Skip to main content
New! Browse Circulars by Event, Advanced Search, Sample Codes, Schema Release. 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. GRB990506 Optical observations
  3. GRB990506 observation plan
  4. New IPN/RXTE error box for GRB990506
  5. IPN localization for GRB990506
  6. GRB 970228: Redshift and properties of the host galaxy
  7. IPN localization of GRB990427
  8. GRB981220 VLBA observations
  9. GRB980425 Optical observations of exponential decline at late time
  10. GRB990321 REFINED IPN ANNULUS
  11. GRB990323 PRECISE IPN POSITION
  12. GRB990321 IPN TRIANGULATION
  13. GRB 990316 Optical Observations
  14. GRB 990316, Radio observations
  15. GRB 990316, Optical observations
  16. GRB990316, Optical observations
  17. GRB 990316 optical observations
  18. GRB990316: simultaneous optical observation
  19. GRB990316 - Optical null results
  20. ASM/IPN error box for GRB 990308 (BATSE #7457)
  21. GRB990308 not a new SGR
  22. GRB 990308a and GRB 990308b
  23. GRB990308 (Trig. 7457), optical observations
  24. GRB990308, Possible new SGR~0209+70
  25. GRB981220, IPN localization
  26. GRB 981220, radio observations
  27. GRB 990123, Field Photometry
  28. GRB 990217 Optical Observations
  29. GRB 990217, radio observations
  30. BATSE Resumes Normal Operations
  31. BATSE Flight Anomaly
  32. GRB990217: BeppoSAX/GRBM data
  33. Optical Observations of GRB990217
  34. GRB990123: Caltech STIS Photometry and Images
  35. GRB990123 observations
  36. GRB990217 Optical observation
  37. GRB990217, WFC position
  38. GRB990123, Optical Observation
  39. GRB 990123: Discovery of the Probable Host Galaxy
  40. GRB 990123: Reduced HST Images
  41. For Immediate Posting to GCN - HST Data GRB 990123 Available
  42. GRB19990123 observations
  43. GRB 990123: BVRI standards in the field
  44. GRB 990123: Updated Keck Spectroscopy Results
  45. GRB981220, field photometry
  46. GRB 990123 NOT Spectrum Update
  47. GRB990123, Optical observation
  48. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  49. GRB 990123: Publicly available reduced HST images
  50. GRB990123, Upcoming HST Service Observations
  51. GRB990123, 15-GHz limits
  52. GRB 990123: New Constraints on Possible Foreground Galaxies
  53. GRB990123 Optical Observations
  54. GRB990123, Probability of gravitational lensing
  55. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  56. GRB 990123: Continued Radio Observations
  57. GRB990123, Preliminary Lens Search Results
  58. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  59. On the Lensing Interpretation of GRB 990123
  60. Search for Potential Images of GRB 990123
  61. Search for Potential Images of GRB 990123
  62. GRB990123, Optical BVRI Observations
  63. GRB 990123: near-infrared observations.
  64. GRB990123, OSSE observations
  65. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  66. GRB990123: NIR Observation
  67. GRB990123, ASCA X-ray observation of afterglow
  68. "GRB 990123: New BV Observations"
  69. GRB 990123 Optical Follow-Up
  70. GRB 990123; Addendum to GCN 223
  71. GRB 990123: BATSE Observations
  72. GRB 990123 Keck Spectrum update
  73. GRB990123 IPN annulus
  74. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  75. GRB990123 Optical Observations
  76. GRB 990123 Spectroscopic Redshifts
  77. GRB 990123: New Optical Observations, Decay Measure
  78. GRB 990123 Optical Follow-Up
  79. GRB 990123: Possible Gravitationally Lensed Burst?
  80. GRB990123, optical observation
  81. GRB 990123 optical observations
  82. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  83. GRB 990123 radio observations
  84. GRB 990123, new radio source
  85. GRB990123 optical observations
  86. GRB990123, Optical observation
  87. GRB 990123: Optical Decay Slope
  88. GRB 990123 r-band photometry
  89. GRB 990123 Optical Follow-up
  90. GRB990123, early optical counterpart detection
  91. GRB990123 Optical Observation
  92. GRB990123, BeppoSAX-NFI X-ray afterglow detection
  93. GRB990123, refined SAX-WFC position
  94. GRB 990123: Bright New Source, Possible Optical Transient
  95. GRB 990123, Radio observations
  96. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  97. SN 1999E & GRB 980919
  98. Possible identification of SN1999E with GRB980910
  99. Optical Observations of GRB 981220
  100. GRB 981226: radio variable

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