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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"

16273 results found.

  1. Possible Short GRB 211023B: CAHA 2.2m Detection
  2. GRB 211023A: 1.5m OSN optical observation
  3. GRB 210610B: Sintesz-Newton/CrAO optical observations
  4. GRB 211024B: Nanshan/NEXT optical afterglow detection
  5. GRB 211023A: MASTER OT J045237.07+851925.2 - optical counterpart discovery
  6. GRB 211023B: BOOTES-4/MET and 1.5m OSN optical upper limit
  7. GRB 211023B: RATIR Optical and NIR Upper Limits
  8. GRB 211023B: TSHAO optical observation
  9. GRB 211023B: Swift detection of a possibly short burst with an optical counterpart
  10. BepiColombo MGNS joins the IPN
  11. Swift trigger 1078701: MITSuME Akeno optical upper limits
  12. GRB 210919A: LDT optical observations and candidate host galaxies
  13. IceCube-20210922A: No optical counterparts found by MITSuME observations
  14. Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart
  15. IceCube-20210922A: DESNU Optical counterpart candidate from 5 nights of DECam observations
  16. IceCube-210922A: DESI Observations
  17. GRB 210928A: Kinder SLT-40cm optical limits
  18. Swift GRB211001.03 / trigger 1076121 : MASTER OT retraction
  19. GRB 210930A: CAHA 2.2m telescope optical limit
  20. GRB 210927A: GIT optical follow-up of ZTF21acdwctm.
  21. Swift GRB211001.03: Global MASTER-Net OT detection
  22. GRB 210930A: Swift/UVOT Upper Limits
  23. GRB 210919A: iTelescope T-11 upper limits
  24. IceCube-210922A: JCMT/SCUBA2 observations
  25. GRB 210912A: LBT optical observations
  26. GRB 210919A: Swift/UVOT Upper Limits
  27. GRB 210919A: LOAO and LSGT optical upper limits
  28. GRB 210919A: MITSuME Akeno optical upper limits
  29. GRB 210919A: NOT upper limits
  30. GRB 210919A: AbAO optical upper limit
  31. GRB 210919A: LCO Optical Upper Limit
  32. GRB 210919A: BOOTES-2/TELMA optical upper limit
  33. GRB 210912A: BOOTES-5/JGT optical afterglow candidate (Correction to GCNC 30823)
  34. GRB 210912A: Tautenburg observations
  35. GRB 210912A: Swift/UVOT Detection
  36. GRB 210912A: Mondy optical afterglow confirmation
  37. GRB 210912A: BOOTES-5/JGT optical afterglow candidate
  38. GRB 210619B: Maidanak and Assy optical observations, broken power law parametrization
  39. GRB 210905A: Swift/UVOT Upper Limits
  40. GRB 210905A: ATCA detection
  41. GRB 210905A: ALMA detection
  42. GRB 210610A: Maidanak and AbAO optical observations
  43. GRB 210905A: REM NIR afterglow detection
  44. GRB 210905A: Continued LCO Optical Observations
  45. GRB 210905A: LCO Optical Detection
  46. GRB 210901A: Swift/UVOT Upper Limits
  47. GRB 210820A: TSHAO optical upper limit
  48. GRB 210901A: LCO Optical Upper Limit
  49. GRB 210827A: Swift/UVOT Upper Limits
  50. GRB 210827A: BOOTES-5/JGT optical upper limit
  51. GRB 210820A: CAHA 2.2m Optical Detection
  52. GRB 210824A: Swift/UVOT Upper Limits
  53. GRB 210826A: Swift/UVOT Upper Limits
  54. GRB 210822A: CAHA 2.2m observations
  55. GRB 210824A: MITSuME Akeno optical upper limits
  56. GRB 210822A: TSHAO continued optical observation
  57. GRB 210822A: VLA detection
  58. GRB 210822A: TSHAO optical observation
  59. GRB 210824A: BOOTES-5/JGT optical upper limit
  60. GRB 210824A: Nanshan/NEXT optical upper limit
  61. GRB 210822A: Abbey Ridge Observatory optical afterglow observation
  62. GRB 210822A: NOT photometry and spectroscopy
  63. GRB 210820A: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  64. GRB 210822A: Nanshan/NEXT optical observations
  65. GRB 210822A: RATIR Optical Detections
  66. GRB 210822A: KAIT Optical Afterglow Confirmation
  67. GRB 210822A: Swift detection of a burst with an optical afterglow
  68. GRB 210820A: LT optical upper limit
  69. GRB 210820A: LCO Optical Upper Limit
  70. GRB 210820A: RATIR Optical Detections
  71. GRB 210820A: NOT optical upper limit
  72. GRB 210820A: Nanshan/NEXT optical upper limit
  73. GRB 210820A: Swift detection of a burst with an optical counterpart
  74. GRB 210818A: Swift detection of a burst with an optical counterpart
  75. GRB 210807A: continued Assy, AbAO and Mondy observations
  76. GRB 210807A: Tautenburg observations
  77. GRB 210807C: Swift/UVOT Upper Limits
  78. GRB 210807A: correction to the GCN Circ. #30614 Assy optical observations
  79. GRB 210610B: Assy optical observations
  80. GRB 210807A: BOOTES-5/JGT optical afterglow detection
  81. GRB 210807A: Swift detection of a burst with an optical counterpart
  82. GRB 210802A: MITSuME Okayama optical upper limits
  83. GRB 210802A: BOOTES-2/TELMA optical upper limit
  84. GRB 210731A: continued GROND observations
  85. GRB 210731A: KAIT Optical Detection
  86. GRB 210731A: MASTER optical afterglow detection
  87. GRB 210731A: GROND observations
  88. GRB 210731A: Swift/UVOT Detection of an optical afterglow
  89. GRB 210731A: MeerLICHT optical afterglow detection
  90. GRB 210730A: Campo Imperatore optical observations
  91. GRB 210730A: BOOTES-5/JGT and 2.2m CAHA telescopes optical limit
  92. GRB 210730A: TNG optical observations
  93. GRB 210730A: Swift/UVOT Upper Limits
  94. GRB 210724A: Corrected Swift-XRT enhanced position
  95. GRB 210702A: MeerKAT radio detection
  96. GRB 210726A: RATIR Optical Upper Limits and Candidate Host Galaxy
  97. GRB 210725A: AbAO optical upper limit
  98. GRB 210724A: Swift/UVOT Upper Limits
  99. GRB 210723A: Swift/UVOT Upper Limits
  100. GRB 210725A: Swift/UVOT Upper Limits

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