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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"

36146 results found.

  1. EP240506a: CrAO ZTSH optical upper limit
  2. GRB 240504A: Fermi GBM Observation
  3. Fermi Gamma-ray Burst Monitor trigger 736837160/240508208 is not a GRB
  4. IPN triangulation of GRB 240504A
  5. GRB 240502A: 1.3m DFOT Optical upper limit
  6. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  7. GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
  8. IPN triangulation of GRB 240501B and GRB 240501A - possible episodes of ultra long GRB
  9. Fermi GRB 240504A: Global MASTER-Net observations report
  10. GRB 240503A: AstroSat CZTI detection
  11. GRB 240504A: BALROG localization (Fermi Trigger 736492377 / GRB 240504217)
  12. GRB 240504A: Fermi GBM Final Real-time Localization
  13. LXT 240402A / GRB 240402B: VLT X-shooter redshift of host
  14. GRB 240502A: GOTO optical upper limit
  15. GRB 240502A: Fermi GBM Observation
  16. GRB 240415A 1.3m DFOT Optical upper limit
  17. GRB 240502C: GOTO possible optical counterpart candidates
  18. Fermi GRB 240502B: Global MASTER-Net observations report
  19. GRB 240502C: Fermi GBM Final Localization
  20. Fermi GRB 240502A: Global MASTER-Net observations report
  21. GRB 240501B: GRBAlpha detection
  22. GRB 240430A: GRBAlpha detection
  23. GRB 240502B: Fermi GBM Final Real-time Localization
  24. GRB 240502A long GRB detected by INTEGRAL
  25. GRB 240502A: Fermi GBM Final Real-time Localization
  26. Fermi GRB 240501A: Global MASTER-Net observations report
  27. GRB 240426A: VZLUSAT-2 detection
  28. GRB 240425A: VZLUSAT-2 detection
  29. GRB240430A: Fermi GBM Final Localization
  30. GRB 240501B: AstroSat CZTI detection
  31. GRB 240501A: Fermi GBM Final Real-time Localization
  32. GRB 240408B: VZLUSAT-2 detection
  33. GRB 240407A: VZLUSAT-2 detection
  34. X-ray transient EP240414a: Detection of associated supernova
  35. GRB 240425A: GRBAlpha detection
  36. GRB 240429A: Fermi GBM Final Real-time Localization
  37. Fermi GRB 240428A: Global MASTER-Net observations report
  38. GRB 240428A: Fermi GBM Final Real-time Localization
  39. GRB 240426A: AstroSat CZTI detection
  40. EP240426a: YAHPT optical upper limit
  41. GRB 240414A: NOEMA detection
  42. IceCube-240424A: Upper limits from a search for additional neutrino events in IceCube
  43. LIGO/Virgo/KAGRA S240422ed: Upper limits from GECAM Observations
  44. GRB 240425A: Fermi GBM Final Real-time Localization
  45. GRB 240419B: Swift-BAT refined analysis
  46. GRB 240421B: Swift-BAT refined analysis
  47. GRB 240422A: Glowbug gamma-ray detection
  48. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  49. GRB 240421B: GRBAlpha detection
  50. IceCube-240419A: Upper limits from a search for additional neutrino events in IceCube
  51. GRB 240419A: Swift-BAT refined analysis
  52. GRB 240418A: Swift-BAT refined analysis
  53. LXT240402A/GRB240402B: Chandra X-ray detection
  54. GRB 240419A: Possible ATCA radio detection
  55. GRB 240421B: ATCA radio observations
  56. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  57. LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits
  58. LIGO/Virgo/KAGRA S240422ed: Upper limits from Fermi-GBM Observations
  59. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  60. GRB 240421A: Glowbug gamma-ray detection
  61. GRB 240414A: radio detection with the VLA
  62. GRB 240414A: AMI-LA radio observations
  63. GRB 240414A: LBT optical detection
  64. GRB 240419B : MITSuME Akeno optical upper limits
  65. GRB 240415B: Swift-XRT observations
  66. GRB 240415A: Swift-XRT refined Analysis
  67. Fermi GRB 240422A: Global MASTER-Net observations report
  68. GRB 240421B: AstroSat CZTI detection
  69. GRB 240422A: Fermi GBM Final Real-time Localization
  70. GRB240421B: Zadko Observations
  71. Fermi GRB 240421B: Global MASTER-Net observations report
  72. Swift GRB 240421B: Global MASTER-Net observations report
  73. GRB 240421B: Fermi GBM Observation
  74. GRB 240421B: Swift-XRT refined Analysis
  75. GRB240421B: BOOTES-5/JGT optical upper limit
  76. GRB 240421B: J-band upper limits from WINTER
  77. GRB 240421B: Swift/UVOT Upper Limits
  78. GRB 240421B: Enhanced Swift-XRT position
  79. Fermi GRB 240421A: Global MASTER-Net observations report
  80. GRB 240421B: Swift detection of a burst
  81. EP240420a: Nanshan optical counterpart observations
  82. GRB 240421A: Fermi GBM Final Real-time Localization
  83. GRB240419A: Skynet Optical Afterglow Analysis
  84. GRB240418A - Candidate afterglow from NIRES
  85. GRB 240419B: Swift/UVOT Upper Limits
  86. GRB 240419A: Swift/UVOT Upper Limits
  87. GRB 240419B: Swift-XRT refined Analysis
  88. GRB 240419B: optical afterglow from the NOT
  89. Swift GRB 240419B: Global MASTER-Net observations report
  90. EP240414A: Terskol Zeiss-2000 optical upper limit
  91. GRB 240419B: Enhanced Swift-XRT position
  92. Swift GRB 240419A: Global MASTER-Net observations report
  93. GRB 240418A: Swift/UVOT Upper Limits
  94. GRB 240419A: REM NIR afterglow detection
  95. GRB 240419A: Swift-XRT refined Analysis
  96. GRB 240418A: Swift-XRT refined Analysis
  97. GRB 240419B: Swift detection of a burst
  98. GRB 240411B: Swift/UVOT Detection
  99. GRB240418A: YAHPT Upper Limits
  100. GRB 240419A: VLT/UVES redshift of z = 5.178

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