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"

22062 results found.

  1. Late-time HST/STIS Observation of GRB 990123
  2. GRB 990506 - Optical Observations
  3. Optical Observations of GRB 990506
  4. GRB990527 Optical Observations
  5. IPN error box for GRB990527
  6. Late Afterglows of GRBs 990510, 990123
  7. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  8. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  9. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  10. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  11. radio observations of X-ray/GRB transient field
  12. Optical report on X-ray/GRB transient
  13. radio detection of X-ray/GRB transient
  14. BeppoSAX: A new fast X-ray transient
  15. GRB 990510: optical observations
  16. GRB990510: photometric and spectroscopic observations with the VLT
  17. GRB 990510: optical observations
  18. GRB990510, VI observations
  19. GRB 990506 R band observations
  20. GRB990510: X-ray afterglow
  21. GRB 990510: Broad Band Break
  22. GRB 990510: BATSE Observations
  23. GRB 990510 Optical Observations
  24. GRB 990510, BVI photometry
  25. GRB 990510 optical observations
  26. GRB 990510: BeppoSAX/GRBM observations
  27. GRB990510 optical observations
  28. GRB990510
  29. GRB 990510 optical observations
  30. GRB 990510 optical observations
  31. GRB 990510 optical observations
  32. GRB 990506 Radio Observations
  33. GRB 990123, optical monitoring
  34. GRB 990506: BATSE Observations
  35. GRB 990506, optical observations
  36. GRB 990506, Optical Observations
  37. GRB 990506 optical observations
  38. GRB 990506 optical observations
  39. GRB 990506, optical observations
  40. GRB990506 observation plan
  41. Refined IPN error box for GRB990506
  42. GRB 990506: Limits on the possible optical transient
  43. GRB 990506, optical observations from +1 to +3 hours
  44. GRB 990506, optical observations
  45. GRB990506 Optical observations
  46. IPN localization of GRB990427
  47. GRB981220 VLBA observations
  48. GRB980425 Optical observations of exponential decline at late time
  49. GRB990321 REFINED IPN ANNULUS
  50. GRB990323 PRECISE IPN POSITION
  51. GRB990321 IPN TRIANGULATION
  52. GRB 990316 Optical Observations
  53. GRB 990316, Radio observations
  54. GRB 990316, Optical observations
  55. GRB990316, Optical observations
  56. GRB 990316 optical observations
  57. GRB990316: simultaneous optical observation
  58. GRB990308 not a new SGR
  59. GRB990308 (Trig. 7457), optical observations
  60. GRB990308, Possible new SGR~0209+70
  61. GRB 981220, radio observations
  62. GRB 990217 Optical Observations
  63. GRB 990217, radio observations
  64. Optical Observations of GRB990217
  65. GRB990123 observations
  66. GRB990123, Optical Observation
  67. GRB 990123: Reduced HST Images
  68. For Immediate Posting to GCN - HST Data GRB 990123 Available
  69. GRB19990123 observations
  70. GRB 990123: Updated Keck Spectroscopy Results
  71. GRB981220, field photometry
  72. GRB 990123 NOT Spectrum Update
  73. GRB990123, Optical observation
  74. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  75. GRB 990123: Publicly available reduced HST images
  76. GRB990123, Upcoming HST Service Observations
  77. GRB990123, 15-GHz limits
  78. GRB 990123: New Constraints on Possible Foreground Galaxies
  79. GRB990123 Optical Observations
  80. GRB990123, Probability of gravitational lensing
  81. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  82. GRB 990123: Continued Radio Observations
  83. GRB990123, Preliminary Lens Search Results
  84. GRB990123, Optical BVRI Observations
  85. GRB 990123: near-infrared observations.
  86. GRB990123, OSSE observations
  87. GRB990123: NIR Observation
  88. "GRB 990123: New BV Observations"
  89. GRB 990123 Optical Follow-Up
  90. GRB 990123; Addendum to GCN 223
  91. GRB 990123: BATSE Observations
  92. GRB990123 Optical Observations
  93. GRB 990123 Spectroscopic Redshifts
  94. GRB 990123: New Optical Observations, Decay Measure
  95. GRB 990123: Possible Gravitationally Lensed Burst?
  96. GRB 990123 optical observations
  97. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  98. GRB 990123 radio observations
  99. GRB 990123, new radio source
  100. GRB990123 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