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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"

20901 results found.

  1. GRB 130427A: Nishi-Harima Optical Spectroscopic Observations
  2. GRB 130427A: Continued RATIR Optical and NIR Observations
  3. GRB 130427A: Challis Observatory optical observations
  4. GRB 130427A: Continued Skynet/PROMPT Observations
  5. GRB 130427A: further GMG observations
  6. GRB 130427A: Continued RATIR Optical and NIR Observations
  7. GRB 130425: MASTER-Net optical observations
  8. GRB 100728A: GROND host detection and X-shooter redshift
  9. GRB 130427A: Skynet/PROMPT Observations
  10. GRB 130427B: RATIR Optical and NIR Observations
  11. GRB 130427A: Nishi-Harima NIR Observations
  12. GRB 130427A: CARMA 3mm observations
  13. GRB 130427A optical time series
  14. GRB 130427A, Optical Observations
  15. GRB 130427A: Continued iTelescope T21 optical observations
  16. Konus-Wind observation of GRB 130427A
  17. GRB 130427A: SPI-ACS/INTEGRAL observations
  18. GRB 130427A: Continued RATIR Optical and NIR Observations
  19. GRB 130427A: CARMA 85 GHz detection
  20. GRB 130427A: SNUO/SOAO/BOAO Observation
  21. GRB 130427A: VLA 5 GHz detection
  22. GRB 130427A: NOT optical photometry and redshift
  23. GRB 130427A: T100 observations
  24. GRB 130427A: optical observations in CrAO
  25. GRB130427A: Swift/UVOT followup observations of an Optical Afterglow
  26. GRB 130427A: Zadko observatory - Gingin optical observations
  27. GRB 130427A: GMG optical observation
  28. GRB 130427A: Optical Observations
  29. GRB 130427A: RATIR Optical and NIR Observations
  30. GRB 130427A: Weihai optical observations
  31. GRB 130427A: iTelescope T11 optical observations
  32. GRB 130427A: Continued P60 follow-up of an extremely bright optical afterglow
  33. GRB 130427A: Gemini-North redshift
  34. GRB 130427A: PAIRITEL NIR Detections
  35. GRB 130427A: Faulkes Telescope North detection
  36. GRB 130427A: P60 early detection
  37. GRB 130427A: early optical observations
  38. GRB 130427A: P60 early nondetection
  39. GRB 130420A: Continued Skynet/GORT Observations/Detections
  40. GRB 130420B: CARMA and VLA radio observations
  41. Trigger 554491: Swift detection of a spike possibly from Sgr A*
  42. GRB 130420A: Continued RATIR Optical and NIR Observations
  43. GRB 130420A: ROTSE-III data analysis
  44. GRB 130420A: Continued RATIR Optical and NIR Observations
  45. GRB 130418A: Continued RATIR Optical and NIR Observations
  46. GRB 130420A: Early RAPTOR Simultaneous Multi-Color Observations
  47. GRB 130418A: WSRT radio observation
  48. GRB 130420B: RATIR Optical and NIR Observations
  49. GRB 130420A: Continued RATIR Optical and NIR Observations
  50. GRB 130420A: ISON-NM optical observations
  51. Skynet/GORT observations of GRB130420A
  52. GRB 130420B: Swift/UVOT Upper Limits
  53. GRB 130420A: Swift/UVOT Detection
  54. GRB130420B: GMG optical upper limit
  55. GRB 130420A: GMG optical observation
  56. GRB 130420B: Faulkes Telescope North observations
  57. GRB 130420A: Weihai Optical Observations
  58. GRB 130420B: MASTER-Net optical observations
  59. GRB 130420A: T21 optical observations
  60. GRB 130420A: RATIR Optical and NIR Observations
  61. GRB 130420A: PAIRITEL NIR detections
  62. GRB 130420A: ROTSE-III Detection of Optical Counterpart
  63. GRB 130418A: Continued RATIR Optical and NIR Observations
  64. GRB 130418A: SMARTS optical/IR afterglow observations
  65. GRB 130418A: Submm observations from SMA
  66. GRB 130327B: Swift/XRT source is not the afterglow
  67. GRB 130419B (Swift trigger Trigger 553930): MASTER-Net optical observations
  68. GRB 130418A: T18 and T21 optical observations
  69. GRB 130418A: LOAO Observation
  70. GRB 130418A, Swift-BAT refined analysis
  71. GRB 130418A: REM NIR observations
  72. GRB 130418A: RATIR Optical and NIR Observations
  73. GRB 130418A: CARMA 3mm detection
  74. GRB 130418A: GROND detection of the optical-NIR afterglow
  75. GRB 130418A: Swift/UVOT Detection and request for continuing coverage
  76. GRB 130418A: TAROT Calern and TAROT la Silla observatory optical observations
  77. GRB 130418A: TNG optical observations
  78. GRB 130418A: Redshift from 10.4m GTC
  79. GRB 130418A: Bassano Bresciano Observatory optical observations
  80. GRB 130418A: 1.23m I-band observations
  81. GRB 130408a: Skynet Optical Observations
  82. GRB 130408A: SMARTS optical/IR afterglow observations
  83. GRB 130408A: Zadko observatory - Gingin optical observations
  84. GRB 130407A: Swift-XRT observations
  85. GRB130408A: Swift/UVOT followup observations
  86. GRB 130408A - VLT/X-shooter redshift determination
  87. GRB 130408A: GROND detection of the afterglow
  88. GRB 130408A: Liverpool Telescope Optical candidate detection
  89. GRB 130407A Tiled Swift observations
  90. GRB 130211A: Retraction of afterglow candidate
  91. Swift/XRT observation of GRB 130327B
  92. GRB 130327A: RATIR Optical/NIR afterglow confirmation
  93. GRB 130310A: RATIR Observations
  94. GRB 130327B: gamma-ray detection by AGILE
  95. GRB 130327A: Gemini Observations
  96. GRB 130327A: Weihai optical obsevations
  97. GRB 130327A: Swift/UVOT Upper Limits
  98. GRB 130325A Tiled Swift observations
  99. GRB 130327A: RATIR Optical and NIR Observations
  100. GRB 130327A: PAIRITEL NIR Afterglow Candidate

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