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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"

20456 results found.

  1. GRB 130420A: Early RAPTOR Simultaneous Multi-Color Observations
  2. GRB 130418A: WSRT radio observation
  3. GRB 130420B: RATIR Optical and NIR Observations
  4. GRB 130420A: Continued RATIR Optical and NIR Observations
  5. GRB 130420A: ISON-NM optical observations
  6. Skynet/GORT observations of GRB130420A
  7. GRB 130420B: Swift/UVOT Upper Limits
  8. GRB 130420A: Swift/UVOT Detection
  9. GRB130420B: GMG optical upper limit
  10. GRB 130420A: GMG optical observation
  11. GRB 130420B: Faulkes Telescope North observations
  12. GRB 130420A: Weihai Optical Observations
  13. GRB 130420B: MASTER-Net optical observations
  14. GRB 130420A: T21 optical observations
  15. GRB 130420A: RATIR Optical and NIR Observations
  16. GRB 130420A: PAIRITEL NIR detections
  17. GRB 130420A: ROTSE-III Detection of Optical Counterpart
  18. GRB 130418A: Continued RATIR Optical and NIR Observations
  19. GRB 130418A: SMARTS optical/IR afterglow observations
  20. GRB 130418A: Submm observations from SMA
  21. GRB 130327B: Swift/XRT source is not the afterglow
  22. GRB 130419B (Swift trigger Trigger 553930): MASTER-Net optical observations
  23. GRB 130418A: T18 and T21 optical observations
  24. GRB 130418A: LOAO Observation
  25. GRB 130418A, Swift-BAT refined analysis
  26. GRB 130418A: REM NIR observations
  27. GRB 130418A: RATIR Optical and NIR Observations
  28. GRB 130418A: CARMA 3mm detection
  29. GRB 130418A: GROND detection of the optical-NIR afterglow
  30. GRB 130418A: Swift/UVOT Detection and request for continuing coverage
  31. GRB 130418A: TAROT Calern and TAROT la Silla observatory optical observations
  32. GRB 130418A: TNG optical observations
  33. GRB 130418A: Redshift from 10.4m GTC
  34. GRB 130418A: Bassano Bresciano Observatory optical observations
  35. GRB 130418A: 1.23m I-band observations
  36. GRB 130408a: Skynet Optical Observations
  37. GRB 130408A: SMARTS optical/IR afterglow observations
  38. GRB 130408A: Zadko observatory - Gingin optical observations
  39. GRB 130407A: Swift-XRT observations
  40. GRB130408A: Swift/UVOT followup observations
  41. GRB 130408A - VLT/X-shooter redshift determination
  42. GRB 130408A: GROND detection of the afterglow
  43. GRB 130408A: Liverpool Telescope Optical candidate detection
  44. GRB 130407A Tiled Swift observations
  45. GRB 130211A: Retraction of afterglow candidate
  46. Swift/XRT observation of GRB 130327B
  47. GRB 130327A: RATIR Optical/NIR afterglow confirmation
  48. GRB 130310A: RATIR Observations
  49. GRB 130327B: gamma-ray detection by AGILE
  50. GRB 130327A: Gemini Observations
  51. GRB 130327A: Weihai optical obsevations
  52. GRB 130327A: Swift/UVOT Upper Limits
  53. GRB 130325A Tiled Swift observations
  54. GRB 130327A: RATIR Optical and NIR Observations
  55. GRB 130327A: PAIRITEL NIR Afterglow Candidate
  56. report: GRB 130315A: Zadko observatory - Gingin optical observations
  57. GRB 130305A: Gemini follow-up observations
  58. GRB 130315A: GROND afterglow candidate
  59. GRB 130315A: Swift/UVOT Upper Limits
  60. GRB 130315A: SALT optical observations
  61. GRB 130313A: 5.8 GHz VLA upper limit
  62. Swift XRT observations of GRB 130310A
  63. GRB 130313A: Swift/UVOT Upper Limits
  64. GRB 130305A: TLS Tautenburg observations
  65. GRB 130313A: RATIR Optical and NIR Observations
  66. GRB 130313A: TNG optical observations
  67. GRB 130313A: Fading X-ray Afterglow
  68. GRB 130215A: Detection of the SN with the 10.4m GTC
  69. GRB130313A: Optical observations from GTC
  70. GRB 130313A: NOT optical upper limit
  71. GRB 130313A: simultaneous and follow-up optical observations at BOOTES-3 and BOOTES-4
  72. GRB 130313A: Weihai optical upper limit
  73. GRB 130313A: Zadko observatory - Gingin optical observations
  74. GRB 130313A: MASTER-Net optical observations
  75. GRB 100424A: Keck host detection and VLT/X-shooter redshift
  76. Swift XRT RETRACTION of GRB 130310A afterglow detection
  77. GRB 130310A: optical observations
  78. Swift XRT observations of GRB 130310A
  79. GRB 130306A: Swift Detection of a Possible Afterglow
  80. GRB 130131B: host detection and redshift
  81. GRB 130131A: JCMT SCUBA-2 sub-mm observations
  82. GRB 130305A: Further Swift-XRT Observations
  83. GRB 130305A: Optical Observations
  84. GRB 111123A: Keck-I host detection and VLT/X-shooter redshift
  85. GRB 130305A: Gemini-North upper limit
  86. GRB 130306A: MASTER-Net pre-Swift alert observation
  87. GRB 130305A: Swift/UVOT Upper Limit
  88. GRB 130305A: RATIR Observations
  89. GRB 130305A: P60 Observations
  90. GRB 100615A: HST host detection and X-shooter redshift
  91. GRB 130305A: Swift/XRT detection of the afterglow
  92. GRB 121128A: optical observations in Mondy observatory
  93. GRB 130216A: Swift/UVOT Upper Limit
  94. GRB 130216A: possible radio counterpart is steady field source
  95. GRB 130216A: Swift/XRT observations
  96. GRB 130215A: PTF P48 optical detection
  97. GRB 130216B: Swift/XRT observations
  98. GRB 130216B: MASTER-Net early observation
  99. GRB 130216A: MASTER-Net early observations
  100. GRB 130215A: Continued RATIR Optical and NIR Monitoring

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