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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"

36180 results found.

  1. GRB 240415A: Swift-XRT refined Analysis
  2. Fermi GRB 240422A: Global MASTER-Net observations report
  3. GRB 240421B: AstroSat CZTI detection
  4. GRB 240422A: Fermi GBM Final Real-time Localization
  5. GRB240421B: Zadko Observations
  6. Fermi GRB 240421B: Global MASTER-Net observations report
  7. Swift GRB 240421B: Global MASTER-Net observations report
  8. GRB 240421B: Fermi GBM Observation
  9. GRB 240421B: Swift-XRT refined Analysis
  10. GRB240421B: BOOTES-5/JGT optical upper limit
  11. GRB 240421B: J-band upper limits from WINTER
  12. GRB 240421B: Swift/UVOT Upper Limits
  13. GRB 240421B: Enhanced Swift-XRT position
  14. Fermi GRB 240421A: Global MASTER-Net observations report
  15. GRB 240421B: Swift detection of a burst
  16. EP240420a: Nanshan optical counterpart observations
  17. GRB 240421A: Fermi GBM Final Real-time Localization
  18. GRB240419A: Skynet Optical Afterglow Analysis
  19. GRB240418A - Candidate afterglow from NIRES
  20. GRB 240419B: Swift/UVOT Upper Limits
  21. GRB 240419A: Swift/UVOT Upper Limits
  22. GRB 240419B: Swift-XRT refined Analysis
  23. GRB 240419B: optical afterglow from the NOT
  24. Swift GRB 240419B: Global MASTER-Net observations report
  25. EP240414A: Terskol Zeiss-2000 optical upper limit
  26. GRB 240419B: Enhanced Swift-XRT position
  27. Swift GRB 240419A: Global MASTER-Net observations report
  28. GRB 240418A: Swift/UVOT Upper Limits
  29. GRB 240419A: REM NIR afterglow detection
  30. GRB 240419A: Swift-XRT refined Analysis
  31. GRB 240418A: Swift-XRT refined Analysis
  32. GRB 240419B: Swift detection of a burst
  33. GRB 240411B: Swift/UVOT Detection
  34. GRB240418A: YAHPT Upper Limits
  35. GRB 240419A: VLT/UVES redshift of z = 5.178
  36. GRB 240419A: VLT optical afterglow detection
  37. GRB 240419A: Enhanced Swift-XRT position
  38. GRB 240419A: Prompt enhanced Swift-XRT position
  39. GRB 240419A: Swift detection of a burst
  40. GRB 240418A: TSHAO Zeiss-1000 optical upper limit
  41. GRB 240418A: NOT optical upper limits
  42. GRB 240418A: Enhanced Swift-XRT position
  43. GRB 240418A: AKO Upper Limit
  44. GRB 240411A: GOTO early optical upper limits
  45. GRB 240418A: Swift detection of a burst
  46. Fermi GRB 240417A: Global MASTER-Net observations report
  47. EP240416A: Terskol Zeiss-2000 optical upper limit
  48. EP240416A: Khureltogoot optical upper limit
  49. Improved IPN triangulation of GRB 240411A
  50. GRB 240417A: Fermi GBM Final Real-time Localization
  51. GRB 240415A: Glowbug gamma-ray detection
  52. GRB 240414A: Glowbug gamma-ray detection
  53. GRB 240415B: GECAM-B detection
  54. EP 240416a: Xinglong and NOT decaying optical counterpart
  55. GRB 240415A: Swift-BAT refined analysis
  56. GRB 240411A: Glowbug gamma-ray detection
  57. GRB 240414A: Swift-BAT refined analysis
  58. GRB 240414A: AbAO optical upprer limit
  59. GRB 240415A: Swift/UVOT Detection
  60. GRB 240415A: Fermi GBM Observation
  61. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  62. GRB 240415A: Earliest optical followup with the Kinder observations
  63. GRB 240414A: GMG observation
  64. GRB 240415A: Enhanced Swift-XRT position
  65. GRB 240415B: Swift ToO observations
  66. GRB 240415B: Swift/BAT-GUANO Correction
  67. GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
  68. GRB 240415A: OHP/T193 optical observations
  69. GRB 240415A: optical afterglow detection from the INAF Asiago Observatory
  70. GRB 240415A: SAO RAS optical observations
  71. GRB 240415A: Mondy optical transient detection (photometry correction in GCN 36118 )
  72. GRB 240414A: Fermi GBM Observation
  73. Fermi GRB 240415A: Global MASTER-Net observations report
  74. GRB 240415A: Mondy optical transient detection
  75. GRB 240414A: Photometric observation from 2.2m CAHA
  76. IceCube-240412A: Upper limits from a search for additional neutrino events in IceCube
  77. GRB 240414A: Swift/UVOT Detection
  78. LXT 240402A/GRB 240402B: Swift follow-up observations
  79. GRB 240414A: Mondy optical observations
  80. GRB 240414B: Fermi GBM Final Real-time Localization
  81. GRB 240414A: AKO Optical Upper Limit
  82. GRB 240415A: Prompt Swift-XRT observations
  83. GRB 240415A: Swift detection of a burst
  84. GRB 240415A: Fermi GBM Final Real-time Localization
  85. EP240413a: Upper limits from GECAM-B Observation
  86. GRB 240414A: Swift-XRT refined Analysis
  87. GRB240414A : J-band upper limits from WINTER
  88. GRB 240414A: Enhanced Swift-XRT position
  89. GRB 240414A : OHP/T193 second epoch of optical follow-up and afterglow detection
  90. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  91. GRB 240414A: Skynet Optical Afterglow Observations
  92. Swift GRB 240414A: Global MASTER-Net observations report
  93. IPN triangulation of GRB 240410A
  94. IPN triangulation of GRB 240411A
  95. GRB 240414A : MITSuME Akeno optical upper limits
  96. GRB 240414A: Redshift confirmation from GTC/OSIRIS+
  97. GRB 240414A : OHP/T193 redshift determination
  98. GRB 240414A : OHP/T193 optical counterpart detection
  99. GRB 240414A: Swift detection of a burst
  100. GRB 240411B: CrAO/ZTSh optical observations

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