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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"

19316 results found.

  1. EP260221a: EP-FXT follow-up observation
  2. Fermi GRB 260221B: Global MASTER-Net observations report
  3. GRB 260221B: Fermi GBM Final Real-time Localization
  4. EP-WXT01709258519: Xinglong optical upper limit
  5. EP260221a: Xinglong optical upper limit
  6. Fermi GRB 260221A: Global MASTER-Net observations report
  7. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  8. GRB 260221A: Fermi GBM Final Real-time Localization
  9. EP260221a: GOTO optical upper limit
  10. EP260221a: COLIBRÍ optical upper limit
  11. SVOM alert sb26021801: LCO optical upper limit
  12. EP260221a: Einstein Probe detection of an X-ray transient
  13. The EP-WXT trigger 01709258519 is likely caused by Mrk 421
  14. GRB 260219A: AstroSat CZTI detection
  15. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  16. GRB 260219A: GECAM-B observation of a long burst
  17. Fermi GRB 260219A: Global MASTER-Net observations report
  18. GRB 260219A: Fermi GBM Final Real-time Localization
  19. SVOM alert sb26021801: LAST optical upper limit
  20. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  21. IceCube Alert 260217A: Global MASTER-Net observations report
  22. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  23. GRB 260217A: Fermi GBM Final Localization
  24. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  25. sb26021801: SVOM detection of a long faint X-ray transient
  26. The EP-WXT trigger 01709258455 is likely a flaring star
  27. EP-WXT 01709258455: NOT optical upper limits
  28. EP260214b: Mondy optical observations
  29. EP260214b: 1.3m DFOT optical upper limit
  30. EP260210a: Mondy optical upper limits
  31. Konus-Wind detection of GRB 260212A
  32. GRB 260208A: AbAO and Terskol optical upper limits
  33. GRB 260208A: continued Mondy optical observations
  34. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  35. GRB 260213A: GECAM-B observation of a short burst
  36. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  37. GRB 260216A: Fermi GBM Final Real-time Localization
  38. EP260214b: Liverpool Telescope optical observations
  39. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  40. EP260214b: Optical upper limit with Kinder observations
  41. EP260214a: Optical upper limits with Kinder observations
  42. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  43. EP260214b: DDOTI Optical Detection
  44. EP260214b: GROWTH-India Telescope optical upper limit
  45. EP260214b: SVOM/VT optical observation
  46. EP260214a: NOT optical upper limits
  47. EP260214a: COLIBRÍ optical upper limits
  48. EP260214b: OHP/T120 optical observations
  49. EP260214a: refined analysis of the EP-FXT observation
  50. EP260214b: LCO optical counterpart detection
  51. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  52. GRB 260211A: SVOM/VT optical counterpart
  53. EP260214b: COLIBRÍ optical observations
  54. EP260214a: SVOM/VT optical upper limits
  55. EP260214b: Einstein Probe detection of a fast X-ray transient
  56. EP260214a: Global MASTER-Net observations report
  57. EP260214a: Einstein Probe detection of an X-ray transient
  58. GRB 260212A: AstroSat CZTI detection
  59. GRB 260212A: Fermi GBM Observation
  60. EP260213a: Liverpool Telescope optical upper limits
  61. EP260213a: Global MASTER-Net observations report
  62. EP260213a: COLIBRÍ optical upper limits
  63. GRB 260212A: GECAM-B observation
  64. EP260213a: Optical upper limits with Kinder observations
  65. EP260213a: SVOM/VT optical upper limit
  66. EP260213a: Mondy R-band optical upper limit
  67. EP260213a: NUTTelA-TAO Early Optical Limits
  68. EP260213a: SVOM/C-GFT upper limit
  69. EP260213a: refined analysis of the EP-FXT observation
  70. EP260213a: Einstein Probe detection of a fast X-ray transient
  71. EP/WXT 01709258378: NOT optical upper limits
  72. GRB 260212A: SVOM/GRM observation of a long burst
  73. GRB 260213B: Fermi GBM Final Localization
  74. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  75. GRB 260211A - SVOM/ECLAIRs refined analysis
  76. GRB 260204A: SVOM/ECLAIRs refined analysis
  77. GRB 260213A: Fermi GBM Final Localization
  78. GRB 260211A: EP-FXT follow-up observation
  79. GRB 260211A: SVOM/VT optical observation
  80. GRB 260212A: Glowbug gamma-ray detection
  81. GRB 260211A: GOTO optical upper limit
  82. Fermi GRB 260212A: Global MASTER-Net observations report
  83. GRB 260212A: Fermi GBM Final Real-time Localization
  84. GRB 260211A: LAST optical upper limit
  85. GRB 260210A: SVOM/GRM observation
  86. Fermi GBM Sub-Threshold Detection of GRB 260211A
  87. GRB 260128B: SVOM/ECLAIRs refined analysis
  88. GRID detection of GRB 260207B
  89. GRB 260211A: LCO optical upper limits
  90. GRB260131A/B: 3.6m DOT Optical Observations
  91. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  92. Fermi trigger No 792537871: Global MASTER-Net observations report
  93. GRB 260211A: SVOM detection of a burst
  94. Swift Operations Update + Community Forum (Friday, February 13 @ 10:00 AM EST)
  95. Konus-Wind detection of GRB 260209B
  96. EP260209a: COLIBRÍ optical upper limit
  97. Fermi GRB 260210C: Global MASTER-Net observations report
  98. EP260209a: LCO optical upper limits
  99. EP260210a: Global MASTER-Net observations report
  100. EP260210a: refined analysis of the EP-FXT observation

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