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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"

26918 results found.

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

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