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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"

32725 results found.

  1. GRB 251230A / EP251230a: GECAM-B detection
  2. GRB 260102A: SVOM/VT optical counterpart
  3. GRB 251230A / EP251230a: Insight-HXMT/HE detection
  4. GRB 260102A: Swift ToO observations
  5. GRB 260101A: Fermi GBM Observation
  6. EP260101a: refined analysis of the EP-WXT and EP-FXT observations
  7. GRB 260101A: GECAM-B detection
  8. GRB 260101A: NOT spectroscopic observations
  9. GRB 260101A: SVOM/GRM observation
  10. Swift GRB 260101A: Global MASTER-Net observations report
  11. GRB 260101A: OSIRIS+ redshift z = 2.623 for the new year burst
  12. GRB 260101A: LCO detection of the optical counterpart
  13. GRB 251230A / EP251230a: SVOM/VT optical continued observations and upper limit
  14. GRB 251230A: GRANDMA/TAROT Early Detection
  15. GRB 251230A / EP251230a: further NOT optical observations revealing shallower decay or possible rebrightening
  16. GRB 251230A/EP251230a: Optical upper limit with Kinder observations
  17. EP251229a: Optical upper limit with Kinder observations
  18. GRB 251230A: 1.3m DFOT optical upper limit
  19. GRB 251222A: Mondy Optical Observations
  20. EP251230a / GRB 251230A: refined analysis of the EP-WXT and EP-FXT observations
  21. GRB 251230A: Swift/UVOT detection
  22. GRB251230A: 7DT optical upper limits
  23. GRB 251230A / EP251230a: NOT observations and spectroscopic redshift upper limit z < 2.2
  24. EP251229a: BOOTES-2 early optical upper limit
  25. GRB 251230A: GOTO optical upper limit
  26. EP251229a: NOT optical upper limits
  27. GRB 251230A / EP251230a: SVOM/VT optical observation
  28. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  29. GRB 251230A: Early optical counterpart detection by LCO.
  30. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  31. GRB 251230A: Optical Observations via Virtual Telescope Project, Italy
  32. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  33. GRB 251230A/EP#01709250693 (likely EP251230a): FTW optical and NIR observations
  34. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  35. Swift GRB 251230A: Global MASTER-Net observations report
  36. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  37. EP251229a: Global MASTER-Net observations report
  38. GRB 251226A: Glowbug gamma-ray detection
  39. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  40. GRB 251129A: redshift correction and SN detection at z = 0.505 with GTC
  41. Fermi GRB 251228A: Global MASTER-Net observations report
  42. GRB 251226A: SVOM/GRM observation
  43. IceCube-251225A: Upper limits from a search for additional neutrino events in IceCube
  44. GRB 251222A: NUTTelA-TAO Early Measurements
  45. GRB 251222A/EP251222b: Optical detection with Kinder observations
  46. EP251222a: Optical upper limit with Kinder observations
  47. GRB 251221A: Swift-BAT refined analysis
  48. GRB 251222A/EP251222b: FTW optical and NIR observations
  49. EP251222a: FTW optical and NIR observations
  50. GRB 251205A: Kilonova-Catcher optical afterglow detection
  51. GRB 251222A: AbAO optical observations
  52. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  53. GRB 251129A / EP251129a: VLA detection of a radio counterpart
  54. EP251222a: VLT/FORS2 spectroscopic redshift z = 0.505
  55. GRB 251222A: ZTSH BVRI optical observations
  56. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  57. GRB 251222A: Continued 1.3m DFOT optical observation
  58. EP251220a: 3.6m DOT optical afterglow detection
  59. GRB 251222A: Fermi GBM Observation
  60. EP251220a: CrAO ZTSh optical observations
  61. EP251221a: PRIME upper limit
  62. EP251222a: Global MASTER-Net observations report
  63. GRB 251222A / EP251222b: GECAM-B observation
  64. EP251221a: Liverpool Telescope upper limits
  65. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  66. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  67. Konus-Wind detection of GRB 251222A / EP251222b
  68. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  69. EP251222a: NTT/ULTRACAM optical observations
  70. EP251222a: GOTO optical upper limit
  71. GRB 251222A / EP251222b: GOTO optical counterpart detection
  72. GRB 251222A / EP251222b: LCO optical observations
  73. GRB 251222A: 1.3m DFOT optical detection
  74. GRB251221A: 7DT optical upper limits
  75. EP251222a: GSP Optical Counterpart Detection
  76. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  77. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  78. EP251222b/GRB 251222A: SVOM/GRM observation
  79. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  80. EP251221a: Global MASTER-Net observations report
  81. GRB 251222A: PRIME near-infrared detection
  82. EP251221a: NOT optical upper limit
  83. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  84. GRB 251222A: NOT optical observations
  85. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  86. IPN triangulation of GRB 251220B (short)
  87. GRB 251222A: Swift ToO observations
  88. GRB 251222A: SVOM/VT optical candidate
  89. GRB 251222A: SVOM detection of a long burst
  90. EP251220a: PRIME upper limit
  91. EP251220a: VLT/FORS2 spectroscopic redshift z = 2.375
  92. GRB 251221A: PRIME near-infrared observation
  93. EP251220a: NOT optical observations
  94. EP251220a: FTW optical and NIR observations
  95. GRB 251221A: UAFO and Mondy optical upper limit
  96. GRB 251221A: Swift/UVOT Upper Limits
  97. GRB 251221A: Fermi GBM Observation
  98. EP251220a: EP-FXT follow-up observation
  99. GRB 251220B: SVOM/GRM observation of a short burst
  100. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4

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