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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"

28094 results found.

  1. GRB 210306A: MITSuME Akeno optical observation
  2. GRB 210306A: NEXT optical observations
  3. GRB 210306A: Fermi GBM observation
  4. GRB 210306A: Tautenburg observations
  5. GRB 210306A: LCO Optical Afterglow Detection
  6. GRB 210306A: iTelescope optical afterglow observations
  7. GRB 210306A: DDOTI Afterglow Confirmation
  8. GRB 210306A: Swift detection of a burst with a bright optical counterpart
  9. GRB 210305A: Swift detection of a burst
  10. GRB 210228B: Insight-HXMT/HE detection
  11. Trigger 1035744: Swift detection of Sco X-1 due to Star Tracker loss of lock
  12. GRB 210217A: 3.6m DOT optical observations
  13. GRB 210226A: Swift/UVOT Upper Limits
  14. Fermi trigger No 636187116: Global MASTER-Net observations report
  15. GRB 210228A: GECAM detection
  16. GRB 210225A: Insight-HXMT/HE detection
  17. Integral GRB210227.19: Global MASTER-Net OT detection
  18. GRB 210226A: Swift-BAT refined analysis
  19. GRB 210226A: Fermi GBM detection
  20. GRB 210217A: Mondy optical observations
  21. GRB 210226A: Swift-XRT refined Analysis
  22. GRB 210218A: Swift-XRT confirmation of afterglow
  23. GRB 210226A: Burke-Gaffney Observatory optical upper limit
  24. GRB 210226A: Enhanced Swift-XRT position
  25. GRB 210222B: 1.3m DFOT Optical upper limit
  26. GRB 210226A: Swift detection of a burst
  27. GRB 210222B: REM observations of the optical/NIR afterglow
  28. GRB 210222B: MITSuME Akeno optical upper limits
  29. GRB 210222B: Zeiss-1000 of Koshka observatory, optical observations
  30. GRB 210222B: VIRT optical detection
  31. GRB 210222B: Swift-BAT refined analysis
  32. GRB 210222B: Swift-XRT refined Analysis
  33. GRB 210222B: Swift/UVOT Detection
  34. GRB 210218A: Swift/UVOT observations
  35. GRB 210217A: Swift/UVOT Detection
  36. GRB 210222B: MASTER OT observation
  37. GRB 210222B: Redshift from FORS2/VLT
  38. GRB 210222B: NEXT early optical afterglow observations
  39. GRB 210222B: GOTO confirmation of afterglow detection (correction to GCN29548)
  40. GRB 210222B: Liverpool Telescope optical detection
  41. GRB 210222B: GOTO confirmation of afterglow detection
  42. GRB210222B: LCO Optical Afterglow Detection
  43. GRB210222B: BOOTES-1 optical afterglow detection
  44. GRB 210222B: Swift detection of a burst with an optical counterpart
  45. GRB 210222A: MAXI/GSC detection
  46. GRB 210218A: Swift-XRT observations
  47. GRB 210212A: Lowell Discovery Telescope observations
  48. GRB 210217A: Swift-XRT refined Analysis
  49. GRB 210218A: Swift-BAT refined analysis
  50. Fermi GBM Sub-Threshold Detection of GRB 210217A
  51. GRB 210217A: Liverpool Telescope First Hour Observations
  52. GRB 210217A: Swift-BAT refined analysis
  53. GRB 210218A: MITSuME Akeno optical upper limits
  54. GRB 210218A: NEXT optical upper limit
  55. ZTF21aakruew/AT2021cwd: GROND observations
  56. GRB 210212A: REM early-time optical/NIR upper limits
  57. GRB 210217A: Enhanced Swift-XRT position
  58. GRB 210217A: NEXT early optical afterglow observations
  59. GRB 210212A: Mondy optical observations
  60. GRB 210217A: Swift detection of a burst with an optical counterpart
  61. IceCube-210210A: Two Additional Optical Candidate Counterparts Found by DECam
  62. GRB 210208A: 1.3m DFOT Optical upper limit
  63. Swift Trigger 1033144: Detection of SGR 1830-0645
  64. GRB 210211A: ePESSTO+ NTT optical observations
  65. Konus-Wind detection of GRB 210212B / ZTF21aakruew
  66. IPN triangulation of GRB 210212B (consistent with ZTF21aakruew/AT2021cwd)
  67. GRB 210212A: 1.3m DFOT Optical upper limit
  68. GRB 210213B: Insight-HXMT/HE detection
  69. GRB 210212A: Gemini South optical observations
  70. IceCube-210210A: Four Candidate Optical Counterparts from DECam Observations
  71. Swift Trigger 1032350: Detection of SGR 1830-0645
  72. GRB 210212A: Possible host galaxy counterpart with the NOT
  73. GRB 210212A: MITSuME Akeno optical upper limits
  74. GRB 210212A: Swift-XRT refined Analysis
  75. IceCube-210210A: Upper limits from a search for additional neutrino events in IceCube
  76. GRB 210212A: Swift/UVOT Upper Limits
  77. GRB 210212A: Swift-BAT refined analysis
  78. GRB 210212A: Enhanced Swift-XRT position
  79. GRB 210212A: Swift detection of a burst
  80. GRB 210207B: GECAM detection
  81. GRB 210211A: Swift/UVOT Detection
  82. GRB 210211A: Swift-XRT refined Analysis
  83. GRB 210211A: Swift-BAT refined analysis
  84. GRB 210211A: Fermi GBM observation
  85. GRB 210210A as a BdHN II
  86. Swift-XRT observations of IceCube-210210A
  87. GRB 210209A: Swift-BAT refined analysis
  88. GRB 210211A: Enhanced Swift-XRT position
  89. GRB 210211A: MASTER optical observation of REM OT
  90. IceCube-210210A: No neutrino counterpart in ANTARES
  91. GRB 210211A: REM optical/NIR afterglow detection
  92. Fermi-LAT Gamma-ray Observations of IceCube-210210A
  93. GRB 210211A: Swift detection of a burst
  94. GRB 210210A: Swift-BAT refined analysis
  95. IceCube-210210A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  96. GRB 210210A: LCO Optical Afterglow Detection
  97. GRB 210210A: Swift/UVOT Detection
  98. GRB 210112A: LBT host detection and correction to GCN 29319 (CAHA observations)
  99. GRB 210209A: MITSuME Akeno optical upper limits
  100. GRB 210209A: Swift/UVOT Upper Limits

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