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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"

19548 results found.

  1. Swift-BAT trigger 155535 is definitely not a GRB
  2. GRB050916 : Swift-XRT refined analysis
  3. GRB 050916: XRT position
  4. GRB 050915B: Swift-BAT refined analysis
  5. GRB 050915B: Swift/UVOT Upper Limits
  6. GRB 050915a: IR Transient
  7. GRB 050915B: XRT position
  8. GRB 050915b, SMARTS optical/IR observations
  9. GRB050915B: Swift-BAT detection of a long bright burst
  10. GRB050915: Swift/UVOT upper limits
  11. GRB 050915: IR Observations
  12. GRB 050915: Swift-BAT refined analysis
  13. GRB050915: XRT position
  14. GRB 050915: Swift detection of a GRB
  15. Swift-BAT trigger 155072 is probably not a GRB
  16. GRB 050911: z~0.16 cluster in the field
  17. GRB050911: Swift-BAT detection of a long burst
  18. GRB 050910a: TAROT early optical limits
  19. GRB 050906: Possible X-ray Counterpart
  20. GRB050908: Swift/UVOT Early upper limits
  21. GRB050908 : Swift-XRT refined analysis
  22. GRB 050908: Swift-BAT refined analysis
  23. GRB 050908: Optical observations
  24. GRB 050908: spectroscopic redshift
  25. GRB 050908: Swift detection of a burst
  26. Swift trigger 154073 is not a GRB
  27. GRB 050906: Optical observations at the Very Large Telescope
  28. GRB 050904: Subaru Optical Spectroscopy
  29. GRB 050906: Swift-BAT refined analysis
  30. GRB 050906: Swift XRT upper limit
  31. GRB 050904: Keck I-band Imaging
  32. GRB050906: P60 Observations
  33. GRB 050904: photometric redshift
  34. GRB 050904: Swift/UVOT observations
  35. GRB 050904: NIR object inside the XRT error box
  36. GRB 050904: TAROT optical measurements
  37. GRB050904: Optical Observations
  38. GRB 050904: Environmental Constraints
  39. GRB050904: P60 Observations
  40. GRB 050904: TAROT optical limits
  41. GRB 050827 : OSN 1.5m optical observations
  42. GRB 050827: P200 NIR Observations
  43. GRB050827: Swift/UVOT upper limits
  44. GRB 050827: XRT possible afterglow detection
  45. GRB050824: Maidanak optical limits
  46. Subaru Observations of GRB050724
  47. GRB 050826: Optical Candidate
  48. GRB 050826: BAT refined analysis
  49. GRB050826: Swift/UVOT early upper limits
  50. GRB 050826: Swift XRT position
  51. GRB050826: Swift-BAT detection of a long burst
  52. XRF050509c: Radio upper limits from GMRT
  53. GRB050822: Swift/UVOT upper limits
  54. GRB050813: Maidanak I-band observations
  55. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  56. GRB050820B at FRAM
  57. Swift/UVOT UV Photometry of GRB 050820B
  58. GRB 050822: Swift detection of a long burst
  59. GRB050820a BVRcIc field photometry
  60. GRB050820B XMM-Newton observation
  61. GRB 050820B: Swift XRT position
  62. GRB050820B: Refined analysis of the Swift-BAT burst
  63. GRB050820: refined XRT analysis
  64. GRB 050820: Early RAPTOR detections
  65. GRB050819: refined XRT analysis
  66. GRB 050820: Swift detection of a GRB
  67. GRB050819: Swift XRT position
  68. GRB050819: Swift-BAT detection of a weak burst
  69. GRB 050817: Optical observations
  70. GRB 050814: continued fading
  71. GRB050815: XRT refined analysis
  72. GRB 050815: ROTSE-III Optical Limits
  73. GRB050815: Swift XRT afterglow localization
  74. GRB050815: Swift-BAT detection of a burst
  75. GRB050814: Fading red source
  76. GRB050814: P60 Optical Afterglow Candidate
  77. GRB 050813: Non-fading of afterglow candidate
  78. GRB 050814: XRT refined analysis
  79. GRB050814: SWIFT/UVOT observation
  80. GRB 050814: Swift XRT Afterglow Localization
  81. GRB 050814: Swift detection of a burst
  82. GRB 050813: Magellan detection of a high redshift galaxy cluster
  83. GRB050813, SDSS pre-burst observations
  84. GRB050813: SWIFT/UVOT observation
  85. GRB 050813: Swift XRT afterglow localization
  86. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  87. Detection of an intermediate burst from SGR 1806-20 on August 8
  88. GRB050805b: CrAO optical limit
  89. GRB050803, optical observations
  90. Retraction of Swift Trigger 149131 (GRB 050805B)
  91. GRB 050805b: OHP optical limits
  92. GRB 050805b: TAROT optical limits
  93. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  94. Swift-BAT trigger 149118 is probably not a GRB
  95. GRB050802: TNG optical observations
  96. GRB050803: Radio Observation
  97. GRB 050803: RTT150 optical observations
  98. GRB050801: Radio Observation
  99. GRB050730: Radio Detection
  100. GRB 050803: Keck Observations

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