Skip to main content
New! BOOM Notices and Schema v7.0.0. 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"

36784 results found.

  1. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  2. GRB 990506 optical observation
  3. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  4. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  5. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  6. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  7. radio observations of X-ray/GRB transient field
  8. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  9. Optical report on X-ray/GRB transient
  10. radio detection of X-ray/GRB transient
  11. BeppoSAX: A new fast X-ray transient
  12. GRB 990510: optical observations
  13. GRB990510: photometric and spectroscopic observations with the VLT
  14. GRB 990510: optical linear polarization
  15. GRB 990510: optical observations
  16. GRB990510, VI observations
  17. GRB 990506 R band observations
  18. GRB990510: X-ray afterglow
  19. GRB 990510: optical observation
  20. VLT spectrum of GRB990510
  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. GRB 990510 optical observations
  29. GRB 990510 optical observations
  30. Galactic extinction towards GRB 990510
  31. GRB 990510 optical observations
  32. IPN localization of GRB990510
  33. GRB 990506 Radio Observations
  34. GRB 990123, optical monitoring
  35. GRB 990506: BATSE Observations
  36. GRB 990506, optical observations
  37. GRB 990510: Final BeppoSAX-WFC Coordinates
  38. GRB 990506, Optical Observations
  39. GRB 990506 optical observations
  40. GRB 990506 optical observations
  41. GRB 990506, optical observations
  42. GRB990506 observation plan
  43. Refined IPN error box for GRB990506
  44. GRB 990506: Limits on the possible optical transient
  45. GRB 990506, armchair astronomy
  46. GRB 990506, optical observations from +1 to +3 hours
  47. GRB 990506, optical observations
  48. GRB990506 observation plan
  49. New IPN/RXTE error box for GRB990506
  50. IPN localization for GRB990506
  51. GRB 970228: Redshift and properties of the host galaxy
  52. IPN localization of GRB990427
  53. GRB981220 VLBA observations
  54. GRB990321 REFINED IPN ANNULUS
  55. GRB990323 PRECISE IPN POSITION
  56. GRB990321 IPN TRIANGULATION
  57. GRB 990316 Optical Observations
  58. GRB 990316, Radio observations
  59. GRB 990316, Optical observations
  60. GRB990316, Optical observations
  61. GRB 990316 optical observations
  62. GRB990316: simultaneous optical observation
  63. ASM/IPN error box for GRB 990308 (BATSE #7457)
  64. GRB990308 not a new SGR
  65. GRB 990308a and GRB 990308b
  66. GRB990308 (Trig. 7457), optical observations
  67. GRB981220, IPN localization
  68. GRB 981220, radio observations
  69. GRB 990123, Field Photometry
  70. GRB 990217 Optical Observations
  71. GRB 990217, radio observations
  72. Optical Observations of GRB990217
  73. GRB990123: Caltech STIS Photometry and Images
  74. GRB990123 observations
  75. GRB990123, Optical Observation
  76. GRB 990123: Discovery of the Probable Host Galaxy
  77. GRB 990123: Reduced HST Images
  78. For Immediate Posting to GCN - HST Data GRB 990123 Available
  79. GRB19990123 observations
  80. GRB 990123: BVRI standards in the field
  81. GRB 990123: Updated Keck Spectroscopy Results
  82. GRB981220, field photometry
  83. GRB 990123 NOT Spectrum Update
  84. GRB990123, Optical observation
  85. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  86. GRB 990123: Publicly available reduced HST images
  87. GRB990123, Upcoming HST Service Observations
  88. GRB 990123: New Constraints on Possible Foreground Galaxies
  89. GRB990123 Optical Observations
  90. GRB990123, Probability of gravitational lensing
  91. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  92. GRB 990123: Continued Radio Observations
  93. GRB990123, Preliminary Lens Search Results
  94. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  95. On the Lensing Interpretation of GRB 990123
  96. Search for Potential Images of GRB 990123
  97. Search for Potential Images of GRB 990123
  98. GRB990123, Optical BVRI Observations
  99. GRB 990123: near-infrared observations.
  100. GRB990123, OSSE observations

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