Skip to main content
JSON Notices via Email, Kafka Cron Jobs, Submitter Profile, GCN is Hiring. See news and announcements

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"

28111 results found.

  1. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  2. EP251222a: NTT/ULTRACAM optical observations
  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. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  9. EP251222a: Einstein Probe detection of an X-ray transient
  10. EP251221a: Global MASTER-Net observations report
  11. GRB 251222A: PRIME near-infrared detection
  12. EP251221a: NOT optical upper limit
  13. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  14. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  15. IPN triangulation of GRB 251220B (short)
  16. GRB 251222A: BALROG localization (Fermi Trigger / GRB 251222712)
  17. GRB 251222A: SVOM/VT optical candidate
  18. GRB 251222A: SVOM detection of a long burst
  19. SVOM GRB251222A: Global MASTER-Net observations report
  20. EP251220a: PRIME upper limit
  21. GRB 251221A: PRIME near-infrared observation
  22. GRB 251221A: UAFO and Mondy optical upper limit
  23. GRB 251221A: Swift-XRT refined Analysis
  24. EP251221a: Einstein Probe detection of a fast X-ray transient
  25. GRB 251221A: Swift/UVOT Upper Limits
  26. GRB 251221A: Enhanced Swift-XRT position
  27. GRB 251221A: Fermi GBM 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. Swift GRB251221A: Global MASTER-Net observations report
  35. EP251220a: Global MASTER-Net observations report
  36. EP251220a: EP detection of a fast X-ray transient
  37. SVOM GRB251220.98: Global MASTER-Net observations report
  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 Alert 251218.85: Global MASTER-Net observations report
  47. GRB 251214B: VIRT Optical Upper Limit
  48. Fermi trigger No 787736968: Global MASTER-Net observations report
  49. Fermi GRB 251217A: Global MASTER-Net observations report
  50. GRB 251215A: Swift/UVOT Upper LImits
  51. GRB 251215A: Fermi GBM Observation
  52. Fermi GRB 251216A: Global MASTER-Net observations report
  53. GRB 251202A/EP251202a: Koshka optical upper limit
  54. GRB 251214B: Mondy optical upper limit
  55. GRB 251215A: COLIBRÍ optical upper limit
  56. EP251214b: KAIT optical upper limit
  57. GRB 251215A: Swift-XRT observations
  58. Fermi GRB 251215A: Global MASTER-Net observations report
  59. EP251214a: Optical upper limit with Kinder observations
  60. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  61. GRB 251215A: Glowbug gamma-ray detection
  62. GRB 251214B: UAFO optical upper limit
  63. GRB 251214B: VLT/X-shooter observations
  64. GRB 251214B: Swift-BAT refined analysis
  65. GRB 251202A: radio detection with the VLA
  66. EP251214b: Global MASTER-Net observations report
  67. EP251214b : Einstein Probe detection of a fast X-ray transient
  68. EP251214b : Einstein Probe detection of a fast X-ray transient
  69. GRB 251214B: AbAO optical observations
  70. GRB 251214B: LCO detection of the optical counterpart
  71. GRB 251214B: Fermi GBM Observation
  72. EP251214b (EP trigger 01709250023): LCO optical limits
  73. GRB 251203B: AbAO optical observations
  74. GRB 251215A: Swift/BAT-GUANO arcminute localization of a burst
  75. GRB 251214B: Swift-XRT refined Analysis
  76. GRB 251213A: SVOM/GRM observation
  77. EP251214a: KAIT optical upper limit
  78. GRB 251213A: AstroSat CZTI detection
  79. GRB 251214A: AstroSat CZTI detection
  80. GRB 251213A: GECAM-B detection
  81. GRB 251214B: Swift/UVOT Detection
  82. GRB 251214B: COLIBRÍ observations of the afterglow
  83. EP251214a: EP-FXT non-detection and upper limit
  84. GRB 251214B: 1.3m DFOT optical detection
  85. EP251214a: Global MASTER-Net observations report
  86. GRB 251214B: Enhanced Swift-XRT position
  87. GRB 251214B: Xinglong-2.16m optical observation
  88. GRB 251214B : MASTER optical afterglow detection
  89. Fermi trigger No 787396657: Global MASTER-Net observations report
  90. GRB 251214B: SVOM/C-GFT optical observations
  91. EP251214a: COLIBRÍ optical upper limit
  92. Swift GRB 251214B: Global MASTER-Net observations report
  93. EP251214.305: COLIBRÍ optical upper limit
  94. GRB 251214B: Swift detection of a burst with an optical counterpart
  95. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  96. Fermi GRB 251214A: Global MASTER-Net observations report
  97. EP251212a: Global MASTER-Net observations report
  98. EP251212a: KAIT optical upper limit
  99. GRB 251211B: AstroSat CZTI detection
  100. GRB 251209A: NuSTAR detection of prompt emission

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov