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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"

42595 results found.

  1. GRB 140305A: Swift-BAT refined analysis
  2. Trigger 590503: Swift-BAT triggered on noise
  3. GRB 140304A: MASTER OT light curve
  4. GRB 140304A: CARMA 3mm detection
  5. GRB 140304A: VLA Detection
  6. GRB 140305A: Swift detection of a burst
  7. GRB 140304A: RATIR g-band Dropout
  8. GRB 140304A: Swift-BAT refined analysis
  9. GRB 140304A: Swift-XRT refined Analysis
  10. GRB 140304A: Enhanced Swift-XRT position
  11. GRB 140304A: Redshift from the NOT
  12. GRB 140304A: Fermi GBM detection
  13. GRB 140304A: 10.4m GTC redshift z = 5.39
  14. GRB 140304A: NOT observations and redshift estimate
  15. GRB 140304A: Swift/UVOT Upper Limits
  16. iPTF14yb: JVLA and CARMA observations
  17. GRB 140304A: Khureltogot optical observations
  18. GRB 140304A: Mondy optical observations
  19. GRB 140304A: Afterglow decay from Nanshan observations
  20. GRB 140304A: Swift detection of a burst
  21. GRB 140304A: MASTER OT detecton
  22. GRB140302A: Fermi GBM detection
  23. GRB 140302A: Swift-XRT refined Analysis
  24. GRB 140302A: Swift-BAT refined analysis
  25. GRB 140302A: Enhanced Swift-XRT position
  26. GRB 140301A: Swift-BAT refined analysis
  27. GRB 140301A: Swift-XRT refined Analysis
  28. GRB 140301A: GROND Detection of the Optical/NIR Afterglow
  29. GRB 140302A: GROND afterglow candidate
  30. GRB 140302A: Prompt enhanced Swift-XRT position
  31. GRB 140302A: Swift detection of a burst
  32. GRB 140301A: VLT/X-shooter redshift
  33. GRB 140301A: NOT afterglow candidate
  34. GRB 140301A: Enhanced Swift-XRT position
  35. GRB 140301A: Skynet R-COP Observations
  36. GRB 140301A: Swift detection of a burst
  37. GRB 140226A/iPTF14yb: 1.23m CAHA observations
  38. GRB 140226A/iPTF14yb: Swift/UVOT Observations
  39. GRB 140226A/iPTF14yb: Mondy optical observations
  40. GRB 140226A/iPTF14yb: RATIR Optical and NIR Observations
  41. GRB 140226A / iPTF14yb: Swift-XRT confirms a fading X-ray source
  42. GRB 140219A: Mondy optical observations of XRT source #5
  43. Konus-Wind observation of GRB 140226A
  44. IPN triangulation of GRB 140226A, a possible GRB counterpart to iPTF14yb
  45. PTF14yb: GROND Transient Detection
  46. iPTF14yb: RATIR Optical and NIR Observations of the optical transient
  47. GRB 140219A: Suzaku WAM observation of the prompt emission
  48. iPTF14yb: Swift-XRT detection
  49. iPTF14yb: iPTF Discovery of an Optical Afterglow-like Transient
  50. GRB 140219A: MAXI/GSC detection
  51. GRB 140219A: the confirmation of the brightening SDSS J102406.41+062937.6 star
  52. GRB 140219A: Retraction of X-ray afterglow
  53. GRB 140219A: MASTER optical brightening inside XRT-5 error box detection
  54. GRB 140219A: iPTF optical observations
  55. GRB 140102A: TAOS early optical afterglow detection
  56. GRB 140219A: optical observations of XRT source #5
  57. GRB 140219A: XRT afterglow candidate
  58. GRB 140221A: Results from Swift XRT tiled observations
  59. GRB 140219A: Xuyi and Nanshan upper limits
  60. GRB 140219A: results from Swift XRT and UVOT tiled observations
  61. GRB 140219A: MASTER before and after GRB observational arguments of the exceptionally Dark GRB
  62. Konus-Wind observation of exceptionally bright GRB 140219A
  63. GRB 140221A Tiled Swift observations
  64. GRB 140221A: MAXI/GSC detection
  65. GRB 140219A: Fermi-LAT detection of a burst
  66. GRB 140219A: Fermi GBM Detection
  67. GRB 140219A Tiled Swift observations
  68. IPN Triangulation of extremely bright long GRB 140219A
  69. Swift follow-up of an Integral weak transient
  70. GRB 140213A: Continued Skynet R-COP/PROMPT Observations of the Optical Afterglow
  71. GRB 140215A: RAPTOR Observations During Gamma-Ray Emitting Interval
  72. Fermi GBM trigger 140214230 is not a GRB
  73. GRB 140213A: Continued Skynet R-COP/PROMPT Detections of a Rebrightening Optical Afterglow
  74. GRB 140215A: Continued Skynet PROMPT Observations of the Optical Afterglow
  75. GRB 140215A: WSRT radio observation
  76. GRB 140211A: Khureltogot optical upper limits
  77. GRB 140215A: Continued RATIR Optical and NIR Observations
  78. Konus-Wind observation of GRB 140213A
  79. Konus-Wind observation of GRB 140215A
  80. GRB 140215A: Swift/UVOT Detection
  81. GRB 140211A: Swift-XRT and UVOT observations
  82. GRB140215A: Continued Discovery Channel Telescope Observations
  83. GRB 140215A: Continued RATIR Optical and NIR Observations
  84. GRB 140215A: Swift-BAT refined analysis
  85. GRB 140215A: ISON-NM optical observations
  86. GRB 140215A: Swift-XRT refined Analysis
  87. GRB 140215A: P60 observations
  88. GRB 140215A: T24 optical observations
  89. GRB 140215A: Enhanced Swift-XRT position
  90. GRB 140215A: RATIR Optical and NIR Observations
  91. GRB140215A: Skynet PROMPT Optical Observations
  92. GRB 140215A: KAIT Optical Detection
  93. GRB140215A: Prompt Observations with Discovery Channel Telescope
  94. GRB 140215A: Swift detection of a burst with optical counterpart
  95. GRB 140213A: Swift-BAT refined analysis
  96. GRB140206A: Discovery Channel Telescope Optical Detection
  97. GRB 140213A: Fermi GBM Detection
  98. GRB 140213A: Swift-XRT refined Analysis
  99. GRB140213A: VLT/X-shooter redshift
  100. GRB 140213A: Enhanced Swift-XRT position

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