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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"

32500 results found.

  1. ZTF23aaarlti/AT2023avj: AMI-LA radio detection
  2. ZTF23aabmzlp/AT2023azs: AMI-LA radio upper limit
  3. Fermi GRB 230201B: Global MASTER-Net observations report
  4. Fermi-LAT gamma-ray observations of IceCube-230201A
  5. GRB 230126A: Detection by VZLUSAT-2
  6. Fermi GRB 230201A: Global MASTER-Net observations report
  7. GRB 221009A: radio afterglow detection with the EVN
  8. ZTF23aabmzlp/AT2023azs: LCOGT Optical Detection
  9. ZTF23aaarlti/AT2023avj: Assy continued optical observations
  10. ZTF23aabmzlp/AT2023azs: Mondy and AbAO optical observations
  11. AT2023avj: X-ray Detection with Swift/XRT
  12. ZTF23aabmzlp/AT2023azs: 1.3m DFOT optical observations
  13. GRB 230129A: AstroSat CZTI detection
  14. GRB 230128A: AstroSat CZTI detection
  15. ZTF23aaarlti/AT2023avj: VLA radio detection
  16. ZTF23aabmzlp/AT2023azs: GIT confirmation of the likely afterglow
  17. IceCube-230122A: BOOTES-2/TELMA Optical Upper Limit
  18. AT2023avj ZTF Candidate: Assy optical observations
  19. Swift-XRT observations of NuEm-230125A
  20. GRB 230124A: Fermi GBM Observation
  21. GRB 230124A: Swift/BAT-GUANO detection outside the coded FOV
  22. GRB 230123A: LCOGT Optical Upper Limits
  23. Fermi GRB 230124A: Global MASTER-Net observations report
  24. GRB 230123A: Swift-BAT refined analysis
  25. Fermi-LAT gamma-ray observations of IceCube-230122A
  26. GRB 230123A: Swift/UVOT Upper Limits
  27. GRB 230123A: Swift-XRT refined Analysis
  28. GRB 230123A: Zadko observatory - Gingin optical observations
  29. GRB 230116C: Swift-XRT observations
  30. GRB 230116B: Fermi GBM observation
  31. IPN triangulation of GRB 230116B (short)
  32. GRB 230119A: CALET Gamma-Ray Burst Monitor detection
  33. GRB 230116D: 3.6m DOT optical upper limit
  34. Fermi GRB 230118A: Global MASTER-Net observations report
  35. GRB 230116D: Swift-BAT refined analysis
  36. GRB 230116C: Swift-BAT refined analysis
  37. GRB 230116D: SAO RAS further observations
  38. GRB 230116D: SAO RAS photometry
  39. GRB 230116D: KGO RC-25 optical observations
  40. GRB 230116D: Sintez-Newton/CrAO optical observations
  41. GRB 230116D: LCOGT Optical Upper Limit
  42. GRB 230116D: SAO RAS redshift
  43. GRB 230116D: Swift-XRT refined Analysis
  44. Fermi GRB 230117A: Global MASTER-Net observations report
  45. GRB 230116D: GIT optical follow-up
  46. GRB 230116D: SAO RAS observations of OT brightening
  47. GRB 230116D: Sintez-Newton/CrAO optical afterglow detection
  48. GRB 230116D: Nanshan/NEXT optical afterglow detection
  49. IceCube-230112A: No Candidate Counterparts from the Zwicky Transient Facility
  50. GRB 230114A: Detection by VZLUSAT-2
  51. Fermi-LAT gamma-ray observations of IceCube-230112A
  52. IceCube-230112A: BOOTES-4/MET Optical Upper Limit
  53. GRB 230111A: Fermi GBM Observation
  54. Fermi GRB 230112A: Global MASTER-Net observations report
  55. IceCube-221223A: JCMT/SCUBA2 observations
  56. GRB 230102A: Fermi GBM Observation
  57. GRB 221231A: 3.6m DOT optical upper limit
  58. GRB 230102A: Swift/BAT-GUANO detection outside the coded FOV
  59. GRB 221231A: Fermi GBM Observation
  60. GRB 230102A: Detection by GRBAlpha
  61. GRB 230101A: AstroSat CZTI detection
  62. GRB 221231A: Swift-XRT afterglow detection
  63. GRB 230102A: AGILE/MCAL detection
  64. GRB 221231A: AKO Upper Limit
  65. IceCube-221223A: No Candidate Counterparts from the Zwicky Transient Facility
  66. GRB 221231A: Swift ToO observations
  67. GRB 221231A: Swift/BAT-GUANO arcminute localization of a possibly short burst
  68. Fermi-LAT gamma-ray observations of IceCube-221229A
  69. GRB 221226A: Fermi GBM detection
  70. IceCube-221229A: BOOTES-2/TELMA Optical Upper Limit
  71. IPN triangulation of GRB 221226A
  72. GRB 221226A: Swift/BAT-GUANO detection outside the coded FOV
  73. GRB 221226B: LCOGT Optical Upper Limits
  74. IceCube-221223A: Upper limits from a search for additional neutrino events in IceCube
  75. GRB 221226B Swift-BAT refined analysis
  76. GRB 221226B: Swift-UVOT Detection
  77. GRB 221226A: AGILE detection
  78. GRB 221226B: Fermi GBM Observation
  79. GRB 221226B: Swift-XRT refined Analysis
  80. GRB 221226B: VLT/X-shooter redshift and host galaxy
  81. Fermi GRB 221226A: Global MASTER-Net observations report
  82. Fermi-LAT gamma-ray observations of IceCube-221224A
  83. IceCube-221224A: BOOTES-4/MET Optical Upper Limit
  84. IceCube-221223A: BOOTES-4/MET Optical Observations
  85. Fermi-LAT gamma-ray observations of IceCube-221223A
  86. Fermi GRB 221223A: Global MASTER-Net observations report
  87. GRB 221221A: AGILE detection
  88. Fermi GRB 221221A: Global MASTER-Net observations report
  89. GRB 221218A: 3.6m DOT optical upper limit
  90. IceCube-221216A: No Candidate Counterparts from the Zwicky Transient Facility
  91. GRB 221216A: Detection by VZLUSAT-2
  92. GRB 221218A: MITSuME Akeno optical upper limits
  93. GRB 221218A: KAIT Optical Upper Limit
  94. IceCube-221210A: BOOTES-4/MET and Lijiang 2.4-meter Telescopes Optical Observations
  95. GRB 221215A: Fermi GBM Detection
  96. Fermi-LAT gamma-ray observations of IceCube-221216A
  97. IceCube-221216A: Upper limits from a search for additional neutrino events in IceCube
  98. GRB 221216A: Swift/UVOT Upper Limits
  99. GRB 221216A: Fermi GBM observation
  100. GRB 221216A: Swift-XRT refined Analysis

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