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"
  1. An interactive program for GRB pseudo-redshift computations
  2. GRB060424: optical afterglow detection
  3. GRB060418: Further Analysis of MIKE Spectroscopy
  4. GRB 060424: Refined analysis of the Swift-BAT burst
  5. GRB 060424: Swift detection of a burst
  6. GRB 060421: TTT Observations
  7. OT 060420: Likely Not a New Cosmic Transient
  8. No OT 060420 in MASCOT images
  9. Swift-BAT detection of Mrk 421
  10. OT 060420: CONCAM detection of a candidate new magnitude 5 optical
  11. GRB060421: Swift/UVOT observations
  12. GRB 060421: Swift-BAT Refined Analysis
  13. GRB 060421: Swift-XRT refined analysis
  14. GRB 060418: prediction of t_break
  15. GRB060418: optical observations
  16. Konus-Wind observation of GRB 060418
  17. GRB(?)060421:MASTER optical limit
  18. GRB(?)060421 : XRT position
  19. Possible GRB060421: BART limits
  20. GRB(?) 060421: Swift detection of a burst
  21. Erratum of GCN 4983 for GRB 060418 IR follow-up
  22. GRB 060418 : IR afterglow observations
  23. GRB 060418 : Lulin Optical follow-up
  24. GRB 060418: JHKs PAIRITEL Observations of Afterglow
  25. GRB 060418: Radio Observations
  26. GRB060418, BVRcIc field calibration
  27. GRB060418: Swift/UVOT Observations
  28. GRB060418: Optical Observations
  29. GRB 060418: FRAM early afterglow observation
  30. GRB 060418: Refined Analysis of the Swift-BAT burst
  31. VLT/UVES observations of GRB060418
  32. GRB060418: Swift XRT Team Refined Analysis
  33. GRB 060418, SMARTS continuing afterglow observations
  34. GRB 060418: PROMPT Detections
  35. GRB 060418, SMARTS optical/IR afterglow observations
  36. GRB060418: Magellan/MIKE Spectroscopic Redshift
  37. GRB060418 : LT optical afterglow observation
  38. GRB 060418: REM candidate afterglow
  39. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow
  40. SGR 1900+14: Refined analysis of the Swift-BAT outburst
  41. GRB060413: Swift/UVOT upper limits
  42. GRB 060413: REM NIR Observations
  43. SGR 1900+14: Swift detection of an outburst
  44. GRB 060413: Refined analysis of the Swift-BAT burst
  45. GRB 060413: Watcher UBVR observations
  46. GRB 060413: XRT refined analysis
  47. GRB 060413: No Optical Afterglow in Swift/UVOT TDRSS Data
  48. GRB 060413: Swift detection of a burst
  49. GRB060403: optical observations
  50. GRB 060403 Optical observations
  51. GRB 060403: MITSuME optical observation
  52. GRB060403: Optical Limit
  53. GRB060403: XRT refined analysis
  54. GRB 060403: Swift/UVOT upper limits
  55. HETE Triggers H4043 and H4044 Not Due to New Cosmic Source
  56. SGR 1900+14: BAT observations
  57. GRB 060403: Refined analysis of the Swift-BAT burst
  58. GRB060403: Swift XRT refined position
  59. Konus-Wind observation of the recent SGR 1900+14 activity. Will
  60. GRB 060403: Swift detection of a burst
  61. HETE trigger H4044: RTT150 optical observations
  62. GRB060331: Swift/UVOT upper limits
  63. H4044, a Repeat Outburst From The Source of H4043 (="GRB060331")
  64. Swift XRT observations of the HETE transient H4043
  65. HETE Trigger 4043: ROTSE-III Optical Limits
  66. Correction to Circular 4938, =H4043, an unusual high energy transient observed by HETE
  67. H4043, an unusual high-energy transient observed by HETE
  68. GRB 060322: LNA optical limit
  69. SGR 1900+14: bright burst detected by Konus-Wind on March 28
  70. INTEGRAL and XMM ToO observations of SGR1900+14
  71. SGR 1900+14: Swift-BAT detection of a cluster of outbursts
  72. SGR 1900+14: Swift-BAT detection of a bright outburst
  73. GRB 060218SN 2006aj: optical observations at Rozhen Observatory
  74. GRB 060323 : WIDGET simultaneous optical observations
  75. GRB 060323: Early optical observation at Xinglong
  76. GRB060218, optical observations
  77. GRB 060322: Confirmation of Swift XRT afterglow
  78. GRB 060211A: optical observation
  79. GRB060323: optical limit
  80. GRB060211B: optical observation
  81. SGR 1900+14: CORRECTION to GCN 4923
  82. SGR 1900+14: Refined Swift-BAT analysis of the renewed activity
  83. SGR 1900+14: Swift detection of renewed activity
  84. GRB060323: NOT optical observations
  85. GRB 060322: IAC80 optical observations
  86. GRB 060322: Swift XRT afterglow candidate
  87. GRB060323: P60 Observations
  88. GRB 060323: Swift/UVOT Observations
  89. GRB 060323: optical afterglow confirmed
  90. GRB060323: NOT observations
  91. GRB 060323: Optical Observations
  92. GRB 060323: Tautenburg OT candidate retraction
  93. GRB 060323: Refined analysis of the Swift-BAT burst
  94. GRB 060323: optical observations at TNG
  95. GRB 060323: Swift XRT refined analysis
  96. GRB 060323: BVRI observations at Tautenburg, aftreglow candidate
  97. GRB 060323: Swift/XRT position
  98. GRB 060322: Refined analysis of the Swift-BAT burst
  99. GRB060323, optical observation
  100. GRB060323 - SDSS Pre-Burst Observations

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov