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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"

22208 results found.

  1. GRB260307B: GROWTH-India Telescope optical upper limit
  2. GRB 260307B: SVOM/C-GFT upper limit
  3. GRB 260211A: late-time NOT i-band observations consistent with archival flux
  4. EP260306a: refined analysis of the EP-WXT and EP-FXT observations
  5. GRB 260207A: TESS Detection and Possible VLA Counterpart
  6. EP260306a: COLIBRÍ optical observations of the fading and red counterpart
  7. GRB 260228A: further EP-FXT observations and X-ray afterglow confirmation
  8. GRB 260303A: 1.3m DFOT optical upper limit
  9. EP260214b: ATCA 6 GHz observations
  10. GRB 260211A: SVOM/VT optical rebrightening at 20 days after the burst, SN candidate
  11. GRB 260303A: SVOM/ECLAIRs refined analysis
  12. Fermi GRB 260305A: Global MASTER-Net observations report
  13. GRB 260303A: SVOM/VT optical observations
  14. GRB 260303A: J-band observations with WINTER
  15. EP260302a: Global MASTER-Net observations report
  16. Fermi GRB 260303B: Global MASTER-Net observations report
  17. IceCube-260217A: No Candidate Transients from the Zwicky Transient Facility
  18. GRB 260228A: SVOM/ECLAIRs refined analysis
  19. GRB 260225A: SVOM/ECLAIRs refined analysis
  20. EP260227a: Gemini-South optical observations
  21. EP260302a: LCO observations
  22. GRB 260303A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  23. EP260227a: Mondy optical observations
  24. EP260227a: Mephisto optical detection
  25. EP-WXT trigger 01709258652: 50cm Telescope multi-band observations
  26. EP260227a: further LCO observations
  27. EP260227A: 3.6m DOT optical afterglow detection
  28. EP260227a: FTW optical and NIR observations
  29. EP260227a: Liverpool Telescope optical observations
  30. EP260227a: LCOGT Optical Observations
  31. GRB 260226A: Asiago r-band upper limit
  32. EP260227a: Thai National Telescope observations
  33. EP260227a: likely GTC/OSIRIS+ redshift z = 2.714
  34. EP260227a: Liverpool Telescope observations
  35. EP260227a: COLIBRÍ optical observations
  36. EP260227a: NOT optical observations
  37. GRB 260225A: SVOM/VT optical continued observations and upper limit
  38. EP260227a: Global MASTER-Net observations report
  39. EP/WXT trigger 01709258681 (EP260227a?): LCO candidate afterglow
  40. Konus-Wind detection of GRB 260226A
  41. GRB 260223A: 7DT detection and Medium-band SED of Afterglow
  42. EP260214a: VLT/FORS2 optical observations
  43. GRB 260225A: WINTER J-band upper limit
  44. EP-WXT trigger 01709258652: SVOM/C-GFT confirmation of a stellar flare
  45. GRB 260226A : GROWTH-India Telescope optical observations
  46. GRB 260226A: LAST optical upper limit
  47. LAT GRB260226.44: Global MASTER-Net observations report
  48. Fermi GRB 260226A: Global MASTER-Net observations report
  49. EP260214a: VLA 6 GHz detection
  50. GRB 260225A: SVOM/COLIBRÍ (FM-GFT) Detection of an Optical Counterpart Candidate
  51. EP260126a: VLA 6 GHz detection
  52. GRB 260225A: SVOM detection of a burst
  53. EP260224a: Einstein Probe detection of an X-ray transient
  54. GRB 260223A: COLIBRÍ optical afterglow decay confirmation
  55. sb26021801: SVOM/C-GFT upper limit
  56. EP260223a: Einstein Probe detection of an X-ray transient
  57. GRB 260223A: COLIBRÍ further optical observations and a brightening
  58. EP260221a: Optical upper limit with Kinder observations
  59. GRB 260223A: COLIBRÍ optical observations
  60. GRB 260223A: DDOTI Optical Candidate
  61. Fermi GRB 260223A: Global MASTER-Net observations report
  62. EP260221a: Global MASTER-Net observations report
  63. Fermi GRB 260221B: Global MASTER-Net observations report
  64. Fermi GRB 260221A: Global MASTER-Net observations report
  65. ZTF26aaglqak/AT2026dbl: COLIBRÍ Optical Observations
  66. EP260221a: GOTO optical upper limit
  67. Fermi GRB 260219A: Global MASTER-Net observations report
  68. SVOM alert sb26021801: LAST optical upper limit
  69. IceCube Alert 260217A: Global MASTER-Net observations report
  70. Fermi-LAT Gamma-ray Observations of IceCube-260217A
  71. EP-WXT 01709258455: NOT optical upper limits
  72. EP260214b: Mondy optical observations
  73. EP260214b: 1.3m DFOT optical upper limit
  74. EP260210a: Mondy optical upper limits
  75. Konus-Wind detection of GRB 260212A
  76. GRB 260208A: continued Mondy optical observations
  77. EP260214b: Liverpool Telescope optical observations
  78. GRB 260206A: probable hard X-ray burst from 4U 0513-40
  79. EP260214b: Optical upper limit with Kinder observations
  80. EP260214a: Optical upper limits with Kinder observations
  81. EP260214b: DDOTI Optical Detection
  82. EP260214b: GROWTH-India Telescope optical upper limit
  83. EP260214a: VLT near-infrared observation
  84. EP260214a: NOT optical upper limits
  85. EP260214b: OHP/T120 optical observations
  86. EP260214a: refined analysis of the EP-FXT observation
  87. EP260214b: LCO optical counterpart detection
  88. EP260214b: VLT/X-shooter spectroscopic redshift z = 1.208
  89. GRB 260211A: SVOM/VT optical counterpart
  90. EP260214b: COLIBRÍ optical observations
  91. EP260214a: Global MASTER-Net observations report
  92. EP260213a: Global MASTER-Net observations report
  93. EP260213a: Optical upper limits with Kinder observations
  94. EP260213a: NUTTelA-TAO Early Optical Limits
  95. EP260213a: SVOM/C-GFT upper limit
  96. EP260213a: refined analysis of the EP-FXT observation
  97. EP/WXT 01709258378: NOT optical upper limits
  98. GRB 260211A - SVOM/ECLAIRs refined analysis
  99. GRB 260204A: SVOM/ECLAIRs refined analysis
  100. GRB 260211A: GOTO optical upper limit

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