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"

22056 results found.

  1. GRB 260818A: Continued ATCA observations
  2. SVOM GRB260913.32: Global MASTER-Net observations report
  3. GRB 260913A: SVOM/C-GFT optical upper limit
  4. GRB 260909A: CrAO and AbAO optical upper limits
  5. GRB 260909A: SVOM/ECLAIRs refined analysis
  6. GRB 260910B: GOTO tentative optical counterpart candidates
  7. GRB 260909A: Swift ToO observations
  8. GRB 260909A: KAIT optical upper limit
  9. GRB 260903A: Swift-XRT observations
  10. EP260806a: VLA+ALMA radio detections
  11. GRB 260909A: OHP/T193 z-band upper limit
  12. GRB 260909A: VLT optical and near-infrared upper limits
  13. EP Alert 260909.53: Global MASTER-Net observations report
  14. EP260806a: NOEMA detection
  15. EP260623a: NOEMA detections
  16. GRB 260909A: SVOM/VT optical upper limits
  17. GRB 260909A: Mondy optical observations and afterglow candidate
  18. GRB 260909A: SVOM/C-GFT optical upper limit
  19. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  20. Fermi trigger No 810554827: Global MASTER-Net observations report
  21. EP Alert 260908.60: Global MASTER-Net observations report
  22. GRB 260903A: Swift ToO observations
  23. Fermi GRB 260907B: Global MASTER-Net observations report
  24. GRB 260903A: SAO RAS optical upper limit
  25. Fermi GRB 260907A: Global MASTER-Net observations report
  26. EP260903a: EP-FXT follow-up observation
  27. EP Alert 260905.11: Global MASTER-Net observations report
  28. GRB 260903A: J-band upper limit with WINTER
  29. EP Alert 260903.47: Global MASTER-Net observations report
  30. GRB 260903A: SVOM/ECLAIRs refined analysis
  31. GRB260903A: Liverpool Telescope optical observations
  32. GRB 260903A: SAO RAS optical observations
  33. EP260903a: EP-WXT detection of a fast X-ray transient
  34. EP Alert 260903.62: Global MASTER-Net observations report
  35. GRB 260903A: OHP/T193 optical afterglow detection
  36. GRB 260903A: NOT optical observations and afterglow fading
  37. NuSTAR Transient 260828: SOAR Optical Upper Limits
  38. SVOM GRB260903A: Global MASTER-Net observations report
  39. GRB 260903A: LCO optical observations
  40. GRB 260903A: SVOM/VT optical candidate
  41. Konus-Wind detection of GRB 260829A
  42. GRB 260818A: ATCA detection of a candidate radio counterpart
  43. EP260901a: Global MASTER-Net observations report
  44. IceCube-260827A: No transient candidates from the Zwicky Transient Facility
  45. GRB 260831B / sb26083106: SVOM/VT optical variability of V* GK Per
  46. NuSTAR Transient 260828: LCO Optical Upper Limits
  47. EP260901a: EP-WXT detection of a fast X-ray transient
  48. EP260830a: Global MASTER-Net observations report
  49. EP260830a: EP-WXT detection of a fast X-ray transient
  50. NuSTAR 260828: a 1100s hard X-ray transient
  51. EP260727a: ATCA 10 GHz detection
  52. Fermi-LAT Gamma-ray Observations of IceCube-260827A
  53. Fermi-LAT Gamma-ray Observations of IceCube-260825A
  54. GRB 260818B: VLT optical and nIR observations
  55. GRB 260818B: TNG NIR observations
  56. MAXI GRB260827.40: Global MASTER-Net observations report
  57. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  58. GRB 260818B: 6 GHz VLA observations
  59. GRB 260818B: SVOM/VT optical upper limit and continuous observations
  60. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  61. GRB 260808B: SAO RAS observations of the optical rebrightening
  62. EP260822a: Global MASTER-Net observations report
  63. EP Alert 260820.31: Global MASTER-Net observations report
  64. IceCube-260825A: No transient candidates from the Zwicky Transient Facility
  65. GRB 260807A: EP-FXT follow-up observations
  66. GRB 260822A: SVOM/ECLAIRs refined analysis
  67. GRB 260809A: SVOM/ECLAIRs refined analysis
  68. GRB 260822A: SVOM/VT optical upper limits
  69. IceCube Alert 260825A: Global MASTER-Net observations report
  70. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  71. GRB 260822A: EP/FXT follow-up observations
  72. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  73. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  74. GRB 260822A: GOTO optical counterpart detection
  75. GRB 260822A: SVOM/VT optical detection of COLIBRÍ candidate
  76. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  77. EP260822a: Einstein Probe detection of a fast X-ray transient
  78. GRB 260822A: LCO optical upper limits
  79. GRB 260822A: GOTO optical upper limit
  80. GRB 260822A: SVOM detection of a short burst
  81. Fermi-LAT Gamma-ray Observations of IceCube-260821A
  82. Fermi-LAT Gamma-ray Observations of IceCube-260807A
  83. GRB 260818B: VLA radio observations
  84. GRB 260818B: SVOM/C-GFT optical upper limit
  85. IceCube Alert 260821A: Global MASTER-Net observations report
  86. GRB 260818A: J-band observations with WINTER
  87. GRB 260818B: SVOM/ECLAIRs refined analysis
  88. GRB 260818A: SVOM/ECLAIRs refined analysis
  89. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  90. EP260806a: SAO RAS multicolor optical observations
  91. EP260812a: AbAO optical upper limit
  92. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  93. EP260806a: NUTTELA-TAO optical observations
  94. EP260812a: AZT-22 optical upper limit
  95. EP260812b: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.034
  96. EP260806a: WFST optical observations
  97. EP260812b: Optical upper limit with Kinder
  98. GRB 260808B: Liverpool Telescope further optical observations
  99. EP260812a: NOT and Liverpool Telescope upper limits:
  100. EP260812b: Liverpool Telescope observations

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