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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"

20955 results found.

  1. GRB 150413A: GMG observation
  2. GRB 150413A: AMI 15 GHz detection of possible radio counterpart
  3. GRB 150413A: additional P60 observations
  4. GRB 150413A : Virtual Telescope optical observations
  5. GRB 150413A: Bassano Bresciano Observatory optical observations
  6. GRB 150413A: T7 and T18 optical observations
  7. GRB150413A, optical observations
  8. GRB 150413A: optical observations
  9. GRB 150413A: redshift determination with the 2.2m CAHA
  10. GRB 150413A: P60 photometry
  11. GRB 150413A: Khureltogot optical observations
  12. GRB 150413A: Tautenburg observations
  13. GRB 150413A: Nanshan optical and radio follow-ups
  14. GRB 150413A: Khureltogot optical observations
  15. GRB 150413A: MASTER very bright unusual OT observations
  16. Swift detection of SAX J1808.4-3658
  17. Swift GRB150402A: further XRT observations
  18. GRB 150407A: Swift-XRT observations
  19. GRB 150407A: optical observations
  20. GRB 150407A: Swift ToO observations
  21. GRB 150403A: Swift/UVOT Detection
  22. GRB 150403A: VLT/X-shooter redshift
  23. GRB 150323C: CrAO optical observations
  24. GRB 150323C: additional optical observations in Mondy
  25. GRB 150323C: Khureltogot optical observations
  26. GRB 150402A: results of Swift observations
  27. GRB 150402A: RATIR Optical Observations
  28. GRB 150402A: Swift ToO observations
  29. GRB 150323B: Swift-XRT afterglow detection
  30. GRB 141212A: GMG observation limit
  31. GRB 141220A: GMG observation limit
  32. GRB 141225A: GMG observation limit
  33. GRB 150120B: GMG observation
  34. GRB 150323B: Khureltogot optical observations
  35. GRB 150323C: Nishi-Harima NIR Observations
  36. GRB 150323A: AAO optical observations
  37. GRB 150220A: Optical observations at Kyiv comet station
  38. GRB 150323C; Konkoly optical observations
  39. GRB 150323B; Konkoly optical observations
  40. GRB 150323A; Konkoly optical observations
  41. GRB 150323C: Mondy optical observations
  42. GRB 150323C: RATIR Optical Afterglow Observations - Errata
  43. GRB 150323C: Swift/UVOT Upper Limits
  44. GRB 150323B: Swift-XRT observations
  45. GRB 150323C: RATIR Optical Afterglow Observations
  46. GRB 150323C: Xingming upper limit
  47. GRB 150323A: KAIT Optical Observations
  48. GRB 150323C: Nanshan optical afterglow detection
  49. GRB 150323B: Swift ToO observations
  50. GRB150323A: Swift-UVOT detection of the afterglow
  51. GRB 150314A: GMG observation limit
  52. GRB 150323A: RATIR Optical Afterglow Observations
  53. GRB 150323A: P60 Optical Afterglow Candidate
  54. Swift Triggers 635788-635794 are probably not real.
  55. Confirmation that Swift trigger 635306 is not an astrophysical source
  56. GRB 150314A: Further VLA observations
  57. GRB 150318A: Skynet PROMPT-CTIO Observations
  58. GRB 150318A: Swift/UVOT Upper Limits
  59. GRB 150318A : GROND upper limits
  60. GRB 150317A: Swift/UVOT Upper Limits
  61. GRB 150317A: NOT optical observations
  62. GRB 150314A: VLA observations
  63. GRB 150314A: Early RAPTOR Detection
  64. GRB 150314A: NOT further optical observations
  65. GRB 150314A: KAIT Optical Observations
  66. GRB 150314A: P60 observations
  67. GRB 150314A: Redshift from OSIRIS/GTC
  68. GRB 150314A: NOT optical observations
  69. GRB 150314A: Swift/UVOT Detection
  70. GRB 150314A: Skynet Yerkes-41 Observations of the Optical Afterglow
  71. GRB 150314A: KAIT Optical Candidate
  72. GRB150309A: Optical observations at Crni Vrh
  73. GRB 150309A: Swift/UVOT Upper Limits
  74. GRB 150309A : Liverpool Telescope observations
  75. GRB 150309A: BOOTES-1 and -2 upper limit
  76. GRB 150305A: Swift XRT confirms weak INTEGRAL event as a new GRB
  77. Chandra X-ray observations of SWIFT J0045.2+4151 (aka Sw J0045 aka GRB 150301C aka p[PFH2005] 622)
  78. Swift J0045.2+4151: analysis of XMM-Newton archival data
  79. Further UVOT Observations of Swift J0045.2+4151
  80. GRB 150301C: VLA Observations
  81. Further X-ray observations of Swift J0045.2+4151 (aka Sw J0045 aka GRB 150301C aka [PFH2005] 622)
  82. BAT trigger 633105 (GRB 150301C): NOT r-band upper limit
  83. Trigger 633105 (aka GRB150301C): Swift/UVOT Observations of XRT Counterpart
  84. GRB 150302A: Swift/UVOT Upper Limits
  85. GRB 150301C: XRT detection of a potential counterpart of BAT trigger 633105
  86. GRB 150220A: further Swift-XRT observations
  87. GRB 150301B: Swift/UVOT Observations
  88. GRB 150301B: LCOGT-Sutherland observations
  89. GRB 150302A: KAIT Optical Upper Limit
  90. GRB 150302A: UVOT Observations
  91. GRB 150302A: NOT afterglow candidate
  92. GRB 150301B: X-shooter spectroscopy
  93. GRB 150301B: GROND afterglow observations
  94. GRB 150301A: Swift/UVOT Upper Limits
  95. GRB 150301C : (Swift trigger 633105) Swift observations
  96. GRB 150301A: GROND Observations
  97. GRB 150301A: Swift detection of a short burst or new SGR
  98. Fermi GBM Observations of Magnetar 4U 0142+61
  99. Trigger 632888: Swift detection of the magnetar 4U 0142+61
  100. GRB 150222A: Further GROND Observations

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