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"

25770 results found.

  1. GRB 990506 Radio Observations
  2. GRB 990123, optical monitoring
  3. GRB 990506: BATSE Observations
  4. GRB 990506, optical observations
  5. GRB 990506, Optical Observations
  6. GRB 990506 optical observations
  7. GRB 990506, optical observations
  8. GRB 990506, armchair astronomy
  9. GRB 990506, optical observations from +1 to +3 hours
  10. GRB 990506, optical observations
  11. GRB990506 observation plan
  12. IPN localization for GRB990506
  13. GRB990323 PRECISE IPN POSITION
  14. GRB 990316 Optical Observations
  15. GRB 990316 optical observations
  16. GRB990316: simultaneous optical observation
  17. GRB990316 - Optical null results
  18. GRB990308 not a new SGR
  19. GRB 990308a and GRB 990308b
  20. GRB990308, Possible new SGR~0209+70
  21. GRB 990123, Field Photometry
  22. GRB 990217 Optical Observations
  23. BATSE Flight Anomaly
  24. GRB990217: BeppoSAX/GRBM data
  25. GRB990123 observations
  26. GRB990217 Optical observation
  27. GRB990123, Optical Observation
  28. GRB 990123: Discovery of the Probable Host Galaxy
  29. GRB 990123: Reduced HST Images
  30. GRB19990123 observations
  31. GRB 990123: BVRI standards in the field
  32. GRB981220, field photometry
  33. GRB990123, Optical observation
  34. GRB990123, 15-GHz limits
  35. GRB 990123: New Constraints on Possible Foreground Galaxies
  36. GRB990123 Optical Observations
  37. GRB990123, Probability of gravitational lensing
  38. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  39. GRB990123, Preliminary Lens Search Results
  40. On the Lensing Interpretation of GRB 990123
  41. Search for Potential Images of GRB 990123
  42. Search for Potential Images of GRB 990123
  43. GRB990123, Optical BVRI Observations
  44. GRB 990123: near-infrared observations.
  45. GRB990123, OSSE observations
  46. GRB990123: NIR Observation
  47. GRB990123, ASCA X-ray observation of afterglow
  48. "GRB 990123: New BV Observations"
  49. GRB 990123 Optical Follow-Up
  50. GRB 990123: BATSE Observations
  51. GRB990123 Optical Observations
  52. GRB 990123: New Optical Observations, Decay Measure
  53. GRB 990123 Optical Follow-Up
  54. GRB 990123: Possible Gravitationally Lensed Burst?
  55. GRB990123, optical observation
  56. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  57. GRB990123, Optical observation
  58. GRB 990123: Optical Decay Slope
  59. GRB 990123 r-band photometry
  60. GRB 990123 Optical Follow-up
  61. GRB990123, early optical counterpart detection
  62. GRB990123 Optical Observation
  63. Possible identification of SN1999E with GRB980910
  64. Optical Observations of GRB 981220
  65. GRB 981226: radio variable
  66. GRB981220
  67. GRB981220, Correction to GCN 179
  68. GRB 981220 Optical observations
  69. GRB 981226 Optical Observations
  70. GRB 981220 and GRB 981226, optical observations
  71. GRB981226 Optical Observations
  72. GRB981226 BeppoSAX follow up
  73. GRB 981226
  74. GRB 981226 optical observations
  75. GRB981220 B, R and I band observations
  76. Optical Observations of GRB981226
  77. GRB 981220:Optical Observations
  78. GRB 981226 optical observations
  79. GRB 981220
  80. GRB 981220, radio observations
  81. GRB981220 I-band Observations
  82. GRB 981220
  83. GRB 980326/Host Galaxy
  84. GRB 981220: RXTE/ASM and BeppoSAX/GRBM results
  85. BeppoSAX NFI Observation of GRB980425
  86. GRB980329 R,I flux calibration and R,I,K upper limits
  87. GRB980425 Optical Follow-up
  88. GRB 980923 BATSE Observations
  89. SGR1900+14, BeppoSAX-GRBM observations
  90. GRB970508 optical observations
  91. GRB971214, association with a Galactic star?
  92. GRB980519, Optical Observations
  93. GRB980703 - BeppoSAX/GRBM detection
  94. GRB980703 optical photometry
  95. GRB 980703: BATSE Observations
  96. GRB980703 optical observations
  97. GRB980703: Radio transient
  98. GRB 980703: Spectrum of the proposed optical counterpart
  99. GRB980703 Transient Optical Follow-Up
  100. GRB980703: LOTIS observation at early times

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