Skip to main content
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"
  1. GRB 990506, optical observations
  2. GRB 990510: Final BeppoSAX-WFC Coordinates
  3. GRB 990506, Optical Observations
  4. GRB 990506 optical observations
  5. GRB 990506 optical observations
  6. GRB 990506, optical observations
  7. GRB990506 observation plan
  8. Refined IPN error box for GRB990506
  9. GRB 990506: Limits on the possible optical transient
  10. GRB 990506, armchair astronomy
  11. GRB 990506, optical observations from +1 to +3 hours
  12. GRB 990506, optical observations
  13. GRB990506 Optical observations
  14. GRB990506 observation plan
  15. New IPN/RXTE error box for GRB990506
  16. IPN localization for GRB990506
  17. GRB 970228: Redshift and properties of the host galaxy
  18. IPN localization of GRB990427
  19. GRB981220 VLBA observations
  20. GRB980425 Optical observations of exponential decline at late time
  21. GRB990321 REFINED IPN ANNULUS
  22. GRB990323 PRECISE IPN POSITION
  23. GRB990321 IPN TRIANGULATION
  24. GRB 990316 Optical Observations
  25. GRB 990316, Radio observations
  26. GRB 990316, Optical observations
  27. GRB990316, Optical observations
  28. GRB 990316 optical observations
  29. GRB990316: simultaneous optical observation
  30. GRB990316 - Optical null results
  31. ASM/IPN error box for GRB 990308 (BATSE #7457)
  32. GRB990308 not a new SGR
  33. GRB 990308a and GRB 990308b
  34. GRB990308 (Trig. 7457), optical observations
  35. GRB990308, Possible new SGR~0209+70
  36. GRB981220, IPN localization
  37. GRB 981220, radio observations
  38. GRB 990123, Field Photometry
  39. GRB 990217 Optical Observations
  40. GRB 990217, radio observations
  41. BATSE Resumes Normal Operations
  42. BATSE Flight Anomaly
  43. GRB990217: BeppoSAX/GRBM data
  44. Optical Observations of GRB990217
  45. GRB990123: Caltech STIS Photometry and Images
  46. GRB990123 observations
  47. GRB990217 Optical observation
  48. GRB990217, WFC position
  49. GRB990123, Optical Observation
  50. GRB 990123: Discovery of the Probable Host Galaxy
  51. GRB 990123: Reduced HST Images
  52. For Immediate Posting to GCN - HST Data GRB 990123 Available
  53. GRB19990123 observations
  54. GRB 990123: BVRI standards in the field
  55. GRB 990123: Updated Keck Spectroscopy Results
  56. GRB981220, field photometry
  57. GRB 990123 NOT Spectrum Update
  58. GRB990123, Optical observation
  59. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  60. GRB 990123: Publicly available reduced HST images
  61. GRB990123, Upcoming HST Service Observations
  62. GRB990123, 15-GHz limits
  63. GRB 990123: New Constraints on Possible Foreground Galaxies
  64. GRB990123 Optical Observations
  65. GRB990123, Probability of gravitational lensing
  66. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  67. GRB 990123: Continued Radio Observations
  68. GRB990123, Preliminary Lens Search Results
  69. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  70. On the Lensing Interpretation of GRB 990123
  71. Search for Potential Images of GRB 990123
  72. Search for Potential Images of GRB 990123
  73. GRB990123, Optical BVRI Observations
  74. GRB 990123: near-infrared observations.
  75. GRB990123, OSSE observations
  76. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  77. GRB990123: NIR Observation
  78. GRB990123, ASCA X-ray observation of afterglow
  79. "GRB 990123: New BV Observations"
  80. GRB 990123 Optical Follow-Up
  81. GRB 990123; Addendum to GCN 223
  82. GRB 990123: BATSE Observations
  83. GRB 990123 Keck Spectrum update
  84. GRB990123 IPN annulus
  85. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  86. GRB990123 Optical Observations
  87. GRB 990123 Spectroscopic Redshifts
  88. GRB 990123: New Optical Observations, Decay Measure
  89. GRB 990123 Optical Follow-Up
  90. GRB 990123: Possible Gravitationally Lensed Burst?
  91. GRB990123, optical observation
  92. GRB 990123 optical observations
  93. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  94. GRB 990123 radio observations
  95. GRB 990123, new radio source
  96. GRB990123 optical observations
  97. GRB990123, Optical observation
  98. GRB 990123: Optical Decay Slope
  99. GRB 990123 r-band photometry
  100. GRB 990123 Optical Follow-up

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