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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"

45470 results found.

  1. GRB 050904: NIR object inside the XRT error box
  2. GRB 050904: early Swift XRT analysis results
  3. GRB 050904: SOAR YJ and PROMPT Ic Observations
  4. GRB 050904: BAT refined analysis of partial data set
  5. GRB 050904: TAROT optical measurements
  6. GRB050904: Optical Observations
  7. GRB 050904: Environmental Constraints
  8. GRB 050904: Possible High-Redshift GRB
  9. GRB 050904: SOAR/PROMPT Observations
  10. GRB050904: P60 Observations
  11. GRB 050904: TAROT optical limits
  12. GRB050904: Swift-BAT detection of a probable burst
  13. Swift-BAT triggers 153461-153465 are not GRBs
  14. Retraction of Swift-BAT trigger #153355
  15. GRB 050824: MDM Observations
  16. GRB 050827: Swift XRT preliminary analysis results
  17. IBAS Alerts 2641 and 2642: not a real GRB
  18. Swift Trigger #152652 is not a GRB
  19. GRB 050827 : OSN 1.5m optical observations
  20. GRB 050827: P200 NIR Observations
  21. GRB050827: Swift/UVOT upper limits
  22. GRB 050827: Optical Limit
  23. GRB 050827: XRT possible afterglow detection
  24. GRB 050826 : Lulin R band observation
  25. GRB050824: Maidanak optical limits
  26. GRB050820A: RTT150 optical observations
  27. GRB050827: RTT150 optical observations
  28. GRB 050827: Swift-BAT refined analysis
  29. GRB050827: Swift-BAT detection of a burst
  30. Subaru Observations of GRB050724
  31. GRB 050826: Optical Candidate
  32. GRB050824, HETE-2 Observation
  33. GRB 050826: Swift XRT preliminary analysis results
  34. GRB 050826: BAT refined analysis
  35. GRB050826: Swift/UVOT early upper limits
  36. GRB050824: First 2 hours of power low optical decay?
  37. GRB 050826: Swift XRT position
  38. GRB050826: Swift-BAT detection of a long burst
  39. GRB050824: MASTER final analysis of the OT observations
  40. Possible GRB050825:MASTER optical observations
  41. Swift-BAT trigger 152038 is definitely not a GRB
  42. GRB050824: CORRECTION to UVOT observing times
  43. Swift-BAT trigger 152038 is probably not a GRB
  44. GRB050824: Swift/UVOT detection of fading afterglow
  45. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  46. GRB050824, I-band imaging
  47. GRB050824: Radio Observations
  48. GRB 050824: Spectroscopic redshift from the VLT
  49. GRB 050822: refined XRT analysis
  50. GRB 050824: XRT refined analysis and possible afterglow detection
  51. GRB 050824: BAT refined analysis of a soft weak burst
  52. GRB050824: MASTER:OT decay
  53. GRB050824: MASTER observation OT
  54. GRB050805a: MASTER optical candidat
  55. GRB 050824: ROTSE-III Optical Limits
  56. GRB050824: Swift-BAT detection of a burst
  57. GRB 050824 optical candidate
  58. GRB050820A: RTT150 optical observations
  59. GRB050820a: PROMPT RcIc Observations
  60. GRB050815: Maidanak optical observation
  61. XRF050509c: Radio upper limits from GMRT
  62. VLT/UVES spectroscopy of GRB050820
  63. GRB050822: Swift/UVOT upper limits
  64. GRB 050820A BAT observations of second, larger episode of emission
  65. GRB050813: Maidanak I-band observations
  66. GRB 050822: Swift-BAT refined analysis
  67. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  68. GRB050820B at FRAM
  69. GRB050820A: RTT150 optical observations
  70. GRB 050820a - corrections to GCN 3846
  71. Swift/UVOT UV Photometry of GRB 050820B
  72. GRB 050822: ROTSE-III Prompt Optical Limits
  73. GRB 050822: Swift detection of a long burst
  74. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  75. GRB050820A: Radio Observation
  76. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  77. GRB050820a BVRcIc field photometry
  78. GRB050820B XMM-Newton observation
  79. GRB 050820a: NIR Observations by WIRO
  80. GRB 050820B: Swift XRT position
  81. GRB050820B: Planned XMM-Newton observation
  82. GRB050820B: Refined analysis of the Swift-BAT burst
  83. GRB050820B: BAT-Swift detection of a bright GRB
  84. Swift/UVOT photometry of GRB050820
  85. GRB050820: refined XRT analysis
  86. GRB 050820: Early RAPTOR detections
  87. GRB 050820 Swift-BAT refined analysis
  88. GRB 050820: P60 Temporal Decay Index
  89. GRB 050820: High Resolution Spectroscopy from Keck
  90. GRB050819: refined XRT analysis
  91. GRB050819: RTT150 optical observations
  92. GRB 050820: Swift detection of a GRB
  93. GRB050820: Optical afterglow from P60
  94. GRB 050819 Swift-BAT refined analysis
  95. GRB050819: Swift XRT position
  96. GRB050819: Swift-BAT detection of a weak burst
  97. Swift-BAT trigger 150993 is not a GRB
  98. Swift Trigger 150823 is HETE J1900.1-2455
  99. GRB 050817: Optical observations
  100. GRB 050815: Radio Observation

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