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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 140430A: MITSuME Akeno upper limits
  2. GRB 140502A: ISON-NM early optical limit
  3. GRB 140506A: Fermi GBM Detection
  4. GRB 140506A: Swift/UVOT Detection
  5. GRB 140506A: Swift-BAT refined analysis
  6. GRB 140506A: VLT/X-shooter spectroscopy
  7. GRB 140506A: Swift-XRT refined Analysis
  8. GRB 140506A: Enhanced Swift-XRT position
  9. GRB 140506A: Swift detection of a burst with an optical counterpart
  10. Konus-Wind observation of GRB 140423A
  11. GRB 140430A: iTelescope.Net T16 Optical Observation
  12. GRB 140430A: r'-band STELLA-I observations
  13. GRB 140502A: Swift/UVOT Upper Limits
  14. GRB 140502A: MITSuME Okayama upper limits
  15. GRB 140502A: Swift-BAT refined analysis
  16. GRB 140502A: Swift-XRT refined Analysis
  17. GRB 140502A: Enhanced Swift-XRT position
  18. GRB 140430A: BVR-band IAC80 observations
  19. Swift Trigger 597860 is probably not a GRB
  20. GRB 140502A: Fermi GBM observation
  21. GRB 140502A: Swift detection of a burst
  22. GRB 140430A: Further VATT Optical Observations
  23. GRB 140430A: Swift-BAT refined analysis
  24. GRB 140501A: Fermi GBM detection
  25. GRB 140430A: Swift/UVOT Observations
  26. GRB 140430A: Swift-XRT refined Analysis
  27. GRB 140430A: VATT Optical Observations
  28. GRB 140430A: Enhanced Swift-XRT position
  29. GRB 140430A: VLT/X-shooter redshift
  30. GRB 140430A: NOT optical observations
  31. GRB 140430A : Liverpool Telescope optical afterglow observations
  32. GRB 140428A: GROND observations
  33. GRB140430A: Swift detection of a burst with an optical counterpart
  34. GRB 140428B: Fermi GBM observation
  35. Konus-Wind observation of GRB 140428B
  36. GRB 140428A: Swift/UVOT Upper Limits
  37. GRB 140428A: Swift-BAT refined analysis
  38. GRB 140423A: RTT150 optical observations
  39. IPN Triangulation of GRB 140428B (short/hard)
  40. Trigger 597570: Swift detection of SGR 1806-20
  41. GRB 140428A: 1.5m OSN I-band detection
  42. GRB 140428A: Keck redshift estimate
  43. GRB 140428A: Keck detection of a red optical afterglow candidate
  44. GRB 140428A: NOT observations
  45. GRB 140428A: Swift-XRT detection of a source
  46. GRB 140428A: Swift Detection of a Possible Burst
  47. GRB 140423A: MITSuME Akeno upper limits
  48. GRB 140423A Third epoch pODI photometry
  49. GRB 140423A: Continued RATIR Optical and NIR Observations
  50. GRB 140423A: MITSuME Akeno Optical observation
  51. GRB 140413A: GROND Afterglow Confirmation
  52. DG CVn: optical observations
  53. GRB 140423A: RATIR Optical and NIR Observations
  54. GRB 140423A: NOT Afterglow Observations
  55. GRB 140419A: Continued Mondy optical observations
  56. GRB 140423A: Nishi-Harima NIR Observations
  57. GRB 140423A: TNG NIR observations
  58. GRB 140423A pODI/WIYN afterglow photometry
  59. GRB 140423A, Optical Observations
  60. GRB 140423A: Kanata/HONIR Optical and NIR Observations
  61. GRB 140423A: Swift-XRT refined Analysis
  62. GRB 140423A: Swift-BAT refined analysis
  63. GRB 140423A: MITSuME Okayama Optical Observation
  64. Swift Trigger 596958 is positionally consistent with V* DG CVn/2XMM J133146.4+291635
  65. Swift Trigger 596958 is probably the flare star: DG CVn
  66. GRB 140423A: Further Observations with Swift/UVOT
  67. GRB 140423A: KAIT Optical Detection
  68. GRB 140423A: Enhanced Swift-XRT position
  69. GRB 140423A: Nanshan optical upper limit
  70. GRB 140423A: P60 Observations
  71. GRB 140423A: Fermi GBM observation
  72. GRB 140423A: KWFC z-band photometry
  73. GRB 140423A: Gemini-N redshift
  74. GRB 140419A, LOAO R-band observations
  75. GRB 140423A: ISON-MN early photometry and correction to the GCN circ. 16143
  76. GRB 140423A: Swift/UVOT detection of a possible counterpart
  77. GRB 140423A: Swift-XRT observations
  78. GRB 140423A: ROTSE-III Detection of Optical Counterpart
  79. GRB 140423A optical observations with pODI/WIYN at KPNO
  80. GRB 140423A: optical afterglow candidate
  81. GRB 140423A: Swift detection of a burst
  82. GRB 140419A: Mondy optical observations
  83. GRB 140419A: Refined NOT photometry
  84. GRB 140419A: Continued RATIR Optical and NIR Observations
  85. GRB140419A: NOT optical observations
  86. GRB 140419A: KAIT Refined Analysis
  87. GRB 140419A: Continued RATIR Optical and NIR Observations
  88. Swift Trigger 596641 is not a GRB
  89. Konus-Wind observation of GRB 140419A
  90. GRB 140419A, Optical Observations
  91. GRB 140419A: MITSuME Ishigakijima Optical Observation
  92. GRB 140419A: MITSuME Okayama Optical Observation
  93. GRB 140419A: Swift UVOT refined analysis
  94. GRB 140419A: P60 Observations
  95. GRB 140419A: Swift-XRT refined Analysis
  96. GRB 140419A: Swift-BAT refined analysis
  97. GRB 140419A: T24 optical observations
  98. GRB 140419A: Gemini-N redshift
  99. GRB 140419A: Enhanced Swift-XRT position
  100. GRB140419A: UVOT detects fading afterglow in white but not in u filter

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