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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

26125 results found.

  1. GRB 210731A: Fermi GBM Observation
  2. GRB 210731A: Swift/UVOT Detection of an optical afterglow
  3. Swift GRB210731.62: Global MASTER-Net observations report
  4. GRB 210731A: MeerLICHT optical afterglow detection
  5. GRB210731A: Enhanced Swift-XRT position
  6. GRB 210731A: Swift detection of a burst
  7. Swift GRB210731.93: Global MASTER-Net observations report
  8. Trigger 1062273: Swift detection of 4U 1700-377
  9. GRB 210730A: Campo Imperatore optical observations
  10. GRB 210730A: BOOTES-5/JGT and 2.2m CAHA telescopes optical limit
  11. Swift GRB 210730A: Global MASTER-Net observations report
  12. GRB 210730A: TNG optical observations
  13. GRB 210726A: Chandra detection of the X-ray afterglow
  14. GRB 210730A: Fermi GBM observation
  15. GRB 210730A: AstroSat CZTI detection
  16. GRB 210730A: Swift-BAT refined analysis
  17. GRB 210730A: Swift-XRT refined Analysis
  18. GRB 210730A: Swift/UVOT Upper Limits
  19. GRB 210724A: Early CAHA 2.2m limit
  20. GRB 210730A: Enhanced Swift-XRT position
  21. GRB 210730A: Swift detection of a burst near M82
  22. GRB 210724A: Corrected Swift-XRT enhanced position
  23. Fermi GBM Sub-Threshold Detection of GRB 210725B
  24. GRB 210726A: OSIRIS/GTC observations
  25. GRB 210726A: Deep CAHA 2.2m limit
  26. GRB 210726A: 6 GHz VLA radio upper limit
  27. IPN triangulation of GRB 210727A (short)
  28. Fermi GBM Sub-Threshold Detection of GRB 210726A
  29. GRB 210726A: Swift-XRT refined Analysis
  30. GRB 210726A: Swift-BAT refined analysis
  31. GRB 210726A: Likely a short burst
  32. GRB 210726A: RATIR Optical Upper Limits and Candidate Host Galaxy
  33. GRB 210725A: AbAO optical upper limit
  34. GRB 210724A: Swift/UVOT Upper Limits
  35. GRB 210723A: Swift/UVOT Upper Limits
  36. GRB 210725A: Swift/UVOT Upper Limits
  37. GRB 210725B: Swift/UVOT Upper Limits
  38. GRB 210726A: CAHA 2.2m telescope optical limit
  39. GRB 210726A: Enhanced Swift-XRT position
  40. GRB 210726A: Swift detection of a burst
  41. Swift GRB210726.80: Global MASTER-Net observations report
  42. GRB 210725B: Swift-XRT refined Analysis
  43. GRB 210725A: Fermi GBM detection
  44. GRB 210724A: Zeiss-1000 of Koshka observatory, optical upper limit
  45. GRB 210725A: Swift-XRT refined Analysis
  46. GRB 210725B: Swift-BAT refined analysis
  47. GRB 210724A: Swift-XRT refined Analysis
  48. GRB 210725A: Swift-BAT refined analysis
  49. GRB 210724A: Swift-BAT refined analysis
  50. Swift GRB 210725B: Global MASTER-Net observations report
  51. GRB 210724A: Afterglow candidate from OSIRIS/GTC
  52. GRB 210725B: Enhanced Swift-XRT position
  53. GRB 210725A: MITSuME Akeno optical upper limits
  54. GRB 210725B: Swift detection of a burst
  55. GRB 210725A: CALET Gamma-Ray Burst Monitor detection
  56. GRB 210723A: CALET Gamma-Ray Burst Monitor detection
  57. GRB 210722A: continued Assy optical observations
  58. GRB 210722A: Nanshan/NEXT further optical observations
  59. GRB 210725A: KAIT Optical Upper Limit
  60. GRB 210725A: Swift detection of a burst
  61. Swift GRB210725.16: Global MASTER-Net observations report
  62. GRB 210723A: Fermi GBM Observation
  63. GRB210724A: MeerLICHT upper limits
  64. GRB 210724A: Swift detection of a burst
  65. Swift GRB210724.84: Global MASTER-Net observations report
  66. GRB 210723A: Swift-BAT refined analysis
  67. GRB 210722A: continued Assy optical observations
  68. GRB 210723A: Swift-XRT refined Analysis
  69. GRB 210722A: D50 optical detection
  70. Swift GRB 210723A: Global MASTER-Net observations report
  71. GRB 210722A: Fermi GBM observation
  72. GRB 210722A: Swift-BAT refined analysis
  73. GRB 210722A: Kitab optical observations, light curve
  74. GRB 210722A: Redshift from OSIRIS/GTC
  75. GRB 210723A: Prompt enhanced Swift-XRT position
  76. GRB 210723A: Swift detection of a burst
  77. GRB 210722A: RATIR Optical Observations
  78. GRB 210722A: Swift-XRT refined Analysis
  79. GRB 210722A: Swift/UVOT Detection
  80. GRB 210722A: GIT optical detection and preliminary analysis
  81. Swift GRB 210722A: Global MASTER-Net observations report
  82. GRB 210702A: ALMA detection of mm-band rebrightening
  83. GRB 210722A: Assy optical detection
  84. GRB 210702A: ATCA detection of radio rebrightening
  85. GRB 210722A: Nanshan/NEXT optical afterglow observations
  86. GRB 210722A: Swift detection of a burst with a bright optical counterpart
  87. Konus-Wind detection of GRB 210714A
  88. Fermi trigger No 647942198: MASTER optical afterglow detection
  89. GRB 210704A: Zeiss-1000/SAO-RAS optical observations
  90. GRB 210715B: DDOTI Upper Limits on the Afterglow
  91. GRB 210712A: Swift-BAT refined analysis
  92. GRB 210712A: Swift-XRT refined Analysis
  93. GRB 210712A: Swift/UVOT Upper Limits
  94. GRB 210712A: BOOTES-3/YA optical upper limit
  95. GRB 210712A: Enhanced Swift-XRT position
  96. GRB 210704A: Lowell Discovery Telescope Optical Observations
  97. GRB 210712A: Swift detection of a burst
  98. GRB 210704A: Continued Gemini-North NIR K-band Detections
  99. GRB 210704A: NOT optical observations and color change
  100. GRB210704A: Gemini near-infrared upper limits

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