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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"

19725 results found.

  1. GRB 230307A: Tiled Swift observations
  2. IPN triangulation of GRB 230307A (long/very bright)
  3. GRB 230228A: Swift/UVOT Upper Limits
  4. GRB 230228A: Mondy optical upper limit
  5. GRB 230228A: Enhanced Swift-XRT position
  6. GRB 230228A: Nanshan/NEXT optical upper limit
  7. GRB 230228A: Miryang Arirang Astronomical Observatory (MAAO) 0.7-m telescope optical upper limit
  8. GRB 230228A: Swift detection of a possibly short burst
  9. GRB 230217A: VLT/FORS2 optical observations and candidate counterpart
  10. GRB 230216A Mondy Observations
  11. GRB 230217A: Swift/UVOT Upper Limits
  12. GRB 230216A: Swift/UVOT Upper Limits
  13. GRB 230217A: Swift-XRT afterglow detection
  14. Fermi-LAT gamma-ray observations of IceCube-230220A
  15. Fermi-LAT gamma-ray observations of IceCube-230217A
  16. GRB 230216A: Swift-XRT refined Analysis
  17. GRB 230205A: Lowell Discovery Telescope Observations
  18. GRB 230204B: Lowell Discovery Telescope Observations
  19. GRB 230216A: Enhanced Swift-XRT position
  20. GRB 230216A: AKO Upper Limit
  21. GRB 230216A: Zadko observatory - Gingin optical observations
  22. GRB 230216A: Swift detection of a burst
  23. IPN triangulation of GRB 230209B
  24. GRB 230204B: ATCA radio detection
  25. Swift Trigger 1153670 is probably not a GRB
  26. GRB 230205A: SUBARU HSC pre-imaging for host galaxy search
  27. GRB 230205A: possible host galaxy detection with the Schmidt - Asiago telescope
  28. GRB 230204B: MASTER early OT detection
  29. GRB 230208A: Fermi GBM Final Real-time Localization
  30. GRB 230204B: LCOGT Optical Upper Limits
  31. GRB 230204B: Swift/UVOT Upper Limits
  32. GRB 230205A: Swift/UVOT Upper Limits
  33. GRB 230205A: LCOGT Optical Upper Limits
  34. GRB 230204B: Swift-XRT afterglow detection
  35. GRB 230204B: 3.6m DOT optical observation
  36. GRB 230205A: OHP/T193 optical observations
  37. GRB 230204B: ATLAS detection of the optical afterglow and a projected location in a nearby galaxy group
  38. GRB 230204B: Swift ToO observations
  39. GRB 230205A: Enhanced Swift-XRT position
  40. GRB 230205A: Swift detection of a burst
  41. GRB 230204B: GIT discovery of the likely optical afterglow
  42. GRB 230204A: Swift/UVOT Upper Limits
  43. GRB 230204A: Swift-XRT refined Analysis
  44. GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
  45. GRB 230204A: Enhanced Swift-XRT position
  46. GRB 230204A: Swift detection of a possible burst (or possible transient Swift J1552.8-5055)
  47. GRB 230201B: TURBO Optical Upper Limits
  48. ZTF23aabmzlp/AT2023azs: Lulin 1m LOT optical observations
  49. ZTF23aaarlti/AT2023avj: AMI-LA radio detection
  50. ZTF23aabmzlp/AT2023azs: AMI-LA radio upper limit
  51. ZTF23aabmzlp/AT2023azs: LCOGT Optical Detection
  52. ZTF23aabmzlp/AT2023azs: GIT confirmation of the likely afterglow
  53. ZTF23aabmzlp/AT2023azs: Zwicky Transient Facility discovery of a fast optical transient
  54. IceCube-230122A: BOOTES-2/TELMA Optical Upper Limit
  55. Swift-XRT observations of NuEm-230125A
  56. GRB 230123A: LCOGT Optical Upper Limits
  57. GRB 230123A: Swift/UVOT Upper Limits
  58. GRB 230123A: Swift-XRT refined Analysis
  59. GRB 230123A: Enhanced Swift-XRT position
  60. GRB 230123A: Zadko observatory - Gingin optical observations
  61. GRB 230116C: Swift-XRT observations
  62. GRB 230123A: Swift detection of a burst
  63. Trigger 1150107: Swift detection of LS V +44 17
  64. GRB 230116D: 3.6m DOT optical upper limit
  65. GRB 230116D: SAO RAS further observations
  66. GRB 230116D: KGO RC-25 optical observations
  67. GRB 230116D: LCOGT Optical Upper Limit
  68. GRB 230116D: GIT optical follow-up
  69. GRB 230116D: Enhanced Swift-XRT position
  70. GRB 230116D: SAO RAS observations of OT brightening
  71. GRB 230116D: Nanshan/NEXT optical afterglow detection
  72. GRB 230116D: Swift detection of a burst
  73. Fermi-LAT gamma-ray observations of IceCube-230112A
  74. Fermi-LAT Gamma-ray Observations of IceCube-Cascade-230109A
  75. Fermi-LAT Gamma-ray Observations of IceCube-Cascade-221229A
  76. IceCube-221223A: JCMT/SCUBA2 observations
  77. GRB 221231A: 3.6m DOT optical upper limit
  78. GRB 230101A: AstroSat CZTI detection
  79. GRB 221231A: Swift-XRT afterglow detection
  80. GRB 221231A: Swift ToO observations
  81. Fermi-LAT gamma-ray observations of IceCube-221229A
  82. IPN triangulation of GRB 221226A
  83. GRB 221226B: LCOGT Optical Upper Limits
  84. GRB 221226B: Swift-UVOT Detection
  85. GRB 221226B: Fermi GBM Observation
  86. GRB 221226B: VLT/X-shooter redshift and host galaxy
  87. GRB 221226B: Enhanced Swift-XRT position
  88. GRB 221226B: Swift detection of a burst
  89. Fermi GRB 221226A: Global MASTER-Net observations report
  90. Fermi-LAT gamma-ray observations of IceCube-221224A
  91. Fermi-LAT gamma-ray observations of IceCube-221223A
  92. GRB 221218A: 3.6m DOT optical upper limit
  93. GRB 221218A: MITSuME Akeno optical upper limits
  94. IceCube-221210A: BOOTES-4/MET and Lijiang 2.4-meter Telescopes Optical Observations
  95. Fermi-LAT gamma-ray observations of IceCube-221216A
  96. GRB 221216A: Swift/UVOT Upper Limits
  97. GRB 221216A: AKO Upper Limit
  98. GRB 221215A: Swift-XRT observations
  99. GRB 221216A: Enhanced Swift-XRT position
  100. GRB 221216A: Zadko observatory - Gingin optical observations

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