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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"

32542 results found.

  1. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  2. EP260214a: VLT/FORS2 optical observations
  3. GRB 260225A: WINTER J-band upper limit
  4. GRB 260226A: CALET Gamma-Ray Burst Monitor detection
  5. GRB 260226A: COLIBRÍ optical upper limits
  6. GRB 260226A: LCOGT Optical Upper Limit
  7. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  8. GRB 260226A: Glowbug gamma-ray detection
  9. GRB 260226A: NuSTAR detection of bright prompt emission
  10. GRB 260226A : GROWTH-India Telescope optical observations
  11. GRB 260226A: LAST optical upper limit
  12. GRB 260226A: Fermi GBM observation
  13. GRB 260226A: Fermi-LAT refined analysis
  14. Fermi GRB 260226A: Global MASTER-Net observations report
  15. GRB 260226A: AstroSat CZTI detection of bright long burst
  16. EP260214a: VLA 6 GHz detection
  17. GRB 260226A: Fermi-LAT detection of a bright burst
  18. EP260224a: LCO optical upper limits
  19. GRB260225A: SVOM/ECLAIRs refined position
  20. GRB 260225A: EP-FXT follow-up observation
  21. GRB 260225A: SVOM/VT optical observation
  22. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  23. GRB 260223A: Fermi GBM Observation
  24. GRB 260225A: SVOM/VT optical upper limits
  25. EP260126a: VLA 6 GHz detection
  26. EP260223a: Liverpool Telescope upper limits
  27. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) optical upper limits
  28. EP 260225.148: COLIBRÍ Confirmation of flaring star
  29. EP260223a: Xinglong optical upper limit
  30. GRB 260223A: Glowbug gamma-ray detection
  31. EP260213a: Mephisto optical upper limits
  32. EP260223a: EP-FXT follow-up observation
  33. sb26021801: SVOM/VT optical upper limits
  34. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  35. sb26021801: SVOM/C-GFT upper limit
  36. EP260223a: COLIBRÍ optical upper limits
  37. GRB 260223A: SVOM/VT optical observation
  38. GRB 260223A: SVOM/GRM observation
  39. GRB 260223A: COLIBRÍ further optical observations and a brightening
  40. EP260221a: Optical upper limit with Kinder observations
  41. GRB 260223A: COLIBRÍ optical observations
  42. GRB 260223A: DDOTI Optical Candidate
  43. Fermi GRB 260223A: Global MASTER-Net observations report
  44. EP260221a: Liverpool Telescope detection of COLIBRÍ counterpart candidate
  45. EP260221a: COLIBRÍ optical counterpart candidate
  46. EP260221a: Gemini South z-band upper limit
  47. EP260221a: Global MASTER-Net observations report
  48. EP260221a: EP-FXT follow-up observation
  49. Fermi GRB 260221B: Global MASTER-Net observations report
  50. EP260221a: Xinglong optical upper limit
  51. Fermi GRB 260221A: Global MASTER-Net observations report
  52. EP260221a: GOTO optical upper limit
  53. EP260221a: COLIBRÍ optical upper limit
  54. SVOM alert sb26021801: LCO optical upper limit
  55. GRB 260219A: AstroSat CZTI detection
  56. IceCube-260217A: Upper limits from a search for additional neutrino events in IceCube
  57. GRB 260219A: GECAM-B observation of a long burst
  58. Fermi GRB 260219A: Global MASTER-Net observations report
  59. SVOM alert sb26021801: LAST optical upper limit
  60. sb26021801: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  61. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  62. GRB 260214B/EP260214b: SVOM/ECLAIRs detection through targeted search
  63. EP260214b: Mondy optical observations
  64. EP260214b: 1.3m DFOT optical upper limit
  65. EP260210a: Mondy optical upper limits
  66. Konus-Wind detection of GRB 260212A
  67. GRB 260208A: AbAO and Terskol optical upper limits
  68. GRB 260208A: continued Mondy optical observations
  69. IPN triangulation of GRB 260212A
  70. IceCube-260217A - IceCube observation of a high-energy neutrino candidate track-like event
  71. GRB 260213A: GECAM-B observation of a short burst
  72. EP260214b: Liverpool Telescope optical observations
  73. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  74. EP260214b: Optical upper limit with Kinder observations
  75. EP260214a: Optical upper limits with Kinder observations
  76. EP260214b: EP-FXT follow-up observation
  77. EP260214a / GRB 260214A: Fermi-GBM Sub-Threshold Detection
  78. EP260214b: DDOTI Optical Detection
  79. EP260214b: GROWTH-India Telescope optical upper limit
  80. EP260214a: VLT near-infrared observation
  81. EP260214b: SVOM/VT optical observation
  82. EP260214a: NOT optical upper limits
  83. EP260214a: COLIBRÍ optical upper limits
  84. EP260214b: OHP/T120 optical observations
  85. EP260214a: refined analysis of the EP-FXT observation
  86. EP260214b: LCO optical counterpart detection
  87. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  88. GRB 260211A: SVOM/VT optical counterpart
  89. EP260214b: COLIBRÍ optical observations
  90. EP260214a: SVOM/VT optical upper limits
  91. EP260214b: NOT optical counterpart detection
  92. EP260214a: Global MASTER-Net observations report
  93. GRB 260212A: AstroSat CZTI detection
  94. GRB 260212A: Fermi GBM Observation
  95. EP260213a: Liverpool Telescope optical upper limits
  96. EP260213a: Global MASTER-Net observations report
  97. EP260213a: COLIBRÍ optical upper limits
  98. GRB 260212A: GECAM-B observation
  99. EP260213a: Optical upper limits with Kinder observations
  100. EP260213a: SVOM/VT optical upper limit

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