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"

24806 results found.

  1. BeppoSAX NFI Observation of GRB990705
  2. BeppoSAX NFI Observation of GRB990705
  3. GRB 990705, R-band observations
  4. Infrared and Optical Observations of GRB990705
  5. GRB990704: SAX-NFI results summary
  6. GRB990704 radio and optical observations
  7. GRB990704
  8. GRB990704, optical observations
  9. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  10. Optical Observations of GRB990627
  11. BeppoSAX: GRB990625
  12. Late-time HST/STIS Observation of GRB 990123
  13. Optical Observations of GRB 990506
  14. GRB990527 Optical Observations
  15. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  16. Late Afterglows of GRBs 990510, 990123
  17. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  18. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  19. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  20. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  21. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  22. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  23. radio observations of X-ray/GRB transient field
  24. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  25. Optical report on X-ray/GRB transient
  26. radio detection of X-ray/GRB transient
  27. BeppoSAX: A new fast X-ray transient
  28. GRB 990510: optical observations
  29. GRB 990510: optical linear polarization
  30. GRB 990510: optical observations
  31. GRB990510: X-ray afterglow
  32. GRB 990510: Broad Band Break
  33. GRB 990510: BATSE Observations
  34. GRB 990510: BeppoSAX/GRBM observations
  35. GRB990510 optical observations
  36. GRB 990510 optical observations
  37. GRB 990506 Radio Observations
  38. GRB 990123, optical monitoring
  39. GRB 990506: BATSE Observations
  40. GRB 990506, optical observations
  41. GRB 990506, Optical Observations
  42. GRB 990506 optical observations
  43. GRB 990506, optical observations
  44. GRB 990506, armchair astronomy
  45. GRB 990506, optical observations from +1 to +3 hours
  46. GRB 990506, optical observations
  47. GRB990506 observation plan
  48. IPN localization for GRB990506
  49. GRB990323 PRECISE IPN POSITION
  50. GRB 990316 Optical Observations
  51. GRB 990316 optical observations
  52. GRB990316: simultaneous optical observation
  53. GRB990316 - Optical null results
  54. GRB990308 not a new SGR
  55. GRB 990308a and GRB 990308b
  56. GRB990308, Possible new SGR~0209+70
  57. GRB 990123, Field Photometry
  58. GRB 990217 Optical Observations
  59. BATSE Flight Anomaly
  60. GRB990217: BeppoSAX/GRBM data
  61. GRB990123 observations
  62. GRB990217 Optical observation
  63. GRB990123, Optical Observation
  64. GRB 990123: Discovery of the Probable Host Galaxy
  65. GRB 990123: Reduced HST Images
  66. GRB19990123 observations
  67. GRB 990123: BVRI standards in the field
  68. GRB981220, field photometry
  69. GRB990123, Optical observation
  70. GRB990123, 15-GHz limits
  71. GRB 990123: New Constraints on Possible Foreground Galaxies
  72. GRB990123 Optical Observations
  73. GRB990123, Probability of gravitational lensing
  74. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  75. GRB990123, Preliminary Lens Search Results
  76. On the Lensing Interpretation of GRB 990123
  77. Search for Potential Images of GRB 990123
  78. Search for Potential Images of GRB 990123
  79. GRB990123, Optical BVRI Observations
  80. GRB 990123: near-infrared observations.
  81. GRB990123, OSSE observations
  82. GRB990123: NIR Observation
  83. GRB990123, ASCA X-ray observation of afterglow
  84. "GRB 990123: New BV Observations"
  85. GRB 990123 Optical Follow-Up
  86. GRB 990123: BATSE Observations
  87. GRB990123 Optical Observations
  88. GRB 990123: New Optical Observations, Decay Measure
  89. GRB 990123 Optical Follow-Up
  90. GRB 990123: Possible Gravitationally Lensed Burst?
  91. GRB990123, optical observation
  92. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  93. GRB990123, Optical observation
  94. GRB 990123: Optical Decay Slope
  95. GRB 990123 r-band photometry
  96. GRB 990123 Optical Follow-up
  97. GRB990123, early optical counterpart detection
  98. GRB990123 Optical Observation
  99. Possible identification of SN1999E with GRB980910
  100. Optical Observations of GRB 981220

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