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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

32720 results found.

  1. GRB 260101A: Fermi GBM Observation
  2. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  3. GRB 260101A: GECAM-B detection
  4. GRB 260101A: NOT spectroscopic observations
  5. GRB 260101A: SVOM/GRM observation
  6. Swift GRB 260101A: Global MASTER-Net observations report
  7. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  8. GRB 260101A: LCO detection of the optical counterpart
  9. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  10. GRB 251230A: GRANDMA/TAROT Early Detection
  11. GRB 251230A / EP251230a: further NOT optical observations revealing shallower decay or possible rebrightening
  12. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  13. EP251229a: Optical upper limit with Kinder observations
  14. GRB 251230A: 1.3m DFOT optical upper limit
  15. GRB 251222A: Mondy Optical Observations
  16. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  17. GRB 251230A: Swift/UVOT detection
  18. GRB251230A: 7DT optical upper limits
  19. GRB 251230A / EP251230a: NOT observations and spectroscopic redshift upper limit z < 2.2
  20. EP251229a: BOOTES-2 early optical upper limit
  21. GRB 251230A: GOTO optical upper limit
  22. EP251229a: NOT optical upper limits
  23. GRB 251230A / EP251230a: SVOM/VT optical observation
  24. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  25. GRB 251230A: Early optical counterpart detection by LCO.
  26. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  27. GRB 251230A: Optical Observations via Virtual Telescope Project, Italy
  28. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  29. GRB 251230A/EP#01709250693 (likely EP251230a): FTW optical and NIR observations
  30. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  31. Swift GRB 251230A: Global MASTER-Net observations report
  32. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  33. EP251229a: Global MASTER-Net observations report
  34. GRB 251226A: Glowbug gamma-ray detection
  35. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  36. GRB 251129A: redshift correction and SN detection at z = 0.505 with GTC
  37. Fermi GRB 251228A: Global MASTER-Net observations report
  38. GRB 251226A: SVOM/GRM observation
  39. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  40. GRB 251222A: NUTTelA-TAO Early Measurements
  41. GRB 251222A/EP251222b: Optical detection with Kinder observations
  42. EP251222a: Optical upper limit with Kinder observations
  43. GRB 251221A: Swift-BAT refined analysis
  44. GRB 251222A/EP251222b: FTW optical and NIR observations
  45. EP251222a: FTW optical and NIR observations
  46. GRB 251205A: Kilonova-Catcher optical afterglow detection
  47. GRB 251222A: AbAO optical observations
  48. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  49. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  50. EP251222a: VLT/FORS2 spectroscopic redshift z = 0.505
  51. GRB 251222A: ZTSH BVRI optical observations
  52. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  53. GRB 251222A: Continued 1.3m DFOT optical observation
  54. EP251220a: 3.6m DOT optical afterglow detection
  55. GRB 251222A: Fermi GBM Observation
  56. EP251220a: CrAO ZTSh optical observations
  57. EP251221a: PRIME upper limit
  58. EP251222a: Global MASTER-Net observations report
  59. GRB 251222A / EP251222b: GECAM-B observation
  60. EP251221a: Liverpool Telescope upper limits
  61. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  62. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  63. Konus-Wind detection of GRB 251222A / EP251222b
  64. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  65. EP251222a: NTT/ULTRACAM optical observations
  66. EP251222a: GOTO optical upper limit
  67. GRB 251222A / EP251222b: GOTO optical counterpart detection
  68. GRB 251222A / EP251222b: LCO optical observations
  69. GRB 251222A: 1.3m DFOT optical detection
  70. GRB251221A: 7DT optical upper limits
  71. EP251222a: GSP Optical Counterpart Detection
  72. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  73. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  74. EP251222b/GRB 251222A: SVOM/GRM observation
  75. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  76. EP251221a: Global MASTER-Net observations report
  77. GRB 251222A: PRIME near-infrared detection
  78. EP251221a: NOT optical upper limit
  79. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  80. GRB 251222A: NOT optical observations
  81. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  82. IPN triangulation of GRB 251220B (short)
  83. GRB 251222A: Swift ToO observations
  84. GRB 251222A: SVOM/VT optical candidate
  85. GRB 251222A: SVOM detection of a long burst
  86. EP251220a: PRIME upper limit
  87. EP251220a: VLT/FORS2 spectroscopic redshift z = 2.375
  88. GRB 251221A: PRIME near-infrared observation
  89. EP251220a: NOT optical observations
  90. EP251220a: FTW optical and NIR observations
  91. GRB 251221A: UAFO and Mondy optical upper limit
  92. GRB 251221A: Swift/UVOT Upper Limits
  93. GRB 251221A: Fermi GBM Observation
  94. EP251220a: EP-FXT follow-up observation
  95. GRB 251220B: SVOM/GRM observation of a short burst
  96. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  97. EP 251220a: GOTO optical counterpart detection
  98. GRB 251221A: COLIBRÍ detection of the optical counterpart
  99. EP 251220a: COLIBRÍ detection of the optical counterpart
  100. EP251220a: Global MASTER-Net observations report

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