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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"

28041 results found.

  1. GRB 260918A: LCO optical upper limits
  2. EP260917a: Einstein Probe detection of an X-ray transient
  3. GRB 260918A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  4. GRB 260918A: SVOM detection of a burst
  5. GRB 260917B: FRAM-Auger optical limits
  6. GRB 260916B: Fermi GBM Detection
  7. IceCube-260916A: Upper limits from a search for additional neutrino events in IceCube
  8. GRB 260917A: Glowbug gamma-ray detection
  9. GRB 260915A: SVOM/ECLAIRs refined analysis
  10. GRB 260917B: WINTER J-band observations
  11. GRB 260917B: SVOM/VT optical observations
  12. SVOM GRB260917.16: Global MASTER-Net observations report
  13. GRB 260917B: LCO optical observation
  14. GRB 260917B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  15. GRB 260917B: SVOM detection of a faint burst
  16. GRB 260917A: BALROG localization (Fermi Trigger 811304653 / GRB 260917100)
  17. Fermi trigger No 811304653: Global MASTER-Net observations report
  18. GRB 260915A: J-band upper limit with WINTER
  19. Fermi trigger No 811264269: Global MASTER-Net observations report
  20. GRB 260909A: NOEMA detection
  21. GRB 260914A: Mondy and TShAO optical observations
  22. GRB 260914A: SVOM/ECLAIRs refined analysis
  23. GRB 260909A: Swift-XRT observations
  24. GRB 260916A: MAXI/GSC detection
  25. MAXI GRB260916.37: Global MASTER-Net observations report
  26. GRB 260915A: J-band upper limit by SYSU 80cm infrared telescope
  27. GRB 260915A: SVOM/C-GFT optical upper limits
  28. GRB 260915A: EP-FXT follow-up observation
  29. GRB 260915A: SVOM/VT refined early optical upper limits
  30. GRB 260915A: REM optical/NIR observations
  31. GRB 260914A: REM optical/NIR observations
  32. GRB 260914A: VLT/X-shooter observations and redshift confirmation
  33. GRB 260915A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  34. GRB 260915A: NOT optical upper limit
  35. SVOM GRB260915.05: Global MASTER-Net observations report
  36. GRB 260915A: SVOM/VT optical upper limits from VHF data
  37. Fermi GBM Sub-Threshold Detection of GRB 260915A
  38. GRB 260915A: LCO optical upper limits
  39. EP Alert 260914.53: Global MASTER-Net observations report
  40. GRB 260914A: EP-FXT follow-up observation
  41. GRB 260915A: SVOM detection of a burst
  42. Fermi GBM Sub-Threshold Detection of GRB 260914A
  43. GRB 260914A: LCO optical observation
  44. GRB 260914A: SVOM/C-GFT optical observations
  45. GRB 260914A: SVOM/VT optical observation from VHF data
  46. GRB 260914A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  47. SVOM GRB260914.47: Global MASTER-Net observations report
  48. GRB 260914A: SVOM detection of a burst
  49. GRB 260913A: SVOM trigger sb26091302 is not an astrophysical event
  50. GRB 260818A: Continued ATCA observations
  51. SVOM GRB260913.32: Global MASTER-Net observations report
  52. GRB 260913A: SVOM/C-GFT optical upper limit
  53. GRB 260913A: SVOM detection of a faint burst
  54. GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
  55. GRB 260907A: SVOM/GRM observation
  56. GRB 260909A: CrAO and AbAO optical upper limits
  57. GRB 260909A: KAIT optical upper limit
  58. GRB 260903A: Swift-XRT observations
  59. GRB 260909A: OHP/T193 z-band upper limit
  60. GRB 260909A: VLT optical and near-infrared upper limits
  61. EP Alert 260909.53: Global MASTER-Net observations report
  62. GRB 260909A: EP-FXT follow-up observation
  63. EP260806a: NOEMA detection
  64. EP260623a: NOEMA detections
  65. GRB 260909A: Mondy optical observations and afterglow candidate
  66. GRB 260909A: Xinglong 2.16m optical upper limit
  67. GRB 260909A: SVOM/C-GFT optical upper limit
  68. GRB 260909A: SVOM detection of a burst
  69. Fermi trigger No 810554827: Global MASTER-Net observations report
  70. EP Alert 260908.60: Global MASTER-Net observations report
  71. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  72. Fermi GRB 260907B: Global MASTER-Net observations report
  73. GRB 260903A: SAO RAS optical upper limit
  74. Fermi GRB 260907A: Global MASTER-Net observations report
  75. EP260903a: EP-FXT follow-up observation
  76. EP Alert 260905.11: Global MASTER-Net observations report
  77. GRB 260903A: J-band upper limit with WINTER
  78. EP Alert 260903.47: Global MASTER-Net observations report
  79. GRB260903A: Liverpool Telescope optical observations
  80. GRB 260903A: SAO RAS optical observations
  81. GRB 260830A: GECAM-B detection of a burst
  82. EP260903a: EP-WXT detection of a fast X-ray transient
  83. EP Alert 260903.62: Global MASTER-Net observations report
  84. GRB 260830A: Insight-HXMT/HE detection
  85. GRB 260903A: EP-FXT follow-up observation
  86. GRB 260903A: OHP/T193 optical afterglow detection
  87. NuSTAR Transient 260828: SOAR Optical Upper Limits
  88. SVOM GRB260903A: Global MASTER-Net observations report
  89. GRB 260903A: LCO optical counterpart detection
  90. GRB 260827A: Insight-HXMT/HE detection
  91. EP260901a: SVOM/VT optical upper limits
  92. EP260901a: EP-FXT follow-up observation
  93. GRB 260829A: SVOM/GRM observation
  94. GRB 260818A: ATCA detection of a candidate radio counterpart
  95. EP260830a: EP-FXT follow-up observation
  96. EP260901a: Global MASTER-Net observations report
  97. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  98. NuSTAR Transient 260828: LCO Optical Upper Limits
  99. EP260901a: EP-WXT detection of a fast X-ray transient
  100. GRB 260830A: NuSTAR detection of prompt emission

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