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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 140515A: VLA Detection
  2. GRB 140515A : TNG near-infrared observations
  3. GRB 140419A: Continued Mondy optical observations
  4. GRB 140515A: GROND observation of the afterglow
  5. GRB 140515A: Spectroscopy from the 10.4m GTC
  6. GRB 140515A: Optical observations from the 2.5 m NOT
  7. GRB 140515A: Swift-XRT refined Analysis
  8. GRB 140515B: MAXI/GSC detection
  9. GRB 140515A: KAIT Optical Upper Limit
  10. GRB 140515A: Gemini-North imaging
  11. GRB 140515A: Swift/UVOT Upper Limits
  12. GRB 140423A: HCT optical observations
  13. GRB 140515A: MITSuME Akeno upper limits
  14. GRB 140515A: Enhanced Swift-XRT position
  15. GRB 140515A: Gemini-N redshift
  16. Trigger 599041: Swift detection of SFXT IGR J16479-4514
  17. GRB 140515A: Swift detection of a burst
  18. GRB 140508A: VLA detection
  19. Konus-Wind observation of GRB 140512A
  20. GRB 140423A: AAO optical upper limits
  21. GRB 140512A: Continued UVOT Observations
  22. GRB 140512A: Fermi GBM detection
  23. GRB 140512A: Xinglong TNT optical observation
  24. GRB 140508A: Mondy upper limit
  25. GRB 140508A: MITSuME Akeno Optical observation
  26. GRB 140512A: Swift-BAT refined analysis
  27. GRB140512A : GROND observations
  28. GRB 140512A: Swift-XRT refined Analysis
  29. GRB 140512A: Enhanced Swift-XRT position
  30. Swift Observations of GRB 140508A
  31. GRB 140512A: Optical observations from the 2.5 m NOT
  32. GRB 140428A: GROND afterglow confirmation
  33. GRB 140512A: Mondy optical detection
  34. GRB 140512A: MASTER OT decay and early light curve
  35. GRB 140512A: Swift detection of a burst with an optical counterpart
  36. GRB 140512A: MASTER optical observations
  37. GRB 140423A: Mondy optical observations
  38. GRB 140508A: Continued RATIR Optical and NIR Observations
  39. Fermi GBM Trigger 140429551 - Detection of a burst from SGR 1806-20
  40. GRB 140508A: ​HCT spectroscopy
  41. GRB 140508A: Swift/UVOT Detection
  42. GRB 140509B: MAXI/GSC detection
  43. GRB 140509A: Swift/UVOT Detection and photo-z
  44. GRB 140509A: Swift-BAT refined analysis
  45. VHE gamma-ray observations by MAGIC of SWIFT Trigger 596958
  46. GRB 140509A: Swift-XRT refined Analysis
  47. GRB 140508A: RATIR Optical and NIR Observations
  48. GRB 140508A: Optical Observations via Virtual Telescope
  49. Konus-Wind observation of GRB 140508A
  50. GRB 140509A: Enhanced Swift-XRT position
  51. GRB 140508A: Swift-XRT observations
  52. GRB 140508A: WHT spectroscopy
  53. GRB 140509A: Swift detection of a burst with an optical counterpart
  54. GRB 140508A: NOT photometry and spectroscopy
  55. GRB 140508A: SAO RAS and MASTER photometric and spectroscopic observations
  56. GRB 140508A: 1.23m CAHA BVRI-band observations
  57. GRB 140508A: iPTF optical transient candidate
  58. IPN triangulation of GRB 140508A
  59. GRB 140508A: Fermi GBM detection
  60. Konus-Wind observation of GRB 140506A
  61. GRB 140430A: MITSuME Akeno upper limits
  62. GRB 140502A: ISON-NM early optical limit
  63. GRB 140506A: Fermi GBM Detection
  64. GRB 140506A: Swift/UVOT Detection
  65. GRB 140506A: Swift-BAT refined analysis
  66. GRB 140506A: VLT/X-shooter spectroscopy
  67. GRB 140506A: Swift-XRT refined Analysis
  68. GRB 140506A: Enhanced Swift-XRT position
  69. GRB 140506A: Swift detection of a burst with an optical counterpart
  70. Konus-Wind observation of GRB 140423A
  71. GRB 140430A: iTelescope.Net T16 Optical Observation
  72. GRB 140430A: r'-band STELLA-I observations
  73. GRB 140502A: Swift/UVOT Upper Limits
  74. GRB 140502A: MITSuME Okayama upper limits
  75. GRB 140502A: Swift-BAT refined analysis
  76. GRB 140502A: Swift-XRT refined Analysis
  77. GRB 140502A: Enhanced Swift-XRT position
  78. GRB 140430A: BVR-band IAC80 observations
  79. Swift Trigger 597860 is probably not a GRB
  80. GRB 140502A: Fermi GBM observation
  81. GRB 140502A: Swift detection of a burst
  82. GRB 140430A: Further VATT Optical Observations
  83. GRB 140430A: Swift-BAT refined analysis
  84. GRB 140501A: Fermi GBM detection
  85. GRB 140430A: Swift/UVOT Observations
  86. GRB 140430A: Swift-XRT refined Analysis
  87. GRB 140430A: VATT Optical Observations
  88. GRB 140430A: Enhanced Swift-XRT position
  89. GRB 140430A: VLT/X-shooter redshift
  90. GRB 140430A: NOT optical observations
  91. GRB 140430A : Liverpool Telescope optical afterglow observations
  92. GRB 140428A: GROND observations
  93. GRB140430A: Swift detection of a burst with an optical counterpart
  94. GRB 140428B: Fermi GBM observation
  95. Konus-Wind observation of GRB 140428B
  96. GRB 140428A: Swift/UVOT Upper Limits
  97. GRB 140428A: Swift-BAT refined analysis
  98. GRB 140423A: RTT150 optical observations
  99. IPN Triangulation of GRB 140428B (short/hard)
  100. Trigger 597570: Swift detection of SGR 1806-20

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