Skip to main content
New! Browse Circulars by Event, Advanced Search, Sample Codes, Schema Release. 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. GRB 060502B: AROMA optical observations
  2. GRB 060502B: Refined analysis of the Swift-BAT short burst
  3. GRB060502B: Swift XRT Team refined analysis
  4. Short GRB 060502B: Tautenburg Observation
  5. GRB 060427B Milagro GeV/TeV Observations
  6. GRB 060502A: TTT Observations
  7. GRB060502B: correction to XRT position
  8. GRB 060501: P60 Observations and Candidate Retraction
  9. GRB 060502B: Xinglong optical observation
  10. GRB 060502B: MASTER optical observations
  11. GRB 060502B: Swift detection of a short burst
  12. GRB060502: Swift-XRT refined analysis
  13. GRB 060502: Swift-BAT refined analysis
  14. GRB060502: Gemini spectroscopy
  15. GRB 060502: APO Spectroscopic Observations
  16. GRB060501: Swift UVOT followup observations
  17. GRB060502: Super-LOTIS Observations
  18. GRB 060502: P60 Afterglow Confirmation
  19. GRB 060502: Swift detection of a burst with an optical counterpart
  20. GRB 060501: MDM Observations
  21. GRB060501: Super-LOTIS observations
  22. GRB060501: P60 imaging and afterglow candidate
  23. GRB 060501: Refined analysis of the Swift-BAT burst
  24. GRB060501: Swift XRT position
  25. GRB 060501: ROTSE-III Optical Limits
  26. GRB 060501: Swift detection of a burst
  27. IPN triangulation of GRB060429 (short/hard)
  28. Konus-Wind observation of GRB 060427B
  29. GRB060428B - SDSS Pre-Burst Observations
  30. GRB060428B: optical observation
  31. GRB060428B: possible detection of an optical counterpart by Swift/UVOT.
  32. GRB 060428B: MDM Observations
  33. GRB 060428A: PROMPT Observations
  34. GRB 060427B: MASTER optical observations
  35. GRB060428B: Swift XRT Team refined analysis
  36. GRB 060427B: IPN localization of a short hard burst
  37. GRB 060428B: Refined analysis of the Swift-BAT burst
  38. GRB 060428B: Xinglong I-band limit
  39. GRB 060428B: KAIT observations
  40. GRB060425:MASTER optical limit
  41. GRB 051117A: Bright host galaxy not confirmed
  42. GRB060428A: Swift/UVOT observations.
  43. GRB060428B, optical observation
  44. GRB 060428A: Refined analysis of the Swift-BAT burst
  45. GRB 060428b : Kiso R-band limit
  46. GRB060427:MASTER optical limit
  47. GRB 060428b: Optical afterglow candidate
  48. GRB060428A: Swift XRT Team refined analysis
  49. GRB 060428B: Swift detection of a burst
  50. GRB 060427: NIR observations
  51. GRB060427: Xinglong optical Observations
  52. GRB 060428: Swift detection of a burst
  53. GRB 060427: NOT observations
  54. GRB 060427: Swift/UVOT upper limits.
  55. GRB 060427: Refined analysis of the Swift-BAT burst
  56. GRB060427: Swift XRT Team refined analysis
  57. GRB060418: Swift XRT Team Further Refined Analysis
  58. GRB060425:MASTER survey observations
  59. GRB 060427, optical observation
  60. GRB 060427: Swift detection of a burst
  61. GRB 060425: IPN localization and KW spectrum of a short, hard burst
  62. An interactive program for GRB pseudo-redshift computations
  63. GRB060424: optical afterglow detection
  64. GRB060418: Further Analysis of MIKE Spectroscopy
  65. GRB 060424: Refined analysis of the Swift-BAT burst
  66. GRB 060424: Swift detection of a burst
  67. GRB 060421: TTT Observations
  68. OT 060420: Likely Not a New Cosmic Transient
  69. No OT 060420 in MASCOT images
  70. Swift-BAT detection of Mrk 421
  71. OT 060420: CONCAM detection of a candidate new magnitude 5 optical
  72. GRB060421: Swift/UVOT observations
  73. GRB 060421: Swift-BAT Refined Analysis
  74. GRB 060421: Swift-XRT refined analysis
  75. GRB 060418: prediction of t_break
  76. GRB060418: optical observations
  77. Konus-Wind observation of GRB 060418
  78. GRB(?)060421:MASTER optical limit
  79. GRB(?)060421 : XRT position
  80. Possible GRB060421: BART limits
  81. GRB(?) 060421: Swift detection of a burst
  82. Erratum of GCN 4983 for GRB 060418 IR follow-up
  83. GRB 060418 : IR afterglow observations
  84. GRB 060418 : Lulin Optical follow-up
  85. GRB 060418: JHKs PAIRITEL Observations of Afterglow
  86. GRB 060418: Radio Observations
  87. GRB060418, BVRcIc field calibration
  88. GRB060418: Swift/UVOT Observations
  89. GRB060418: Optical Observations
  90. GRB 060418: FRAM early afterglow observation
  91. GRB 060418: Refined Analysis of the Swift-BAT burst
  92. VLT/UVES observations of GRB060418
  93. GRB060418: Swift XRT Team Refined Analysis
  94. GRB 060418, SMARTS continuing afterglow observations
  95. GRB 060418: PROMPT Detections
  96. GRB 060418, SMARTS optical/IR afterglow observations
  97. GRB060418: Magellan/MIKE Spectroscopic Redshift
  98. GRB060418 : LT optical afterglow observation
  99. GRB 060418: REM candidate afterglow
  100. GRB 060418: Swift detection of a burst with bright x-ray and optical afterglow

Advanced

Download all Circulars as a .tar.gz archive:
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