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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"

2803 results found.

  1. GRB 141229A: Swift-XRT observations
  2. GRB 141220A: Photometry from OSIRIS/GTC
  3. GRB 141215A: Swift-XRT observations
  4. GRB141208.63: MASTER OT Detection During the Fermi Error Box inspection
  5. GRB141202A: Discovery Channel Telescope Optical Observations
  6. GRB 141202A: Swift XRT observations
  7. GRB 141121A: Mondy optical observations
  8. IPN Triangulation of GRB 141121A (initial episode)
  9. GRB 141121A: Mondy optical observations
  10. GRB 141121A: LCO-FTN observations
  11. X-shooter redshift of GRB 141109A
  12. GRB 141104A: Swift-XRT observations
  13. GRB 141102A possible precursor was another, known source
  14. Konus-Wind observation of GRB 141102A
  15. GRB 141102A found in ground analysis of BAT data
  16. MAXI GRB 141029A is likely an X-ray flare from 1RXS J043657.1-161258
  17. GRB 141031A: Swift/UVOT Upper Limits
  18. GRB 141031A: GROND detection of a possible optical afterglow candidate
  19. GRB 141028A: GROND Afterglow confirmation (MASTER source)
  20. GRB 141026A: P60 early observations
  21. GRB 141022A: GROND Detection of a possible Optical Afterglow Candidate
  22. GRB 141004A: La Palma late-time observations and possible brightening
  23. GRB 141020B: MAXI/GSC detection
  24. GRB 141017A: GROND Afterglow Confirmation
  25. GRB 140930B: MASTER early possible OT detection
  26. Swift possible detection of the Be star HD 305560
  27. Possible radio detection of GRB 140903A with the GMRT
  28. Refined IPN Triangulation of GRB 140906C
  29. GRB 140906A - Fermi GBM Detection
  30. GRB 140906A: iPTF optical transient candidates
  31. GRB 140903A: Possible optical variability
  32. GRB 140903A: FTN observations
  33. GRB 140903A: Swift detection of a possible burst
  34. GRB 140831A: iPTF observations of a possible short burst detected by Fermi GBM
  35. GRB140818B, the review of the sky area in plate archives
  36. Swift Burst Response Reenabled
  37. Fermi GBM Trigger 140819576/ 430148973/ MASTER OT
  38. Fermi trigger 430148973: Swift-XRT observation
  39. Radio upper limit on the GRB 140808A with the GMRT
  40. GRB 140818A - Fermi GBM Detection
  41. Swift Mission Operations Center Moving
  42. GRB140809A: Fermi GBM observation
  43. Swift trigger 609139 is probably 4U 1850-03
  44. Swift observations of possible GRB 140809A candidate
  45. GRB 140809A (FERMI trigger 429246673): MASTER follow-up inspection
  46. GRB 140808A: Fermi GBM detection
  47. GRB 140808A: optical afterglow candidate iPTF14eag
  48. GRB 140709A, the review of the sky area in plate archives
  49. Swift Trigger 607945: possible noise event in the direction of NGC2559
  50. Radio upper limit on the GRB 140713A with the GMRT
  51. GRB 140723A: LCO-Sutherland optical candidate retraction
  52. GRB 140723A: LCO-Sutherland optical candidate
  53. GRB 140709A: Possible AMI 15 GHz detection
  54. Radio upper limits on the GRB 140703A with the GMRT
  55. GRB 140705A: Swift-BAT refined analysis of a possible newly discovered SGR 1935+2154
  56. GRB 140619A: Swift detection of a burst with a possible optical counterpart
  57. Swift-BAT trigger 601928: Detection of a possible outburst from V490 Cep
  58. GRB 140614A: Swift-BAT refined analysis
  59. GRB 140611A Detection of a source in BAT ground analysis
  60. Swift XRT status update
  61. Swift XRT is off-line
  62. Chandra late-time observations of GRB140515A
  63. Swift Trigger 600114 in M31: Archival and Prompt UVOT Imaging
  64. IPN Triangulation of GRB 140523A
  65. GRB 140523A: Nanshan optical upper limit
  66. GRB 140523A: possible X-ray afterglow candidate from tiled Swift/XRT observations
  67. GRB 140518A: RATIR Optical and NIR Observations
  68. GRB 140502A: ISON-NM early optical limit
  69. GRB 140428A: Swift-XRT detection of a source
  70. GRB 140428A: Swift Detection of a Possible Burst
  71. GRB 140423A: Nishi-Harima NIR Observations
  72. GRB 140423A: Swift/UVOT detection of a possible counterpart
  73. Konus-Wind observation of GRB 140413A
  74. Swift Trigger 595616: a possible GRB
  75. Swift-BAT trigger 595162 is noise
  76. Swift Trigger 595162: a possible GRB
  77. Swift trigger 594286: Is likely a noise trigger
  78. GRB 140330A: intense and persistent gamma-ray emission detected by AGILE
  79. GRB 140226A/iPTF14yb: Mondy optical observations
  80. GRB 140320C: Mondy optical observations and afterglow confirmation
  81. GRB 140311C: MASTER optical observations
  82. GRB 140311C: Swift-XRT and UVOT observations
  83. Fermi416242156: possible iPTF counterpart
  84. GRB 140226A/iPTF14yb: Mondy optical observations
  85. GRB 140219A: Mondy optical observations of XRT source #5
  86. Konus-Wind observation of GRB 140226A
  87. IPN triangulation of GRB 140226A, a possible GRB counterpart to iPTF14yb
  88. iPTF14yb: Swift-XRT detection
  89. GRB 140219A: Xuyi and Nanshan upper limits
  90. GRB 140209A, Swift-BAT refined analysis
  91. GRB 140209A: optical observations
  92. GRB 140206A: theoretical prediction of redshift and of supernova occurrence
  93. GRB 140110A: Second Follow-up Swift-XRT Observation
  94. GRB 140104B: Further Swift XRT observations
  95. GRB 140108A: theoretical prediction of redshift and of supernova occurrence
  96. GRB 140105A/Fermi410578384: MASTER-Net early optical observations
  97. Fermi410578384: iPTF optical afterglow candidates for a possible short GRB
  98. GRB 131202A: theoretical estimation of the redshift
  99. GRB 060614: theoretical derivation of the redshift and need for deeper search of the host galaxy
  100. GRB 131128A: Swift detection of a burst

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