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"

41639 results found.

  1. NuSTAR 260828: a 1100s hard X-ray transient
  2. GRB 260831B: SVOM detection of a possible burst
  3. GRB 260827A: Glowbug gamma-ray detection
  4. EP260727a: ATCA 10 GHz detection
  5. GRB 260831A: Fermi GBM Final Real-time Localization
  6. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  7. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  8. GRB 260829A: GECAM-B observation of a long burst
  9. GRB 260825A: SVOM/GRM observation of a long burst
  10. GRB 260825A: GECAM-B observation
  11. GRB 260829A: Fermi GBM Detection
  12. GRB 260825A: AstroSat CZTI detection
  13. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  14. GRB 260829A: Fermi GBM Final Real-time Localization
  15. IceCube-260827A: Upper limits from a search for additional neutrino events in IceCube
  16. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  17. IceCube-260825A: Upper limits from a search for additional neutrino events in IceCube
  18. GRB 260818B: Further EP-FXT observation
  19. GRB 260818B: VLT optical and nIR observations
  20. GRB 260818B: TNG NIR observations
  21. MAXI GRB260827.40: Global MASTER-Net observations report
  22. IceCube-260827A - IceCube observation of a high-energy neutrino candidate track-like event
  23. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  24. GRB 260827A: Fermi GBM Final Real-time Localization
  25. GRB 260818B: 6 GHz VLA observations
  26. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  27. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  28. GRB 260808B: SAO RAS observations of the optical rebrightening
  29. EP260822a: Global MASTER-Net observations report
  30. EP Alert 260820.31: Global MASTER-Net observations report
  31. IceCube-260825A: No transient candidates from the Zwicky Transient Facility
  32. GRB 260807A: EP-FXT follow-up observations
  33. GRB 260822A: SVOM/ECLAIRs refined analysis
  34. GRB 260809A: SVOM/ECLAIRs refined analysis
  35. GRB 260822A: SVOM/VT optical upper limits
  36. IceCube Alert 260825A: Global MASTER-Net observations report
  37. IceCube-Cascade 260824A: Upper limits from a search for additional neutrino events in IceCube
  38. GRB 260825A: Fermi GBM Final Real-time Localization
  39. IceCube-260825A - IceCube observation of a high-energy neutrino candidate track-like event
  40. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  41. GRB 260822A: EP/FXT follow-up observations
  42. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  43. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  44. EP260822a: EP-FXT non-detection and upper limit
  45. GRB 260822A: Retraction of GOTO optical counterpart detection GCN 45431
  46. GRB 260822A: GOTO optical counterpart detection
  47. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  48. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  49. EP260822a: Einstein Probe detection of a fast X-ray transient
  50. GRB 260822A: LCO optical upper limits
  51. The EP-WXT trigger 01709287395 is likely a flaring star
  52. GRB260822B: Fermi GBM Final Localization
  53. GRB 260822A: GROWTH-India Telescope Upper Limits
  54. GRB 260822A: GOTO optical upper limit
  55. GRB 260822A: SVOM detection of a short burst
  56. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  57. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  58. IceCube-260821A: Upper limits from a search for additional neutrino events in IceCube
  59. GRB 260818B: VLA radio observations
  60. GRB 260818B: SVOM/C-GFT optical upper limit
  61. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  62. IceCube Alert 260821A: Global MASTER-Net observations report
  63. The EP-WXT trigger 01709286204 is likely a flaring star
  64. GRB 260820A: Insight-HXMT/HE detection
  65. IceCube-260821A - IceCube observation of a high-energy neutrino candidate track-like event
  66. GRB 260818B: SVOM/GRM observation
  67. EP detected a brightening of LMXB 1ES 1735-26.9
  68. GRB260820A: Fermi GBM Final Real-Time Localization
  69. GRB 260818B: Insight-HXMT detection
  70. GRB 260818B: EP-FXT follow-up observation
  71. GRB 260818A: J-band observations with WINTER
  72. GRB 260818B: SVOM/ECLAIRs refined analysis
  73. GRB 260818A: SVOM/ECLAIRs refined analysis
  74. GRB 260810A: SVOM/GRM observation
  75. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  76. GRB260818A: EP-FXT follow-up observation
  77. GRB 260818B: LCO optical upper limits
  78. GRB 260818B: SVOM detection of a short burst
  79. SVOM trigger sb26081806 is not a GRB
  80. EP260806a: SAO RAS multicolor optical observations
  81. GRB 260818A: LCO optical upper limits
  82. EP260812a: AbAO optical upper limit
  83. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  84. GRB 260810A: Insight-HXMT/HE detection
  85. GRB 260818A: SVOM possible detection of a long and faint GRB
  86. EP260806a: SVOM/ECLAIRs detection through targeted search
  87. EP260806a: NUTTELA-TAO optical observations
  88. The EP-WXT trigger 01709281429 is likely a flaring star
  89. EP260812a: AZT-22 optical upper limit
  90. EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
  91. EP260806a: WFST optical observations
  92. The EP-WXT trigger 01709280562 is likely a flaring star
  93. EP260812b: Optical upper limit with Kinder
  94. The EP-WXT trigger 01709279838 is likely a flaring star
  95. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  96. GRB 260808B: Liverpool Telescope further optical observations
  97. GRB 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
  98. GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
  99. GRB 260813A: Fermi GBM Final Real-time Localization
  100. EP260812a: NOT and Liverpool Telescope upper limits:

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov