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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"

26206 results found.

  1. The EP-WXT trigger 01709251871 is likely a flaring star
  2. Fermi GRB 260120C: Global MASTER-Net observations report
  3. GRB 260120B: Swift-BAT refined analysis
  4. GRB 260120B: Swift-XRT refined Analysis
  5. EP260116a: COLIBRÍ further observations
  6. GRB 260120B: Fermi GBM Observation
  7. EP260105a: GTC/HiPERCAM optical observations
  8. GRB 260120B: Swift/UVOT Detection
  9. GRB 260120B: COLIBRÍ optical upper limits
  10. SVOM GRB260121.06: Global MASTER-Net observations report
  11. GRB 260120B: SVOM/C-GFT optical counterpart detection
  12. GRB 260120C: Fermi GBM Final Real-time Localization
  13. EP260116a: COLIBRÍ observations of a tentative optical rebrightening
  14. GRB 260120B: Swift detection of a burst
  15. Swift GRB260120B: Global MASTER-Net observations report
  16. GRB 260120B: Fermi GBM Final Real-time Localization
  17. Fermi trigger No 790601190: Global MASTER-Net observations report
  18. Fermi trigger No 790570272: Global MASTER-Net observations report
  19. GRB 260114A: Swift/UVOT Upper Limits
  20. EP260119a: Liverpool Telescope optical follow-up observations
  21. Trigger 1442421: Swift detection of HMXB 1A 1118-61
  22. EP260119A: GTC/OSIRIS+ spectroscopic redshift z = 5.47
  23. GRB 260120A: Fermi GBM Final Real-time Localization
  24. EP260119a: SVOM/VT optical observation
  25. EP260119a: update of EP-FXT follow-up observation
  26. EP260119a: NOT optical observations
  27. SVOM GRB260119.92: Global MASTER-Net observations report
  28. SVOM GRB260119.92: Global MASTER-Net observations report
  29. SVOM GRB260119.90: Global MASTER-Net observations report
  30. EP260116a: COLIBRÍ detection of a fading optical source
  31. GRB 251208D: SVOM/ECLAIRs refined analysis
  32. GRB 251208D: SVOM/ECLAIRs refined analysis
  33. EP260119a: COLIBRÍ photometric redshift z ≈ 5.6
  34. EP260119a: Global MASTER-Net observations report
  35. EP260119a: LCO optical observations
  36. EP260119a: COLIBRÍ optical counterpart candidate
  37. EP260119a: preliminary result from the EP-FXT observation
  38. GRB 260110A: SVOM detection of a burst through offline search
  39. EP260119a: EP-WXT detection of a fast X-ray transient
  40. Swift GRB260118.48: Global MASTER-Net observations report
  41. GRB 260117A: SVOM/COLIBRÍ (FM-GFT) optical observations
  42. SVOM GRB260117.82: Global MASTER-Net observations report
  43. Swift trigger on the HMXB 1A 1118-61
  44. GRB 260117A: SVOM/VT optical candidate
  45. GRB 260117A: SVOM/C-GFT upper limit
  46. GRB 260117A: SVOM detection of a long faint burst
  47. EP 260116a: COLIBRÍ optical upper limit
  48. Swift triggered on the HMXB 1A 1118-61
  49. GRB 260115A: GECAM-B observation
  50. EP260116a: Liverpool Telescope upper limits
  51. EP260116A: 1.3m DFOT optical upper limit
  52. GRB 260114A: VLT/MUSE spectroscopic observations
  53. EP260116a: Global MASTER-Net observations report
  54. GRB 260111A: COLIBRÍ fading of the optical counterpart candidate
  55. EP260116a: Xinglong optical upper limit
  56. EP260116a: Einstein Probe detection of an X-ray transient
  57. GRB 260114A: VLT/HAWK-I further near-infrared upper limits
  58. IceCube Alert 260115.73: Global MASTER-Net observations report
  59. GRB 260115A: BALROG localization (Fermi Trigger 790192010 / GRB 260115741)
  60. Fermi GRB 260115A: Global MASTER-Net observations report
  61. GRB 260115A: Fermi GBM Final Real-time Localization
  62. GRB260114A: STEP/T80S optical limits
  63. GRB 260114A: VLT/HAWK-I near-infrared upper limits
  64. GRB 260114A: Swift-XRT refined Analysis
  65. GRB 260114A: VLT/X-shooter redshift of the putative host galaxy
  66. GRB 260114A : MITSuME Akeno optical upper limits
  67. GRB 260114A: COLIBRÍ optical upper limits
  68. GRB 260114A: NOT optical observations
  69. GRB 260114A: SVOM/GRM observation of a short burst
  70. Swift GRB 260114A: Global MASTER-Net observations report
  71. GRB 260114A: GECAM-B observation of a short burst
  72. GRB 260114A: Fermi GBM observation
  73. GRB 260112B: GECAM-B observation
  74. GRB 260114A: GMG Optical Observation
  75. GRB 260114A: Swift detection of a short burst
  76. GRB 260114A: Fermi GBM Final Real-time Localization
  77. EP-WXT trigger 01709251266: SVOM/C-GFT confirmation of a stellar flare
  78. Swift GRB260113.43: Global MASTER-Net observations report
  79. EP260110a: NOT and GTC Optical and Near-Infrared Observations
  80. EP260110a: TRT optical upper limits
  81. Konus-Wind detection of GRB 260101A
  82. Swift Trigger 1439093: is probably not GRB 260113A
  83. GRB 260111A: COLIBRÍ optical afterglow candidate
  84. GRB 260111A: GECAM-B observation of a burst
  85. GRB 260111A: Fermi GBM Observation
  86. The EP-WXT trigger 01709251266 is likely a flaring star
  87. Swift Trigger 1434591 is not a GRB
  88. GRB 260111A: GOTO optical upper limits
  89. GRB 260112B: Fermi GBM Final Real-time Localization
  90. GRB 251230A: Mondy Optical Observations
  91. GRB 260111A: Swift/BAT-GUANO arcminute localization of a burst
  92. GRB 260112A: Fermi GBM Final Real-time Localization
  93. EP260110a: SVOM/VT optical upper limits
  94. IceCube Alert 260111A: Global MASTER-Net observations report
  95. EP260110a: Global MASTER-Net observations report
  96. Fermi GRB 260111A: Global MASTER-Net observations report
  97. GRB 260111A: Fermi GBM Final Real-time Localization
  98. Swift trigger 1436759 is not an astrophysical event
  99. EP260110a: refined analysis of the EP-WXT and EP-FXT observations
  100. EP 260110a: COLIBRÍ optical observations

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