Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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. BATSE Flight Anomaly
  2. GRB990217: BeppoSAX/GRBM data
  3. Optical Observations of GRB990217
  4. GRB990123: Caltech STIS Photometry and Images
  5. GRB990123 observations
  6. GRB990217 Optical observation
  7. GRB990217, WFC position
  8. GRB990123, Optical Observation
  9. GRB 990123: Discovery of the Probable Host Galaxy
  10. GRB 990123: Reduced HST Images
  11. For Immediate Posting to GCN - HST Data GRB 990123 Available
  12. GRB19990123 observations
  13. GRB 990123: BVRI standards in the field
  14. GRB 990123: Updated Keck Spectroscopy Results
  15. GRB981220, field photometry
  16. GRB 990123 NOT Spectrum Update
  17. GRB990123, Optical observation
  18. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  19. GRB 990123: Publicly available reduced HST images
  20. GRB990123, Upcoming HST Service Observations
  21. GRB990123, 15-GHz limits
  22. GRB 990123: New Constraints on Possible Foreground Galaxies
  23. GRB990123 Optical Observations
  24. GRB990123, Probability of gravitational lensing
  25. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  26. GRB 990123: Continued Radio Observations
  27. GRB990123, Preliminary Lens Search Results
  28. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  29. On the Lensing Interpretation of GRB 990123
  30. Search for Potential Images of GRB 990123
  31. Search for Potential Images of GRB 990123
  32. GRB990123, Optical BVRI Observations
  33. GRB 990123: near-infrared observations.
  34. GRB990123, OSSE observations
  35. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  36. GRB990123: NIR Observation
  37. GRB990123, ASCA X-ray observation of afterglow
  38. "GRB 990123: New BV Observations"
  39. GRB 990123 Optical Follow-Up
  40. GRB 990123; Addendum to GCN 223
  41. GRB 990123: BATSE Observations
  42. GRB 990123 Keck Spectrum update
  43. GRB990123 IPN annulus
  44. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  45. GRB990123 Optical Observations
  46. GRB 990123 Spectroscopic Redshifts
  47. GRB 990123: New Optical Observations, Decay Measure
  48. GRB 990123 Optical Follow-Up
  49. GRB 990123: Possible Gravitationally Lensed Burst?
  50. GRB990123, optical observation
  51. GRB 990123 optical observations
  52. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  53. GRB 990123 radio observations
  54. GRB 990123, new radio source
  55. GRB990123 optical observations
  56. GRB990123, Optical observation
  57. GRB 990123: Optical Decay Slope
  58. GRB 990123 r-band photometry
  59. GRB 990123 Optical Follow-up
  60. GRB990123, early optical counterpart detection
  61. GRB990123 Optical Observation
  62. GRB990123, BeppoSAX-NFI X-ray afterglow detection
  63. GRB990123, refined SAX-WFC position
  64. GRB 990123: Bright New Source, Possible Optical Transient
  65. GRB 990123, Radio observations
  66. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  67. SN 1999E & GRB 980919
  68. Possible identification of SN1999E with GRB980910
  69. Optical Observations of GRB 981220
  70. GRB 981226: radio variable
  71. GRB981220
  72. GRB981220, Correction to GCN 179
  73. GRB981220, Optical Observations
  74. GRB 981220 Optical observations
  75. GRB 981226 Optical Observations
  76. GRB 980613: Spectroscopy of the host galaxy
  77. GRB981226, sub-millimeter observations
  78. GRB981220, sub-millimeter observations
  79. GRB 981220 and GRB 981226, optical observations
  80. GRB981226 Optical Observations
  81. GRB981226 BeppoSAX follow up
  82. GRB 981226 radio observations
  83. GRB 981226
  84. GRB 981226 optical observations
  85. radio observations of GRB 981226
  86. GRB981220 B, R and I band observations
  87. GRB981226, BeppoSAX-NFI follow-up
  88. Optical Observations of GRB981226
  89. GRB 981220:Optical Observations
  90. GRB 981220 optical R and I observations
  91. GRB981226, BeppoSAX Christmas GRB
  92. GRB 981226 - Infrared Observations
  93. GRB 981226 optical observations
  94. GRB 981220
  95. GRB 981220, radio observations
  96. GRB981226 Optical Observation
  97. GRB 981220, radio observations
  98. GRB 981220: BeppoSAX/GRBM results
  99. GRB981220 I-band Observations
  100. GRB981220 Optical Observations

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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