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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"

35154 results found.

  1. GRB 260228A: SVOM/VT optical upper limits
  2. GRB 260225D: SVOM/GRM observation
  3. GRB 260225B: SVOM/GRM observation
  4. GRB 260228A: SVOM detection of a burst
  5. GRB 260226A: Asiago r-band upper limit
  6. GRB 260225A: SVOM/VT optical continued observations and upper limit
  7. GRID detection of GRB 260223A
  8. GRB 260226A: Insight-HXMT/HE detection of the very bright burst
  9. Konus-Wind detection of GRB 260226A
  10. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  11. GRB 260225A: WINTER J-band upper limit
  12. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  13. GRB 260226A: COLIBRÍ optical upper limits
  14. GRB 260226A: LCOGT Optical Upper Limit
  15. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  16. GRB 260226A: Glowbug gamma-ray detection
  17. GRB 260226A: NuSTAR detection of bright prompt emission
  18. GRB 260226A : GROWTH-India Telescope optical observations
  19. GRB 260226A: LAST optical upper limit
  20. GRB 260226A: Fermi GBM observation
  21. GRB 260226A: Fermi-LAT refined analysis
  22. Fermi GRB 260226A: Global MASTER-Net observations report
  23. GRB 260226A: AstroSat CZTI detection of bright long burst
  24. GRB 260226A: Fermi-LAT detection of a bright burst
  25. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  26. GRB260225A: SVOM/ECLAIRs refined position
  27. GRB 260226A: Fermi GBM Final Real-time Localization
  28. GRB 260225A: EP-FXT follow-up observation
  29. GRB 260225A: SVOM/VT optical observation
  30. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  31. GRB 260225C: Fermi GBM Final Real-time Localization
  32. GRB 260223A: Fermi GBM Observation
  33. GRB 260225A: SVOM/VT optical upper limits
  34. GRB 260225B: Fermi GBM Final Real-time Localization
  35. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  36. GRB 260225A: SVOM detection of a burst
  37. GRB 260223A: Glowbug gamma-ray detection
  38. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  39. GRB 260223A: SVOM/VT optical observation
  40. GRB 260223A: SVOM/GRM observation
  41. GRB 260223A: COLIBRÍ further optical observations and a brightening
  42. GRB 260223A: COLIBRÍ optical observations
  43. GRB 260223A: DDOTI Optical Candidate
  44. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  45. Fermi GRB 260223A: Global MASTER-Net observations report
  46. GRB 260223A: Fermi GBM Final Real-time Localization
  47. GRB 260222A: Fermi GBM Final Real-time Localization
  48. Fermi GRB 260221B: Global MASTER-Net observations report
  49. GRB 260221B: Fermi GBM Final Real-time Localization
  50. Fermi GRB 260221A: Global MASTER-Net observations report
  51. GRB 260221A: Fermi GBM Final Real-time Localization
  52. GRB 260219A: AstroSat CZTI detection
  53. GRB 260219A: GECAM-B observation of a long burst
  54. Fermi GRB 260219A: Global MASTER-Net observations report
  55. GRB 260219A: Fermi GBM Final Real-time Localization
  56. GRB 260217A: Fermi GBM Final Localization
  57. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  58. EP260214b: Mondy optical observations
  59. EP260210a: Mondy optical upper limits
  60. Konus-Wind detection of GRB 260212A
  61. GRB 260208A: AbAO and Terskol optical upper limits
  62. GRB 260208A: continued Mondy optical observations
  63. IPN triangulation of GRB 260212A
  64. GRB 260213A: GECAM-B observation of a short burst
  65. GRB 260216A: Fermi Gamma-ray Burst Monitor trigger 792969362/260216886 is not a GRB
  66. GRB 260216A: Fermi GBM Final Real-time Localization
  67. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  68. EP260214a: Optical upper limits with Kinder observations
  69. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  70. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  71. GRB 260211A: SVOM/VT optical counterpart
  72. GRB 260212A: AstroSat CZTI detection
  73. GRB 260212A: Fermi GBM Observation
  74. GRB 260212A: GECAM-B observation
  75. EP260213a: Mondy R-band optical upper limit
  76. GRB 260212A: SVOM/GRM observation of a long burst
  77. GRB 260213B: Fermi GBM Final Localization
  78. GRB 260213B: BALROG localization (Fermi Trigger 792697214 / GRB 260213736)
  79. GRB 260211A - SVOM/ECLAIRs refined analysis
  80. GRB 260204A: SVOM/ECLAIRs refined analysis
  81. GRB 260213A: Fermi GBM Final Localization
  82. GRB 260211A: EP-FXT follow-up observation
  83. GRB 260211A: SVOM/VT optical observation
  84. GRB 260212A: Glowbug gamma-ray detection
  85. GRB 260211A: GOTO optical upper limit
  86. Fermi GRB 260212A: Global MASTER-Net observations report
  87. GRB 260212A: Fermi GBM Final Real-time Localization
  88. GRB 260211A: LAST optical upper limit
  89. GRB 260210A: SVOM/GRM observation
  90. Fermi GBM Sub-Threshold Detection of GRB 260211A
  91. Konus-Wind detection of GRB 260207B
  92. GRB 260128B: SVOM/ECLAIRs refined analysis
  93. GRID detection of GRB 260207B
  94. GRB 260211A: LCO optical upper limits
  95. GRB260131A/B: 3.6m DOT Optical Observations
  96. GRB 260211A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  97. GRB 260211A: SVOM detection of a burst
  98. Konus-Wind detection of GRB 260209B
  99. GRB 260208A: Swift UVOT detection
  100. Konus-Wind detection of GRB 260127B

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