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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"

22062 results found.

  1. GRB 221120A: GIT upper limits on optical afterglow
  2. LAT GRB221119.63: Global MASTER-Net observations report
  3. GRB 221009A: Japanese VLBI Network observation
  4. Correction to GCN 32646 (GRB 221009A (Swift J1913.1+1946): MeerLICHT observations)
  5. GRB 221115B : MeerLICHT upper limits
  6. GRB 221115B: Swift/BAT-GUANO arcminute localization
  7. GRB 221115A: Swift/BAT-GUANO detection
  8. GRB 221110A: GRANDMA observations
  9. GRB 221110A: COATLI Second-Epoch Upper Limits
  10. GRB 221009A: GRANDMA/Kilonova-Catcher observations
  11. GRB 221110A: Swift/UVOT Detection and Corrected UVOT Position
  12. GRB 221110A: COATLI Afterglow detection
  13. Swift GRB221110.10: Global MASTER-Net observations report
  14. Fermi-GBM Observations of High Bursting Activity from SGR J1935+2154
  15. GRB 221009A: Hubble Space Telescope observations
  16. GRB 221107A: Swift/BAT-GUANO detection outside the coded FOV
  17. Correction to GCN 32852 (GRB 221009A: SARA-RM 1m Optical Afterglow Detection)
  18. IceCube Alert 221104.26: Global MASTER-Net observations report
  19. Fermi-LAT gamma-ray observations of IceCube-221104A
  20. High-precision position of the compact radio counterpart to GRB221009A
  21. GRB 221028A: GRANDMA observations
  22. GRB 221027B: GRANDMA observations
  23. GRB 221028A: 1.3m DFOT Optical upper limit
  24. GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
  25. GRB 221028A: NUTTelA-TAO / BSTI Early Optical Limits
  26. GRB 221029A: Swift/BAT-GUANO detection outside the coded FOV
  27. GRB 221028A: HCT optical upper limit
  28. Swift GRB 221028A: Global MASTER-Net observations report
  29. GRB 221027B: Swift/UVOT Upper Limits
  30. Konus-Wind detection of GRB 221017A
  31. Swift GRB 221027B: Global MASTER-Net observations report
  32. Konus-Wind detection of GRB 221022B
  33. GRB 221024A: Mondy optical observations
  34. GRB 221009A: Further Gemini-South Infrared Observations
  35. GRB 221024A: GRANDMA observations
  36. GRB 221009A: SARA-RM 1m Optical Afterglow Detection
  37. GRB 221009A: spectroscopic confirmation of SN in LBT spectra
  38. Konus-Wind detection of GRB 221023A
  39. GRB 221024A: Swift/UVOT UV upper limits
  40. GRB 221022A: Swift-XRT observations
  41. LAT GRB221025.04: Global MASTER-Net observations report
  42. GRB 221022A: Swift ToO observations
  43. GRB 221022A: Swift/BAT-GUANO detection
  44. GRB 221022B: Swift/BAT-GUANO detection outside the coded FOV
  45. GRB 221009A: James Webb Space Telescope Observations
  46. GRB 221009A: optical observations, SN photometric evidence
  47. GRB 221021A: Swift/BAT-GUANO detection outside the coded FOV
  48. GRB 221009A: 1.3m DFOT Optical Observations
  49. GRB221009A: LBT optical imaging
  50. GRB 221009A: Peak luminosity of the supernova vs. synchrotron afterglow
  51. GRB 221017A: Swift-XRT observations
  52. GRB 221009A: TNG NIR detection
  53. GRB 221009A: BOAO NIR detections
  54. GRB 221009A X-ray light-curve and the indication of TeV light-curve
  55. GRB 221009A: Spectroscopic detection of emerging SN features
  56. GRB 221009A: Continued LDT Afterglow Monitoring
  57. GRB 221013B: Swift/BAT-GUANO detection
  58. AGILE detection of the 2022 October 17 burst from SGR J1935+2154 reported by Konus-Wind
  59. GRB 221009A: GRANDMA observations
  60. GRB 221009A: Medicina Radio Telescope observations
  61. GRB 221017A: Swift ToO observations
  62. GRB 221009A: Second epoch of NuSTAR data
  63. GRB 221016A: Swift/UVOT Detection
  64. Konus-Wind detection of GRB 221016A
  65. MAXI GRB221017.24: Global MASTER-Net observations report
  66. Swift GRB221016.99: Global MASTER-Net observations report
  67. GRB 221009A: continued Assy optical afterglow observations, possible SN evidence
  68. GRB 221009A: ATCA radio spectrum
  69. GRB 221009A: VLT spectroscopic detection of the host galaxy
  70. GRB 221009A: ATCA detection
  71. GRB 221009A: ALMA and ACA detections
  72. GRB 221009A: Fermi LAT data rate effects due to extremely high flux
  73. GRB 221009A: Large Binocular Telescope Observatory optical afterglow detection
  74. GRB 221009A: Pan-STARRS optical photometry
  75. GRB 221009A: VLA detection
  76. GRB 221009A: continued REM optical/NIR observations and evidence for an achromatic steepening in the afterglow light curve
  77. GRB 221009A: OHP optical observations
  78. GRB221009A: RTT-150 optical observations
  79. GRB 221009A: Gemini-South Infrared Afterglow Detection
  80. GRB221009A: Gemini-South Optical Afterglow Detection
  81. GRB 221009A: a 397.7 GeV photon observed by Fermi-LAT at 0.4 day after the GBM trigger
  82. GRB221009A: Detection as sudden ionospheric disturbances (SID)
  83. GRB221009A: RTT-150 optical observations
  84. MAXI GRB 221006A: Redshifts of the possible host galaxies
  85. GRB 221009A: MeerKAT detection
  86. GRB 221009A: Lowell Discovery Telescope Afterglow Detection
  87. GRB221009A: LCOGT Continued Observations - Optical Upper Limits
  88. GRB 221009A/Swift J1913.1+1946: low-frequency ASKAP observations
  89. Fermi trigger No 687345829: Global MASTER-Net observations report
  90. Fermi trigger No 687344475: Global MASTER-Net observations report
  91. Fermi trigger No 687340841: Global MASTER-Net observations report
  92. Fermi trigger No 687337536: Global MASTER-Net observations report
  93. GRB 221006A: Swift-XRT afterglow detection
  94. GRB 221009A: Sayan observatory 1.6-m telescope observations
  95. Fermi trigger No 687281393: Global MASTER-Net observations report
  96. Integral GRB221013.04: Global MASTER-Net observations report
  97. Integral GRB221013.00: Global MASTER-Net observations report
  98. Integral GRB221012.99: Global MASTER-Net observations report
  99. Integral GRB221012.94: Global MASTER-Net observations report
  100. Integral GRB221012.91: Global MASTER-Net observations report

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