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. GRB060209: RTT150 optical observations
  2. GRB 060209 : TAROT optical observation
  3. GRB060209A: MASTER optical observation
  4. GRB 060209(?): Swift-BAT detection of a possible burst
  5. GRB 060206: near-infrared observations (JK' imaging)
  6. GRB 060206: WSRT Radio Observations
  7. GRB 060203: Swift/UVOT upper limits
  8. GRB 060206: TTT Observations
  9. GRB 060206: More PROMPT Detections
  10. GRB 060121 : WIDGET Pre-trigger limit
  11. GRB 060206: Tenagra II Observations
  12. GRB 060206: PROMPT Detections
  13. Retraction of orphan GRB afterglow candidate
  14. GRB060204a: Swift XRT Source is not GRB Afterglow
  15. GRB 060206: optical observations at Asiago
  16. Orphan GRB Afterglow candidate
  17. GRB 060204b: pseudo-z from spectral parameters of the prompt emission
  18. GRB 060206: Subaru/FOCAS optical spectroscopy
  19. GRB 060206: IR Detection of the Afterglow
  20. GRB 060206: Lick 3m Spectroscopy
  21. GRB 060204A: ROSAT Pointing
  22. GRB 060206: Super-LOTIS observations
  23. GRB060204A: Swift/UVOT observations
  24. GRB 060206: Swift-BAT refined analysis
  25. GRB 060206 : Lulin optical observations
  26. GRB060206: SDSS Pre-Burst Observations
  27. GRB060206: Swift XRT Refined Analysis
  28. GRB060206: Liverpool Telescope observation
  29. GRB 060206: Spectroscopic Redshift
  30. GRB060206: P60 Optical Observations
  31. GRB 060206: KAIT observations
  32. GRB060206: Swift XRT Position
  33. GRB060206: SARA Detection
  34. GRB 060206: RAPTOR observations of afterglow candidate variability.
  35. GRB 060206: High redshift burst
  36. GRB060204a: Swift XRT Detection of an Afterglow Candidate
  37. GRB060206 - Swift UVOT Confirmation of Optical Afterglow
  38. GRB060206: Optical afterglow
  39. GRB060206: Swift-BAT detection of a burst
  40. GRB 060204C: XRT analysis of Swift J061223.0+701243.9
  41. GRB060203: WHT Z-band observations
  42. BAT GRB 060204C is probably not a GRB
  43. GRB060204C: optical observation
  44. GRB 060204B: BVRi-band detections of optical afterglow
  45. GRB 060204A: Swift XRT upper limit
  46. GRB 060204A: FRAM optical observations
  47. GRB060204B: Swift/UVOT refined analysis
  48. GRB 060204C: optical observations
  49. Swift XRT Observation of GRB 060204C
  50. GRB 060204B: Swift-BAT refined analysis
  51. GRB 060204B: ART early limit
  52. GRB060204B: Swift XRT Team Refined Analysis
  53. GRB 060204C: OSN limits
  54. GRB 060204b: Keck/LRIS Afterglow Confirmation
  55. GRB 060204C: BOOTES-IR optical limits
  56. GRB 060204C: Liverpool Telescopes optical limit
  57. GRB 060204C: ROTSE-III Optical Limits
  58. GRB 060204C: Swift-BAT detection of a burst
  59. GRB 060124: Radio Observations
  60. GRB060204B: Faulkes OT candidate
  61. GRB 060204B: ART optical limit
  62. GRB 060204A: further INTEGRAL results
  63. GRB060204B, optical observation
  64. GRB060204B - SDSS pre-burst observations
  65. GRB 060203: Swift-BAT refined analysis
  66. GRB 060204B: Swift detection of a burst
  67. GRB 060204: a long GRB detected by INTEGRAL
  68. GRB 060202: UKIRT/WFCAM K-band and KeckI/LRIS I-band Observation
  69. GRB 060203: RTT150 optical observations
  70. GRB060203: Swift XRT Team Refined Analysis
  71. GRB060203 - Swift UVOT observation
  72. Swift-BAT trigger is GRB 060203
  73. GRB 060203: IR Counterpart
  74. GRB060203: Observations with SARA
  75. GRB 060203: P60 Confirmation of Optical Afterglow
  76. Possible GRB 060203: candidate optical counterpart
  77. Swift BAT Trigger 180151: Swift XRT source detection
  78. Possible GRB 060203: optical observations at Asiago
  79. GRB 060202: PROMPT Observations
  80. Swift-BAT trigger 180151 is unknown origin at this time
  81. GRB 060202: GETS observation
  82. GRB 060202: Gemini-N J, H, K_s observations
  83. GRB 060202 : Kiso B and R band limit
  84. GRB 060202: Near-IR Observation with UKIRT/WFCAM
  85. GRB 060202: Optical Afterglow Candidate from Keck/LRIS
  86. GRB 060202: Refined analysis of the Swift-BAT burst
  87. GRB060202, optical observation
  88. GRB 060202: Swift/UVOT upper limits
  89. GRB 060202: Swift XRT Team Refined Analysis
  90. GRB 060202 : Lulin R and I band limit
  91. GRB060202: Faulkes North observation
  92. GRB 060202: Swift detection of a burst
  93. GRB 060121: Gemini Late-time Observations
  94. Erratum: SDSS pre-burst observations of GRB fields
  95. GRB 060130: PROMPT Observations
  96. GRB060130: Further R-band imaging
  97. GRB 060130: Swift/XRT observation
  98. GRB 051211A: MDM Observations
  99. GRB 060123: Gemini spectroscopy of the putative host galaxy
  100. GRB 060123: VLA Radio Observations

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