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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"

19701 results found.

  1. GRB 210826A: Swift-XRT observations
  2. GRB 210824A: Swift-BAT refined analysis
  3. GRB 210826A: Tiled Swift observations
  4. GRB 210824A: MITSuME Akeno optical upper limits
  5. Swift detection of an outburst from SGR Swift J1555.2-5402
  6. GRB 210822A: Swift/UVOT Detection
  7. GRB 210824A: Nanshan/NEXT optical upper limit
  8. GRB 210822A: GROND observations
  9. GRB 210824A: Enhanced Swift-XRT position
  10. GRB 210824A: Swift detection of a burst
  11. GRB 210822B: DDOTI Upper Limits on the Afterglow
  12. GRB 210820A: GROND observations
  13. GRB 210822A: NOT photometry and spectroscopy
  14. GRB 210820A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  15. GRB 210820A: Swift/UVOT Detection
  16. GRB 210822A: Nanshan/NEXT optical observations
  17. GRB 210822A: Enhanced Swift-XRT position
  18. GRB 210822A: RATIR Optical Detections
  19. GRB 210822A: Swift detection of a burst with an optical afterglow
  20. GRB 210820A: RATIR Optical Detections
  21. GRB 210820A: NOT optical upper limit
  22. GRB 210820A: Nanshan/NEXT optical upper limit
  23. GRB 210820A: Enhanced Swift-XRT position
  24. GRB 210820A: Swift detection of a burst with an optical counterpart
  25. Swift Trigger 1069242 is Cyg X-1
  26. GRB 210818A: Enhanced Swift-XRT position
  27. GRB 210818A: Swift detection of a burst with an optical counterpart
  28. GRB 210712A: Fermi GBM observation
  29. Fermi-LAT Gamma-ray Observations of IceCube-210811A
  30. GRB 210730A: Tautenburg observations
  31. GRB 210807A: Tautenburg observations
  32. GRB 210807C: Swift/UVOT Upper Limits
  33. GRB 210807A: Swift/UVOT Detection
  34. GRB 210807C: Enhanced Swift-XRT position
  35. GRB 210610B: Assy optical observations
  36. GRB 210807C: Swift detection of a burst
  37. GRB 210807A: Enhanced Swift-XRT position
  38. GRB 210807A: Swift detection of a burst with an optical counterpart
  39. IPN Triangulation of a bright burst from SGR 1935+2154
  40. GRB 210802A: MITSuME Okayama optical upper limits
  41. GRB 210802A: DDOTI Upper Limits
  42. GRB 210802A: Swift-XRT afterglow detection
  43. GRB 210802A: Tiled Swift observations
  44. IceCube-210730A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  45. GRB 210731A: Swift-XRT refined Analysis
  46. GRB 210731A: GROND observations
  47. GRB 210731A: Swift/UVOT Detection of an optical afterglow
  48. GRB 210731A: MeerLICHT optical afterglow detection
  49. GRB210731A: Enhanced Swift-XRT position
  50. GRB 210731A: Swift detection of a burst
  51. Fermi-LAT Gamma-ray Observations of IceCube-210730A
  52. GRB 210730A: Campo Imperatore optical observations
  53. GRB 210730A: TNG optical observations
  54. GRB 210730A: Swift/UVOT Upper Limits
  55. GRB 210730A: Enhanced Swift-XRT position
  56. GRB 210730A: Swift detection of a burst near M82
  57. IPN triangulation of GRB 210727A (short)
  58. GRB 210726A: Swift-BAT refined analysis
  59. GRB 210726A: RATIR Optical Upper Limits and Candidate Host Galaxy
  60. GRB 210725A: AbAO optical upper limit
  61. GRB 210724A: Swift/UVOT Upper Limits
  62. GRB 210723A: Swift/UVOT Upper Limits
  63. GRB 210725A: Swift/UVOT Upper Limits
  64. GRB 210725B: Swift/UVOT Upper Limits
  65. GRB 210726A: Enhanced Swift-XRT position
  66. GRB 210726A: Swift detection of a burst
  67. GRB 210724A: Zeiss-1000 of Koshka observatory, optical upper limit
  68. GRB 210725A: Swift-XRT refined Analysis
  69. GRB 210724A: Swift-XRT refined Analysis
  70. GRB 210724A: Afterglow candidate from OSIRIS/GTC
  71. GRB 210725B: Enhanced Swift-XRT position
  72. GRB 210725A: MITSuME Akeno optical upper limits
  73. GRB 210725B: Swift detection of a burst
  74. GRB 210722A: continued Assy optical observations
  75. GRB 210722A: Nanshan/NEXT further optical observations
  76. GRB 210725A: Swift detection of a burst
  77. GRB210724A: MeerLICHT upper limits
  78. GRB 210724A: Swift detection of a burst
  79. GRB 210722A: continued Assy optical observations
  80. GRB 210723A: Swift-XRT refined Analysis
  81. GRB 210722A: Kitab optical observations, light curve
  82. GRB 210722A: Redshift from OSIRIS/GTC
  83. GRB 210723A: Swift detection of a burst
  84. GRB 210722A: RATIR Optical Observations
  85. GRB 210722A: Swift-XRT refined Analysis
  86. GRB 210722A: Swift/UVOT Detection
  87. GRB 210722A: GIT optical detection and preliminary analysis
  88. GRB 210722A: Assy optical detection
  89. GRB 210722A: Nanshan/NEXT optical afterglow observations
  90. Fermi-LAT Gamma-ray Observations of IceCube-210717A
  91. IceCube-210717A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  92. GRB 210715B: DDOTI Upper Limits on the Afterglow
  93. Recent activity of SGR 1935+2154 as observed by CGBM
  94. GRB 210712A: Swift/UVOT Upper Limits
  95. GRB 210712A: Enhanced Swift-XRT position
  96. GRB 210704A: classification as long GRB and redshift estimating
  97. GRB 210704A: Lowell Discovery Telescope Optical Observations
  98. GRB 210712A: Swift detection of a burst
  99. GRB210704A: Gemini near-infrared upper limits
  100. GRB 210704A: OSIRIS/GTC Observations and Archival Detection of the Possible Host Galaxy

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