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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"

2623 results found.

  1. Swift Trigger 635306 is probably not an astrophysical source
  2. GRB 150220A, the review of the sky area in plate archives
  3. GRB 150314A: Fermi-LAT detection
  4. GRB 150311A: MAXI/GSC possible afterglow detection
  5. GRB 150309A: Swift-BAT refined analysis
  6. GRB 150301C: VLA Observations
  7. Trigger 633105 (aka GRB150301C): Swift/UVOT Observations of XRT Counterpart
  8. GRB 150301C : (Swift trigger 633105) Swift observations
  9. Swift Trigger 633173 is probably not an astrophysical source
  10. Trigger 633105 is likely not a GRB
  11. GRB 150213B, the review of the sky area in plate archives
  12. GRB 150212A, the review of the sky area in plate archives
  13. GRB 150206B: Fermi GBM detection
  14. GRB 150204A: Swift/UVOT Upper Limits
  15. GRB 150201A: Fermi GBM observation
  16. GRB 150120A: 9.8 GHz VLA upper limit
  17. GRB 150120A: possible AMI 15 GHz detection
  18. GRB 150110B: AMI 15 GHz detection of possible radio counterpart
  19. GRB 150101B/Swift J123205.1-105602, deep VLT observations
  20. Radio upper limit on the GRB 141121A with the GMRT
  21. GRB 141229A: Swift-XRT observations
  22. GRB 141220A: Photometry from OSIRIS/GTC
  23. GRB 141215A: Swift-XRT observations
  24. GRB141208.63: MASTER OT Detection During the Fermi Error Box inspection
  25. GRB141202A: Discovery Channel Telescope Optical Observations
  26. GRB 141202A: Swift XRT observations
  27. GRB 141121A: Mondy optical observations
  28. IPN Triangulation of GRB 141121A (initial episode)
  29. GRB 141121A: Mondy optical observations
  30. GRB 141121A: LCO-FTN observations
  31. X-shooter redshift of GRB 141109A
  32. GRB 141104A: Swift-XRT observations
  33. GRB 141102A possible precursor was another, known source
  34. Konus-Wind observation of GRB 141102A
  35. GRB 141102A found in ground analysis of BAT data
  36. MAXI GRB 141029A is likely an X-ray flare from 1RXS J043657.1-161258
  37. GRB 141031A: Swift/UVOT Upper Limits
  38. GRB 141031A: GROND detection of a possible optical afterglow candidate
  39. GRB 141028A: GROND Afterglow confirmation (MASTER source)
  40. GRB 141026A: P60 early observations
  41. GRB 141022A: GROND Detection of a possible Optical Afterglow Candidate
  42. GRB 141004A: La Palma late-time observations and possible brightening
  43. GRB 141020B: MAXI/GSC detection
  44. GRB 141017A: GROND Afterglow Confirmation
  45. GRB 140930B: MASTER early possible OT detection
  46. Swift possible detection of the Be star HD 305560
  47. Possible radio detection of GRB 140903A with the GMRT
  48. Refined IPN Triangulation of GRB 140906C
  49. GRB 140906A - Fermi GBM Detection
  50. GRB 140906A: iPTF optical transient candidates
  51. GRB 140903A: Possible optical variability
  52. GRB 140903A: FTN observations
  53. GRB 140903A: Swift detection of a possible burst
  54. GRB 140831A: iPTF observations of a possible short burst detected by Fermi GBM
  55. GRB140818B, the review of the sky area in plate archives
  56. Swift Burst Response Reenabled
  57. Fermi GBM Trigger 140819576/ 430148973/ MASTER OT
  58. Fermi trigger 430148973: Swift-XRT observation
  59. Radio upper limit on the GRB 140808A with the GMRT
  60. GRB 140818A - Fermi GBM Detection
  61. Swift Mission Operations Center Moving
  62. GRB140809A: Fermi GBM observation
  63. Swift trigger 609139 is probably 4U 1850-03
  64. Swift observations of possible GRB 140809A candidate
  65. GRB 140809A (FERMI trigger 429246673): MASTER follow-up inspection
  66. GRB 140808A: Fermi GBM detection
  67. GRB 140808A: optical afterglow candidate iPTF14eag
  68. GRB 140709A, the review of the sky area in plate archives
  69. Swift Trigger 607945: possible noise event in the direction of NGC2559
  70. Radio upper limit on the GRB 140713A with the GMRT
  71. GRB 140723A: LCO-Sutherland optical candidate retraction
  72. GRB 140723A: LCO-Sutherland optical candidate
  73. GRB 140709A: Possible AMI 15 GHz detection
  74. Radio upper limits on the GRB 140703A with the GMRT
  75. GRB 140705A: Swift-BAT refined analysis of a possible newly discovered SGR 1935+2154
  76. GRB 140619A: Swift detection of a burst with a possible optical counterpart
  77. Swift-BAT trigger 601928: Detection of a possible outburst from V490 Cep
  78. GRB 140614A: Swift-BAT refined analysis
  79. GRB 140611A Detection of a source in BAT ground analysis
  80. Swift XRT status update
  81. Swift XRT is off-line
  82. Chandra late-time observations of GRB140515A
  83. Swift Trigger 600114 in M31: Archival and Prompt UVOT Imaging
  84. IPN Triangulation of GRB 140523A
  85. GRB 140523A: Nanshan optical upper limit
  86. GRB 140523A: possible X-ray afterglow candidate from tiled Swift/XRT observations
  87. GRB 140518A: RATIR Optical and NIR Observations
  88. GRB 140502A: ISON-NM early optical limit
  89. GRB 140428A: Swift-XRT detection of a source
  90. GRB 140428A: Swift Detection of a Possible Burst
  91. GRB 140423A: Nishi-Harima NIR Observations
  92. GRB 140423A: Swift/UVOT detection of a possible counterpart
  93. Konus-Wind observation of GRB 140413A
  94. Swift Trigger 595616: a possible GRB
  95. Swift-BAT trigger 595162 is noise
  96. Swift Trigger 595162: a possible GRB
  97. Swift trigger 594286: Is likely a noise trigger
  98. GRB 140330A: intense and persistent gamma-ray emission detected by AGILE
  99. GRB 140226A/iPTF14yb: Mondy optical observations
  100. GRB 140320C: Mondy optical observations and afterglow confirmation

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