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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"

28045 results found.

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

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