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"

27030 results found.

  1. GRB 260831A: GECAM-B observation
  2. GRB 260903A: LCO optical counterpart detection
  3. GRB 260903A: SVOM detection of a soft faint burst
  4. EP260901a: SVOM/VT optical upper limits
  5. EP260901a: EP-FXT follow-up observation
  6. GRB 260829A: SVOM/GRM observation
  7. GRB 260818A: ATCA detection of a candidate radio counterpart
  8. EP260830a: EP-FXT follow-up observation
  9. EP260901a: Global MASTER-Net observations report
  10. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  11. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  12. EP260901a: EP-WXT detection of a fast X-ray transient
  13. SVOM trigger sb26083106 is not a GRB
  14. GRB 260831B: EP-FXT follow-up observation
  15. GRB 260831B: LCO optical upper limits
  16. EP260830a: Global MASTER-Net observations report
  17. EP260830a: EP-WXT detection of a fast X-ray transient
  18. GRB 260827A: SVOM/GRM observation
  19. GRB 260831B: SVOM detection of a possible burst
  20. IPN triangulation of GRB 260829A
  21. EP260727a: ATCA 10 GHz detection
  22. GRB 260831A: Fermi GBM Final Real-time Localization
  23. GRB 260829A: GECAM-B observation of a long burst
  24. GRB 260825A: SVOM/GRM observation of a long burst
  25. GRB 260825A: GECAM-B observation
  26. GRB 260829A: Fermi GBM Detection
  27. GRB 260829A: BALROG localization (Fermi Trigger 809676494 / GRB 260829256)
  28. GRB 260829A: Fermi GBM Final Real-time Localization
  29. Fermi GBM trigger 809666623/260829141 is not a GRB
  30. GRB 260818B: Further EP-FXT observation
  31. GRB 260818B: VLT optical and nIR observations
  32. GRB 260818B: TNG NIR observations
  33. MAXI GRB260827.40: Global MASTER-Net observations report
  34. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  35. GRB 260827A: Fermi GBM Final Real-time Localization
  36. GRB 260818B: 6 GHz VLA observations
  37. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  38. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  39. EP260822a: Global MASTER-Net observations report
  40. EP Alert 260820.31: Global MASTER-Net observations report
  41. GRB 260807A: EP-FXT follow-up observations
  42. GRB 260822A: SVOM/ECLAIRs refined analysis
  43. GRB 260809A: SVOM/ECLAIRs refined analysis
  44. GRB 260822A: SVOM/VT optical upper limits
  45. IceCube Alert 260825A: Global MASTER-Net observations report
  46. GRB 260825A: Fermi GBM Final Real-time Localization
  47. GRB 260822A: EP/FXT follow-up observations
  48. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  49. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  50. EP260822a: EP-FXT non-detection and upper limit
  51. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  52. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  53. EP260822a: Einstein Probe detection of a fast X-ray transient
  54. GRB 260822A: LCO optical upper limits
  55. The EP-WXT trigger 01709287395 is likely a flaring star
  56. GRB260822B: Fermi GBM Final Localization
  57. GRB 260822A: GROWTH-India Telescope Upper Limits
  58. GRB 260822A: GOTO optical upper limit
  59. GRB 260822A: SVOM detection of a short burst
  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 260818B: SVOM/GRM observation
  65. EP detected a brightening of LMXB 1ES 1735-26.9
  66. GRB260820A: Fermi GBM Final Real-Time Localization
  67. GRB 260818B: EP-FXT follow-up observation
  68. GRB 260818A: J-band observations with WINTER
  69. GRB 260818B: SVOM/ECLAIRs refined analysis
  70. GRB 260818A: SVOM/ECLAIRs refined analysis
  71. GRB 260818B: NOT optical upper limits
  72. GRB 260810A: SVOM/GRM observation
  73. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  74. GRB260818A: EP-FXT follow-up observation
  75. GRB 260818B: LCO optical upper limits
  76. GRB 260818B: SVOM detection of a short burst
  77. SVOM trigger sb26081806 is not a GRB
  78. EP260806a: SAO RAS multicolor optical observations
  79. GRB 260818A: LCO optical upper limits
  80. EP260812a: AbAO optical upper limit
  81. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  82. GRB 260818A: SVOM possible detection of a long and faint GRB
  83. EP260806a: SVOM/ECLAIRs detection through targeted search
  84. The EP-WXT trigger 01709281429 is likely a flaring star
  85. EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
  86. EP260806a: WFST optical observations
  87. The EP-WXT trigger 01709280562 is likely a flaring star
  88. The EP-WXT trigger 01709279838 is likely a flaring star
  89. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  90. GRB 260808B: Liverpool Telescope further optical observations
  91. GRB 260808B: GTC/OSIRIS+ spectroscopic redshift z = 1.295
  92. GRB 260813A: BALROG localization (Fermi Trigger 808341387 / GRB 260813803)
  93. GRB 260813A: Fermi GBM Final Real-time Localization
  94. EP260812a: NOT and Liverpool Telescope upper limits:
  95. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  96. EP260812a: SVOM/C-GFT optical upper limit
  97. EP260812b: COLIBRÍ optical observations
  98. EP260812b: SVOM/VT optical observation
  99. GRB 260808A: SVOM/GRM observation
  100. EP260812b: Einstein Probe detection of an X-ray transient

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