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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"

38302 results found.

  1. GRB 240418A: Enhanced Swift-XRT position
  2. GRB 240418A: AKO Upper Limit
  3. GRB 240411A: GOTO early optical upper limits
  4. Swift GRB240418.85: Global MASTER-Net observations report
  5. GRB 240418A: Swift detection of a burst
  6. Fermi GRB 240417A: Global MASTER-Net observations report
  7. EP240416A: Terskol Zeiss-2000 optical upper limit
  8. EP240416A: Khureltogoot optical upper limit
  9. Improved IPN triangulation of GRB 240411A
  10. EP240414a: GSP detects optical candidate counterpart AT2024gsa
  11. GRB 240417A: Fermi GBM Final Real-time Localization
  12. GRB 240415A: Glowbug gamma-ray detection
  13. GRB 240414A: Glowbug gamma-ray detection
  14. GRB 240415B: GECAM-B detection
  15. EP 240416a: Xinglong and NOT decaying optical counterpart
  16. GRB 240415A: Swift-BAT refined analysis
  17. EP240416A: MASTER optical observations
  18. GRB 240411A: Glowbug gamma-ray detection
  19. GRB 240414A: Swift-BAT refined analysis
  20. GRB 240414A: AbAO optical upprer limit
  21. GRB 240415A: Swift/UVOT Detection
  22. GRB 240415A: Fermi GBM Observation
  23. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  24. GRB 240415A: Earliest optical followup with the Kinder observations
  25. GRB 240414A: GMG observation
  26. EP 240414a: BOOTES-4/MET Optical Upper Limits
  27. GRB 240415A: Enhanced Swift-XRT position
  28. GRB 240415B: Swift ToO observations
  29. GRB 240415B: Swift/BAT-GUANO Correction
  30. GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
  31. GRB 240415A: OHP/T193 optical observations
  32. GRB 240415A: optical afterglow detection from the INAF Asiago Observatory
  33. GRB 240415A: SAO RAS optical observations
  34. GRB 240415A: Mondy optical transient detection (photometry correction in GCN 36118 )
  35. GRB 240414A: Fermi GBM Observation
  36. Fermi GRB 240415A: Global MASTER-Net observations report
  37. GRB 240415A: Mondy optical transient detection
  38. GRB 240414A: Photometric observation from 2.2m CAHA
  39. GRB 240414A: Swift/UVOT Detection
  40. LXT 240402A/GRB 240402B: Swift follow-up observations
  41. GRB 240414A: Mondy optical observations
  42. GRB 240414B: Fermi GBM Final Real-time Localization
  43. GRB 240414A: AKO Optical Upper Limit
  44. GRB 240415A: Prompt Swift-XRT observations
  45. GRB 240415A: Swift detection of a burst
  46. GRB 240415A: Fermi GBM Final Real-time Localization
  47. EP240413a: Upper limits from GECAM-B Observation
  48. GRB 240414A: Swift-XRT refined Analysis
  49. GRB240414A : J-band upper limits from WINTER
  50. GRB 240414A: Enhanced Swift-XRT position
  51. GRB 240414A : OHP/T193 second epoch of optical follow-up and afterglow detection
  52. GRB 240414A: MarSEC Observatory, Vicenza, Italy, UPPER LIMIT
  53. GRB 240414A: Skynet Optical Afterglow Observations
  54. Fermi trigger No 734754044: Global MASTER-Net observations report
  55. Swift GRB 240414A: Global MASTER-Net observations report
  56. IPN triangulation of GRB 240410A
  57. IPN triangulation of GRB 240411A
  58. Fermi-LAT gamma-ray observations of IceCube-240412A
  59. GRB 240414A : MITSuME Akeno optical upper limits
  60. GRB 240414A: Redshift confirmation from GTC/OSIRIS+
  61. GRB 240414A : OHP/T193 redshift determination
  62. GRB 240414A : OHP/T193 optical counterpart detection
  63. GRB 240414A: Swift detection of a burst
  64. LIGO/Virgo/KAGRA S240413p: Global MASTER-Net observations report
  65. EP240408a: GSP optical upper limit
  66. GRB 240411B: CrAO/ZTSh optical observations
  67. GRB 240411B: Kinder observations with Lulin observatory
  68. LIGO/Virgo/Kagra S240413p: NED Galaxies in the Localization Volume
  69. GRB 240411B: HiPERCAM/GTC observation
  70. IceCube Alert 240412.23: Global MASTER-Net observations report
  71. GRB 240411B: Swift-BAT refined analysis
  72. GRB 240411B: Swift-XRT refined Analysis
  73. GRB 240411B: 1.3m DFOT Optical observations
  74. GRB 240411A: GRBAlpha detection
  75. GRB 240411B: OHP/T193 optical observations
  76. GRB 240405A: Glowbug gamma-ray detection
  77. GRB 240411B: Enhanced Swift-XRT position
  78. GRB 240411B: LCO optical afterglow detection
  79. GRB 240411B: Swift detection of a burst
  80. GRB 240408B: GRBAlpha detection
  81. GRB 240411A: Fermi GBM Final Real-time Localization
  82. EP240408A: MASTER optical observations
  83. EP240408a: GROND detection of a candidate counterpart
  84. EP240408a: Upper limits from GECAM-B Observation
  85. GRB 240405A: GRBAlpha detection
  86. Swift Trigger 1220736: detection of 4U 1543-62.
  87. GRB 240408B: AstroSat CZTI detection
  88. Fermi GRB 240408A: Global MASTER-Net observations report
  89. GRB 240408A: Fermi GBM Final Real-time Localization
  90. GRB 240407A: BALROG localization (Fermi Trigger 734144396 / GRB 240407042)
  91. GRB 240402C: CALET Gamma-Ray Burst Monitor detection
  92. Fermi GRB 240407A: Global MASTER-Net observations report
  93. GRB 240407A: Fermi GBM Final Real-time Localization
  94. Fermi-LAT gamma-ray observations of IceCube-240327B
  95. Fermi-LAT gamma-ray observations of IceCube-240327A
  96. LXT 240402A/GRB 240402B: rest-frame energetics from Konus-Wind observation
  97. Fermi GRB 240405B: Global MASTER-Net observations report
  98. GRB 240405B: Fermi GBM Final Real-time Localization
  99. GRB 240402C: Glowbug gamma-ray detection
  100. GRB 240405A: Fermi GBM Final Real-time Localization

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