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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"

32531 results found.

  1. GRB 050826: Swift XRT position
  2. GRB050824: MASTER final analysis of the OT observations
  3. GRB050824: CORRECTION to UVOT observing times
  4. GRB050824: Swift/UVOT detection of fading afterglow
  5. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  6. GRB050824: Radio Observations
  7. GRB 050824: Spectroscopic redshift from the VLT
  8. GRB 050822: refined XRT analysis
  9. GRB 050824: BAT refined analysis of a soft weak burst
  10. GRB050824: MASTER:OT decay
  11. GRB050824: MASTER observation OT
  12. GRB050805a: MASTER optical candidat
  13. GRB 050824: ROTSE-III Optical Limits
  14. GRB050820A: RTT150 optical observations
  15. GRB050820a: PROMPT RcIc Observations
  16. GRB050815: Maidanak optical observation
  17. XRF050509c: Radio upper limits from GMRT
  18. VLT/UVES spectroscopy of GRB050820
  19. GRB050822: Swift/UVOT upper limits
  20. GRB 050820A BAT observations of second, larger episode of emission
  21. GRB050813: Maidanak I-band observations
  22. GRB 050822: Swift-BAT refined analysis
  23. GRB050820A: RTT150 optical observations
  24. GRB 050820a - corrections to GCN 3846
  25. Swift/UVOT UV Photometry of GRB 050820B
  26. GRB 050822: ROTSE-III Prompt Optical Limits
  27. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  28. GRB050820A: Radio Observation
  29. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  30. GRB050820a BVRcIc field photometry
  31. GRB 050820a: NIR Observations by WIRO
  32. GRB 050820B: Swift XRT position
  33. GRB050820B: Refined analysis of the Swift-BAT burst
  34. Swift/UVOT photometry of GRB050820
  35. GRB050820: refined XRT analysis
  36. GRB 050820: Early RAPTOR detections
  37. GRB 050820 Swift-BAT refined analysis
  38. GRB 050820: P60 Temporal Decay Index
  39. GRB 050820: High Resolution Spectroscopy from Keck
  40. GRB050819: refined XRT analysis
  41. GRB050819: RTT150 optical observations
  42. GRB 050820: Swift detection of a GRB
  43. GRB 050819 Swift-BAT refined analysis
  44. GRB050819: Swift XRT position
  45. Swift-BAT trigger 150993 is not a GRB
  46. Swift Trigger 150823 is HETE J1900.1-2455
  47. GRB 050817: Optical observations
  48. GRB 050815: Radio Observation
  49. GRB050814: Radio Observation
  50. GRB050817: Negative Optical Observations
  51. GRB 050814: continued fading
  52. GRB050815: XRT refined analysis
  53. GRB 050813: Radio Observations
  54. GRB050815: Refined analysis of the Swift-BAT burst
  55. GRB 050815: ROTSE-III Optical Limits
  56. GRB050815: Swift XRT afterglow localization
  57. GRB 050730: Third Epoch WSRT Radio Observations
  58. GRB050814: Fading red source
  59. GRB 050813: Gemini Spectra Revisited
  60. GRB050814: P60 Optical Afterglow Candidate
  61. GRB 050813: Non-fading of afterglow candidate
  62. GRB 050814: XRT refined analysis
  63. GRB050814: SWIFT/UVOT observation
  64. GRB050814: Refined analysis of the Swift-BAT burst
  65. GRB050813: Gemini Imaging
  66. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  67. GRB 050814: Swift XRT Afterglow Localization
  68. GRB 050814: Swift detection of a burst
  69. GRB 050813: Magellan detection of a high redshift galaxy cluster
  70. GRB050813: RTT150 optical observations
  71. GRB 050813: I-band observations
  72. GRB050813, SDSS pre-burst observations
  73. GRB 050813: KAIT optical limit
  74. GRB 050813: Swift-BAT refined analysis
  75. GRB 050813: Photometry of object in XRT error circle
  76. GRB050813: SWIFT/UVOT observation
  77. GRB 050813: Swift XRT afterglow localization
  78. RBO GRB 050714A and GRB 050716 observations
  79. Swift-BAT trigger 150131 is not a GRB
  80. GRB050807(=H3889): An X-Ray Rich GRB Localized by HETE
  81. GRB050803: CrAO optical observations, no OT candidate
  82. GRB 050730: WSRT Radio Observations
  83. GRB 050803: PROMPT BVRcIc Observations
  84. GRB 050807: ROTSE-III Optical Limits
  85. GRB 050730, optical observation
  86. GRB050805a : Null detection report
  87. GRB050730, optical observations
  88. GRB050803, optical observations
  89. GRB 050805b: TAROT optical limits
  90. GRB050802: TNG optical observations
  91. GRB050803: Radio Observation
  92. GRB 050803: RTT150 optical observations
  93. GRB050801: Radio Observation
  94. GRB050730: Radio Detection
  95. GRB050803: CrAO optical observations, possible OT candidate
  96. GRB050803: Optical/UV Upper Limits from Swift-UVOT
  97. GRB 050803: Keck Observations
  98. GRB 050803: Swift-BAT refined analysis
  99. GRB 050802.422: Fading of the afterglow and detection of the host
  100. GRB050803: MASTER further analys

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