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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"

3296 results found.

  1. GRB 260706A: REM optical/NIR observations
  2. GRB 260706A: LCO optical upper limit
  3. GRB 260706A: EP-FXT follow-up observation
  4. The EP-WXT trigger 01709274151 is likely a flaring star
  5. The EP-WXT trigger 01709274141 is likely a flaring star
  6. The EP-WXT trigger 01709274014: KAIT confirmation of a stellar flare
  7. The EP-WXT trigger 01709274014 is likely a flaring star
  8. GRB 260704A: NOT optical upper limits
  9. GRB 260704A: EP-FXT follow-up observation
  10. EP260703a: EP-FXT follow-up observation
  11. EP260703a: EP-WXT detection of a fast X-ray transient
  12. EP260628b: EP-WXT detection of an X-ray transient and EP-FXT follow-up observation
  13. EP260628a: EP-FXT follow-up observation
  14. EP260628a: EP-WXT detection of a fast X-ray transient
  15. The EP-WXT trigger 01709272671 is likely a flaring star
  16. EP260626a: further Liverpool Telescope optical upper limits
  17. EP260626a: EP-FXT follow-up observation
  18. EP260626a: COLIBRÍ optical upper limit
  19. EP260626a: Liverpool Telescope upper limits
  20. EP260626a: EP-WXT detection of a fast X-ray transient
  21. Konus-Wind detection of GRB 260623B / EP260623a
  22. EP260623a: TNG NIR afterglow detection
  23. GRB 260618A: Fermi GBM Observation
  24. MASS-Cube (GRID 2.0) detection of GRB 260616B
  25. EP260623a: Liverpool Telescope optical observations
  26. Konus-Wind detection of GRB 260618B
  27. EP260623a:refined analysis of the EP-WXT and EP-FXT observation
  28. EP260623a: WINTER J-band observations
  29. EP260623a: Optical follow-up observations with Kinder
  30. EP260623a: TRT optical observations
  31. EP260623a: REM optical/NIR afterglow detection
  32. EP 260623a: COLIBRÍ optical observations
  33. EP260623a: OSIRIS+/GTC redshift z = 0.703
  34. EP260623a: Las Cumbres discovery of the optical counterpart
  35. EP260623a: Einstein Probe detection of an X-ray transient
  36. GRB 260614B: EP-FXT follow-up observation
  37. EP260618a: Liverpool Telescope optical observations
  38. The EP-WXT trigger 01709271197 is likely a flaring star
  39. EP260618a: JinShan optical observations
  40. GRB 260616B/EP260616a: SVOM/GRM detection of a burst
  41. Konus-Wind detection of GRB 260617A
  42. GRB 260616B: AstroSat CZTI detection
  43. EP260618a: EP-FXT follow-up observation
  44. EP260618a: EP-WXT detection of an X-ray transient
  45. EP260616a/GRB 260616B: EP-FXT follow-up observation
  46. Konus-Wind detection of GRB 260616B/EP260616a
  47. Konus-Wind detection of GRB 260616A
  48. GRB 260616B: CALET Gamma-Ray Burst Monitor detection
  49. EP260616a/GRB260616B: COLIBRÍ optical upper limit
  50. EP260616a: EP-WXT detection of a fast X-ray transient
  51. The EP-WXT trigger 01709270148 is likely a flaring star
  52. The EP-WXT trigger 01709269893 is likely a flaring star
  53. The EP-WXT trigger 01709269488 is likely a flaring star
  54. EP260605a: COLIBRÍ optical upper limits
  55. IceCube-260610A: EP-FXT follow-up observation
  56. The EP-WXT trigger 01709269176: SVOM/C-GFT confirmation of a stellar flare
  57. EP260610b: GTC likely spectroscopic redshift z = 1.10
  58. The EP-WXT trigger 01709269176 is likely a flaring star
  59. EP260610b: refined analysis of the EP-WXT and follow-up EP-FXT observations
  60. EP260610a: refined analysis of the EP-WXT and follow-up EP-FXT observations
  61. EP260610b: MAO/AZT-22 optical observations
  62. EP260610b: NOT optical observation
  63. EP260610a: SVOM/VT optical upper limits
  64. EP260610b: Einstein Probe detection of an X-ray transient
  65. Konus-Wind detection of GRB 260601A
  66. EP260610a: COLIBRÍ optical upper limits
  67. EP260610a: Einstein Probe detection of a fast X-ray transient
  68. Konus-Wind detection of GRB 260604C
  69. Konus-Wind detection of GRB 260607B
  70. EP260605a: EP-FXT follow-up observation
  71. EP260605a: Einstein Probe detection of a fast X-ray transient
  72. The EP-WXT trigger 01709267001 is likely a flaring star
  73. EP260602d: EP-FXT follow-up observation
  74. EP260602c: EP-FXT follow-up observation
  75. The EP-WXT trigger 01709266798 is likely a flaring star
  76. EP260602d: J-band upper limit with WINTER
  77. EP260602b: J-band upper limit with WINTER
  78. EP260602a: EP-FXT follow-up observation
  79. EP260603a: Global MASTER-Net observations report
  80. EP260603a: Einstein Probe detection of a fast X-ray transient
  81. EP260602d: Optical Upper limits with kinder observations
  82. Konus-Wind detection of GRB 260601B/EP260601a
  83. GRB 260603A: EP-FXT follow-up observation
  84. EP260601a/GRB 260601B: EP-FXT follow-up observation
  85. EP260602b: EP-FXT follow-up observation
  86. EP260602a: NOT NIR J-band observations
  87. EP260602d: Einstein Probe detection of a fast X-ray transient
  88. EP260602c: Einstein Probe detection of a fast X-ray transient
  89. EP260602b: Einstein Probe detection of a fast X-ray transient
  90. GRB 260601B/EP260601a: Insight-HXMT detection
  91. EP-WXT trigger 01709266414 (EP260602b): JinShan optical counterpart detection
  92. GRB 260601B: CALET Gamma-Ray Burst Monitor detection
  93. EP260602a: Optical upper limits with Kinder observations
  94. GRB 260601B / EP260601a: NuSTAR detection of prompt emission
  95. EP260602a: Einstein Probe detection of a fast X-ray transient
  96. GRB 260601B/EP260601a: GECAM-B analysis suggests a possible long duration Type I burst
  97. GRB 260601B: GECAM-B detection of a burst probably associated with EP260601a
  98. EP260601a: Einstein Probe detection of an X-ray transient
  99. EP-WXT trigger 01709266307 (EP260601a): COLIBRÍ optical observations
  100. EP-WXT trigger 01709266307 (EP260601a): JinShan optical counterpart detection

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