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"

45430 results found.

  1. GRB 260909A: SVOM/ECLAIRs refined analysis
  2. GRB 260910B: GOTO tentative optical counterpart candidates
  3. GRB 260909A: Swift ToO observations
  4. GRB 260910B: Fermi GBM Final Real-time Localization
  5. GRB 260909A: KAIT optical upper limit
  6. GRB 260903A: Swift-XRT observations
  7. EP260806a: VLA+ALMA radio detections
  8. GRB 260909A: OHP/T193 z-band upper limit
  9. GRB 260909A: VLT optical and near-infrared upper limits
  10. EP Alert 260909.53: Global MASTER-Net observations report
  11. GRB 260909A: EP-FXT follow-up observation
  12. GRB 260910A: Fermi GBM Final Real-time Localization
  13. EP260806a: NOEMA detection
  14. EP260623a: NOEMA detections
  15. GRB 260909A: SVOM/VT optical upper limits
  16. GRB 260909A: SVOM/GRM observation
  17. GRB 260909A: Mondy optical observations and afterglow candidate
  18. GRB 260909A: Xinglong 2.16m optical upper limit
  19. GRB 260909A: SVOM/C-GFT optical upper limit
  20. GRB 260909A: SVOM detection of a burst
  21. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  22. Fermi trigger No 810554827: Global MASTER-Net observations report
  23. EP Alert 260908.60: Global MASTER-Net observations report
  24. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  25. GRB 260903A: Swift ToO observations
  26. Fermi GRB 260907B: Global MASTER-Net observations report
  27. GRB 260903A: SAO RAS optical upper limit
  28. The EP-WXT trigger 01709305715 is likely a flaring star
  29. GRB 260907B: Fermi GBM Final Real-time Localization
  30. Fermi GRB 260907A: Global MASTER-Net observations report
  31. GRB 260907A: Fermi GBM Final Real-time Localization
  32. EP260903a: EP-FXT follow-up observation
  33. EP Alert 260905.11: Global MASTER-Net observations report
  34. The EP-WXT trigger 01709302592 is likely a flaring star
  35. GRB 260903A: J-band upper limit with WINTER
  36. EP Alert 260903.47: Global MASTER-Net observations report
  37. GRB 260903A: SVOM/ECLAIRs refined analysis
  38. GRB260903A: Liverpool Telescope optical observations
  39. GRB 260903A: SAO RAS optical observations
  40. GRB 260830A: GECAM-B detection of a burst
  41. EP260903a: EP-WXT detection of a fast X-ray transient
  42. EP Alert 260903.62: Global MASTER-Net observations report
  43. GRB 260830A: Insight-HXMT/HE detection
  44. GRB 260903A: EP-FXT follow-up observation
  45. GRB 260903A: OHP/T193 optical afterglow detection
  46. GRB 260903A: NOT optical observations and afterglow fading
  47. NuSTAR Transient 260828: SOAR Optical Upper Limits
  48. SVOM GRB260903A: Global MASTER-Net observations report
  49. GRB 260903A: LCO optical observations
  50. GRB 260903A: SVOM/VT optical candidate
  51. GRB 260903A: Retraction of optical counterpart of GCN 45501
  52. GRB 260831A: GECAM-B observation
  53. GRB 260903A: LCO optical counterpart detection
  54. GRB 260827A: Insight-HXMT/HE detection
  55. GRB 260903A: SVOM detection of a soft faint burst
  56. EP260901a: SVOM/VT optical upper limits
  57. EP260901a: EP-FXT follow-up observation
  58. Konus-Wind detection of GRB 260829A
  59. GRB 260829A: SVOM/GRM observation
  60. GRB 260818A: ATCA detection of a candidate radio counterpart
  61. EP260830a: EP-FXT follow-up observation
  62. EP260901a: Global MASTER-Net observations report
  63. IceCube-260827A: No transient candidates from the Zwicky Transient Facility
  64. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  65. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  66. NuSTAR Transient 260828: LCO Optical Upper Limits
  67. EP260901a: EP-WXT detection of a fast X-ray transient
  68. SVOM trigger sb26083106 is not a GRB
  69. GRB 260829A: AstroSat CZTI detection
  70. GRB 260831B: EP-FXT follow-up observation
  71. GRB 260830A: NuSTAR detection of prompt emission
  72. GRB 260831B: LCO optical upper limits
  73. EP260830a: Global MASTER-Net observations report
  74. EP260830a: EP-WXT detection of a fast X-ray transient
  75. GRB 260827A: SVOM/GRM observation
  76. NuSTAR 260828: a 1100s hard X-ray transient
  77. GRB 260831B: SVOM detection of a possible burst
  78. IPN triangulation of GRB 260829A
  79. GRB 260827A: Glowbug gamma-ray detection
  80. EP260727a: ATCA 10 GHz detection
  81. GRB 260831A: Fermi GBM Final Real-time Localization
  82. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  83. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  84. GRB 260829A: GECAM-B observation of a long burst
  85. GRB 260825A: SVOM/GRM observation of a long burst
  86. GRB 260825A: GECAM-B observation
  87. GRB 260829A: Fermi GBM Detection
  88. GRB 260825A: AstroSat CZTI detection
  89. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  90. GRB 260829A: Fermi GBM Final Real-time Localization
  91. IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
  92. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  93. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  94. Fermi GBM trigger 809666623/260829141 is not a GRB
  95. GRB 260818B: Further EP-FXT observation
  96. GRB 260818B: VLT optical and nIR observations
  97. GRB 260818B: TNG NIR observations
  98. MAXI GRB260827.40: Global MASTER-Net observations report
  99. IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
  100. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203

Advanced

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