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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"

5809 results found.

  1. GRB 260915A: J-band upper limit with WINTER
  2. Fermi trigger No 811264269: Global MASTER-Net observations report
  3. IceCube-260916A - IceCube observation of a high-energy neutrino candidate track-like event
  4. GRB 260914A: SVOM/GRM observation
  5. GRB 260914A: Mondy and TShAO optical observations
  6. GRB 260914A: SVOM/ECLAIRs refined analysis
  7. GRB 260916A: MAXI/GSC detection
  8. MAXI GRB260916.37: Global MASTER-Net observations report
  9. GRB 260915A: SVOM/C-GFT optical upper limits
  10. GRB 260915A: EP-FXT follow-up observation
  11. GRB 260915A: REM optical/NIR observations
  12. GRB 260914A: REM optical/NIR observations
  13. GRB 260914A: VLT/X-shooter observations and redshift confirmation
  14. GRB 260915A: SVOM/VT optical upper limits
  15. GRB 260915A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  16. GRB 260915A: NOT optical upper limit
  17. SVOM GRB260915.05: Global MASTER-Net observations report
  18. GRB 260915A: SVOM/VT optical upper limits from VHF data
  19. Fermi GBM Sub-Threshold Detection of GRB 260915A
  20. GRB 260915A: LCO optical upper limits
  21. EP Alert 260914.53: Global MASTER-Net observations report
  22. GRB 260914A: EP-FXT follow-up observation
  23. GRB 260915A: SVOM detection of a burst
  24. Fermi GBM Sub-Threshold Detection of GRB 260914A
  25. GRB 260914A: LCO optical observation
  26. GRB 260914A: SVOM/C-GFT optical observations
  27. GRB 260914A: SVOM/VT optical counterpart confirmation
  28. GRB 260914A: SVOM/VT optical observation from VHF data
  29. GRB 260914A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  30. SVOM GRB260914.47: Global MASTER-Net observations report
  31. GRB 260914A: SVOM detection of a burst
  32. GRB 260913A: SVOM trigger sb26091302 is not an astrophysical event
  33. GRB 260818A: Continued ATCA observations
  34. SVOM GRB260913.32: Global MASTER-Net observations report
  35. GRB 260913A: SVOM/C-GFT optical upper limit
  36. GRB 260913A: SVOM detection of a faint burst
  37. GRB 260907A: SVOM/GRM observation
  38. GRB 260909A: CrAO and AbAO optical upper limits
  39. GRB 260909A: SVOM/ECLAIRs refined analysis
  40. GRB 260910B: GOTO tentative optical counterpart candidates
  41. EP Alert 260909.53: Global MASTER-Net observations report
  42. GRB 260909A: EP-FXT follow-up observation
  43. GRB 260909A: SVOM/VT optical upper limits
  44. GRB 260909A: SVOM/GRM observation
  45. GRB 260909A: Mondy optical observations and afterglow candidate
  46. GRB 260909A: Xinglong 2.16m optical upper limit
  47. GRB 260909A: SVOM/C-GFT optical upper limit
  48. GRB 260909A: SVOM detection of a burst
  49. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  50. Fermi trigger No 810554827: Global MASTER-Net observations report
  51. EP Alert 260908.60: Global MASTER-Net observations report
  52. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  53. Fermi GRB 260907B: Global MASTER-Net observations report
  54. GRB 260903A: SAO RAS optical upper limit
  55. The EP-WXT trigger 01709305715 is likely a flaring star
  56. Fermi GRB 260907A: Global MASTER-Net observations report
  57. EP260903a: EP-FXT follow-up observation
  58. EP Alert 260905.11: Global MASTER-Net observations report
  59. The EP-WXT trigger 01709302592 is likely a flaring star
  60. GRB 260903A: J-band upper limit with WINTER
  61. EP Alert 260903.47: Global MASTER-Net observations report
  62. GRB 260903A: SVOM/ECLAIRs refined analysis
  63. GRB260903A: Liverpool Telescope optical observations
  64. GRB 260903A: SAO RAS optical observations
  65. EP260903a: EP-WXT detection of a fast X-ray transient
  66. EP Alert 260903.62: Global MASTER-Net observations report
  67. GRB 260903A: EP-FXT follow-up observation
  68. NuSTAR Transient 260828: SOAR Optical Upper Limits
  69. SVOM GRB260903A: Global MASTER-Net observations report
  70. GRB 260903A: SVOM/VT optical candidate
  71. GRB 260831A: GECAM-B observation
  72. GRB 260903A: LCO optical counterpart detection
  73. GRB 260903A: SVOM detection of a soft faint burst
  74. EP260901a: SVOM/VT optical upper limits
  75. EP260901a: EP-FXT follow-up observation
  76. EP260830a: EP-FXT follow-up observation
  77. EP260901a: Global MASTER-Net observations report
  78. NuSTAR Transient 260828: LCO Optical Upper Limits
  79. EP260901a: EP-WXT detection of a fast X-ray transient
  80. GRB 260831B: LCO optical upper limits
  81. EP260830a: Global MASTER-Net observations report
  82. IPN triangulation of GRB 260829A
  83. GRB 260831A: Fermi GBM Final Real-time Localization
  84. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  85. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  86. GRB 260825A: AstroSat CZTI detection
  87. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  88. GRB 260829A: Fermi GBM Final Real-time Localization
  89. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  90. EP260822a: Global MASTER-Net observations report
  91. IceCube Alert 260825A: Global MASTER-Net observations report
  92. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  93. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  94. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  95. GRB 260818B: SVOM/C-GFT optical upper limit
  96. IceCube Alert 260821A: Global MASTER-Net observations report
  97. GRB 260810A: SVOM/GRM observation
  98. GRB 260810A: Insight-HXMT/HE detection
  99. EP260812a: NOT and Liverpool Telescope upper limits:
  100. EP trigger #01709278129 (EP260812b?): NOT optical counterpart

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