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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"

20258 results found.

  1. GRB 050922C: ROTSE-IIId Refined Analysis
  2. GRB 050922B: ROTSE-III Optical Limits
  3. GRB 050922B,optical observation
  4. GRB050922B: Swift-BAT detection of a weak long burst
  5. GRB050918: Possible Swift/XRT detected afterglow
  6. GRB050820B: analysis of the XMM-Newton observation
  7. GRB050916: Swift/UVOT Upper Limits
  8. Swift-BAT trigger 155764 is not a GRB
  9. Swift-BAT trigger 155764 is probably not a GRB
  10. Swift trigger 155764: bad XRT centroid
  11. Swift-BAT trigger 155535 is definitely not a GRB
  12. GRB050916 : Swift-XRT refined analysis
  13. GRB 050915B: Swift/UVOT Upper Limits
  14. GRB 050915a: IR Transient
  15. GRB 050915b, SMARTS optical/IR observations
  16. GRB050915B: Swift-BAT detection of a long bright burst
  17. GRB050915: Swift/UVOT upper limits
  18. GRB 050915: IR Observations
  19. GRB 050915: ROTSE-III optical limits
  20. GRB 050915: Swift detection of a GRB
  21. Swift-BAT trigger 155072 ground analysis
  22. Swift-BAT trigger 155072 is probably not a GRB
  23. GRB 050911, optical observations
  24. GRB 050911: z~0.16 cluster in the field
  25. GRB050911: Swift-BAT detection of a long burst
  26. GRB 050910a: TAROT early optical limits
  27. GRB 050906: Possible X-ray Counterpart
  28. GRB050908: Swift/UVOT Early upper limits
  29. GRB050908 : Swift-XRT refined analysis
  30. GRB 050908: Optical observations
  31. GRB 050908: Optical Observations
  32. GRB 050908: Swift detection of a burst
  33. GRB 050906: Optical observations at the Very Large Telescope
  34. GRB 050904: Subaru Optical Spectroscopy
  35. GRB 050906: Swift XRT upper limit
  36. GRB 050904: Keck I-band Imaging
  37. GRB050906: P60 Observations
  38. GRB 050904: photometric redshift
  39. GRB 050904: Swift/UVOT observations
  40. GRB 050904: NIR object inside the XRT error box
  41. GRB050904: Optical Observations
  42. GRB050904: P60 Observations
  43. GRB 050904: TAROT optical limits
  44. GRB 050827: P200 NIR Observations
  45. GRB050827: Swift/UVOT upper limits
  46. GRB050824: Maidanak optical limits
  47. GRB050820A: RTT150 optical observations
  48. Subaru Observations of GRB050724
  49. GRB050826: Swift/UVOT early upper limits
  50. GRB050826: Swift-BAT detection of a long burst
  51. GRB050824: CORRECTION to UVOT observing times
  52. GRB050824: Swift/UVOT detection of fading afterglow
  53. GRB 050824: BAT refined analysis of a soft weak burst
  54. GRB050824: MASTER observation OT
  55. GRB050805a: MASTER optical candidat
  56. GRB 050824: ROTSE-III Optical Limits
  57. GRB050820a: PROMPT RcIc Observations
  58. XRF050509c: Radio upper limits from GMRT
  59. GRB050822: Swift/UVOT upper limits
  60. GRB 050820A BAT observations of second, larger episode of emission
  61. GRB050813: Maidanak I-band observations
  62. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  63. GRB050820B at FRAM
  64. Swift/UVOT UV Photometry of GRB 050820B
  65. GRB 050822: ROTSE-III Prompt Optical Limits
  66. GRB 050822: Swift detection of a long burst
  67. GRB050820a BVRcIc field photometry
  68. GRB050820B XMM-Newton observation
  69. GRB 050820B: Swift XRT position
  70. Swift/UVOT photometry of GRB050820
  71. GRB050820: refined XRT analysis
  72. GRB050819: refined XRT analysis
  73. GRB 050820: Swift detection of a GRB
  74. GRB050819: Swift-BAT detection of a weak burst
  75. GRB 050817: Optical observations
  76. GRB050817: Negative Optical Observations
  77. GRB 050814: continued fading
  78. GRB 050815: ROTSE-III Optical Limits
  79. GRB050815: Swift-BAT detection of a burst
  80. GRB050814: Fading red source
  81. GRB050814: P60 Optical Afterglow Candidate
  82. GRB 050813: Non-fading of afterglow candidate
  83. GRB 050814: XRT refined analysis
  84. GRB050814: SWIFT/UVOT observation
  85. GRB050814: Refined analysis of the Swift-BAT burst
  86. GRB 050814: Swift XRT Afterglow Localization
  87. GRB 050814: Swift detection of a burst
  88. GRB 050813: Magellan detection of a high redshift galaxy cluster
  89. GRB050813, SDSS pre-burst observations
  90. GRB050813: SWIFT/UVOT observation
  91. GRB 050813: Swift XRT afterglow localization
  92. RBO GRB 050714A and GRB 050716 observations
  93. GRB 050813: Possible Short Swift-BAT GRB
  94. Ongoing activity of SGR 1806-20: an intermediate burst 050811
  95. Detection of an intermediate burst from SGR 1806-20 on August 8
  96. GRB 050730: WSRT Radio Observations
  97. GRB 050807: ROTSE-III Optical Limits
  98. GRB050805b: CrAO optical limit
  99. GRB050803, optical observations
  100. Retraction of Swift Trigger 149131 (GRB 050805B)

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