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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"

28038 results found.

  1. GRB 260917A: Glowbug gamma-ray detection
  2. GRB 260915A: SVOM/ECLAIRs refined analysis
  3. GRB 260917B: WINTER J-band observations
  4. GRB 260917B: SVOM/VT optical observations
  5. SVOM GRB260917.16: Global MASTER-Net observations report
  6. GRB 260917B: LCO optical observation
  7. GRB 260917B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  8. GRB 260917B: SVOM detection of a faint burst
  9. GRB 260917A: BALROG localization (Fermi Trigger 811304653 / GRB 260917100)
  10. Fermi trigger No 811304653: Global MASTER-Net observations report
  11. GRB 260915A: J-band upper limit with WINTER
  12. Fermi trigger No 811264269: Global MASTER-Net observations report
  13. GRB 260909A: NOEMA detection
  14. GRB 260914A: Mondy and TShAO optical observations
  15. GRB 260914A: SVOM/ECLAIRs refined analysis
  16. GRB 260909A: Swift-XRT observations
  17. GRB 260916A: MAXI/GSC detection
  18. MAXI GRB260916.37: Global MASTER-Net observations report
  19. GRB 260915A: J-band upper limit by SYSU 80cm infrared telescope
  20. GRB 260915A: SVOM/C-GFT optical upper limits
  21. GRB 260915A: EP-FXT follow-up observation
  22. GRB 260915A: SVOM/VT refined early optical upper limits
  23. GRB 260915A: REM optical/NIR observations
  24. GRB 260914A: REM optical/NIR observations
  25. GRB 260914A: VLT/X-shooter observations and redshift confirmation
  26. GRB 260915A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  27. GRB 260915A: NOT optical upper limit
  28. SVOM GRB260915.05: Global MASTER-Net observations report
  29. GRB 260915A: SVOM/VT optical upper limits from VHF data
  30. Fermi GBM Sub-Threshold Detection of GRB 260915A
  31. GRB 260915A: LCO optical upper limits
  32. EP Alert 260914.53: Global MASTER-Net observations report
  33. GRB 260914A: EP-FXT follow-up observation
  34. GRB 260915A: SVOM detection of a burst
  35. Fermi GBM Sub-Threshold Detection of GRB 260914A
  36. GRB 260914A: LCO optical observation
  37. GRB 260914A: SVOM/C-GFT optical observations
  38. GRB 260914A: SVOM/VT optical observation from VHF data
  39. GRB 260914A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  40. SVOM GRB260914.47: Global MASTER-Net observations report
  41. GRB 260914A: SVOM detection of a burst
  42. GRB 260913A: SVOM trigger sb26091302 is not an astrophysical event
  43. GRB 260818A: Continued ATCA observations
  44. SVOM GRB260913.32: Global MASTER-Net observations report
  45. GRB 260913A: SVOM/C-GFT optical upper limit
  46. GRB 260913A: SVOM detection of a faint burst
  47. GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
  48. GRB 260907A: SVOM/GRM observation
  49. GRB 260909A: CrAO and AbAO optical upper limits
  50. GRB 260909A: KAIT optical upper limit
  51. GRB 260903A: Swift-XRT observations
  52. GRB 260909A: OHP/T193 z-band upper limit
  53. GRB 260909A: VLT optical and near-infrared upper limits
  54. EP Alert 260909.53: Global MASTER-Net observations report
  55. GRB 260909A: EP-FXT follow-up observation
  56. EP260806a: NOEMA detection
  57. EP260623a: NOEMA detections
  58. GRB 260909A: Mondy optical observations and afterglow candidate
  59. GRB 260909A: Xinglong 2.16m optical upper limit
  60. GRB 260909A: SVOM/C-GFT optical upper limit
  61. GRB 260909A: SVOM detection of a burst
  62. Fermi trigger No 810554827: Global MASTER-Net observations report
  63. EP Alert 260908.60: Global MASTER-Net observations report
  64. GRB 260907A: Glowbug gamma-ray detection of a likely short burst
  65. Fermi GRB 260907B: Global MASTER-Net observations report
  66. GRB 260903A: SAO RAS optical upper limit
  67. Fermi GRB 260907A: Global MASTER-Net observations report
  68. EP260903a: EP-FXT follow-up observation
  69. EP Alert 260905.11: Global MASTER-Net observations report
  70. GRB 260903A: J-band upper limit with WINTER
  71. EP Alert 260903.47: Global MASTER-Net observations report
  72. GRB260903A: Liverpool Telescope optical observations
  73. GRB 260903A: SAO RAS optical observations
  74. GRB 260830A: GECAM-B detection of a burst
  75. EP260903a: EP-WXT detection of a fast X-ray transient
  76. EP Alert 260903.62: Global MASTER-Net observations report
  77. GRB 260830A: Insight-HXMT/HE detection
  78. GRB 260903A: EP-FXT follow-up observation
  79. GRB 260903A: OHP/T193 optical afterglow detection
  80. NuSTAR Transient 260828: SOAR Optical Upper Limits
  81. SVOM GRB260903A: Global MASTER-Net observations report
  82. GRB 260903A: LCO optical counterpart detection
  83. GRB 260827A: Insight-HXMT/HE detection
  84. EP260901a: SVOM/VT optical upper limits
  85. EP260901a: EP-FXT follow-up observation
  86. GRB 260829A: SVOM/GRM observation
  87. GRB 260818A: ATCA detection of a candidate radio counterpart
  88. EP260830a: EP-FXT follow-up observation
  89. EP260901a: Global MASTER-Net observations report
  90. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  91. NuSTAR Transient 260828: LCO Optical Upper Limits
  92. EP260901a: EP-WXT detection of a fast X-ray transient
  93. GRB 260830A: NuSTAR detection of prompt emission
  94. GRB 260831B: LCO optical upper limits
  95. EP260830a: Global MASTER-Net observations report
  96. EP260830a: EP-WXT detection of a fast X-ray transient
  97. GRB 260827A: SVOM/GRM observation
  98. NuSTAR 260828: a 1100s hard X-ray transient
  99. GRB 260831B: SVOM detection of a possible burst
  100. GRB 260827A: Glowbug gamma-ray detection

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