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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"

28048 results found.

  1. GRB 260718A: SVOM/VT optical upper limits
  2. GRB 260718A: SVOM/VT optical upper limits from VHF data
  3. GRB 260714B: SVOM/GRM observation
  4. GRB 260310A / AT2026fgk: Late-time Chandra Detection
  5. GRB 260714B: COLIBRÍ optical counterpart candidate
  6. SVOM sb26071506: Global MASTER-Net observations report
  7. sb26071506: SVOM detection of a X-ray transient
  8. EP260703a: SVOM/ECLAIRs Upper Limit
  9. GRB 260710A: AstroSat CZTI detection
  10. GRB 260714B: Fermi GBM Detection
  11. GRB 260714B: BALROG localization (Fermi Trigger 805746211 / GRB 260714766)
  12. IceCube-260712A: Upper limits from a search for additional neutrino events in IceCube
  13. IceCube-260712A: LAST optical follow-up observations of the IceCube neutrino candidate
  14. EP260713a: Einstein Probe detection of an X-ray transient
  15. GRB 260619A: SVOM/VT continuous optical observations
  16. GRB 260708A: slowly decaying X-ray emission observed by EP/FXT
  17. EP260623a: KAIT optical observations
  18. GRB 260708A: GRANDMA Optical Observations
  19. Fermi-LAT Gamma-ray Observations of IceCube-260712A
  20. Fermi-LAT Gamma-ray Observations of IceCube-260708A
  21. Fermi-LAT Gamma-ray Observations of IceCube-260704A
  22. IceCube-260708A: Upper limits from a search for additional neutrino events in IceCube
  23. GRB 260708A: LCO optical observations
  24. EP260711a: Einstein Probe detection of an X-ray transient
  25. GRB 260709A: SVOM/GRM detection
  26. IceCube-260708A: Observations with the Vera C. Rubin Observatory
  27. EP-WXT trigger 0170924151 : RAPAS optical counterpart candidate detection
  28. GRB 260708A: Glowbug gamma-ray detection
  29. GRB 260706A : GRANDMA Upper limits
  30. GRB 260708A: Kilonova-Catcher optical afterglow detection
  31. IceCube-260708A: One candidate from the Zwicky Transient Facility
  32. GRB 260708A: Fermi-GBM observation
  33. Fermi LAT GRB 260708A: MASTER OT J150237.02-435307.7 optical counterpart detection
  34. IceCube Alert 260709A: Global MASTER-Net observations report
  35. LAT GRB260708.42: Global MASTER-Net observations report
  36. GRB260708B: MAXI/GSC detection
  37. GRB 260705B: SVOM/GRM observation
  38. GRB 260706A: Further EP-FXT follow-up observation
  39. EP260707a (by EP-FXT): NOT optical upper limit
  40. EP260707a is not a real source
  41. EP260707a: LCOGT Optical Upper Limit
  42. EP260707a: TRT optical upper limit
  43. EP260707a: Einstein Probe detection of an X-ray transient
  44. GRB 260705A: Candidate Optical Counterpart from SOAR and Gemini-South and Possible Association with GRB 260705B
  45. GRB 260705C: Glowbug gamma-ray detection of a short burst
  46. GRB 260704A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  47. GRB 260706A: REM optical/NIR observations
  48. GRB 260706A: LCO optical upper limit
  49. GRB 260706A: EP-FXT follow-up observation
  50. The EP-WXT trigger 01709274151 is likely a flaring star
  51. GRB 260706A: Fermi GBM Observation
  52. IceCube-260704A: Upper limits from a search for additional neutrino events in IceCube
  53. GRB 260706A: SVOM detection of a burst
  54. GRB 260705A: LCO optical upper limits
  55. GRB 260704A: NOT optical upper limits
  56. Fermi GBM Sub-Threshold Detection of GRB 260705A
  57. GRB 260704A: EP-FXT follow-up observation
  58. GRB 260629A: SVOM/GRM observation of a short burst
  59. GRB 260629A: AstroSat CZTI detection
  60. EP260703a: EP-FXT follow-up observation
  61. GRB 260704A: SVOM detection of a possible GRB
  62. EP260703a: EP-WXT detection of a fast X-ray transient
  63. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  64. Fermi trigger No 804738310: Global MASTER-Net observations report
  65. Fermi GRB 260703A: Global MASTER-Net observations report
  66. GRB 260623A: Glowbug gamma-ray detection
  67. GRB 260610B / AT2026owq: SAO RAS, CrAO and INASAN further optical observations and light curve
  68. Fermi trigger No 804552016: Global MASTER-Net observations report
  69. GRB 260701A: Fermi GBM Final Real-time Localization
  70. Fermi-LAT Gamma-ray Observations of IceCube-260622A
  71. EP260628a: EP-FXT follow-up observation
  72. Fermi GRB 260628A: Global MASTER-Net observations report
  73. EP260628a: EP-WXT detection of a fast X-ray transient
  74. EP260626a: further Liverpool Telescope optical upper limits
  75. EP260626a: COLIBRÍ optical upper limit
  76. EP260626a: Liverpool Telescope upper limits
  77. EP260626a: EP-WXT detection of a fast X-ray transient
  78. EP260623a: TNG NIR afterglow detection
  79. GRB 260618A: Fermi GBM Observation
  80. GRB 260619A: SVOM/ECLAIRs refined analysis
  81. EP260623a: Liverpool Telescope optical observations
  82. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  83. EP260623a: WINTER J-band observations
  84. GRB 260617A: Glowbug gamma-ray detection of a short burst
  85. IceCube-260622A: Upper limits from a search for additional neutrino events in IceCube
  86. EP260623a: Optical follow-up observations with Kinder
  87. EP260623a: SVOM/VT optical observations
  88. EP260623a: TRT optical observations
  89. EP260623a: REM optical/NIR afterglow detection
  90. EP 260623a: COLIBRÍ optical observations
  91. GRB 260616B/EP260616a: Insight-HXMT/HE detection
  92. EP260623a: Las Cumbres discovery of the optical counterpart
  93. EP260623a: Einstein Probe detection of an X-ray transient
  94. GRB 260614B: EP-FXT follow-up observation
  95. GRB 260618C: SVOM/ECLAIRs detection of a possible burst through on-ground search
  96. EP260618a: Liverpool Telescope optical observations
  97. GRB 260618B: LCO optical observations
  98. EP260618a: JinShan optical observations
  99. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  100. GRB 260618B: Fermi GBM Observation

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