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"

18470 results found.

  1. EP251229a: NOT optical upper limits
  2. GRB 251230A / EP251230a: SVOM/VT optical observation
  3. EP251229a: refined analysis of the EP-WXT and EP-FXT observations
  4. GRB 251230A: Enhanced Swift-XRT position
  5. GRB 251230A: Early optical counterpart detection by LCO.
  6. EP-WXT trigger 01709250662 Mephisto and 50cm telescope follow-up
  7. EP251230a / GRB 251230A: Einstein Probe detection of an X-ray transient
  8. LIGO/Virgo/KAGRA S251112cm: Candidates from the NSF-DOE Vera C. Rubin Observatory
  9. The EP-WXT trigger 01709250693/GRB 251230A: Las Cumbres detection of the optical counterpart
  10. EP251229a: Einstein Probe detection of an X-ray transient
  11. GRB 251230A: Swift detection of a burst with a bright optical counterpart
  12. GRB 251222A/EP251222b: 1.6m Mephisto optical followup
  13. The EP-WXT trigger 01709250662 is likely a flaring star
  14. GRB 251226A: SVOM/GRM observation
  15. The EP-WXT trigger 01709250617 is likely a flaring star
  16. GRB 251222A/EP251222b: Optical detection with Kinder observations
  17. EP251222a: Optical upper limit with Kinder observations
  18. GRB 251205A: Kilonova-Catcher optical afterglow detection
  19. GRB 251222A: AbAO optical observations
  20. GRB 251222A / EP251222b: Kilonova-Catcher optical afterglow detection
  21. GRB 251222A: ZTSH BVRI optical observations
  22. GRB 251222A: SVOM/COLIBRÍ (FM-GFT) optical observations
  23. GRB 251222A: Continued 1.3m DFOT optical observation
  24. EP251220a: 3.6m DOT optical afterglow detection
  25. EP251220a: CrAO ZTSh optical observations
  26. EP251221a: PRIME upper limit
  27. EP251221a: Liverpool Telescope upper limits
  28. EP251222a: refined analysis of the EP-WXT and EP-FXT observations
  29. EP251222b/GRB 251222A: refined analysis of the EP-WXT and EP-FXT observations
  30. GRB 251222A: Swift-XRT afterglow detection
  31. GRB 251222A / EP251222b: LCO detection of the optical counterpart
  32. EP251222a: NTT/ULTRACAM optical observations
  33. GRB 251222A / EP251222b: GOTO optical counterpart detection
  34. GRB 251222A / EP251222b: LCO optical observations
  35. GRB 251222A: 1.3m DFOT optical detection
  36. GRB251221A: 7DT optical upper limits
  37. EP251222b/GRB 251222A: Einstein Probe detection of an X-ray transient
  38. EP251222a: Einstein Probe detection of an X-ray transient
  39. The EP-WXT trigger 01709250397 is likely a flaring star
  40. GRB 251222A: PRIME near-infrared detection
  41. EP251221a: NOT optical upper limit
  42. GRB 251222A: Calapai Observatory, Massa S. Giorgio (Messina), optical observation.
  43. IceCube-251218A: No Candidate Transients from the Zwicky Transient Facility
  44. IPN triangulation of GRB 251220B (short)
  45. GRB 251222A: SVOM/VT optical candidate
  46. GRB 251222A: SVOM detection of a long burst
  47. EP251220a: PRIME upper limit
  48. GRB 251221A: PRIME near-infrared observation
  49. GRB 251221A: UAFO and Mondy optical upper limit
  50. EP251221a: Einstein Probe detection of a fast X-ray transient
  51. GRB 251221A: Swift/UVOT Upper Limits
  52. GRB 251221A: Enhanced Swift-XRT position
  53. EP251220a: EP-FXT follow-up observation
  54. GRB 251220B: SVOM/GRM observation of a short burst
  55. EP251220a: COLIBRÍ confirmation of fading and photometric redshift upper limit of z < 3.4
  56. EP 251220a: GOTO optical counterpart detection
  57. GRB 251221A: COLIBRÍ detection of the optical counterpart
  58. EP 251220a: COLIBRÍ detection of the optical counterpart
  59. GRB 251221A: Swift detection of a burst
  60. EP251220a: EP detection of a fast X-ray transient
  61. GRB 251219A: SVOM/GRM observation of a short burst
  62. GRB 251215A: Swift-XRT afterglow detection
  63. IceCube-251218A: COLIBRÍ optical upper limits
  64. GRB 251214B: VIRT Optical Upper Limit
  65. GRB 251215A: Swift/UVOT Upper LImits
  66. GRB 251202A/EP251202a: Koshka optical upper limit
  67. GRB 251214B: Mondy optical upper limit
  68. GRB 251215A: COLIBRÍ optical upper limit
  69. EP251214b: KAIT optical upper limit
  70. EP251214a: Optical upper limit with Kinder observations
  71. GRB 251214B: 1.6m Mephisto observations with newly installed mosaic cameras
  72. GRB 251214B: UAFO optical upper limit
  73. GRB 251214B: VLT/X-shooter observations
  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. EP251214b (EP trigger 01709250023): LCO optical limits
  80. GRB 251203B: AbAO optical observations
  81. GRB 251213A: SVOM/GRM observation
  82. EP251214a: KAIT optical upper limit
  83. GRB 251213A: AstroSat CZTI detection
  84. GRB 251214B: Swift/UVOT Detection
  85. GRB 251214B: COLIBRÍ observations of the afterglow
  86. EP251214a: EP-FXT non-detection and upper limit
  87. GRB 251214B: 1.3m DFOT optical detection
  88. GRB 251214B: Enhanced Swift-XRT position
  89. GRB 251214B: Xinglong-2.16m optical observation
  90. GRB 251214B: SVOM/C-GFT optical observations
  91. EP251214a: COLIBRÍ optical upper limit
  92. EP251214.305: COLIBRÍ optical upper limit
  93. GRB 251214B: Swift detection of a burst with an optical counterpart
  94. EP251214a: EP-WXT detection of an X-ray transient possibly associated with GRB 251214A
  95. EP251212a: KAIT optical upper limit
  96. EP251212a / GRB 251212A: AstroSat CZTI detection
  97. EP251212a: EP-FXT follow-up observation
  98. EP251212a : COLIBRÍ optical upper limit
  99. EP251212a: Einstein Probe detection of an X-ray transient
  100. IceCube-251210A: DDOTI Optical Upper Limit

Advanced

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