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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"

41682 results found.

  1. GRB 260909A: SVOM/ECLAIRs refined analysis
  2. GRB 260910B: GOTO tentative optical counterpart candidates
  3. GRB 260909A: Swift ToO observations
  4. GRB 260909A: KAIT optical upper limit
  5. GRB 260903A: Swift-XRT observations
  6. EP260806a: VLA+ALMA radio detections
  7. GRB 260909A: OHP/T193 z-band upper limit
  8. GRB 260909A: VLT optical and near-infrared upper limits
  9. EP Alert 260909.53: Global MASTER-Net observations report
  10. GRB 260909A: EP-FXT follow-up observation
  11. EP260806a: NOEMA detection
  12. EP260623a: NOEMA detections
  13. GRB 260909A: SVOM/VT optical upper limits
  14. GRB 260909A: SVOM/GRM observation
  15. GRB 260909A: Mondy optical observations and afterglow candidate
  16. GRB 260909A: Xinglong 2.16m optical upper limit
  17. GRB 260909A: SVOM/C-GFT optical upper limit
  18. GRB 260909A: SVOM detection of a burst
  19. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  20. Fermi trigger No 810554827: Global MASTER-Net observations report
  21. EP Alert 260908.60: Global MASTER-Net observations report
  22. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  23. GRB 260903A: Swift ToO observations
  24. Fermi GRB 260907B: Global MASTER-Net observations report
  25. GRB 260903A: SAO RAS optical upper limit
  26. The EP-WXT trigger 01709305715 is likely a flaring star
  27. Fermi GRB 260907A: Global MASTER-Net observations report
  28. EP260903a: EP-FXT follow-up observation
  29. EP Alert 260905.11: Global MASTER-Net observations report
  30. The EP-WXT trigger 01709302592 is likely a flaring star
  31. GRB 260903A: J-band upper limit with WINTER
  32. EP Alert 260903.47: Global MASTER-Net observations report
  33. GRB 260903A: SVOM/ECLAIRs refined analysis
  34. GRB260903A: Liverpool Telescope optical observations
  35. GRB 260903A: SAO RAS optical observations
  36. GRB 260830A: GECAM-B detection of a burst
  37. EP260903a: EP-WXT detection of a fast X-ray transient
  38. EP Alert 260903.62: Global MASTER-Net observations report
  39. GRB 260830A: Insight-HXMT/HE detection
  40. GRB 260903A: EP-FXT follow-up observation
  41. GRB 260903A: OHP/T193 optical afterglow detection
  42. GRB 260903A: NOT optical observations and afterglow fading
  43. NuSTAR Transient 260828: SOAR Optical Upper Limits
  44. SVOM GRB260903A: Global MASTER-Net observations report
  45. GRB 260903A: LCO optical observations
  46. GRB 260903A: SVOM/VT optical candidate
  47. GRB 260903A: Retraction of optical counterpart of GCN 45501
  48. GRB 260831A: GECAM-B observation
  49. GRB 260903A: LCO optical counterpart detection
  50. GRB 260827A: Insight-HXMT/HE detection
  51. GRB 260903A: SVOM detection of a soft faint burst
  52. EP260901a: SVOM/VT optical upper limits
  53. EP260901a: EP-FXT follow-up observation
  54. Konus-Wind detection of GRB 260829A
  55. GRB 260829A: SVOM/GRM observation
  56. GRB 260818A: ATCA detection of a candidate radio counterpart
  57. EP260830a: EP-FXT follow-up observation
  58. EP260901a: Global MASTER-Net observations report
  59. IceCube-260827A: No transient candidates from the Zwicky Transient Facility
  60. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  61. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  62. NuSTAR Transient 260828: LCO Optical Upper Limits
  63. EP260901a: EP-WXT detection of a fast X-ray transient
  64. SVOM trigger sb26083106 is not a GRB
  65. GRB 260829A: AstroSat CZTI detection
  66. GRB 260831B: EP-FXT follow-up observation
  67. GRB 260830A: NuSTAR detection of prompt emission
  68. GRB 260831B: LCO optical upper limits
  69. EP260830a: Global MASTER-Net observations report
  70. EP260830a: EP-WXT detection of a fast X-ray transient
  71. GRB 260827A: SVOM/GRM observation
  72. NuSTAR 260828: a 1100s hard X-ray transient
  73. GRB 260831B: SVOM detection of a possible burst
  74. IPN triangulation of GRB 260829A
  75. GRB 260827A: Glowbug gamma-ray detection
  76. EP260727a: ATCA 10 GHz detection
  77. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  78. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  79. GRB 260829A: GECAM-B observation of a long burst
  80. GRB 260825A: SVOM/GRM observation of a long burst
  81. GRB 260825A: GECAM-B observation
  82. GRB 260829A: Fermi GBM Detection
  83. GRB 260825A: AstroSat CZTI detection
  84. IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
  85. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  86. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  87. Fermi GBM trigger 809666623/260829141 is not a GRB
  88. GRB 260818B: Further EP-FXT observation
  89. GRB 260818B: VLT optical and nIR observations
  90. GRB 260818B: TNG NIR observations
  91. MAXI GRB260827.40: Global MASTER-Net observations report
  92. IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
  93. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  94. GRB 260818B: 6 GHz VLA observations
  95. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  96. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  97. GRB 260808B: SAO RAS observations of the optical rebrightening
  98. EP260822a: Global MASTER-Net observations report
  99. EP Alert 260820.31: Global MASTER-Net observations report
  100. IceCube-260825A: No transient candidates from the Zwicky Transient Facility

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