Skip to main content
Circulars over Kafka event name backfill. 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 060801: Swift/XRT Astrometry Correction
  2. GRB 061028: Futher P200 Observations
  3. GRB 061028: MDM Observations
  4. GRB 061028: P200 Observations
  5. GRB 061028: SARA upper limit
  6. GRB 061028: z band imaging
  7. GRB061028: XRT refined analysis
  8. GRB 061028: Swift/UVOT Observations
  9. GRB 061028, Swift-BAT refined analysis
  10. GRB 061028: TAROT Calern observatory late optical observations
  11. GRB 061028: TAROT Calern observatory optical observations
  12. GRB 061028: Swift detection of a burst
  13. GRB 061027, Swift refined analysis of a possible burst
  14. GRB 061027: Swift detection of a possible burst
  15. GRB061025: ROTSE-III Confirmation of Optical Counterpart
  16. GRB061025: Swift XRT refined analysis
  17. GRB061025: Swift/UVOT observations
  18. GRB 061019: MITSuME upper limits
  19. GRB 061025: REM observations
  20. GRB 061025: Gemini-S observations
  21. GRB061025: Swift XRT position
  22. GRB 061025: ROTSE-III Optical Limits
  23. GRB 061025: a long GRB detected by INTEGRAL
  24. Swift XRT boresight update
  25. GRB 061021, Swift-BAT Lag analysis
  26. Konus-Wind observation of GRB 061021
  27. GRB 061021 - VLT spectrum without lines
  28. GRB 061021: Swift-XRT refined analysis
  29. GRB 061021: Swift/UVOT Observation
  30. GRB 061021, Swift-BAT refined analysis
  31. GRB 061021: Swift detection of a burst
  32. GRB 061019: Super-LOTIS upper limit
  33. GRB060904b: optical observations
  34. GRB061019: optical observations
  35. GRB061019: optical observations
  36. GRB 061019: SARA upper limit
  37. GRB 061019: dust-scattered X-ray halo detected in Swift/XRT
  38. GRB 060930: MARGE Optical Limits
  39. GRB 061019: Swift/UVOT upper limit
  40. GRB 061019: SMARTS afterglow confirmation
  41. GRB061019: Swift XRT refined analysis
  42. GRB 061019, Swift-BAT refined analysis
  43. GRB 061019: TAROT La Silla observatory optical observations
  44. GRB 061019: REM K-band candidate afterglow
  45. GRB061019: Swift/XRT position
  46. GRB 061019: Swift-BAT detection of a burst
  47. GRB 060825: GORT Observations
  48. GRB 061007: Second Epoch ATCA Radio Observations
  49. GRB 061007: RHESSI Spectral Fit
  50. GRB 061007: Suzaku/WAM observation of the prompt emission
  51. GRB 061006: astrometry-corrected XRT position
  52. Konus-Wind observation of GRB 061007
  53. GRB 060928: Confirmation of the X-ray afterglow detected by Swift
  54. GRB 061007: ATCA Radio Observations
  55. GRB061007: Swift UVOT followup observations
  56. GRB 061006: optical afterglow
  57. GRB 061006 : Suzaku/WAM observation of the prompt emission
  58. GRB 061007: OA fading and VLT redshift
  59. GRB 061007: Magellan Spectroscopy
  60. GRB 061007: Correction to GCN 5712
  61. GRB 061007: Swift-BAT refined analysis
  62. GRB 061007: Swift XRT refined analysis
  63. GRB 061006: Swift/UVOT optical observations
  64. Konus-Wind observation of the short hard GRB 061006
  65. GRB 061007 - FTS early brightening and power law decay
  66. GRB 061007 - Faulkes Telescope South Afterglow Confirmation
  67. GRB 061007: Swift detection of a burst with an optical counterpart
  68. GRB 061007: ROTSE-III Detection of Optical Counterpart
  69. GRB 061006: VLT observation
  70. GRB 061006: Swift-BAT refined analysis of the short-hard burst
  71. GRB 061006: Swift-XRT Team Refined Analysis
  72. GRB061006 (Swift 232585) might be a short-hard GRB
  73. GRB 060930: near-IR afterglow candidate retraction
  74. GRB061006: Faulkes Telescope South Observations
  75. GRB 061006: Swift detection of a burst
  76. GRB 061004: Optical afterglow candidate and redshift
  77. GRB 061004: Las Campanas Optical/NIR Observations
  78. GRB061004: Swift/UVOT optical observations
  79. GRB 061004: Swift-XRT Team Refined Analysis
  80. GRB 061004, Swift BAT refined analysis
  81. GRB 061004: Nearby 2MASS Galaxy
  82. GRB 060928: Correction to GCN 5690
  83. GRB 061004: Swift detection of a burst
  84. GRB 060928: 2 pseudo-z from 2 detections spectral parameters
  85. Konus-Wind observation of GRB 060928
  86. GRB 060928: Suzaku/WAM observation of the prompt emission
  87. IGR J08408-4503 (= V* LM Vel): Swift detection of a transient
  88. GRB 060928: Swift observations
  89. GRB 060928: RHESSI Spectral Fit
  90. IPN triangulation of GRB060928 (long, exceptionally bright)
  91. GRB061002: Swift UVOT followup observations
  92. GRB 060930: near-IR afterglow candidate
  93. GRB 061002: Swift-XRT Team Refined Analysis
  94. VLA observations of GRB 060926
  95. GRB061002 - SDSS Pre-Burst Observations
  96. GRB 061002, Swift-BAT refined analysis
  97. GRB061002: MASTER-VWF-Kislovodsk observations
  98. GRB 061002: Swift detection of a burst: CORRECTED CONTENT
  99. GRB 061002: Swift detection of a burst
  100. GRB 060908: Detection of a possible host

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