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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"

27008 results found.

  1. EP260725a: EP-WXT detection of an X-ray transient
  2. EP260723a: EP-FXT follow-up observation
  3. GRB 260718A: SVOM/ECLAIRs refined analysis
  4. Fermi Gamma-ray Burst Monitor trigger 806592752 / 260724564 is not a GRB
  5. EP260723a: SVOM/VT optical observation
  6. EP260723a: COLIBRÍ optical observations
  7. EP260723a: NOT optical conterpart confirmation
  8. EP260723a: EP-WXT detection of a fast X-ray transient
  9. GRB 260723A: Fermi GBM Final Localization
  10. IceCube Alert 260722A: Global MASTER-Net observations report
  11. GRB 260722A: Fermi GBM Final Real-time Localization
  12. Fermi GBM trigger 806384210/260722151 is not a GRB
  13. GRB 260721A: NuSTAR detection of prompt emission
  14. SVOM trigger sb26071506: SVOM/VT confirmation of a stellar flare
  15. GRB 260705A: Retraction of optical counterpart
  16. GRB 260718A: EP-FXT follow-up observation
  17. Fermi trigger No 806104130: Global MASTER-Net observations report
  18. Fermi GRB 260718A: Global MASTER-Net observations report
  19. GRB 260718A: LCO optical upper limits
  20. GRB 260711A: SVOM/GRM observation
  21. GRB 260710A: SVOM/GRM observation
  22. GRB 260718A: Fermi GBM Observation
  23. GRB 260718A : GRANDMA and KNC upper limits
  24. GRB 260718A: SVOM/VT optical upper limits
  25. GRB 260718A: SVOM/VT optical upper limits from VHF data
  26. GRB 260718A: SVOM detection of a burst
  27. GRB 260714B: SVOM/GRM observation
  28. GRB 260714B: GECAM-B observation of a burst
  29. GRB 260618B: EP-FXT follow-up observation upper limit
  30. GRB 260714B: COLIBRÍ optical counterpart candidate
  31. SVOM sb26071506: Global MASTER-Net observations report
  32. sb26071506: SVOM detection of a X-ray transient
  33. GRB 260715A: Fermi GBM Final Real-time Localization
  34. EP260703a: SVOM/ECLAIRs Upper Limit
  35. GRB 260714B: Fermi-LAT detection
  36. GRB 260714B: Fermi GBM Detection
  37. GRB 260714B: BALROG localization (Fermi Trigger 805746211 / GRB 260714766)
  38. GRB 260714B: Fermi GBM Final Real-time Localization
  39. GRB 260705A: ATCA radio observations
  40. GRB 260714A: Fermi GBM Final Real-time Localization
  41. EP260713a: Einstein Probe detection of an X-ray transient
  42. GRB 260619A: SVOM/VT continuous optical observations
  43. GRB 260618B: SVOM/VT optical observations indicate shallow decay and reddening
  44. GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
  45. EP260711a: EP-FXT follow-up observation
  46. GRB 260708A: GRANDMA Optical Observations
  47. GRB 260708A: LCO optical observations
  48. EP260711a: Einstein Probe detection of an X-ray transient
  49. GRB 260710A: Fermi GBM Detection
  50. GRB 260709A: SVOM/GRM detection
  51. GRB 260709A: GECAM-B observation
  52. The EP-WXT trigger 01709274666 is likely a new outburst of the CV SS Cyg
  53. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  54. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  55. GRB 260710A: Fermi GBM Final Real-time Localization
  56. GRB 260704A: SVOM/ECLAIRs refined analysis
  57. GRB 260706A : GRANDMA Upper limits
  58. GRB 260708A: Kilonova-Catcher optical afterglow detection
  59. GRB 260708A: GECAM-B observation of a burst
  60. GRB 260708A: Fermi-GBM observation
  61. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  62. IceCube Alert 260709A: Global MASTER-Net observations report
  63. GRB 260709A: Fermi GBM Final Real-time Localization
  64. LAT GRB260708.42: Global MASTER-Net observations report
  65. GRB 260708A: Fermi-LAT detection
  66. GRB 260705B: SVOM/GRM observation
  67. GRB 260708A: Fermi-GBM detection
  68. GRB 260706A: Further EP-FXT follow-up observation
  69. GRB 260706A: SVOM/VT optical upper limits
  70. EP260707a is not a real source
  71. EP260707a: LCOGT Optical Upper Limit
  72. EP260707a: TRT optical upper limit
  73. Fermi GBM trigger 805087514/260707142 (GRB 260707A) is not a GRB
  74. EP260707a: Einstein Probe detection of an X-ray transient
  75. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  76. GRB 260706A: SVOM/ECLAIRs refined analysis
  77. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  78. GRB 260706A: SVOM/GRM observation
  79. GRB 260706A: REM optical/NIR observations
  80. GRB 260706A: LCO optical upper limit
  81. GRB 260706A: EP-FXT follow-up observation
  82. GRB 260707A: Fermi GBM Final Real-time Localization
  83. The EP-WXT trigger 01709274151 is likely a flaring star
  84. The EP-WXT trigger 01709274141 is likely a flaring star
  85. GRB 260706A: Fermi GBM Observation
  86. GRB 260705A: SVOM/ECLAIRs refined analysis
  87. GRB 260706A: SVOM detection of a burst
  88. GRB 260706A: Fermi GBM Final Real-time Localization
  89. The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare
  90. The EP-WXT trigger 01709274014 is likely a flaring star
  91. IceCube260704A: OHP/T193 optical observations
  92. GRB 260705A: LCO optical upper limits
  93. GRB 260704A: NOT optical upper limits
  94. GRB 260705C: Fermi GBM Final Localization
  95. GRB 260705B: Fermi GBM Final Real-time Localization
  96. Fermi GBM Sub-Threshold Detection of GRB 260705A
  97. GRB 260705A: SVOM detection of a burst
  98. GRB 260704A: EP-FXT follow-up observation
  99. GRB 260629A: SVOM/GRM observation of a short burst
  100. GRB 260629A: GECAM-A observation of a short burst

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