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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"

37549 results found.

  1. GRB 150424A: 10.4m GTC spectroscopy
  2. GRB 150424A: GROND detects strong fading
  3. GRB 150424A: NOT optical observations
  4. GRB 150423A: VLT/X-shooter spectroscopy and tentative redshift
  5. GRB 150423A: Continued RATIR optical afterglow monitoring
  6. GRB 150424B: Fermi GBM detection
  7. Konus-Wind observation of GRB 150424A
  8. GRB 150424A: Swift/UVOT Observations
  9. GRB 150423A: TSHAO optical observations
  10. GRB 150424A: Enhanced Swift-XRT position
  11. GRB 150424B: Tiled Swift observations
  12. GRB 150423A: WHT observations
  13. GRB 150424B: MAXI/GSC detection
  14. GRB 150424A: Keck detection of optical afterglow
  15. GRB 150423A: Keck redshift of neighboring galaxy
  16. GRB 150424A: Swift detection of a short burst
  17. GRB 150423A: MITSuME Okayama upper limits
  18. GRB 150423A: UKIRT NIR observations
  19. GRB 150423A: Swift-BAT refined analysis
  20. GRB 150423A: Swift/UVOT Upper Limits
  21. GRB 150423A: VLT detection
  22. GRB 150423A: Swift-XRT refined Analysis
  23. GRB 150423A: RATIR optical afterglow monitoring
  24. GRB 150423A: Enhanced Swift-XRT position
  25. GRB 150422A: Fermi GBM detection
  26. GRB 150423A: Keck optical afterglow confirmation
  27. GRB 150423A: GROND afterglow candidate
  28. GRB 150413A: Konus-Wind and Swift/BAT joint spectral analysis
  29. GRB 150423A: KAIT Optical Upper Limit
  30. GRB 150423A: GROND observation
  31. GRB 150423A: Swift detection of a short burst
  32. Konus-Wind observation of GRB 150418A
  33. GRB150418A: Swift/UVOT did not detect a new source
  34. Further Swift XRT observations of GRB 150418A
  35. GRB 150413A: Swift-XRT observations
  36. GRB 150418A: Swift-XRT observations
  37. GRB 150413A: RTT150 optical observations
  38. GRB 150418A: Tiled Swift observations
  39. GRB 150418A: MAXI/GSC detection
  40. GRB 150413A: ISON-Ussuriysk optical observations
  41. GRB 150416A: Fermi GBM detection
  42. Confirmation that Swift trigger 638217 is not an astrophysical source
  43. GRB 150413A: MITSuME Akeno Optical observation
  44. GRB 150413A: SAO RAS observations
  45. LOAO B, R Observations of GRB150413A
  46. GRB 150416A: Fermi-LAT detection
  47. GRB 150413A: Refined redshift
  48. GRB 150413A: GMG observation
  49. GRB 150413A: AMI 15 GHz detection of possible radio counterpart
  50. GRB 150413A: additional P60 observations
  51. GRB 150413A : Virtual Telescope optical observations
  52. GRB 150413A
  53. GRB 150413A: Bassano Bresciano Observatory optical observations
  54. Konus-Wind observation of a bright burst from SGR 1935+2154
  55. GRB 150413A: T7 and T18 optical observations
  56. GRB 150413A: Swift-BAT refined analysis
  57. GRB150413A, optical observations
  58. IPN Triangulation of a bright burst from SGR 1935+2154
  59. GRB 150413A: optical observations
  60. GRB 150413A: redshift determination with the 2.2m CAHA
  61. GRB 150413A: P60 photometry
  62. GRB 150413A: Khureltogot optical observations
  63. GRB 150413A: Tautenburg observations
  64. GRB 150413A: Nanshan optical and radio follow-ups
  65. GRB 150413A: Khureltogot optical observations
  66. GRB 150413A: MAXI/GSC detection
  67. GRB 150413A: MASTER very bright unusual OT observations
  68. GRB 150413A: MASTER bright OT detection
  69. GRB 150413A: Swift detection of a burst
  70. GRB 150407A: Swift-XRT observations
  71. GRB 150407A: optical observations
  72. GRB 150407A: Swift detection of a possible burst
  73. GRB 150407A: Swift ToO observations
  74. GRB 150403A: MASTER-net optical observation
  75. GRB 150404A: Fermi GBM detection
  76. Konus-Wind observation of GRB 150403A
  77. Fermi trigger 449861706: MASTER-SAAO possible candidate to OT of Short GRB
  78. GRB 150403A: Swift-BAT refined analysis
  79. GRB 150403A: Fermi GBM Detection
  80. GRB 150403A: Swift/UVOT Detection
  81. GRB 150403A: VLT/X-shooter redshift
  82. GRB 150323C: CrAO optical observations
  83. GRB 150323C: additional optical observations in Mondy
  84. GRB 150323C: Khureltogot optical observations
  85. GRB 150403A: Swift-XRT refined Analysis
  86. GRB 150403A: Fermi-LAT detection
  87. GRB 150403A: Enhanced Swift-XRT position
  88. GRB 150403A: Swift detection of a burst with an optical counterpart
  89. GRB 150402A: results of Swift observations
  90. GRB 150402A: RATIR Optical Observations
  91. GRB 150402A: Swift ToO observations
  92. GRB 150402A detected in ground analysis of Swift-BAT data
  93. Konus-Wind observation of GRB 150330A
  94. IPN Triangulation of GRB 150330A (long/very intense)
  95. GRB 150330A: Fermi GBM detection
  96. GRB 150323B: Swift-XRT afterglow detection
  97. GRB 141121A: GMG observation
  98. GRB 150323C: possible host galaxy detection
  99. GRB 141212A: GMG observation limit
  100. GRB 141220A: GMG observation limit

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