Skip to main content
Due to the lapse in federal government funding, NASA is not updating this website. See the Operations FAQ for GCN impacts.
New! Super-Kamiokande JSON Notices and Schema v4.5.0. 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"

16759 results found.

  1. GRB 991014, Optical Observations
  2. GRB 991014 - BeppoSAX NFI observations
  3. GRB 991014, radio observations
  4. GRB 991014, Optical Observations
  5. GRB 991014, optical observations
  6. Super-LOTIS optical observation of GRB991014
  7. Optical Observations of GRB990907
  8. GRB990907 and 990908
  9. GRB990806 BeppoSAX follow up
  10. GRB 990806 Optical observations
  11. GRB 990806, optical observations
  12. GRB 990806, Optical Observations
  13. GRB 990712 Optical Observations
  14. GRB 990712
  15. Late-time HST/STIS Observations of GRB 990510
  16. BeppoSAX NFI Observation of GRB990705
  17. BeppoSAX NFI Observation of GRB990705
  18. GRB 990705, R-band observations
  19. GRB990704: SAX-NFI results summary
  20. GRB990704 radio and optical observations
  21. GRB990704
  22. GRB990704, optical observations
  23. Late-time HST/STIS Observation of GRB 990123
  24. Optical Observations of GRB 990506
  25. GRB990527 Optical Observations
  26. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  27. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  28. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  29. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  30. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  31. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  32. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  33. radio observations of X-ray/GRB transient field
  34. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  35. Optical report on X-ray/GRB transient
  36. GRB 990510: optical linear polarization
  37. GRB 990510: optical observations
  38. GRB 990506 R band observations
  39. GRB 990510: BATSE Observations
  40. GRB 990510 optical observations
  41. GRB 990506 Radio Observations
  42. GRB 990123, optical monitoring
  43. GRB 990506, optical observations
  44. GRB 990506, Optical Observations
  45. GRB 990506 optical observations
  46. GRB 990506, optical observations
  47. GRB 990506, optical observations from +1 to +3 hours
  48. GRB 990506, optical observations
  49. GRB990506 observation plan
  50. GRB 970228: Redshift and properties of the host galaxy
  51. GRB 990316 Optical Observations
  52. GRB990316, Optical observations
  53. GRB 990316 optical observations
  54. GRB990316: simultaneous optical observation
  55. GRB 990123, Field Photometry
  56. GRB 990217 Optical Observations
  57. BATSE Flight Anomaly
  58. GRB990123 observations
  59. GRB990123, Optical Observation
  60. GRB 990123: Discovery of the Probable Host Galaxy
  61. GRB 990123: Reduced HST Images
  62. GRB19990123 observations
  63. GRB 990123: BVRI standards in the field
  64. GRB981220, field photometry
  65. GRB990123, Optical observation
  66. GRB990123, Upcoming HST Service Observations
  67. GRB990123, 15-GHz limits
  68. GRB 990123: New Constraints on Possible Foreground Galaxies
  69. GRB990123 Optical Observations
  70. GRB990123, Probability of gravitational lensing
  71. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  72. GRB990123, Preliminary Lens Search Results
  73. GRB990123, Optical BVRI Observations
  74. GRB 990123: near-infrared observations.
  75. GRB990123, OSSE observations
  76. GRB990123: NIR Observation
  77. "GRB 990123: New BV Observations"
  78. GRB 990123: New Optical Observations, Decay Measure
  79. GRB 990123 Optical Follow-Up
  80. GRB 990123: Possible Gravitationally Lensed Burst?
  81. GRB990123, optical observation
  82. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  83. GRB 990123 r-band photometry
  84. GRB 990123 Optical Follow-up
  85. GRB990123, early optical counterpart detection
  86. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  87. Optical Observations of GRB 981220
  88. GRB 981226: radio variable
  89. GRB 981226 Optical Observations
  90. GRB981226 BeppoSAX follow up
  91. GRB 981226
  92. GRB 981226 optical observations
  93. GRB 981220:Optical Observations
  94. GRB981226, BeppoSAX Christmas GRB
  95. GRB 981226 optical observations
  96. GRB 981220, radio observations
  97. GRB 981220
  98. GRB 980326/Host Galaxy
  99. BeppoSAX NFI Observation of GRB980425
  100. GRB980329 R,I flux calibration and R,I,K upper limits

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