Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! See news and announcements

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"

43604 results found.

  1. GRB050820A: RTT150 optical observations
  2. GRB050827: RTT150 optical observations
  3. GRB 050827: Swift-BAT refined analysis
  4. GRB050827: Swift-BAT detection of a burst
  5. Subaru Observations of GRB050724
  6. GRB 050826: Optical Candidate
  7. GRB050824, HETE-2 Observation
  8. GRB 050826: Swift XRT preliminary analysis results
  9. GRB 050826: BAT refined analysis
  10. GRB050826: Swift/UVOT early upper limits
  11. GRB050824: First 2 hours of power low optical decay?
  12. GRB 050826: Swift XRT position
  13. GRB050826: Swift-BAT detection of a long burst
  14. GRB050824: MASTER final analysis of the OT observations
  15. Possible GRB050825:MASTER optical observations
  16. Swift-BAT trigger 152038 is definitely not a GRB
  17. GRB050824: CORRECTION to UVOT observing times
  18. Swift-BAT trigger 152038 is probably not a GRB
  19. GRB050824: Swift/UVOT detection of fading afterglow
  20. GRB050824: decay of the XRT light curve and updated X-ray spectrum
  21. GRB050824, I-band imaging
  22. GRB050824: Radio Observations
  23. GRB 050824: Spectroscopic redshift from the VLT
  24. GRB 050822: refined XRT analysis
  25. GRB 050824: XRT refined analysis and possible afterglow detection
  26. GRB 050824: BAT refined analysis of a soft weak burst
  27. GRB050824: MASTER:OT decay
  28. GRB050824: MASTER observation OT
  29. GRB050805a: MASTER optical candidat
  30. GRB 050824: ROTSE-III Optical Limits
  31. GRB050824: Swift-BAT detection of a burst
  32. GRB 050824 optical candidate
  33. GRB050820A: RTT150 optical observations
  34. GRB050815: Maidanak optical observation
  35. XRF050509c: Radio upper limits from GMRT
  36. VLT/UVES spectroscopy of GRB050820
  37. GRB050822: Swift/UVOT upper limits
  38. GRB 050820A BAT observations of second, larger episode of emission
  39. GRB 050822: Swift-BAT refined analysis
  40. GRB050525, GRB050607, GRB050802 BVRcIc field photometry
  41. GRB050820A: RTT150 optical observations
  42. GRB 050820a - corrections to GCN 3846
  43. Swift/UVOT UV Photometry of GRB 050820B
  44. GRB 050822: ROTSE-III Prompt Optical Limits
  45. GRB 050822: Swift detection of a long burst
  46. Correction to Eiso calculation in GCN 3835 on GRB 050820A
  47. GRB050820A: Radio Observation
  48. GRB050825a - very long GRB like GRB041219a? (Konus-Wind observation)
  49. GRB050820a BVRcIc field photometry
  50. GRB050820B XMM-Newton observation
  51. GRB 050820B: Swift XRT position
  52. GRB050820B: Refined analysis of the Swift-BAT burst
  53. GRB050820B: BAT-Swift detection of a bright GRB
  54. Swift/UVOT photometry of GRB050820
  55. GRB050820: refined XRT analysis
  56. GRB 050820: Early RAPTOR detections
  57. GRB 050820 Swift-BAT refined analysis
  58. GRB 050820: P60 Temporal Decay Index
  59. GRB 050820: High Resolution Spectroscopy from Keck
  60. GRB050819: refined XRT analysis
  61. GRB050819: RTT150 optical observations
  62. GRB 050820: Swift detection of a GRB
  63. GRB050820: Optical afterglow from P60
  64. GRB 050819 Swift-BAT refined analysis
  65. GRB050819: Swift XRT position
  66. GRB050819: Swift-BAT detection of a weak burst
  67. Swift-BAT trigger 150993 is not a GRB
  68. Swift Trigger 150823 is HETE J1900.1-2455
  69. GRB 050817: Optical observations
  70. GRB 050815: Radio Observation
  71. GRB050814: Radio Observation
  72. GRB050817: Negative Optical Observations
  73. GRB050817: Swift-BAT Detection of a burst
  74. GRB 050814: continued fading
  75. GRB050815: Optical afterglow detection by Swift UVOT
  76. GRB050815: XRT refined analysis
  77. GRB 050813: Radio Observations
  78. GRB050815: Refined analysis of the Swift-BAT burst
  79. GRB 050815: ROTSE-III Optical Limits
  80. GRB050815: Swift XRT afterglow localization
  81. GRB050815: Swift-BAT detection of a burst
  82. GRB 050730: Third Epoch WSRT Radio Observations
  83. GRB050814: Fading red source
  84. GRB 050813: Gemini Spectra Revisited
  85. GRB050814: P60 Optical Afterglow Candidate
  86. GRB 050813: Non-fading of afterglow candidate
  87. GRB 050814: XRT refined analysis
  88. GRB050814: SWIFT/UVOT observation
  89. GRB050814: Refined analysis of the Swift-BAT burst
  90. GRB050813: Gemini Imaging
  91. GRB 050813: Gemini spectroscopy and redshifts of galaxies B and C
  92. GRB 050814: Swift XRT Afterglow Localization
  93. GRB 050814: Swift detection of a burst
  94. GRB 050813: Magellan detection of a high redshift galaxy cluster
  95. GRB050813: RTT150 optical observations
  96. GRB 050813: I-band observations
  97. GRB050813, SDSS pre-burst observations
  98. GRB 050813: KAIT optical limit
  99. GRB 050813: Swift-BAT refined analysis
  100. GRB 050813: Photometry of object in XRT error circle

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Looking for U.S. government information and services? Visit USA.gov