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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"

31730 results found.

  1. IceCube-220822A: One Candidate Counterpart from the Zwicky Transient Facility
  2. GRB 220823A: Fermi GBM detection
  3. Fermi-LAT gamma-ray observations of IceCube-220822A and detection of a new gamma-ray source, Fermi J1810.1+2154
  4. Konus-Wind detection of GRB 220813A
  5. GRB 220813A: VLT optical observations and possible host galaxy
  6. GRB 220813A: Swift/UVOT Detection
  7. GRB 220810A: Further Swift-XRT observations
  8. GRB 220813A: Swift-XRT refined Analysis
  9. Swift GRB 220813A: Global MASTER-Net observations report
  10. GRB 220810A: Swift-XRT observations
  11. GRB 220810A: Swift ToO observations
  12. GRB 220810A: MeerLICHT detection of two afterglow candidates
  13. Fermi GRB 220810A: Global MASTER-Net observations report
  14. GRB 220627A: MeerKAT radio observations
  15. GRB 220806A: Swift-BAT refined analysis
  16. Konus-Wind detection of GRB 220730A (short)
  17. GRB 220730A: Swift-BAT refined analysis
  18. GRB 220730A: Fermi GBM detection
  19. GRB 220730A: Swift-XRT afterglow detection
  20. GRB 220730A: Swift/UVOT Upper Limits
  21. GRB 220730A: Swift-XRT observations
  22. Swift GRB 220730A: Global MASTER-Net observations report
  23. Fermi GRB 220728A: Global MASTER-Net observations report
  24. Fermi GRB 220724A: Global MASTER-Net observations report
  25. GRB 220715B: VIRT Optical Upper Limit
  26. Fermi GRB 220721A: Global MASTER-Net observations report
  27. Introducing new GCN Kafka broker and web site for transient alerts, https://gcn.nasa.gov
  28. Retraction: Fermi GBM trigger 679932336.585264/220719587 is not a GRB
  29. GRB 220715A: CALET Gamma-Ray Burst Monitor detection
  30. GRB 220711B: CALET Gamma-Ray Burst Monitor detection
  31. GRB 220715B: Swift-BAT refined analysis
  32. GRB220714B: UVOT detections
  33. GRB 220715B: Fermi GBM detection
  34. GRB 220715B: Swift-XRT refined Analysis
  35. GRB 220715B: Swift/UVOT Upper Limits
  36. Swift GRB 220715B: Global MASTER-Net observations report
  37. GRB 220714B: Swift-BAT refined analysis
  38. GRB 220714B: Fermi GBM observation
  39. GRB 220715A: AGILE/MCAL detection
  40. GRB 220714B: LCO Optical Observations
  41. GRB 220714B: Swift-XRT refined Analysis
  42. Swift/BAT Trigger 1116172 (=GRB 220714A) is not a real astrophysical event
  43. GRB 220714B: UVOT afterglow discovery
  44. GRB 220710A: Swift/UVOT Upper Limits
  45. GRB 220711C: Fermi GBM Observation
  46. Retraction of GRB 220711B: 10.4 m GTC(+EMIR) observations (GCN 32387)
  47. GRB 220711C: Swift/BAT-GUANO detection outside the coded FOV
  48. GRB 220711B, GROND observations
  49. Konus-Wind detection of GRB 220711C
  50. GRB 220711B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  51. GRB 220711B: GIT optical upper limits
  52. Fermi GRB 220711B: Global MASTER-Net observations report
  53. GRB 220712B: NOT optical afterglow confirmation
  54. GRB 220710A: Swift ToO observations
  55. GRB 220710A: Swift/BAT-GUANO arcminute localization
  56. GRB 220711B: Swift-BAT refined analysis
  57. IPN triangulation of GRB 220711C (short)
  58. GRB 220711B: Swift-XRT refined Analysis
  59. GRB 220711B: Swift/UVOT Upper Limits
  60. GRB 220711B: Fermi GBM Detection
  61. GRB 220711B: NOT optical observations
  62. GRB 220711B: LCO Optical Upper Limits
  63. GRB 220708B: GIT optical upper limits
  64. GRB 220708A: Swift-BAT refined analysis
  65. GRB 220708B: T193-OHP optical upper limit
  66. Konus-Wind detection of GRB 220708B (Correction to GCN 32358)
  67. Konus-Wind detection of GRB 220708B
  68. IceCube-220624A: Classification of AT2022nit as a type Ia supernova and AT2021bei as an AGN
  69. GRB 220708B: CALET Gamma-Ray Burst Monitor detection
  70. GRB 220708B: Nanshan/NEXT optical upper limits
  71. GRB 220708A: Swift/UVOT Upper Limits
  72. GRB 220706A : NICER detection of re-brightening 1 day after the Swift trigger
  73. GRB 220708A: Swift-XRT refined Analysis
  74. GRB 220706A: Swift/UVOT Upper Limits
  75. GRB 220706A: Swift-BAT refined analysis
  76. GRB 220708B: Swift ToO observations
  77. GRB 220708B: Swift/BAT-GUANO arcminute localization
  78. GRB 220706A: LCO Optical Upper Limits
  79. GRB 220627A: ATCA detection of radio counterpart
  80. GRB 220706A: Swift-XRT refined Analysis
  81. GRB 220706A, GROND observations
  82. GRB 220706A: Optical observations from NOT
  83. GRB 220706A: MAXI/GSC detection 84 minutes after the Swift Trigger
  84. GRB 220702B: AstroSat CZTI detection
  85. GRB 220706A: Nanshan/NEXT optical upper limits
  86. Swift GRB 220706A: Global MASTER-Net observations report
  87. GRB 220706A: Zadko observatory - Gingin optical observations
  88. GRB 220701A: Swift-BAT refined analysis
  89. GRB220408A: VIRT Optical Upper Limit
  90. GRB220412A: VIRT Optical Upper Limit
  91. GRB220701A: VIRT Optical Upper Limit
  92. GRB 220701A: MITSuME Akeno optical upper limits
  93. GRB 220701A: COATLI Optical Upper Limit
  94. GRB 220701A: AbAO optical upper limit
  95. GRB 220627A: AstroSat CZTI detection
  96. GRB 220701A: Keck/LRIS Optical Upper Limit
  97. GRB 220701A: Swift-XRT refined Analysis
  98. GRB 220701A: LCO Optical Upper Limits
  99. GRB 220701A: Swift/UVOT Upper Limits
  100. GRB 220701A: Lowell Discovery Telescope Optical Observations

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