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 060206: Spectroscopic Redshift
  2. GRB060206: P60 Optical Observations
  3. GRB 060206: KAIT observations
  4. GRB060206: Swift XRT Position
  5. GRB060206: SARA Detection
  6. GRB 060206: RAPTOR observations of afterglow candidate variability.
  7. GRB 060206: High redshift burst
  8. GRB060204a: Swift XRT Detection of an Afterglow Candidate
  9. GRB060206 - Swift UVOT Confirmation of Optical Afterglow
  10. GRB060206: Optical afterglow
  11. GRB060206: Swift-BAT detection of a burst
  12. GRB 060204C: XRT analysis of Swift J061223.0+701243.9
  13. GRB060203: WHT Z-band observations
  14. BAT GRB 060204C is probably not a GRB
  15. GRB060204C: optical observation
  16. GRB 060204B: BVRi-band detections of optical afterglow
  17. GRB 060204A: Swift XRT upper limit
  18. GRB 060204A: FRAM optical observations
  19. GRB060204B: Swift/UVOT refined analysis
  20. GRB 060204C: optical observations
  21. Swift XRT Observation of GRB 060204C
  22. GRB 060204B: Swift-BAT refined analysis
  23. GRB 060204B: ART early limit
  24. GRB060204B: Swift XRT Team Refined Analysis
  25. GRB 060204C: OSN limits
  26. GRB 060204b: Keck/LRIS Afterglow Confirmation
  27. GRB 060204C: BOOTES-IR optical limits
  28. GRB 060204C: Liverpool Telescopes optical limit
  29. GRB 060204C: ROTSE-III Optical Limits
  30. GRB 060204C: Swift-BAT detection of a burst
  31. GRB 060124: Radio Observations
  32. GRB060204B: Faulkes OT candidate
  33. GRB 060204B: ART optical limit
  34. GRB 060204A: further INTEGRAL results
  35. GRB060204B, optical observation
  36. GRB060204B - SDSS pre-burst observations
  37. GRB 060203: Swift-BAT refined analysis
  38. GRB 060204B: Swift detection of a burst
  39. GRB 060204: a long GRB detected by INTEGRAL
  40. GRB 060202: UKIRT/WFCAM K-band and KeckI/LRIS I-band Observation
  41. GRB 060203: RTT150 optical observations
  42. GRB060203: Swift XRT Team Refined Analysis
  43. GRB060203 - Swift UVOT observation
  44. Swift-BAT trigger is GRB 060203
  45. GRB 060203: IR Counterpart
  46. GRB060203: Observations with SARA
  47. GRB 060203: P60 Confirmation of Optical Afterglow
  48. Possible GRB 060203: candidate optical counterpart
  49. Swift BAT Trigger 180151: Swift XRT source detection
  50. Possible GRB 060203: optical observations at Asiago
  51. GRB 060202: PROMPT Observations
  52. Swift-BAT trigger 180151 is unknown origin at this time
  53. GRB 060202: GETS observation
  54. GRB 060202: Gemini-N J, H, K_s observations
  55. GRB 060202 : Kiso B and R band limit
  56. GRB 060202: Near-IR Observation with UKIRT/WFCAM
  57. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  58. GRB 060202: Refined analysis of the Swift-BAT burst
  59. GRB060202, optical observation
  60. GRB 060202: Swift/UVOT upper limits
  61. GRB 060202: Swift XRT Team Refined Analysis
  62. GRB 060202 : Lulin R and I band limit
  63. GRB060202: Faulkes North observation
  64. GRB 060202: Swift detection of a burst
  65. GRB 060121: Gemini Late-time Observations
  66. Erratum: SDSS pre-burst observations of GRB fields
  67. GRB 060130: PROMPT Observations
  68. GRB060130: Further R-band imaging
  69. GRB 060130: Swift/XRT observation
  70. GRB 051211A: MDM Observations
  71. GRB 060123: Gemini spectroscopy of the putative host galaxy
  72. GRB 060123: VLA Radio Observations
  73. GRB060130: Optical imaging
  74. GRB060130: REM infrared observations
  75. GRB 060130, SMARTS optical observations
  76. GRB 060130: FRAM optical observations
  77. GRB 060130: further INTEGRAL IBIS results
  78. GRB 060130: a long GRB detected with INTEGRAL
  79. Possible GRB 051221B: MDM Correction
  80. GRB050121: optical observation
  81. GRB050121b: optical observation
  82. GRB 060121: Confirmation of NIR Afterglow
  83. GRB060124: optical observation
  84. GRB060124: optical observations
  85. GRB 060123: Swift refined analysis of an unusual GRB
  86. GRB060124, BVRcIc field calibration
  87. GRB060105: refined analysis of the Suzaku observation
  88. GRB060124 optical observations
  89. GRB 060121: Probable Detection of NIR Afterglow
  90. GRB060124: optical observation
  91. GRB 060116 HST observations
  92. GRB 060124: HETE detection and spectrum of the main peak
  93. Refined XRT Position for GRB 060123
  94. Konus-Wind observation of GRB 060124
  95. GRB060124: detailed XRT analysis
  96. GRB 060124 Optical Observations
  97. GRB 060124: ART optical limits during the burst
  98. GRB060123: Optical and IR Imaging
  99. GRB 060123: P200 Observations
  100. GRB 060124: Keck optical spectrum

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