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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"

38655 results found.

  1. EP251222b/GRB 251222A: SVOM/GRM observation
  2. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  3. EP251222a: Einstein Probe detection of an X-ray transient
  4. The EP-WXT trigger 01709250397 is likely a flaring star
  5. GRB 251222A: PRIME near-infrared detection
  6. EP251221a: NOT optical upper limit
  7. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  8. GRB 251222A: NOT optical observations
  9. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  10. IPN triangulation of GRB 251220B (short)
  11. GRB 251222A: Swift ToO observations
  12. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  13. GRB 251222A: SVOM/VT optical candidate
  14. GRB 251222A: SVOM detection of a long burst
  15. SVOM GRB251222A: Global MASTER-Net observations report
  16. GRB 251222A: Fermi GBM Final Real-time Localization
  17. EP251220a: VLT/FORS2 spectroscopic redshift z = 2.375
  18. EP251220a: NOT optical observations
  19. GRB 251221A: UAFO and Mondy optical upper limit
  20. GRB 251221A: Swift-XRT refined Analysis
  21. EP251221a: Einstein Probe detection of a fast X-ray transient
  22. GRB 251221A: Swift/UVOT Upper Limits
  23. Fermi Gamma-ray Burst Monitor trigger 788028118/251221696 is not a GRB
  24. GRB 251221A: Enhanced Swift-XRT position
  25. GRB 251221A: Fermi GBM Observation
  26. GRB 251221B: Fermi GBM Final Real-time Localization
  27. EP251220a: EP-FXT follow-up observation
  28. GRB 251220B: SVOM/GRM observation of a short burst
  29. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  30. EP 251220a: GOTO optical counterpart detection
  31. GRB 251221A: COLIBRÍ detection of the optical counterpart
  32. EP 251220a: COLIBRÍ detection of the optical counterpart
  33. GRB 251221A: Swift detection of a burst
  34. GRB 251221A: Fermi GBM Final Real-time Localization
  35. EP251220a: EP detection of a fast X-ray transient
  36. SVOM GRB251220.98: Global MASTER-Net observations report
  37. GRB 251220B: Fermi GBM Final Real-time Localization
  38. GRB 251219A: SVOM/GRM observation of a short burst
  39. GRB 251219A: GECAM-B detection of a possible magnetar X-ray burst from SGR 1830-0645
  40. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  41. GRB 251220A: MAXI/GSC detection
  42. GRB 251215A: Swift-XRT afterglow detection
  43. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  44. IceCube-251218A: COLIBRÍ optical upper limits
  45. SVOM GRB251219.11: Global MASTER-Net observations report
  46. IceCube-251218A - IceCube observation of a high-energy neutrino candidate track-like event
  47. GRB 251214B: VIRT Optical Upper Limit
  48. GRB 251217A: Fermi GBM Final Real-time Localization
  49. GRB 251215A: Swift/UVOT Upper LImits
  50. GRB 251215A: Fermi GBM Observation
  51. GRB 251202A/EP251202a: Koshka optical upper limit
  52. GRB 251214B: Mondy optical upper limit
  53. GRB 251215A: COLIBRÍ optical upper limit
  54. GRB 251216A: Fermi GBM Final Real-time Localization
  55. EP251214b: KAIT optical upper limit
  56. GRB 251215A: Swift-XRT observations
  57. EP251214a: Optical upper limit with Kinder observations
  58. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  59. GRB 251215A: Glowbug gamma-ray detection
  60. GRB 251214B: UAFO optical upper limit
  61. GRB 251214B: VLT/X-shooter observations
  62. GRB 251213A: GRID-10B observation
  63. GRB 251202A: radio detection with the VLA
  64. EP251214b : Einstein Probe detection of a fast X-ray transient
  65. EP251214b : Einstein Probe detection of a fast X-ray transient
  66. GRB 251214B: AbAO optical observations
  67. GRB 251214B: LCO detection of the optical counterpart
  68. GRB 251209A: GECAM-B observation of a long burst
  69. GRB 251214D: GECAM-B observation of a long burst
  70. GRB 251214B: Fermi GBM Observation
  71. GRB 251209A: Insight-HXMT/HE detection
  72. GRB 251215A: Swift ToO observations
  73. EP251214b (EP trigger 01709250023): LCO optical limits
  74. GRID detection of GRB 251213A
  75. GRB 251203B: AbAO optical observations
  76. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  77. GRB 251214B: GECAM-B observation of a long burst
  78. GRB 251214B: Swift-XRT refined Analysis
  79. GRB 251213A: SVOM/GRM observation
  80. EP251214a: KAIT optical upper limit
  81. GRB 251214D: AstroSat CZTI detection of a long burst
  82. GRB 251213A: AstroSat CZTI detection
  83. GRB 251214A: AstroSat CZTI detection
  84. GRB 251213A: GECAM-B detection
  85. GRB 251214B: Swift/UVOT Detection
  86. GRB 251215A: Fermi GBM Final Real-time Localization
  87. GRB 251214B: COLIBRÍ observations of the afterglow
  88. EP251214a: EP-FXT non-detection and upper limit
  89. GRB 251214A: GECAM-B observation of a likely long burst
  90. GRB 251214B: 1.3m DFOT optical detection
  91. GRB 251214B: Enhanced Swift-XRT position
  92. GRB 251214B: Xinglong-2.16m optical observation
  93. GRB 251214C: Fermi GBM Final Localization
  94. GRB 251214B : MASTER optical afterglow detection
  95. GRB 251214B: SVOM/C-GFT optical observations
  96. EP251214a: COLIBRÍ optical upper limit
  97. EP251214.305: COLIBRÍ optical upper limit
  98. GRB 251214B: Swift detection of a burst with an optical counterpart
  99. GRB 251214B: Fermi GBM Final Real-time Localization
  100. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A

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