Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! See news and announcements

GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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"

28076 results found.

  1. GRB 260926C: AstroSat CZTI detection
  2. EP260927a: Einstein Probe detection of a fast X-ray transient
  3. GRB 260926B: Glowbug gamma-ray detection of a likely short burst
  4. GRB 260926A: Glowbug gamma-ray detection
  5. GRB 260924A: VLA detection
  6. GRB 260924A: Swift/UVOT UV grism spectrum results
  7. GRB 260924A: AbAO optical observations
  8. GRB 260928A: Fermi GBM Final Real-time Localization
  9. GRB 260924A: Upper limits from a neutrino search with IceCube
  10. GRB 260926C: Fermi GBM Final Real-time Localization
  11. GRB 260926B: Fermi GBM Final Real-time Localization
  12. GRB 260924A: Near-infrared detection with MDM/MIRAGE
  13. GRB 260926A: Fermi GBM Final Real-time Localization
  14. GRB 260924A: Second-epoch J-band upper limit from the SYSU 80 cm infrared telescope
  15. GRB 260925A: J-band upper limit by SYSU 80cm infrared telescope
  16. GRB 260925A: Swift-XRT refined Analysis
  17. EP260924a: EP-FXT follow-up observation
  18. Swift Trigger 1513439 is probably not a GRB
  19. GRB 260925A: Swift/UVOT Upper Limits
  20. Konus-Wind detection of GRB 260924A
  21. GRB 260923A: Glowbug gamma-ray detection
  22. GRB 260924A: Optical follow-up observations with Kinder
  23. GRB 260922A: Glowbug gamma-ray detection
  24. GRB 260925A: Enhanced Swift-XRT position
  25. GRB 260925A: COLIBRÍ optical upper limits
  26. GRB 260925A: FRAM-Auger optical limit
  27. GRB 260924A: Ondrejov D50 optical afterglow detection
  28. GRB 260924A: SVOM/GRM observation
  29. GRB 260924A: 2.2m CAHA spectroscopic redshift z = 3.51
  30. GRB 260925A: Swift detection of a burst
  31. GRB 260923A: Insight-HXMT/HE detection
  32. EP260924a: EP-WXT detection of an X-ray transient
  33. GRB 260924A: Swift/UVOT Detection
  34. GRB 260924A: NuSTAR detection of prompt emission
  35. GRB 260924A: Swift/UVOT Upper Limits
  36. GRB 260924A: Swift-XRT refined Analysis
  37. Konus-Wind detection of GRB 260922A
  38. GRB 260922A: NuSTAR detection of prompt emission
  39. GRB 260921A: NuSTAR detection of prompt emission
  40. Konus-Wind detection of GRB 260921A (correction to GCN 45722)
  41. GRB 260924A: Fermi GRB Observation
  42. Konus-Wind detection of GRB 260921A (possible merger-origin)
  43. GRB 260924A: Fermi-LAT detection of a bright burst
  44. GRB 260924A: AstroSat CZTI detection
  45. GRB 260924A: NOT optical counterpart confirmation
  46. GRB 260924A: detection of a bright optical afterglow by the 1.5m OSN telescope
  47. GRB 260922A: CALET Gamma-Ray Burst Monitor detection
  48. GRB 260924A: Enhanced Swift-XRT position
  49. GRB 260924A: Swift detection of a burst
  50. GRB 260924A: Fermi GBM Final Real-time Localization
  51. GRB 260923A: Fermi GBM Final Real-time Localization
  52. Trigger_21914: Swift ToO observations
  53. EP260806a: e-MERLIN detection at 5 GHz
  54. GRB 260922A: Ondrejov D50 optical limit
  55. ATCA observations of GRB 260909A
  56. EP260920a: VLT/HAWK-I near-infrared counterpart confirmation
  57. GRB 260922A: Swift/UVOT Upper Limits
  58. GRB 260922A: COLIBRÍ Optical Counterpart Candidate (correction to GCN 45698)
  59. GRB 260922A: COLIBRÍ optical upper limits
  60. GRB 260922A: Swift-XRT refined Analysis
  61. GRB 260922A: Enhanced Swift-XRT position
  62. Konus-Wind detection of GRB 260810A
  63. GRB 260920A: Glowbug gamma-ray detection
  64. GRB 260922A: SVOM/C-GFT optical upper limit
  65. GRB 260922A: Swift detection of a burst
  66. GRB 260917C: AstroSat CZTI detection
  67. GRB 260920B/EP260920b: GECAM-B detection of a burst
  68. GRB 260921A: AstroSat CZTI detection
  69. GRB 260921B: Fermi GBM Final Localization
  70. EP260920b: 2.2m CAHA optical afterglow detection and 10.4m GTC redshift confirmation
  71. Swift GRB 260921A: MASTER OT J094129.58+025052.5 possible optical counterpart detection with host galaxy (z=1.3)
  72. GRB 260921A: Swift detection of a burst
  73. EP260920b: VLT/X-shooter spectroscopic redshift z = 3.582
  74. GRB 260921A: Fermi GBM Final Real-time Localization
  75. GRB 260920A: AstroSat CZTI detection
  76. EP260920b: LCO optical counterpart detection
  77. EP260920b: Einstein Probe detection of an X-ray transient
  78. EP-WXT detected a brightening of HMXB LS V +44 17
  79. EP260920a: NOT early time optical upper limits
  80. GRB 260920A: Fermi GBM Final Real-time Localization
  81. EP260917b: EP-FXT non-detection and upper limit
  82. EP260920a: Einstein Probe detection of an X-ray transient
  83. GRB 260915A: VLT optical and near-infrared upper limits
  84. IceCube-260919A - IceCube observation of a high-energy neutrino candidate track-like event
  85. GRB 260918A: SVOM/C-GFT optical upper limits
  86. Fermi GBM Sub-Threshold Detection of GRB 260918A
  87. Konus-Wind detection of GRB 260916B (short/hard)
  88. GRB 260918A: SVOM/VT optical upper limits
  89. GRB 260916B: Glowbug gamma-ray detection of a short burst
  90. IPN triangulation of GRB 260916B (short)
  91. EP260917b: EP-WXT detection of an X-ray transient
  92. IPN triangulation of GRB 260810A
  93. GRB 260915A: Swift-XRT afterglow detection
  94. EP260917a: Einstein Probe detection of an X-ray transient
  95. GRB 260918A: SVOM detection of a burst
  96. GRB 260917C: Fermi GBM Final Real-time Localization
  97. GRB 260916B: Fermi GBM Detection
  98. GRB 260916B: Fermi GBM Final Localization
  99. GRB 260917A: Glowbug gamma-ray detection
  100. GRB 260917B: SVOM detection of a faint burst

Advanced

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