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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"

37202 results found.

  1. GRB 260307B: SVOM/VT optical candidate
  2. GRB 260307B: SVOM/C-GFT upper limit
  3. GRB 260307B: SVOM detection of a burst
  4. GRB 260307A: Fermi GBM Final Localization
  5. GRB 260211A: late-time NOT i-band observations consistent with archival flux
  6. GRB 260207A: TESS Detection and Possible VLA Counterpart
  7. EP260302a: Optical afterglow rebrightening
  8. GRB 260228A: further EP-FXT observations and X-ray afterglow confirmation
  9. GRB 260303A: 1.3m DFOT optical upper limit (duplicate submission)
  10. GRB 260303A: 1.3m DFOT optical upper limit
  11. GRB 260211A: SVOM/VT optical rebrightening at 20 days after the burst, SN candidate
  12. GRB 260303A: SVOM/ECLAIRs refined analysis
  13. Fermi GRB 260305A: Global MASTER-Net observations report
  14. GRB 260305A: Fermi GBM Final Real-time Localization
  15. GRB 260303B: AstroSat CZTI detection
  16. GRB 260304A: AstroSat CZTI detection of a long burst
  17. GRB 260303A: SVOM/VT optical observations
  18. GRB 260303A: J-band observations with WINTER
  19. GRB 260303B: NuSTAR detection of prompt emission
  20. EP260302a: Global MASTER-Net observations report
  21. Fermi GRB 260303B: Global MASTER-Net observations report
  22. IceCube-260217A: No Candidate Transients from the Zwicky Transient Facility
  23. GRB 260228A: SVOM/ECLAIRs refined analysis
  24. GRB 260225A: SVOM/ECLAIRs refined analysis
  25. GRB 260303B: BALROG localization (Fermi Trigger 794237065 / GRB 260303559)
  26. GRB 260303B: Fermi GBM Final Real-time Localization
  27. GRB 260303A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  28. GRB 260303A: SVOM detection of a burst
  29. GRB 260228A: EP-FXT follow-up observation
  30. GRB 251130B: TERI Gamma-ray detection
  31. GRB 260208A: TERI Gamma-ray detection
  32. GRB 260302A: Fermi GBM Final Real-time Localization
  33. EP260227a: Mondy optical observations
  34. GRB 260228A: CAHA 2.2m telescope optical upper limit
  35. GRB 260228A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  36. GRID detection of GRB 260225D
  37. GRB 260228A: SVOM/VT optical upper limits
  38. GRB 260225D: SVOM/GRM observation
  39. GRB 260225B: SVOM/GRM observation
  40. GRB 260228A: SVOM detection of a burst
  41. GRB 260226A: Asiago r-band upper limit
  42. GRB 260225A: SVOM/VT optical continued observations and upper limit
  43. GRID detection of GRB 260223A
  44. EP260227a: Global MASTER-Net observations report
  45. GRB 260226A: Insight-HXMT/HE detection of the very bright burst
  46. Konus-Wind detection of GRB 260226A
  47. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  48. GRB 260225A: WINTER J-band upper limit
  49. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  50. GRB 260226A: COLIBRÍ optical upper limits
  51. GRB 260226A: LCOGT Optical Upper Limit
  52. GRB 260225D: Glowbug gamma-ray detection of a likely short burst
  53. GRB 260226A: Glowbug gamma-ray detection
  54. GRB 260226A: NuSTAR detection of bright prompt emission
  55. GRB 260226A : GROWTH-India Telescope optical observations
  56. GRB 260226A: LAST optical upper limit
  57. GRB 260226A: Fermi GBM observation
  58. GRB 260226A: Fermi-LAT refined analysis
  59. LAT GRB260226.44: Global MASTER-Net observations report
  60. Fermi GRB 260226A: Global MASTER-Net observations report
  61. GRB 260226A: AstroSat CZTI detection of bright long burst
  62. GRB 260226A: Fermi-LAT detection of a bright burst
  63. GRB 260226A???: BALROG localization (Fermi Trigger 793795080 / GRB 260226443)
  64. GRB260225A: SVOM/ECLAIRs refined position
  65. GRB 260226A: Fermi GBM Final Real-time Localization
  66. GRB 260225A: EP-FXT follow-up observation
  67. GRB 260225A: SVOM/VT optical observation
  68. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  69. GRB 260225C: Fermi GBM Final Real-time Localization
  70. GRB 260223A: Fermi GBM Observation
  71. GRB 260225A: SVOM/VT optical upper limits
  72. GRB 260225B: Fermi GBM Final Real-time Localization
  73. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  74. GRB 260225A: SVOM detection of a burst
  75. GRB 260223A: Glowbug gamma-ray detection
  76. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  77. GRB 260223A: SVOM/VT optical observation
  78. GRB 260223A: SVOM/GRM observation
  79. GRB 260223A: COLIBRÍ further optical observations and a brightening
  80. GRB 260223A: COLIBRÍ optical observations
  81. GRB 260223A: DDOTI Optical Candidate
  82. GRB 260223A: BALROG localization (Fermi Trigger 793512674 / GRB 260223174)
  83. Fermi GRB 260223A: Global MASTER-Net observations report
  84. GRB 260223A: Fermi GBM Final Real-time Localization
  85. GRB 260222A: Fermi GBM Final Real-time Localization
  86. EP260221a: Global MASTER-Net observations report
  87. Fermi GRB 260221B: Global MASTER-Net observations report
  88. GRB 260221B: Fermi GBM Final Real-time Localization
  89. Fermi GRB 260221A: Global MASTER-Net observations report
  90. GRB 260221A: Fermi GBM Final Real-time Localization
  91. GRB 260219A: AstroSat CZTI detection
  92. GRB 260219A: GECAM-B observation of a long burst
  93. Fermi GRB 260219A: Global MASTER-Net observations report
  94. GRB 260219A: Fermi GBM Final Real-time Localization
  95. IceCube Alert 260217A: Global MASTER-Net observations report
  96. GRB 260217A: Fermi GBM Final Localization
  97. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  98. EP260214b: Mondy optical observations
  99. EP260210a: Mondy optical upper limits
  100. Konus-Wind detection of GRB 260212A

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