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"

27835 results found.

  1. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  2. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  3. GRB 260825A: SVOM/GRM observation of a long burst
  4. GRB 260829A: Fermi GBM Detection
  5. GRB 260825A: AstroSat CZTI detection
  6. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  7. IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
  8. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  9. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  10. GRB 260818B: Further EP-FXT observation
  11. GRB 260818B: VLT optical and nIR observations
  12. GRB 260818B: TNG NIR observations
  13. MAXI GRB260827.40: Global MASTER-Net observations report
  14. GRB 260818B: 6 GHz VLA observations
  15. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  16. GRB 260808B: SAO RAS observations of the optical rebrightening
  17. EP260822a: Global MASTER-Net observations report
  18. EP Alert 260820.31: Global MASTER-Net observations report
  19. GRB 260807A: EP-FXT follow-up observations
  20. IceCube Alert 260825A: Global MASTER-Net observations report
  21. IceCube-Cascade 260824A: Upper limits from a search for additional neutrino events in IceCube
  22. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  23. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  24. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  25. EP260822a: EP-FXT non-detection and upper limit
  26. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  27. EP260822a: Einstein Probe detection of a fast X-ray transient
  28. GRB 260822A: LCO optical upper limits
  29. GRB 260822A: GROWTH-India Telescope Upper Limits
  30. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  31. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  32. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  33. GRB 260818B: VLA radio observations
  34. GRB 260818B: SVOM/C-GFT optical upper limit
  35. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  36. IceCube Alert 260821A: Global MASTER-Net observations report
  37. GRB 260820A: Insight-HXMT/HE detection
  38. EP detected a brightening of LMXB 1ES 1735-26.9
  39. GRB 260818A: J-band observations with WINTER
  40. GRB 260818A: SVOM/ECLAIRs refined analysis
  41. GRB 260818B: NOT optical upper limits
  42. GRB 260810A: SVOM/GRM observation
  43. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  44. GRB 260818B: LCO optical upper limits
  45. GRB 260818B: SVOM detection of a short burst
  46. EP260806a: SAO RAS multicolor optical observations
  47. GRB 260818A: LCO optical upper limits
  48. EP260812a: AbAO optical upper limit
  49. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  50. GRB 260810A: Insight-HXMT/HE detection
  51. GRB 260818A: SVOM possible detection of a long and faint GRB
  52. EP260806a: NUTTELA-TAO optical observations
  53. The EP-WXT trigger 01709281429 is likely a flaring star
  54. EP260812a: AZT-22 optical upper limit
  55. EP260806a: WFST optical observations
  56. EP260812b: Optical upper limit with Kinder
  57. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  58. GRB 260808B: Liverpool Telescope further optical observations
  59. GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
  60. EP260812a: NOT and Liverpool Telescope upper limits:
  61. EP260812b: Liverpool Telescope observations
  62. EP260812b: GOTO detection of the optical counterpart
  63. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  64. EP260812a: SVOM/C-GFT optical upper limit
  65. EP260812b: COLIBRÍ optical observations
  66. EP260812b: SVOM/VT optical observation
  67. GRB 260808A: SVOM/GRM observation
  68. EP260812b: Einstein Probe detection of an X-ray transient
  69. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  70. Fermi GBM Sub-Threshold Detection of GRB 260809A
  71. GRB 260810A: Glowbug gamma-ray detection
  72. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  73. GRB 260810A: AstroSat CZTI detection of a long burst
  74. EP260812a: Einstein Probe detection of an X-ray transient
  75. GRB 260809A: SAO RAS optical observations
  76. GRB 260808B: SAO RAS optical observations
  77. GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
  78. EP260806a: MAO/AZT-22 optical observations
  79. IceCube-260807A: Upper limits from a search for additional neutrino events in IceCube
  80. GRB260808B: MAO/AZT-22 optical observations
  81. GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
  82. GRB 260809A: J-band upper limit with WINTER
  83. GRB 260806A: Glowbug gamma-ray detection
  84. GRB260809A/EPF_J234751.2+210212: EP-FXT follow-up observation
  85. GRB 260809A: SVOM/COLIBRÍ (FM-GFT) optical observation
  86. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) optical observation
  87. GRB 260809A: NOT optical observations
  88. GRB260809A: MAO/AZT-22 optical observations
  89. GRB260809A: OHP/T193 optical observations
  90. IceCube-260805A: Upper limits from a search for additional neutrino events in IceCube
  91. EP260809a: J-band upper limit with WINTER
  92. GRB 260808B: J-band upper limit with WINTER
  93. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  94. GRB 260809A: SVOM detection of a faint burst
  95. GRB 260808B: Liverpool Telescope optical observations
  96. GRB 260808B: NOT optical observations
  97. GRB 260808B: LCO optical observations
  98. GRB 260808A: NuSTAR detection of prompt emission
  99. EP260809a: COLIBRÍ optical observations
  100. EP260809a: LCO optical observation

Advanced

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