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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"

38666 results found.

  1. GRB 251222A: Swift-XRT afterglow detection
  2. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  3. EP251222a: NTT/ULTRACAM optical observations
  4. EP251222a: GOTO optical upper limit
  5. GRB 251222A / EP251222b: GOTO optical counterpart detection
  6. GRB 251222A / EP251222b: LCO optical observations
  7. GRB 251222A: 1.3m DFOT optical detection
  8. GRB251221A: 7DT optical upper limits
  9. EP251222a: GSP Optical Counterpart Detection
  10. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  11. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  12. EP251222b/GRB 251222A: SVOM/GRM observation
  13. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  14. EP251222a: Einstein Probe detection of an X-ray transient
  15. The EP-WXT trigger 01709250397 is likely a flaring star
  16. GRB 251222A: PRIME near-infrared detection
  17. EP251221a: NOT optical upper limit
  18. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  19. GRB 251222A: NOT optical observations
  20. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  21. IPN triangulation of GRB 251220B (short)
  22. GRB 251222A: Swift ToO observations
  23. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  24. GRB 251222A: SVOM/VT optical candidate
  25. GRB 251222A: SVOM detection of a long burst
  26. SVOM GRB251222A: Global MASTER-Net observations report
  27. GRB 251222A: Fermi GBM Final Real-time Localization
  28. EP251220a: VLT/FORS2 spectroscopic redshift z = 2.375
  29. EP251220a: NOT optical observations
  30. GRB 251221A: UAFO and Mondy optical upper limit
  31. GRB 251221A: Swift-XRT refined Analysis
  32. EP251221a: Einstein Probe detection of a fast X-ray transient
  33. GRB 251221A: Swift/UVOT Upper Limits
  34. Fermi Gamma-ray Burst Monitor trigger 788028118/251221696 is not a GRB
  35. GRB 251221A: Enhanced Swift-XRT position
  36. GRB 251221A: Fermi GBM Observation
  37. GRB 251221B: Fermi GBM Final Real-time Localization
  38. EP251220a: EP-FXT follow-up observation
  39. GRB 251220B: SVOM/GRM observation of a short burst
  40. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  41. EP 251220a: GOTO optical counterpart detection
  42. GRB 251221A: COLIBRÍ detection of the optical counterpart
  43. EP 251220a: COLIBRÍ detection of the optical counterpart
  44. GRB 251221A: Swift detection of a burst
  45. GRB 251221A: Fermi GBM Final Real-time Localization
  46. EP251220a: EP detection of a fast X-ray transient
  47. SVOM GRB251220.98: Global MASTER-Net observations report
  48. GRB 251220B: Fermi GBM Final Real-time Localization
  49. GRB 251219A: SVOM/GRM observation of a short burst
  50. GRB 251219A: GECAM-B detection of a possible magnetar X-ray burst from SGR 1830-0645
  51. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  52. GRB 251220A: MAXI/GSC detection
  53. GRB 251215A: Swift-XRT afterglow detection
  54. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  55. IceCube-251218A: COLIBRÍ optical upper limits
  56. SVOM GRB251219.11: Global MASTER-Net observations report
  57. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  58. GRB 251214B: VIRT Optical Upper Limit
  59. GRB 251217A: Fermi GBM Final Real-time Localization
  60. GRB 251215A: Swift/UVOT Upper LImits
  61. GRB 251215A: Fermi GBM Observation
  62. GRB 251202A/EP251202a: Koshka optical upper limit
  63. GRB 251214B: Mondy optical upper limit
  64. GRB 251215A: COLIBRÍ optical upper limit
  65. GRB 251216A: Fermi GBM Final Real-time Localization
  66. EP251214b: KAIT optical upper limit
  67. GRB 251215A: Swift-XRT observations
  68. EP251214a: Optical upper limit with Kinder observations
  69. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  70. GRB 251215A: Glowbug gamma-ray detection
  71. GRB 251214B: UAFO optical upper limit
  72. GRB 251214B: VLT/X-shooter observations
  73. GRB 251213A: GRID-10B observation
  74. GRB 251202A: radio detection with the VLA
  75. EP251214b : Einstein Probe detection of a fast X-ray transient
  76. EP251214b : Einstein Probe detection of a fast X-ray transient
  77. GRB 251214B: AbAO optical observations
  78. GRB 251214B: LCO detection of the optical counterpart
  79. GRB 251209A: GECAM-B observation of a long burst
  80. GRB 251214D: GECAM-B observation of a long burst
  81. GRB 251214B: Fermi GBM Observation
  82. GRB 251209A: Insight-HXMT/HE detection
  83. GRB 251215A: Swift ToO observations
  84. EP251214b (EP trigger 01709250023): LCO optical limits
  85. GRID detection of GRB 251213A
  86. GRB 251203B: AbAO optical observations
  87. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  88. GRB 251214B: GECAM-B observation of a long burst
  89. GRB 251214B: Swift-XRT refined Analysis
  90. GRB 251213A: SVOM/GRM observation
  91. EP251214a: KAIT optical upper limit
  92. GRB 251214D: AstroSat CZTI detection of a long burst
  93. GRB 251213A: AstroSat CZTI detection
  94. GRB 251214A: AstroSat CZTI detection
  95. GRB 251213A: GECAM-B detection
  96. GRB 251214B: Swift/UVOT Detection
  97. GRB 251215A: Fermi GBM Final Real-time Localization
  98. GRB 251214B: COLIBRÍ observations of the afterglow
  99. EP251214a: EP-FXT non-detection and upper limit
  100. GRB 251214A: GECAM-B observation of a likely long burst

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