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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"

45562 results found.

  1. GRB 260101A: Fermi GBM Final Real-time Localization
  2. SVOM GRB251231.57: Global MASTER-Net observations report
  3. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  4. GRB 251230A: GRANDMA/TAROT Early Detection
  5. GRB 251230A / EP251230a: further NOT optical observations revealing shallower decay or possible rebrightening
  6. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  7. EP251229a: Optical upper limit with Kinder observations
  8. GRB 251230A: 1.3m DFOT optical upper limit
  9. Fermi Gamma-ray Burst Monitor trigger 788833547/251231018 is not a GRB
  10. GRB 251230A: Swift-XRT refined Analysis
  11. GRB 251231A: Fermi GBM Final Real-time Localization
  12. GRB 251222A: Mondy Optical Observations
  13. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  14. GRB 251230A: Swift/UVOT detection
  15. GRB251230A: 7DT optical upper limits
  16. GRB 251230A / EP251230a: NOT observations and spectroscopic redshift upper limit z < 2.2
  17. EP251229a: BOOTES-2 early optical upper limit
  18. GRB 251230A: GOTO optical upper limit
  19. EP251229a: NOT optical upper limits
  20. GRB 251230A / EP251230a: SVOM/VT optical observation
  21. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  22. GRB 251230A: Enhanced Swift-XRT position
  23. GRB 251230A: Early optical counterpart detection by LCO.
  24. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  25. GRB 251230A: Optical Observations via Virtual Telescope Project, Italy
  26. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  27. GRB 251230A/EP#01709250693 (likely EP251230a): FTW optical and NIR observations
  28. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  29. Swift GRB 251230A: Global MASTER-Net observations report
  30. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  31. EP251229a: Global MASTER-Net observations report
  32. EP251229a: Einstein Probe detection of an X-ray transient
  33. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  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. The EP-WXT trigger 01709250662 is likely a flaring star
  39. GRB 251228A: Fermi GBM Final Real-time Localization
  40. GRB 251226A: SVOM/GRM observation
  41. GRB 251226A: GECAM-B detection
  42. SVOM GRB251227.07: Global MASTER-Net observations report
  43. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  44. The EP-WXT trigger 01709250617 is likely a flaring star
  45. IceCube Alert 251225.84: Global MASTER-Net observations report
  46. IceCube-251225A - IceCube observation of a high-energy neutrino candidate track-like event
  47. Fermi Gamma-ray Burst Monitor trigger 788368008/251225630 is not a GRB
  48. GRB 251222A: NUTTelA-TAO Early Measurements
  49. GRB 251222A/EP251222b: Optical detection with Kinder observations
  50. EP251222a: Optical upper limit with Kinder observations
  51. GRB 251221A: Swift-BAT refined analysis
  52. GRB 251222A/EP251222b: FTW optical and NIR observations
  53. EP251222a: FTW optical and NIR observations
  54. GRB 251205A: Kilonova-Catcher optical afterglow detection
  55. GRB 251222A: AbAO optical observations
  56. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  57. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  58. EP251222a: VLT/FORS2 spectroscopic redshift z = 0.505
  59. GRB 251222A: ZTSH BVRI optical observations
  60. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  61. GRB 251222A: Continued 1.3m DFOT optical observation
  62. EP251220a: 3.6m DOT optical afterglow detection
  63. GRB 251222A: Fermi GBM Observation
  64. EP251220a: CrAO ZTSh optical observations
  65. EP251221a: PRIME upper limit
  66. EP251222a: Global MASTER-Net observations report
  67. GRB 251222A / EP251222b: GECAM-B observation
  68. EP251221a: Liverpool Telescope upper limits
  69. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  70. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  71. Konus-Wind detection of GRB 251222A / EP251222b
  72. GRB 251222A: Swift-XRT afterglow detection
  73. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  74. EP251222a: NTT/ULTRACAM optical observations
  75. EP251222a: GOTO optical upper limit
  76. GRB 251222A / EP251222b: GOTO optical counterpart detection
  77. GRB 251222A / EP251222b: LCO optical observations
  78. GRB 251222A: 1.3m DFOT optical detection
  79. GRB251221A: 7DT optical upper limits
  80. EP251222a: GSP Optical Counterpart Detection
  81. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  82. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  83. EP251222b/GRB 251222A: SVOM/GRM observation
  84. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  85. EP251222a: Einstein Probe detection of an X-ray transient
  86. The EP-WXT trigger 01709250397 is likely a flaring star
  87. EP251221a: Global MASTER-Net observations report
  88. GRB 251222A: PRIME near-infrared detection
  89. EP251221a: NOT optical upper limit
  90. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  91. GRB 251222A: NOT optical observations
  92. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  93. IPN triangulation of GRB 251220B (short)
  94. GRB 251222A: Swift ToO observations
  95. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  96. GRB 251222A: SVOM/VT optical candidate
  97. GRB 251222A: SVOM detection of a long burst
  98. SVOM GRB251222A: Global MASTER-Net observations report
  99. GRB 251222A: Fermi GBM Final Real-time Localization
  100. EP251220a: PRIME upper limit

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