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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"

32756 results found.

  1. EP251222a: NTT/ULTRACAM optical observations
  2. EP251222a: GOTO optical upper limit
  3. GRB 251222A / EP251222b: GOTO optical counterpart detection
  4. GRB 251222A / EP251222b: LCO optical observations
  5. GRB 251222A: 1.3m DFOT optical detection
  6. GRB251221A: 7DT optical upper limits
  7. EP251222a: GSP Optical Counterpart Detection
  8. GRB 251222A / EP251222b: VLT/X-shooter spectroscopic redshift z = 3.171
  9. GRB 251222A / EP251222b: SVOM/VT optical rebrightening
  10. EP251222b/GRB 251222A: SVOM/GRM observation
  11. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  12. EP251221a: Global MASTER-Net observations report
  13. GRB 251222A: PRIME near-infrared detection
  14. EP251221a: NOT optical upper limit
  15. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  16. GRB 251222A: NOT optical observations
  17. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  18. IPN triangulation of GRB 251220B (short)
  19. GRB 251222A: Swift ToO observations
  20. GRB 251222A: SVOM/VT optical candidate
  21. GRB 251222A: SVOM detection of a long burst
  22. EP251220a: PRIME upper limit
  23. EP251220a: VLT/FORS2 spectroscopic redshift z = 2.375
  24. GRB 251221A: PRIME near-infrared observation
  25. EP251220a: NOT optical observations
  26. EP251220a: FTW optical and NIR observations
  27. GRB 251221A: UAFO and Mondy optical upper limit
  28. GRB 251221A: Swift/UVOT Upper Limits
  29. GRB 251221A: Fermi GBM Observation
  30. EP251220a: EP-FXT follow-up observation
  31. GRB 251220B: SVOM/GRM observation of a short burst
  32. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  33. EP 251220a: GOTO optical counterpart detection
  34. GRB 251221A: COLIBRÍ detection of the optical counterpart
  35. EP 251220a: COLIBRÍ detection of the optical counterpart
  36. EP251220a: Global MASTER-Net observations report
  37. GRB 251219A: SVOM/GRM observation of a short burst
  38. Fermi-LAT Gamma-ray Observations of IceCube-251218A
  39. IceCube-251218A: Upper limits from a search for additional neutrino events in IceCube
  40. IceCube-251218A: COLIBRÍ optical upper limits
  41. GRB 251214B: VIRT Optical Upper Limit
  42. Fermi GRB 251217A: Global MASTER-Net observations report
  43. GRB 251215A: Swift/UVOT Upper LImits
  44. GRB 251215A: Fermi GBM Observation
  45. Fermi GRB 251216A: Global MASTER-Net observations report
  46. GRB 251202A/EP251202a: Koshka optical upper limit
  47. GRB 251214B: Mondy optical upper limit
  48. GRB 251215A: COLIBRÍ optical upper limit
  49. EP251214b: KAIT optical upper limit
  50. Fermi GRB 251215A: Global MASTER-Net observations report
  51. EP251214a: Optical upper limit with Kinder observations
  52. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  53. GRB 251215A: Glowbug gamma-ray detection
  54. GRB 251214B: UAFO optical upper limit
  55. GRB 251214B: VLT/X-shooter observations
  56. GRB 251213A: GRID-10B observation
  57. GRB 251214B: Swift-BAT refined analysis
  58. GRB 251202A: radio detection with the VLA
  59. EP251214b: Global MASTER-Net observations report
  60. EP251214b : Einstein Probe detection of a fast X-ray transient
  61. EP251214b : Einstein Probe detection of a fast X-ray transient
  62. GRB 251214B: AbAO optical observations
  63. GRB 251214B: LCO detection of the optical counterpart
  64. GRB 251209A: GECAM-B observation of a long burst
  65. GRB 251214D: GECAM-B observation of a long burst
  66. GRB 251214B: Fermi GBM Observation
  67. GRB 251209A: Insight-HXMT/HE detection
  68. GRB 251215A: Swift ToO observations
  69. EP251214b (EP trigger 01709250023): LCO optical limits
  70. GRID detection of GRB 251213A
  71. GRB 251203B: AbAO optical observations
  72. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  73. GRB 251214B: GECAM-B observation of a long burst
  74. GRB 251213A: SVOM/GRM observation
  75. EP251214a: KAIT optical upper limit
  76. GRB 251213A: AstroSat CZTI detection
  77. GRB 251214A: AstroSat CZTI detection
  78. GRB 251214B: Swift/UVOT Detection
  79. GRB 251214B: COLIBRÍ observations of the afterglow
  80. EP251214a: EP-FXT non-detection and upper limit
  81. GRB 251214A: GECAM-B observation of a likely long burst
  82. GRB 251214B: 1.3m DFOT optical detection
  83. EP251214a: Global MASTER-Net observations report
  84. GRB 251214B: Xinglong-2.16m optical observation
  85. GRB 251214B : MASTER optical afterglow detection
  86. GRB 251214B: SVOM/C-GFT optical observations
  87. EP251214a: COLIBRÍ optical upper limit
  88. Swift GRB 251214B: Global MASTER-Net observations report
  89. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  90. Fermi GRB 251214A: Global MASTER-Net observations report
  91. EP251212a: Global MASTER-Net observations report
  92. EP251212a: KAIT optical upper limit
  93. EP251212a / GRB 251212A: AstroSat CZTI detection
  94. EP251212a: EP-FXT follow-up observation
  95. GRB 251211B: AstroSat CZTI detection
  96. IceCube-251210A: No Candidate Transients from the Zwicky Transient Facility
  97. GRB 251209A: NuSTAR detection of prompt emission
  98. EP251212a : COLIBRÍ optical upper limit
  99. EP251212a: Einstein Probe detection of an X-ray transient
  100. Fermi-LAT Gamma-ray Observations of IceCube-251210A

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