRB 260831A: GECAM-B observation
  12. GRB 260903A: LCO optical counterpart detection
  13. GRB 260827A: Insight-HXMT/HE detection
  14. GRB 260903A: SVOM detection of a soft faint burst
  15. Konus-Wind detection of GRB 260829A
  16. GRB 260829A: SVOM/GRM observation
  17. GRB 260818A: ATCA detection of a candidate radio counterpart
  18. EP260901a: Global MASTER-Net observations report
  19. IceCube-260827A: No transient candidates from the Zwicky Transient Facility
  20. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  21. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  22. SVOM trigger sb26083106 is not a GRB
  23. GRB 260829A: AstroSat CZTI detection
  24. GRB 260831B: EP-FXT follow-up observation
  25. GRB 260830A: NuSTAR detection of prompt emission
  26. GRB 260831B: LCO optical upper limits
  27. EP260830a: Global MASTER-Net observations report
  28. GRB 260827A: SVOM/GRM observation
  29. GRB 260831B: SVOM detection of a possible burst
  30. IPN triangulation of GRB 260829A
  31. GRB 260827A: Glowbug gamma-ray detection
  32. GRB 260831A: Fermi GBM Final Real-time Localization
  33. GRB 260829A: GECAM-B observation of a long burst
  34. GRB 260825A: SVOM/GRM observation of a long burst
  35. GRB 260825A: GECAM-B observation
  36. GRB 260829A: Fermi GBM Detection
  37. GRB 260825A: AstroSat CZTI detection
  38. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  39. GRB 260829A: Fermi GBM Final Real-time Localization
  40. Fermi GBM trigger 809666623/260829141 is not a GRB
  41. GRB 260818B: Further EP-FXT observation
  42. GRB 260818B: VLT optical and nIR observations
  43. GRB 260818B: TNG NIR observations
  44. MAXI GRB260827.40: Global MASTER-Net observations report
  45. GRB 260827A: Fermi GBM Final Real-time Localization
  46. GRB 260818B: 6 GHz VLA observations
  47. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  48. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  49. GRB 260808B: SAO RAS observations of the optical rebrightening
  50. EP260822a: Global MASTER-Net observations report
  51. EP Alert 260820.31: Global MASTER-Net observations report
  52. IceCube-260825A: No transient candidates from the Zwicky Transient Facility
  53. GRB 260807A: EP-FXT follow-up observations
  54. GRB 260822A: SVOM/ECLAIRs refined analysis
  55. GRB 260809A: SVOM/ECLAIRs refined analysis
  56. GRB 260822A: SVOM/VT optical upper limits
  57. IceCube Alert 260825A: Global MASTER-Net observations report
  58. GRB 260825A: Fermi GBM Final Real-time Localization
  59. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  60. GRB 260822A: EP/FXT follow-up observations
  61. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  62. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  63. GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
  64. GRB 260822A: GOTO optical counterpart detection
  65. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  66. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  67. GRB 260822A: LCO optical upper limits
  68. GRB260822B: Fermi GBM Final Localization
  69. GRB 260822A: GROWTH-India Telescope Upper Limits
  70. GRB 260822A: GOTO optical upper limit
  71. GRB 260822A: SVOM detection of a short burst
  72. GRB 260818B: VLA radio observations
  73. GRB 260818B: SVOM/C-GFT optical upper limit
  74. IceCube Alert 260821A: Global MASTER-Net observations report
  75. GRB 260820A: Insight-HXMT/HE detection
  76. GRB 260818B: SVOM/GRM observation
  77. GRB260820A: Fermi GBM Final Real-Time Localization
  78. GRB 260818B: Insight-HXMT detection
  79. GRB 260818B: EP-FXT follow-up observation
  80. GRB 260818A: J-band observations with WINTER
  81. GRB 260818B: SVOM/ECLAIRs refined analysis
  82. GRB 260818A: SVOM/ECLAIRs refined analysis
  83. GRB 260818B: NOT optical upper limits
  84. GRB 260810A: SVOM/GRM observation
  85. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  86. GRB260818A: EP-FXT follow-up observation
  87. GRB 260818B: LCO optical upper limits
  88. GRB 260818B: SVOM detection of a short burst
  89. SVOM trigger sb26081806 is not a GRB
  90. EP260806a: SAO RAS multicolor optical observations
  91. GRB 260818A: LCO optical upper limits
  92. EP260812a: AbAO optical upper limit
  93. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  94. GRB 260810A: Insight-HXMT/HE detection
  95. GRB 260818A: SVOM possible detection of a long and faint GRB
  96. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  97. GRB 260808B: Liverpool Telescope further optical observations
  98. GRB 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
  99. GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
  100. GRB 260813A: Fermi GBM Final Real-time Localization

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