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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"

20352 results found.

  1. GRB050916: Swift/UVOT Upper Limits
  2. Swift-BAT trigger 155764 is not a GRB
  3. Swift-BAT trigger 155764 is probably not a GRB
  4. Swift trigger 155764: bad XRT centroid
  5. Swift-BAT trigger 155535 is definitely not a GRB
  6. GRB050916 : Swift-XRT refined analysis
  7. GRB 050915B: Swift/UVOT Upper Limits
  8. GRB 050915a: IR Transient
  9. GRB 050915b, SMARTS optical/IR observations
  10. GRB050915B: Swift-BAT detection of a long bright burst
  11. GRB050915: Swift/UVOT upper limits
  12. GRB 050915: IR Observations
  13. GRB 050915: ROTSE-III optical limits
  14. GRB 050915: Swift detection of a GRB
  15. Swift-BAT trigger 155072 ground analysis
  16. Swift-BAT trigger 155072 is probably not a GRB
  17. GRB 050911, optical observations
  18. GRB 050911: z~0.16 cluster in the field
  19. GRB050911: Swift-BAT detection of a long burst
  20. GRB 050910a: TAROT early optical limits
  21. GRB 050906: Possible X-ray Counterpart
  22. GRB050908: Swift/UVOT Early upper limits
  23. GRB050908 : Swift-XRT refined analysis
  24. GRB 050908: Optical observations
  25. GRB 050908: Optical Observations
  26. GRB 050908: Swift detection of a burst
  27. GRB 050906: Optical observations at the Very Large Telescope
  28. GRB 050904: Subaru Optical Spectroscopy
  29. GRB 050906: Swift XRT upper limit
  30. GRB 050904: Keck I-band Imaging
  31. GRB050906: P60 Observations
  32. GRB 050904: photometric redshift
  33. GRB 050904: Swift/UVOT observations
  34. GRB 050904: NIR object inside the XRT error box
  35. GRB050904: Optical Observations
  36. GRB050904: P60 Observations
  37. GRB 050904: TAROT optical limits
  38. GRB 050827: P200 NIR Observations
  39. GRB050827: Swift/UVOT upper limits
  40. GRB050824: Maidanak optical limits
  41. GRB050820A: RTT150 optical observations
  42. Subaru Observations of GRB050724
  43. GRB050826: Swift/UVOT early upper limits
  44. GRB050826: Swift-BAT detection of a long burst
  45. GRB050824: CORRECTION to UVOT observing times
  46. GRB050824: Swift/UVOT detection of fading afterglow
  47. GRB 050824: BAT refined analysis of a soft weak burst
  48. GRB050824: MASTER observation OT
  49. GRB050805a: MASTER optical candidat
  50. GRB 050824: ROTSE-III Optical Limits
  51. GRB050820a: PROMPT RcIc Observations
  52. XRF050509c: Radio upper limits from GMRT
  53. GRB050822: Swift/UVOT upper limits
  54. GRB 050820A BAT observations of second, larger episode of emission
  55. GRB050813: Maidanak I-band observations
  56. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  57. GRB050820B at FRAM
  58. Swift/UVOT UV Photometry of GRB 050820B
  59. GRB 050822: ROTSE-III Prompt Optical Limits
  60. GRB 050822: Swift detection of a long burst
  61. GRB050820a BVRcIc field photometry
  62. GRB050820B XMM-Newton observation
  63. GRB 050820B: Swift XRT position
  64. Swift/UVOT photometry of GRB050820
  65. GRB050820: refined XRT analysis
  66. GRB050819: refined XRT analysis
  67. GRB 050820: Swift detection of a GRB
  68. GRB050819: Swift-BAT detection of a weak burst
  69. GRB 050817: Optical observations
  70. GRB050817: Negative Optical Observations
  71. GRB 050814: continued fading
  72. GRB 050815: ROTSE-III Optical Limits
  73. GRB050815: Swift-BAT detection of a burst
  74. GRB050814: Fading red source
  75. GRB050814: P60 Optical Afterglow Candidate
  76. GRB 050813: Non-fading of afterglow candidate
  77. GRB 050814: XRT refined analysis
  78. GRB050814: SWIFT/UVOT observation
  79. GRB050814: Refined analysis of the Swift-BAT burst
  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. RBO GRB 050714A and GRB 050716 observations
  87. GRB 050813: Possible Short Swift-BAT GRB
  88. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  89. Detection of an intermediate burst from SGR 1806-20 on August 8
  90. GRB 050730: WSRT Radio Observations
  91. GRB 050807: ROTSE-III Optical Limits
  92. GRB050805b: CrAO optical limit
  93. GRB050803, optical observations
  94. Retraction of Swift Trigger 149131 (GRB 050805B)
  95. GRB 050805b: OHP optical limits
  96. GRB 050805b: TAROT optical limits
  97. Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
  98. GRB050802: TNG optical observations
  99. GRB050803: Radio Observation
  100. GRB 050803: RTT150 optical observations

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