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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"

27019 results found.

  1. GRB 251222A: SVOM/ECLAIRs refined analysis
  2. GRB 260125A: GOTO candidate optical counterpart
  3. Fermi GRB 260125B: Global MASTER-Net observations report
  4. GRB 260125B: Fermi GBM Final Real-time Localization
  5. GRB 260125A: Fermi GBM Final Real-time Localization
  6. GRB 260114A: SVOM/VT optical upper limits
  7. GRB 260122B: Swift-BAT refined analysis
  8. GRB 260120B: SVOM/GRM observation
  9. GRB 260120A: GECAM-B observation
  10. GRB 260122B: Swift detection of a burst
  11. Swift GRB260122.97: Global MASTER-Net observations report
  12. GRB 260122A: Fermi GBM Final Real-time Localization
  13. EP260119a: Xinglong optical upper limit
  14. The EP-WXT trigger 01709251871 is likely a flaring star
  15. Fermi GRB 260120C: Global MASTER-Net observations report
  16. GRB 260120B: Swift-BAT refined analysis
  17. GRB 260120B: Swift-XRT refined Analysis
  18. EP260116a: COLIBRÍ further observations
  19. GRB 260120B: Fermi GBM Observation
  20. EP260105a: GTC/HiPERCAM optical observations
  21. GRB 260120B: Swift/UVOT Detection
  22. GRB 260120B: COLIBRÍ optical upper limits
  23. SVOM GRB260121.06: Global MASTER-Net observations report
  24. GRB 260120B: SVOM/C-GFT optical counterpart detection
  25. GRB 260120C: Fermi GBM Final Real-time Localization
  26. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  27. GRB 260120B: Swift detection of a burst
  28. Swift GRB260120B: Global MASTER-Net observations report
  29. GRB 260120B: Fermi GBM Final Real-time Localization
  30. Fermi trigger No 790601190: Global MASTER-Net observations report
  31. Fermi trigger No 790570272: Global MASTER-Net observations report
  32. GRB 260114A: Swift/UVOT Upper Limits
  33. EP260119a: Liverpool Telescope optical follow-up observations
  34. Trigger 1442421: Swift detection of HMXB 1A 1118-61
  35. EP260119A: GTC/OSIRIS+ spectroscopic redshift z = 5.47
  36. GRB 260120A: Fermi GBM Final Real-time Localization
  37. EP260119a: SVOM/VT optical observation
  38. EP260119a: update of EP-FXT follow-up observation
  39. EP260119a: NOT optical observations
  40. SVOM GRB260119.92: Global MASTER-Net observations report
  41. SVOM GRB260119.92: Global MASTER-Net observations report
  42. SVOM GRB260119.90: Global MASTER-Net observations report
  43. EP260116a: COLIBRÍ detection of a fading optical source
  44. GRB 251208D: SVOM/ECLAIRs refined analysis
  45. GRB 251208D: SVOM/ECLAIRs refined analysis
  46. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  47. EP260119a: Global MASTER-Net observations report
  48. EP260119a: LCO optical observations
  49. EP260119a: COLIBRÍ optical counterpart candidate
  50. EP260119a: preliminary result from the EP-FXT observation
  51. GRB 260110A: SVOM detection of a burst through offline search
  52. EP260119a: EP-WXT detection of a fast X-ray transient
  53. Swift GRB260118.48: Global MASTER-Net observations report
  54. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  55. SVOM GRB260117.82: Global MASTER-Net observations report
  56. Swift trigger on the HMXB 1A 1118-61
  57. GRB 260117A: SVOM/VT optical candidate
  58. GRB 260117A: SVOM/C-GFT upper limit
  59. GRB 260117A: SVOM detection of a long faint burst
  60. EP 260116a: COLIBRÍ optical upper limit
  61. Swift triggered on the HMXB 1A 1118-61
  62. GRB 260115A: GECAM-B observation
  63. EP260116a: Liverpool Telescope upper limits
  64. EP260116A: 1.3m DFOT optical upper limit
  65. GRB 260114A: VLT/MUSE spectroscopic observations
  66. EP260116a: Global MASTER-Net observations report
  67. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  68. EP260116a: Xinglong optical upper limit
  69. EP260116a: Einstein Probe detection of an X-ray transient
  70. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  71. IceCube Alert 260115.73: Global MASTER-Net observations report
  72. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  73. Fermi GRB 260115A: Global MASTER-Net observations report
  74. GRB 260115A: Fermi GBM Final Real-time Localization
  75. GRB260114A: STEP/T80S optical limits
  76. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  77. GRB 260114A: Swift-XRT refined Analysis
  78. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  79. GRB 260114A : MITSuME Akeno optical upper limits
  80. GRB 260114A: COLIBRÍ optical upper limits
  81. GRB 260114A: NOT optical observations
  82. GRB 260114A: SVOM/GRM observation of a short burst
  83. Swift GRB 260114A: Global MASTER-Net observations report
  84. GRB 260114A: GECAM-B observation of a short burst
  85. GRB 260114A: Fermi GBM observation
  86. GRB 260112B: GECAM-B observation
  87. GRB 260114A: GMG Optical Observation
  88. GRB 260114A: Swift detection of a short burst
  89. GRB 260114A: Fermi GBM Final Real-time Localization
  90. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  91. Swift GRB260113.43: Global MASTER-Net observations report
  92. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  93. EP260110a: TRT optical upper limits
  94. Konus-Wind detection of GRB 260101A
  95. Swift Trigger 1439093: is probably not GRB 260113A
  96. GRB 260111A: COLIBRÍ optical afterglow candidate
  97. GRB 260111A: GECAM-B observation of a burst
  98. GRB 260111A: Fermi GBM Observation
  99. The EP-WXT trigger 01709251266 is likely a flaring star
  100. Swift Trigger 1434591 is not a GRB

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