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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

19311 results found.

  1. Fermi GRB 260221A: Global MASTER-Net observations report
  2. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  3. GRB 260221A: Fermi GBM Final Real-time Localization
  4. EP260221a: GOTO optical upper limit
  5. EP260221a: COLIBRÍ optical upper limit
  6. SVOM alert sb26021801: LCO optical upper limit
  7. EP260221a: Einstein Probe detection of an X-ray transient
  8. The EP-WXT trigger 01709258519 is likely caused by Mrk 421
  9. GRB 260219A: AstroSat CZTI detection
  10. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  11. GRB 260219A: GECAM-B observation of a long burst
  12. Fermi GRB 260219A: Global MASTER-Net observations report
  13. GRB 260219A: Fermi GBM Final Real-time Localization
  14. SVOM alert sb26021801: LAST optical upper limit
  15. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  16. IceCube Alert 260217A: Global MASTER-Net observations report
  17. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  18. GRB 260217A: Fermi GBM Final Localization
  19. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  20. sb26021801: SVOM detection of a long faint X-ray transient
  21. The EP-WXT trigger 01709258455 is likely a flaring star
  22. EP-WXT 01709258455: NOT optical upper limits
  23. EP260214b: Mondy optical observations
  24. EP260214b: 1.3m DFOT optical upper limit
  25. EP260210a: Mondy optical upper limits
  26. Konus-Wind detection of GRB 260212A
  27. GRB 260208A: AbAO and Terskol optical upper limits
  28. GRB 260208A: continued Mondy optical observations
  29. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  30. GRB 260213A: GECAM-B observation of a short burst
  31. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  32. GRB 260216A: Fermi GBM Final Real-time Localization
  33. EP260214b: Liverpool Telescope optical observations
  34. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  35. EP260214b: Optical upper limit with Kinder observations
  36. EP260214a: Optical upper limits with Kinder observations
  37. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  38. EP260214b: DDOTI Optical Detection
  39. EP260214b: GROWTH-India Telescope optical upper limit
  40. EP260214b: SVOM/VT optical observation
  41. EP260214a: NOT optical upper limits
  42. EP260214a: COLIBRÍ optical upper limits
  43. EP260214b: OHP/T120 optical observations
  44. EP260214a: refined analysis of the EP-FXT observation
  45. EP260214b: LCO optical counterpart detection
  46. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  47. GRB 260211A: SVOM/VT optical counterpart
  48. EP260214b: COLIBRÍ optical observations
  49. EP260214a: SVOM/VT optical upper limits
  50. EP260214b: Einstein Probe detection of a fast X-ray transient
  51. EP260214a: Global MASTER-Net observations report
  52. EP260214a: Einstein Probe detection of an X-ray transient
  53. GRB 260212A: AstroSat CZTI detection
  54. GRB 260212A: Fermi GBM Observation
  55. EP260213a: Liverpool Telescope optical upper limits
  56. EP260213a: Global MASTER-Net observations report
  57. EP260213a: COLIBRÍ optical upper limits
  58. GRB 260212A: GECAM-B observation
  59. EP260213a: Optical upper limits with Kinder observations
  60. EP260213a: SVOM/VT optical upper limit
  61. EP260213a: Mondy R-band optical upper limit
  62. EP260213a: NUTTelA-TAO Early Optical Limits
  63. EP260213a: SVOM/C-GFT upper limit
  64. EP260213a: refined analysis of the EP-FXT observation
  65. EP260213a: Einstein Probe detection of a fast X-ray transient
  66. EP/WXT 01709258378: NOT optical upper limits
  67. GRB 260212A: SVOM/GRM observation of a long burst
  68. GRB 260213B: Fermi GBM Final Localization
  69. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  70. GRB 260211A - SVOM/ECLAIRs refined analysis
  71. GRB 260204A: SVOM/ECLAIRs refined analysis
  72. GRB 260213A: Fermi GBM Final Localization
  73. GRB 260211A: EP-FXT follow-up observation
  74. GRB 260211A: SVOM/VT optical observation
  75. GRB 260212A: Glowbug gamma-ray detection
  76. GRB 260211A: GOTO optical upper limit
  77. Fermi GRB 260212A: Global MASTER-Net observations report
  78. GRB 260212A: Fermi GBM Final Real-time Localization
  79. GRB 260211A: LAST optical upper limit
  80. GRB 260210A: SVOM/GRM observation
  81. Fermi GBM Sub-Threshold Detection of GRB 260211A
  82. GRB 260128B: SVOM/ECLAIRs refined analysis
  83. GRID detection of GRB 260207B
  84. GRB 260211A: LCO optical upper limits
  85. GRB260131A/B: 3.6m DOT Optical Observations
  86. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  87. Fermi trigger No 792537871: Global MASTER-Net observations report
  88. GRB 260211A: SVOM detection of a burst
  89. Swift Operations Update + Community Forum (Friday, February 13 @ 10:00 AM EST)
  90. Konus-Wind detection of GRB 260209B
  91. EP260209a: COLIBRÍ optical upper limit
  92. Fermi GRB 260210C: Global MASTER-Net observations report
  93. EP260209a: LCO optical upper limits
  94. EP260210a: Global MASTER-Net observations report
  95. EP260210a: refined analysis of the EP-FXT observation
  96. EP260209a: Global MASTER-Net observations report
  97. GRB 260208A: LCO detection of the optical counterpart
  98. EP260209a: Einstein Probe detection of a fast X-ray transient
  99. EP260210a: Optical upper limits with Kinder observations
  100. GRB 260210C: Fermi GBM Final Real-time Localization

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