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"

19539 results found.

  1. EP260623a: NOEMA detections
  2. GRB 260909A: Mondy optical observations and afterglow candidate
  3. GRB 260909A: Xinglong 2.16m optical upper limit
  4. GRB 260909A: SVOM/C-GFT optical upper limit
  5. GRB 260909A: SVOM detection of a burst
  6. Fermi trigger No 810554827: Global MASTER-Net observations report
  7. EP Alert 260908.60: Global MASTER-Net observations report
  8. GRB 260903A: Swift ToO observations
  9. GRB 260903A: SAO RAS optical upper limit
  10. GRB 260903A: J-band upper limit with WINTER
  11. GRB260903A: Liverpool Telescope optical observations
  12. GRB 260903A: SAO RAS optical observations
  13. EP260903a: EP-WXT detection of a fast X-ray transient
  14. GRB 260903A: OHP/T193 optical afterglow detection
  15. NuSTAR Transient 260828: SOAR Optical Upper Limits
  16. GRB 260903A: LCO optical counterpart detection
  17. GRB 260903A: SVOM detection of a soft faint burst
  18. EP260901a: SVOM/VT optical upper limits
  19. GRB 260829A: SVOM/GRM observation
  20. GRB 260818A: ATCA detection of a candidate radio counterpart
  21. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  22. NuSTAR Transient 260828: LCO Optical Upper Limits
  23. EP260901a: EP-WXT detection of a fast X-ray transient
  24. GRB 260831B: LCO optical upper limits
  25. EP260830a: EP-WXT detection of a fast X-ray transient
  26. GRB 260827A: SVOM/GRM observation
  27. GRB 260831B: SVOM detection of a possible burst
  28. EP260727a: ATCA 10 GHz detection
  29. GRB 260825A: SVOM/GRM observation of a long burst
  30. GRB 260818B: Further EP-FXT observation
  31. GRB 260818B: VLT optical and nIR observations
  32. GRB 260818B: TNG NIR observations
  33. GRB 260818B: 6 GHz VLA observations
  34. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  35. GRB 260808B: SAO RAS observations of the optical rebrightening
  36. EP Alert 260820.31: Global MASTER-Net observations report
  37. GRB 260822A: SVOM/ECLAIRs refined analysis
  38. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  39. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  40. EP260822a: EP-FXT non-detection and upper limit
  41. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  42. EP260822a: Einstein Probe detection of a fast X-ray transient
  43. GRB 260822A: LCO optical upper limits
  44. GRB 260822A: GROWTH-India Telescope Upper Limits
  45. GRB 260822A: SVOM detection of a short burst
  46. GRB 260818B: SVOM/C-GFT optical upper limit
  47. EP260731a: SVOM/ECLAIRs detection through offline targeted search
  48. EP detected a brightening of LMXB 1ES 1735-26.9
  49. GRB 260818A: J-band observations with WINTER
  50. GRB 260818B: SVOM/ECLAIRs refined analysis
  51. GRB 260818A: SVOM/ECLAIRs refined analysis
  52. GRB 260818B: NOT optical upper limits
  53. GRB 260810A: SVOM/GRM observation
  54. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  55. GRB 260818B: LCO optical upper limits
  56. GRB 260818B: SVOM detection of a short burst
  57. EP260806a: SAO RAS multicolor optical observations
  58. GRB 260818A: LCO optical upper limits
  59. EP260812a: AbAO optical upper limit
  60. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  61. GRB 260818A: SVOM possible detection of a long and faint GRB
  62. EP260806a: NUTTELA-TAO optical observations
  63. EP260812a: AZT-22 optical upper limit
  64. EP260806a: WFST optical observations
  65. EP260812b: Optical upper limit with Kinder
  66. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  67. GRB 260808B: Liverpool Telescope further optical observations
  68. EP260812a: NOT and Liverpool Telescope upper limits:
  69. EP260812b: Liverpool Telescope observations
  70. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  71. EP260812a: SVOM/C-GFT optical upper limit
  72. EP260812b: COLIBRÍ optical observations
  73. EP260812b: SVOM/VT optical observation
  74. GRB 260808A: SVOM/GRM observation
  75. EP260812b: Einstein Probe detection of an X-ray transient
  76. EP trigger #01709278129 (EP260812b?): NOT optical counterpart
  77. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) confirmation of the optical rebrightening
  78. EP260812a: Einstein Probe detection of an X-ray transient
  79. GRB 260809A: SAO RAS optical observations
  80. GRB 260808B: SAO RAS optical observations
  81. GRB 260317A: SVOM/ECLAIRs detection through offline targeted search and its possible association to magnetar 1E 1841-04.5
  82. GRB 260807A: SVOM/ECLAIRs refined analysis
  83. EP260806a: MAO/AZT-22 optical observations
  84. GRB260808B: MAO/AZT-22 optical observations
  85. GRB 250607A: SVOM/ECLAIRs detection through offline targeted search
  86. GRB 260809A: J-band upper limit with WINTER
  87. GRB 260808A: CALET Gamma-Ray Burst Monitor detection
  88. GRB 260809A: SVOM/COLIBRÍ (FM-GFT) optical observation
  89. GRB 260808B: SVOM/COLIBRÍ (FM-GFT) optical observation
  90. GRB 260809A: NOT optical observations
  91. GRB260809A: MAO/AZT-22 optical observations
  92. GRB260809A: OHP/T193 optical observations
  93. EP260809a: J-band upper limit with WINTER
  94. GRB 260808B: J-band upper limit with WINTER
  95. GRB 260808B: SVOM/ECLAIRs refined analysis
  96. EP260809a:refined analysis of the EP-WXT and autonomous EP-FXT observation
  97. GRB 260809A: SVOM detection of a faint burst
  98. GRB 260808B: Liverpool Telescope optical observations
  99. GRB 260808B: NOT optical observations
  100. GRB 260808B: LCO optical observations

Advanced

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