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"

32502 results found.

  1. GRB990506 observation plan
  2. New IPN/RXTE error box for GRB990506
  3. IPN localization for GRB990506
  4. GRB 970228: Redshift and properties of the host galaxy
  5. GRB981220 VLBA observations
  6. GRB990321 REFINED IPN ANNULUS
  7. GRB990323 PRECISE IPN POSITION
  8. GRB 990316 Optical Observations
  9. GRB 990316, Radio observations
  10. GRB 990316, Optical observations
  11. GRB990316, Optical observations
  12. GRB 990316 optical observations
  13. GRB990316: simultaneous optical observation
  14. GRB990308 not a new SGR
  15. GRB 990308a and GRB 990308b
  16. GRB990308 (Trig. 7457), optical observations
  17. GRB981220, IPN localization
  18. GRB 981220, radio observations
  19. GRB 990123, Field Photometry
  20. GRB 990217, radio observations
  21. BATSE Resumes Normal Operations
  22. BATSE Flight Anomaly
  23. GRB990123: Caltech STIS Photometry and Images
  24. GRB990123 observations
  25. GRB990123, Optical Observation
  26. GRB 990123: Discovery of the Probable Host Galaxy
  27. GRB 990123: Reduced HST Images
  28. For Immediate Posting to GCN - HST Data GRB 990123 Available
  29. GRB19990123 observations
  30. GRB 990123: Updated Keck Spectroscopy Results
  31. GRB 990123 NOT Spectrum Update
  32. GRB990123, Optical observation
  33. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  34. GRB 990123: Publicly available reduced HST images
  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. GRB 990123: Continued Radio Observations
  40. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  41. On the Lensing Interpretation of GRB 990123
  42. Search for Potential Images of GRB 990123
  43. Search for Potential Images of GRB 990123
  44. GRB990123, Optical BVRI Observations
  45. GRB 990123: near-infrared observations.
  46. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  47. GRB990123: NIR Observation
  48. "GRB 990123: New BV Observations"
  49. GRB 990123 Optical Follow-Up
  50. GRB 990123; Addendum to GCN 223
  51. GRB 990123: BATSE Observations
  52. GRB 990123 Keck Spectrum update
  53. GRB990123 IPN annulus
  54. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  55. GRB990123 Optical Observations
  56. GRB 990123 Spectroscopic Redshifts
  57. GRB 990123: New Optical Observations, Decay Measure
  58. GRB 990123 Optical Follow-Up
  59. GRB 990123: Possible Gravitationally Lensed Burst?
  60. GRB990123, optical observation
  61. GRB 990123 optical observations
  62. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  63. GRB 990123 radio observations
  64. GRB 990123, new radio source
  65. GRB990123, Optical observation
  66. GRB 990123: Optical Decay Slope
  67. GRB 990123 r-band photometry
  68. GRB 990123 Optical Follow-up
  69. GRB990123, early optical counterpart detection
  70. GRB990123 Optical Observation
  71. GRB 990123: Bright New Source, Possible Optical Transient
  72. GRB 990123, Radio observations
  73. SN 1999E & GRB 980919
  74. Optical Observations of GRB 981220
  75. GRB 981226: radio variable
  76. GRB981220
  77. GRB981220, Correction to GCN 179
  78. GRB981220, Optical Observations
  79. GRB 981220 Optical observations
  80. GRB 981226 Optical Observations
  81. GRB 980613: Spectroscopy of the host galaxy
  82. GRB981226, sub-millimeter observations
  83. GRB981220, sub-millimeter observations
  84. GRB 981220 and GRB 981226, optical observations
  85. GRB981226 Optical Observations
  86. GRB 981226 radio observations
  87. GRB 981226
  88. radio observations of GRB 981226
  89. GRB981220 B, R and I band observations
  90. Optical Observations of GRB981226
  91. GRB 981220:Optical Observations
  92. GRB 981220 optical R and I observations
  93. GRB981226, BeppoSAX Christmas GRB
  94. GRB 981226 - Infrared Observations
  95. GRB 981220
  96. GRB 981220, radio observations
  97. GRB 981220, radio observations
  98. GRB 981220: BeppoSAX/GRBM results
  99. GRB981220 I-band Observations
  100. GRB 981220

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