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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"
  1. GRB 130418A: RATIR Optical and NIR Observations
  2. GRB 130418A: CARMA 3mm detection
  3. GRB 130418A: GROND detection of the optical-NIR afterglow
  4. GRB130418A: OSN 1.5m fading afterglow detection
  5. GRB 130418A: Swift/UVOT Detection and request for continuing coverage
  6. GRB 130418A: Enhanced Swift-XRT position
  7. GRB 130418A: TAROT Calern and TAROT la Silla observatory optical observations
  8. GRB 130418A: TNG optical observations
  9. GRB 130418A: Redshift from 10.4m GTC
  10. GRB 130418A: Bassano Bresciano Observatory optical observations
  11. GRB 130418A: 1.23m I-band observations
  12. GRB 130418A: Swift detection of a burst with an optical counterpart
  13. GRB 130408A: Suzaku WAM observation of the prompt emission
  14. GRB 130408a: Skynet Optical Observations
  15. GRB 130408A: SMARTS optical/IR afterglow observations
  16. GRB 130408A, Swift-BAT refined analysis
  17. GRB 130408A: Zadko observatory - Gingin optical observations
  18. GRB 130407A: Swift-XRT observations
  19. GRB130408A: Swift/UVOT followup observations
  20. GRB 130408A: Swift-XRT refined Analysis
  21. Konus-Wind observation of GRB 130408A
  22. GRB 130408A: Enhanced Swift-XRT position
  23. GRB 130408A - Gemini-S/GMOS redshift determination
  24. GRB 130408A - VLT/X-shooter redshift determination
  25. GRB 130408A: GROND detection of the afterglow
  26. GRB 130408A: Swift/UVOT Detection of the Optical Afterglow
  27. GRB 130408A: Liverpool Telescope Optical candidate detection
  28. GRB 130408A: Swift detection of a burst
  29. GRB 130407A Tiled Swift observations
  30. GRB 130407A: MAXI/GSC detection
  31. GRB 130211A: Retraction of afterglow candidate
  32. GRB 130327B: Suzaku WAM observation of the prompt emission
  33. Konus-Wind observation of GRB 130320B
  34. Swift detection of IGR J18245-2452
  35. IPN Triangulation of GRB 130320B (very long/bright)
  36. Swift/XRT observation of GRB 130327B
  37. GRB 130327A: RATIR Optical/NIR afterglow confirmation
  38. GRB 130306A: Confirmation of the X-ray Afterglow
  39. GRB 130310A: RATIR Observations
  40. Swift Trigger 552142 is a noise event
  41. Konus-Wind observation of GRB 130327B
  42. GRB 130327B: Fermi-LAT detection of a burst
  43. GRB 130327B: Fermi GBM detection
  44. Swift Trigger 552142: a possible GRB
  45. GRB 130327B: gamma-ray detection by AGILE
  46. GRB 130327A: Swift-BAT refined analysis
  47. GRB 130327A: Gemini Observations
  48. GRB 130327A: Swift-XRT refined Analysis
  49. GRB 130327A: Weihai optical obsevations
  50. GRB 130327A: Swift/UVOT Upper Limits
  51. Konus-Wind observation of GRB 130325A
  52. GRB 130327A: ISON-NM optical upper limit
  53. GRB 130325A Tiled Swift observations
  54. GRB 130327A: Enhanced Swift-XRT position
  55. GRB 130327A: RATIR Optical and NIR Observations
  56. GRB 130327A: PAIRITEL NIR Afterglow Candidate
  57. GRB 130325A: Fermi LAT detection
  58. GRB 130327A: Swift detection of a burst
  59. report: GRB 130315A: Zadko observatory - Gingin optical observations
  60. GRB 130325A: Fermi GBM detection
  61. Konus-Wind observation of GRB 130320A
  62. IPN Triangulation of GRB 130320A (long/very bright)
  63. GRB 130305A: Gemini follow-up observations
  64. GRB 130315A: GROND afterglow candidate
  65. GRB 130305A: optical upper limit in Mondy observatory
  66. GRB 130315A: Swift/UVOT Upper Limits
  67. GRB 130313A: optical upper limit in CrAO
  68. GRB 130313A: optical upper limit in Mondy observatory
  69. GRB 130315A: SALT optical observations
  70. GRB130313A: GTC early optical limits
  71. GRB 130313A: 5.8 GHz VLA upper limit
  72. GRB 130315A: Swift-XRT refined Analysis
  73. Swift XRT observations of GRB 130310A
  74. GRB 130315A, Swift-BAT refined analysis
  75. GRB 130313A: Swift/UVOT Upper Limits
  76. GRB 130305A: PTF P48 optical upper limits
  77. GRB130315A BOOTES-3 optical limit
  78. GRB 130315A: Swift detection of a burst
  79. GRB 130310A : Suzaku WAM observation of the prompt emission
  80. GRB 130305A: TLS Tautenburg observations
  81. GRB 130313A: RATIR Optical and NIR Observations
  82. GRB 130313A: TNG optical observations
  83. GRB 130313A: Swift-BAT Spectral lag analysis
  84. GRB 130313A: Fading X-ray Afterglow
  85. Swift-BAT trigger 551030 is not astrophysical
  86. GRB 130215A: Detection of the SN with the 10.4m GTC
  87. GRB130313A: Optical observations from GTC
  88. GRB 130313A: NOT optical upper limit
  89. GRB 130313A: Swift-XRT refined Analysis
  90. GRB 130313A: simultaneous and follow-up optical observations at BOOTES-3 and BOOTES-4
  91. GRB 130313A: Weihai optical upper limit
  92. GRB 130313A: Swift-XRT detection of a possible X-ray afterglow
  93. GRB 130313A: Swift-BAT refined analysis
  94. GRB 130313A: Zadko observatory - Gingin optical observations
  95. GRB 130313A: MASTER-Net optical observations
  96. GRB 130313A: Swift detection of a short burst
  97. IPN Triangulation of GRB 130307A
  98. GRB 100424A: Keck host detection and VLT/X-shooter redshift
  99. Swift XRT RETRACTION of GRB 130310A afterglow detection
  100. GRB 130310A: optical observations

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