Skip to main content
Testing. You are viewing the public testing version of GCN. For the production version, go to https://gcn.nasa.gov.
Due to the lapse in federal government funding, NASA is not updating this website. See the Operations FAQ for GCN impacts.
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 991208: HST Imaging of the Host Galaxy
  2. GRB000926: R-image of the host galaxy
  3. GRB 001025B, I-band observations
  4. XMM-Newton observation of GRB001025
  5. GRB001025B, Radio observations
  6. GRB 001025 Optical Observations
  7. GRB 001025A, optical observation
  8. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  9. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  10. IPN triangulation of GRB001025
  11. GRB001007: Optical observations
  12. ASM Localization of GRB 001025
  13. GRB001007, Radio observations
  14. IPN TRIANGULATION OF GRB001020
  15. GRB001019, Optical Observations
  16. GRB 001018, Possible Radio Afterglow
  17. GRB001018, Gamma Ray Observations
  18. IPN TRIANGULATION OF GRB001019
  19. CORRECTION TO PEAK FLUX OF GRB001018
  20. IPN TRIANGULATION OF GRB001018
  21. IPN TRIANGULATION OF GRB 001017
  22. GRB 000926: Improved Absorber Redshift
  23. V,R,I band observations of GRB000926
  24. The Likely Optical/Infrared Afterglow of GRB 001011
  25. HETE positions added to GCN
  26. GRB001011 BeppoSAX/WFC refined position
  27. BeppoSAX ALERT: GRB001011
  28. GRB 001007, BVR-band observations
  29. GRB000926 - Amateur Optical Observations
  30. GRB001007: Optical observations
  31. CONCAM null result on GRB001005
  32. IPN triangulation of GRB001007
  33. GRB 000926 : the host galaxy
  34. HETE-2 Launches Successfully
  35. IPN triangulation of GRB001005
  36. HETE-2 48 hour Launch Delay
  37. GRB 000926 Chandra Observation
  38. IPN triangulation of GRB 001004
  39. Public availability of BeppoSAX data of GRB000926
  40. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  41. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  42. GRB000926 - Optical observations
  43. GRB000926 - Optical observations
  44. GRB 000926, Optical Decay
  45. GRB000911: VLT infrared observation
  46. GRB000926 - Optical observations
  47. GRB000926 - Optical observations
  48. GRB 000926: optical observations
  49. GRB 000926, Optical Observations
  50. GRB000926 - Optical observations
  51. GRB000911: optical VLT observations
  52. GRB000926 K'-band Observation
  53. GRB000926 : increasing optical decay slope
  54. GRB000926 optical observations
  55. GRB000926 - Optical observations
  56. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  57. J and K band observations of GRB 000926
  58. GRB000911 Optical Observations
  59. GRB 000926: Lightcurve Update and Predictions
  60. GRB 000926, optical observation by Oksanen (vsnet-grb)
  61. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  62. GRB000926: Optical observations
  63. CONCAM crude optical limits before and after GRB000926
  64. GRB 000926: Preliminary R-band Lightcurve
  65. GRB 000926 HST/Chandra TOO Status
  66. Spectroscopic Redshift of GRB 000926
  67. GRB 000926, Optical Observation
  68. GRB000926, radio observations
  69. GRB 000926: Optical candidate
  70. Optical candidate for GRB000926
  71. IPN triangulation of GRB000926
  72. IPN triangulation of GRB000926
  73. GRB 000911, BVRI field photometry
  74. GRB000911: Corrected coordinates
  75. GRB000911: Sub-millimeter observations
  76. IPN triangulation of GRB000925
  77. GRB000911: Optical Transient
  78. GRB000911, Radio and Optical observations
  79. GRB000911, Radio observations
  80. GRB000911: Optical observations
  81. IPN triangulation of GRB000911
  82. IPN triangulation of GRB000910
  83. False GRB alarm from RXTE/ASM on 8 Sept 2000
  84. GRB 000830: Optical observations
  85. GRB000830: Optical observations
  86. GRB000830, TNG B-band observations
  87. GRB000830, BVRI field photometry
  88. GRB000830: Optical observations
  89. GRB000210, Optical observations
  90. Chandra Position of GRB000210
  91. "Snapshot" afterglow IDs and GRB 000830
  92. GRB000830: Optical observations
  93. IPN triangulation of GRB000830
  94. HST/STIS observations of the host galaxy of GRB 980329
  95. HST/STIS observations of the chaotic environment of GRB 980613
  96. IPN localization of GRB000820
  97. SGR 1806-20 burst activity
  98. GRB000812, TNG R-band observations
  99. GRB000801 & GRB000730, Gamma Ray Observations
  100. GRB000730, Gamma Ray 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