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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"

19718 results found.

  1. GRB 211120A: AstroSat CZTI detection
  2. GRB 211118A: AstroSat CZTI detection
  3. GRB 211023A: optical observations and photometric evidence of supernova
  4. Fermi trigger No 658971499: Global MASTER-Net observations report
  5. Fermi-LAT Gamma-ray Observations of IceCube-211116A
  6. GRB 211106A: Swift/UVOT upper limits
  7. GRB 211110A: AstroSat CZTI detection
  8. Short GRB 211106A: spectroscopy of galaxies in the field
  9. GRB 211107B: Swift-XRT afterglow detection
  10. GRB 211106A, GROND observations
  11. GRB 211106A: Swift-XRT afterglow detection
  12. GRB 211023A: SAO RAS optical observations
  13. MeerLICHT follow-up of GRB 211106A
  14. GRB 211107B: Swift ToO observations
  15. GRB 211106A: Swift-XRT observations
  16. GRB 211106A: Swift ToO observations
  17. Swift Trigger 1082569 is probably not a GRB
  18. GRB 211023A: optical detection by SBT in Ondrejov
  19. GRB 211023B: Subaru optical observation
  20. GRB 211024A: MITSuME Akeno optical observation
  21. GRB 211023B: MITSuME Akeno optical upper limits
  22. GRB 211024B: Optical afterglow observation by Ondrejov D50
  23. IPN triangulation of GRB 211022A
  24. AMON NuEm-211020A: No Candidate Counterparts from Swift-XRT follow up observations
  25. GRB 211024A: Swift-XRT source 4 is not an afterglow.
  26. GRB 211023B: NUTTelA-TAO / BSTI Early Optical Limits (Preliminary)
  27. GRB 211024A: Possible afterglow candidate from GIT
  28. GRB211023A: optical afterglow detection from Konkoly Observatory
  29. GRB 211024A: Swift ToO observations
  30. GRB 211023B: Mondy optical afterglow confirmation
  31. GRB 211023B: LDT Optical Afterglow Detection
  32. GRB 211024B: Swift-XRT refined Analysis
  33. GRB 211025A: Swift/UVOT Detection
  34. GRB 211024B: Swift-BAT refined analysis
  35. GRB 210610B: Sintesz-Newton/CrAO optical observations
  36. GRB 211025A: Enhanced Swift-XRT position
  37. GRB 211025A: Swift detection of a burst
  38. GRB 211024B: Nanshan/NEXT optical afterglow detection
  39. GRB 210919A: FORS2/VLT observations
  40. Fermi-LAT Gamma-ray Observations of IceCube-211023A
  41. GRB 211023B: Swift/UVOT Detection
  42. GRB 211023B: RATIR Optical and NIR Upper Limits
  43. GRB 211023B: TSHAO optical observation
  44. GRB 211023B: Swift-XRT refined Analysis
  45. GRB 211023B: Enhanced Swift-XRT position
  46. GRB 211023B: Swift detection of a possibly short burst with an optical counterpart
  47. IPN Triangulation of GRB 210927B
  48. AMON IC_HAWC NuEm-211020A: No neutrino counterpart detected with ANTARES
  49. GRB 211018A: Swift ToO observations
  50. BepiColombo MGNS joins the IPN
  51. IceCube-210922A: Hard X-ray flux limit for JCMT/SCUBA2 source from NuSTAR observations
  52. Swift trigger 1078701: MITSuME Akeno optical upper limits
  53. GRB 210919A: LDT optical observations and candidate host galaxies
  54. Swift Trigger 1078701: Mondy, CrAO, AbAO observations, possible optical counterpart
  55. Swift Trigger 1078701 is probably not a GRB
  56. IceCube-20210922A: DESNU Optical counterpart candidate from 5 nights of DECam observations
  57. GRB 210928A: MeerKAT detection
  58. IceCube-210922A: DESI Observations
  59. GRB 210928A: Kinder SLT-40cm optical limits
  60. GRB 210928A: Swift-XRT analysis (replaces GCN 30914)
  61. GRB 210928A: Swift-XRT refined Analysis
  62. GRB 210927A: GIT optical follow-up of ZTF21acdwctm.
  63. Swift Trigger 1076121 is not a GRB
  64. GRB 210930A: Swift/UVOT Upper Limits
  65. GRB 210930A: Enhanced Swift-XRT position
  66. GRB 210930A: Swift detection of a burst
  67. Fermi-LAT Gamma-ray Observations of IceCubeCascade-210926A
  68. IPN triangulation of GRB 210925B
  69. GRB 210919A: iTelescope T-11 upper limits
  70. IceCube-210922A: JCMT/SCUBA2 observations
  71. GRB 210919A: Chandra rapid ToO upper limit
  72. IceCube-210922A: No significant detection in HAWC
  73. GRB 210919A: DECam Upper Limits
  74. Fermi-LAT Gamma-ray Observations of IceCube-210922A
  75. GRB 210912A: LBT optical observations
  76. GRB 210919A: Lowell Discovery Telescope upper limits (correction to GCN 30859)
  77. GRB 210919A: Swift/UVOT Upper Limits
  78. GRB 210919A: LOAO and LSGT optical upper limits
  79. GRB 210919A: MITSuME Akeno optical upper limits
  80. GRB 210919A: NOT upper limits
  81. GRB 210919A: AbAO optical upper limit
  82. GRB 210919A: Enhanced Swift-XRT position
  83. GRB 210919A: Swift detection of a short burst
  84. Swift trigger 1073821: detection of IGR J16418-4532
  85. GRB 210912A: BOOTES-5/JGT optical afterglow candidate (Correction to GCNC 30823)
  86. GRB 210812A is not a compelling example of a lensed GRB
  87. GRB 210912A: Tautenburg observations
  88. GRB 210912A: Swift/UVOT Detection
  89. GRB 210912A: Enhanced Swift-XRT position
  90. GRB 210912A: Mondy optical afterglow confirmation
  91. GRB 210912A: BOOTES-5/JGT optical afterglow candidate
  92. GRB 210912A: Swift detection of a burst
  93. Fermi trigger No 653084584: Global MASTER-Net observations report
  94. IPN triangulation of a bright burst from SGR 1935+2154
  95. GRB 210826A: further Swift-XRT observations
  96. Swift detection of a burst from SGR Swift J1555.2-5402
  97. Fermi trigger No 652927551: Global MASTER-Net observations report
  98. GRB 210619B: Maidanak and Assy optical observations, broken power law parametrization
  99. GRB 210905A: Swift/UVOT Upper Limits
  100. GRB 210905A, GROND observations

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