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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"

32509 results found.

  1. GRB 230204B: AstroSat CZTI detection
  2. GRB 230204B: Swift/BAT-GUANO detection outside the coded FOV
  3. GRB 230204A: Swift/UVOT Upper Limits
  4. GRB 230204A: Swift-XRT refined Analysis
  5. GRB 230204A/Swift J1552.8-5055: LCOGT Optical Counterpart Candidate
  6. GRB 230201B: TURBO Optical Upper Limits
  7. ZTF23aabmzlp/AT2023azs: Lulin 1m LOT optical observations
  8. GRB 221216A: Swift-BAT refined analysis
  9. ZTF23aabmzlp/AT2023azs: VLA radio detection
  10. ZTF23aaarlti/AT2023avj: AMI-LA radio detection
  11. ZTF23aabmzlp/AT2023azs: AMI-LA radio upper limit
  12. Fermi GRB 230201B: Global MASTER-Net observations report
  13. Fermi-LAT gamma-ray observations of IceCube-230201A
  14. GRB 230126A: Detection by VZLUSAT-2
  15. Fermi GRB 230201A: Global MASTER-Net observations report
  16. GRB 221009A: radio afterglow detection with the EVN
  17. ZTF23aabmzlp/AT2023azs: LCOGT Optical Detection
  18. ZTF23aaarlti/AT2023avj: Assy continued optical observations
  19. ZTF23aabmzlp/AT2023azs: Mondy and AbAO optical observations
  20. AT2023avj: X-ray Detection with Swift/XRT
  21. ZTF23aabmzlp/AT2023azs: 1.3m DFOT optical observations
  22. GRB 230129A: AstroSat CZTI detection
  23. GRB 230128A: AstroSat CZTI detection
  24. ZTF23aaarlti/AT2023avj: VLA radio detection
  25. ZTF23aabmzlp/AT2023azs: GIT confirmation of the likely afterglow
  26. IceCube-230122A: BOOTES-2/TELMA Optical Upper Limit
  27. AT2023avj ZTF Candidate: Assy optical observations
  28. Swift-XRT observations of NuEm-230125A
  29. GRB 230124A: Fermi GBM Observation
  30. GRB 230124A: Swift/BAT-GUANO detection outside the coded FOV
  31. GRB 230123A: LCOGT Optical Upper Limits
  32. Fermi GRB 230124A: Global MASTER-Net observations report
  33. GRB 230123A: Swift-BAT refined analysis
  34. Fermi-LAT gamma-ray observations of IceCube-230122A
  35. GRB 230123A: Swift/UVOT Upper Limits
  36. GRB 230123A: Swift-XRT refined Analysis
  37. GRB 230123A: Zadko observatory - Gingin optical observations
  38. GRB 230116C: Swift-XRT observations
  39. GRB 230116B: Fermi GBM observation
  40. IPN triangulation of GRB 230116B (short)
  41. GRB 230119A: CALET Gamma-Ray Burst Monitor detection
  42. GRB 230116D: 3.6m DOT optical upper limit
  43. Fermi GRB 230118A: Global MASTER-Net observations report
  44. GRB 230116D: Swift-BAT refined analysis
  45. GRB 230116C: Swift-BAT refined analysis
  46. GRB 230116D: SAO RAS further observations
  47. GRB 230116D: SAO RAS photometry
  48. GRB 230116D: KGO RC-25 optical observations
  49. GRB 230116D: Sintez-Newton/CrAO optical observations
  50. GRB 230116D: LCOGT Optical Upper Limit
  51. GRB 230116D: SAO RAS redshift
  52. GRB 230116D: Swift-XRT refined Analysis
  53. Fermi GRB 230117A: Global MASTER-Net observations report
  54. GRB 230116D: GIT optical follow-up
  55. GRB 230116D: SAO RAS observations of OT brightening
  56. GRB 230116D: Sintez-Newton/CrAO optical afterglow detection
  57. GRB 230116D: Nanshan/NEXT optical afterglow detection
  58. IceCube-230112A: No Candidate Counterparts from the Zwicky Transient Facility
  59. GRB 230114A: Detection by VZLUSAT-2
  60. Fermi-LAT gamma-ray observations of IceCube-230112A
  61. IceCube-230112A: BOOTES-4/MET Optical Upper Limit
  62. GRB 230111A: Fermi GBM Observation
  63. Fermi GRB 230112A: Global MASTER-Net observations report
  64. IceCube-221223A: JCMT/SCUBA2 observations
  65. GRB 230102A: Fermi GBM Observation
  66. GRB 221231A: 3.6m DOT optical upper limit
  67. GRB 230102A: Swift/BAT-GUANO detection outside the coded FOV
  68. GRB 221231A: Fermi GBM Observation
  69. GRB 230102A: Detection by GRBAlpha
  70. GRB 230101A: AstroSat CZTI detection
  71. GRB 221231A: Swift-XRT afterglow detection
  72. GRB 230102A: AGILE/MCAL detection
  73. GRB 221231A: AKO Upper Limit
  74. IceCube-221223A: No Candidate Counterparts from the Zwicky Transient Facility
  75. GRB 221231A: Swift ToO observations
  76. GRB 221231A: Swift/BAT-GUANO arcminute localization of a possibly short burst
  77. Fermi-LAT gamma-ray observations of IceCube-221229A
  78. GRB 221226A: Fermi GBM detection
  79. IceCube-221229A: BOOTES-2/TELMA Optical Upper Limit
  80. IPN triangulation of GRB 221226A
  81. GRB 221226A: Swift/BAT-GUANO detection outside the coded FOV
  82. GRB 221226B: LCOGT Optical Upper Limits
  83. IceCube-221223A: Upper limits from a search for additional neutrino events in IceCube
  84. GRB 221226B Swift-BAT refined analysis
  85. GRB 221226B: Swift-UVOT Detection
  86. GRB 221226A: AGILE detection
  87. GRB 221226B: Fermi GBM Observation
  88. GRB 221226B: Swift-XRT refined Analysis
  89. GRB 221226B: VLT/X-shooter redshift and host galaxy
  90. Fermi GRB 221226A: Global MASTER-Net observations report
  91. Fermi-LAT gamma-ray observations of IceCube-221224A
  92. IceCube-221224A: BOOTES-4/MET Optical Upper Limit
  93. IceCube-221223A: BOOTES-4/MET Optical Observations
  94. Fermi-LAT gamma-ray observations of IceCube-221223A
  95. Fermi GRB 221223A: Global MASTER-Net observations report
  96. GRB 221221A: AGILE detection
  97. Fermi GRB 221221A: Global MASTER-Net observations report
  98. GRB 221218A: 3.6m DOT optical upper limit
  99. IceCube-221216A: No Candidate Counterparts from the Zwicky Transient Facility
  100. GRB 221216A: Detection by VZLUSAT-2

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