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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"

19539 results found.

  1. GRB 231214A: Swift-BAT refined analysis
  2. GRB 231216A: R-band observations from T120 at Observatoire de Haute-Provence
  3. GRB 231216A: GIT optical upper limit
  4. GRB 231216A: BOOTES-2/TELMA optical upper limit
  5. GRB 231215A: GRBAlpha detection
  6. Swift GRB231216.77: Global MASTER-Net observations report
  7. GRB 231216A: Swift detection of a burst
  8. Konus-Wind detection of GRB 231215A
  9. GRB 231215A: NOT optical observations
  10. GRB 231214A: Swift/UVOT Upper Limits
  11. GRB 231205B: VZLUSAT-2 detection
  12. GRB 231215A: Fermi GBM observation
  13. GRB 231215A: CALET Gamma-Ray Burst Monitor detection
  14. GRB 231215A: Swift/UVOT Detection
  15. GRB 231215A: Swift-XRT refined Analysis
  16. GRB 231215A: BOOTES-4/MET optical detection
  17. GRB 231215A: AKO Optical Upper Limit
  18. GRB 231215A: AGILE detection
  19. GRB 231214A: Fermi GBM observation
  20. Konus-Wind detection of GRB 231210B
  21. GRB 231215A: Enhanced Swift-XRT position
  22. GRB 231214A: REM optical/NIR upper limits
  23. GRB 231215A: GROWTH-India optical follow-up
  24. GRB 231215A : Nanshan/HMT optical observations
  25. GRB 231215A: AstroSat CZTI detection
  26. GRB 231215A : MITSuME Akeno optical afterglow candidate detection
  27. GRB 231214A: Swift-XRT refined Analysis
  28. GRB 231215A: Mondy optical bright afterglow detection
  29. GRB 231214A: AstroSat CZTI detection
  30. GRB 231215C: MASTER OT detection
  31. Swift GRB231215.41: Global MASTER-Net observations report
  32. GRB 231215A: Swift-XRT observations
  33. GRB 231215A: Swift detection of a burst
  34. GRB 231214A: Fermi-LAT detection
  35. GRB 231214A: Enhanced Swift-XRT position
  36. GRB 231214B: Swift/BAT-GUANO detection of a burst
  37. GRB231214A: BOOTES-6/DPRT optical upper limit
  38. Swift GRB231214.85: Global MASTER-Net observations report
  39. GRB 231214A: Swift detection of a burst
  40. GRB 231210B: REM optical/NIR upper limits
  41. LIGO/Virgo/KAGRA S231206cc: Upper limits from Swift/BAT-GUANO
  42. LIGO/Virgo/KAGRA S231206ca: Upper limits from Swift/BAT-GUANO
  43. GRB 231210B: MeerLICHT afterglow observations
  44. GRB 231210B: Swift-BAT refined analysis
  45. GRB 231210B: Swift-XRT refined Analysis
  46. GRB 231210B: Enhanced Swift-XRT position
  47. GRB 231210B: VLT/X-shooter redshift
  48. GRB 231210B: detection of the optical counterpart with the LCOGT 40cm telescope at Sutherland Observatory
  49. GRB 231210B: Swift detection of a burst with optical counterpart
  50. Swift GRB231210.90: Global MASTER-Net OT detection
  51. Swift GRB231210.90: Global MASTER-Net observations report
  52. IPN triangulation of GRB 231129C
  53. GRB231205B: Swift/UVOT Upper Limits
  54. GRB 231205B: Swift-BAT refined analysis
  55. GRB 231205B: 1.3m DFOT Optical upper limit
  56. GRB 231205B: AGILE detection
  57. GRB 231205B: Ondrejov D50 optical upper limit
  58. GRB 231205B: Swift-XRT refined Analysis
  59. GRB 231205B: REM optical/NIR upper limits
  60. GRB 231129C: ASIM MXGS observation and localization
  61. GRB 231205B: r'-band observations from MISTRAL at Observatoire de Haute-Provence
  62. GRB 231205B : MITSuME Akeno optical upper limits
  63. GRB 231205B: Zadko observatory - Gingin optical observations
  64. GRB 231205B: Gaoyazi/GOT optical upper limit
  65. GRB 231205B: Nanshan/HMT optical upper limit
  66. GRB 231205B: GECAM-B detection of a long burst
  67. GRB 231205B: LCOGT Optical Upper Limits
  68. GRB 231205B: Enhanced Swift-XRT position
  69. Swift GRB231205.70: Global MASTER-Net observations report
  70. GRB 231205B: AKO Optical Upper Limit
  71. GRB 231205B: Swift detection of a burst
  72. LIGO/Virgo/KAGRA S231129ac: Upper limits from Swift/BAT-GUANO
  73. GRB 231203A: Fermi GBM Observation
  74. GRB 231203A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  75. Konus-Wind detection of GRB 231129C
  76. GRB 231129C: Swift-XRT afterglow detection
  77. GRB 231129C: PROMPT optical upper limits for the MAXI/GSC X-ray counterpart and the MASTER afterglow candidate
  78. GRB 231129A: VZLUSAT-2 detection
  79. GRB 231129B: Swift-XRT observations
  80. GRB 231129C: AGILE detection
  81. GRB 231129A : MITSuME Akeno optical upper limits
  82. GRB 231129C: Swift/BAT-GUANO localization of a burst outside the coded FOV
  83. GRB 231129A: Swift-BAT refined analysis
  84. GRB 231129C: MASTER OT detection
  85. GRB 231129A: BOOTES-5/JGT optical upper limit
  86. GRB 231129A: JinShan optical upper limit
  87. GRB 231129C: Swift-XRT observations
  88. GRB 231129A: Swift/UVOT Upper Limits
  89. GRB 231129A: optical upper limit in Mondy observatory
  90. GRB 231129C: Tiled Swift observations
  91. GRB 231129A: Enhanced Swift-XRT position
  92. GRB 231129A: Swift-XRT refined Analysis
  93. GRB 231129B: Tiled Swift observations
  94. GRB 231129A: GECAM-C detection of a long burst
  95. GRB 231129A: INTEGRAL detection of a long GRB
  96. GRB 231129A: Swift detection of a burst
  97. GRB 231123C: Fermi GBM Observation
  98. GRB 231123B: Fermi GBM Observation
  99. GRB 231123B: Swift/BAT-GUANO detection of a burst outside the coded FOV
  100. GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy

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