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"

27886 results found.

  1. GRB 260909A: CrAO and AbAO optical upper limits
  2. GRB 260909A: KAIT optical upper limit
  3. GRB 260903A: Swift-XRT observations
  4. GRB 260909A: OHP/T193 z-band upper limit
  5. GRB 260909A: VLT optical and near-infrared upper limits
  6. EP Alert 260909.53: Global MASTER-Net observations report
  7. GRB 260909A: EP-FXT follow-up observation
  8. EP260806a: NOEMA detection
  9. EP260623a: NOEMA detections
  10. GRB 260909A: Mondy optical observations and afterglow candidate
  11. GRB 260909A: Xinglong 2.16m optical upper limit
  12. GRB 260909A: SVOM/C-GFT optical upper limit
  13. GRB 260909A: SVOM detection of a burst
  14. Fermi trigger No 810554827: Global MASTER-Net observations report
  15. EP Alert 260908.60: Global MASTER-Net observations report
  16. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  17. Fermi GRB 260907B: Global MASTER-Net observations report
  18. GRB 260903A: SAO RAS optical upper limit
  19. Fermi GRB 260907A: Global MASTER-Net observations report
  20. EP260903a: EP-FXT follow-up observation
  21. EP Alert 260905.11: Global MASTER-Net observations report
  22. GRB 260903A: J-band upper limit with WINTER
  23. EP Alert 260903.47: Global MASTER-Net observations report
  24. GRB260903A: Liverpool Telescope optical observations
  25. GRB 260903A: SAO RAS optical observations
  26. GRB 260830A: GECAM-B detection of a burst
  27. EP260903a: EP-WXT detection of a fast X-ray transient
  28. EP Alert 260903.62: Global MASTER-Net observations report
  29. GRB 260830A: Insight-HXMT/HE detection
  30. GRB 260903A: EP-FXT follow-up observation
  31. GRB 260903A: OHP/T193 optical afterglow detection
  32. NuSTAR Transient 260828: SOAR Optical Upper Limits
  33. SVOM GRB260903A: Global MASTER-Net observations report
  34. GRB 260903A: LCO optical counterpart detection
  35. GRB 260827A: Insight-HXMT/HE detection
  36. EP260901a: SVOM/VT optical upper limits
  37. EP260901a: EP-FXT follow-up observation
  38. GRB 260829A: SVOM/GRM observation
  39. GRB 260818A: ATCA detection of a candidate radio counterpart
  40. EP260830a: EP-FXT follow-up observation
  41. EP260901a: Global MASTER-Net observations report
  42. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  43. NuSTAR Transient 260828: LCO Optical Upper Limits
  44. EP260901a: EP-WXT detection of a fast X-ray transient
  45. GRB 260830A: NuSTAR detection of prompt emission
  46. GRB 260831B: LCO optical upper limits
  47. EP260830a: Global MASTER-Net observations report
  48. EP260830a: EP-WXT detection of a fast X-ray transient
  49. GRB 260827A: SVOM/GRM observation
  50. NuSTAR 260828: a 1100s hard X-ray transient
  51. GRB 260831B: SVOM detection of a possible burst
  52. GRB 260827A: Glowbug gamma-ray detection
  53. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  54. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  55. GRB 260825A: SVOM/GRM observation of a long burst
  56. GRB 260829A: Fermi GBM Detection
  57. GRB 260825A: AstroSat CZTI detection
  58. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  59. IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
  60. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  61. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  62. GRB 260818B: Further EP-FXT observation
  63. GRB 260818B: VLT optical and nIR observations
  64. GRB 260818B: TNG NIR observations
  65. MAXI GRB260827.40: Global MASTER-Net observations report
  66. GRB 260818B: 6 GHz VLA observations
  67. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  68. GRB 260808B: SAO RAS observations of the optical rebrightening
  69. EP260822a: Global MASTER-Net observations report
  70. EP Alert 260820.31: Global MASTER-Net observations report
  71. GRB 260807A: EP-FXT follow-up observations
  72. IceCube Alert 260825A: Global MASTER-Net observations report
  73. IceCube-Cascade 260824A: Upper limits from a search for additional neutrino events in IceCube
  74. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  75. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  76. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  77. EP260822a: EP-FXT non-detection and upper limit
  78. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  79. EP260822a: Einstein Probe detection of a fast X-ray transient
  80. GRB 260822A: LCO optical upper limits
  81. GRB 260822A: GROWTH-India Telescope Upper Limits
  82. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  83. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  84. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  85. GRB 260818B: VLA radio observations
  86. GRB 260818B: SVOM/C-GFT optical upper limit
  87. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  88. IceCube Alert 260821A: Global MASTER-Net observations report
  89. GRB 260820A: Insight-HXMT/HE detection
  90. EP detected a brightening of LMXB 1ES 1735-26.9
  91. GRB 260818A: J-band observations with WINTER
  92. GRB 260818A: SVOM/ECLAIRs refined analysis
  93. GRB 260818B: NOT optical upper limits
  94. GRB 260810A: SVOM/GRM observation
  95. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  96. GRB 260818B: LCO optical upper limits
  97. GRB 260818B: SVOM detection of a short burst
  98. EP260806a: SAO RAS multicolor optical observations
  99. GRB 260818A: LCO optical upper limits
  100. EP260812a: AbAO 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