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. IPN triangulation of GRB000516
  2. Re: GRB000508B : Optical observations
  3. GRB 000418, Optical observation
  4. GRB000508B, optical photometry
  5. GRB000508B, BVR field photometry
  6. Possible GRB-related phenomenon
  7. RXTE/ASM and IPN localization of GRB 000508B
  8. GRB000424, UBVRI field photometry
  9. GRB 000424 Optical Observations
  10. GRB000418, UBVRI field photometry update
  11. The redshift of GRB 000418
  12. GRB000424, optical observations
  13. GRB 000429, optical observation
  14. GRB 000429, UBVRI field photometry
  15. IPN localization of GRB000429
  16. GRB 000418, UBVRI field photometry
  17. GRB000418, Radio detection
  18. GRB000418, K'-band photometry
  19. GRB 000418, Optical Observation
  20. GRB 000418, optical observation
  21. GRB000424 Optical Observations
  22. GRB 000418, Optical Observation
  23. GRB000424, optical observations
  24. GRB000424, optical observations
  25. GRB 000424, Optical Observations
  26. GRB 000418, Optical Observation
  27. GRB000418, near-infrared observations
  28. BeppoSAX GRB000424
  29. Correction to IPN error box for GRB000419
  30. IPN error box for GRB000418
  31. GRB000419 [IPN Position]
  32. GRB000416 Optical Observations
  33. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  34. GRB000416 BRJK observations
  35. 1SAXJ1715.0-7134 refined position
  36. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  37. X-ray burst or X-ray rich GRB 000416 observed by BeppoSAX
  38. Budget cuts in BeppoSAX operations: impact on GRB observations
  39. GRB 000408, optical observations
  40. Refined IPN error box for GRB000408
  41. GRB 991208, UBVRI field photometry
  42. GRB000301c results
  43. GRB000408: Optical CCD Observations from MIRO
  44. GRB000408, lotis optical observations
  45. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  46. GRB000408 [IPN Position]
  47. GRB000326 Optical Observations
  48. GRB000301C - Addendum to GCN 623
  49. GRB000301C - R magnitude lower limit
  50. GRB000326, Further VLA observations
  51. GRB 000323, optical observations
  52. GRB 000326: Optical Observations
  53. GRB000326, Radio observations
  54. GRB000326 [IPN Position]
  55. GRB 000307 optical observations
  56. GRB000323 [IPN Position]
  57. Single error box for GRB000315
  58. GRB000315 [IPN Positions]
  59. GRB000313, Radio observations
  60. GRB 000313 - optical transient in the BATSE error box
  61. GRB000301C - B and R photometry
  62. GRB000301C - R photometry
  63. GRB 000307, Optical Observations
  64. GRB 000307, BVRI Field Photometry
  65. GRB 000301C: Optical Spectrum and Redshift
  66. GRB 000301C: Optical Spectrum and Redshift
  67. GRB 000301C: A Precise Redshift Determination
  68. GRB 000301C, Optical Observation
  69. GRB 000301C: HST/STIS-PRISM NUV-MAMA spectroscopy
  70. GRB 000301C: HST/STIS CCD Imaging of the field
  71. IPN error box for GRB000307
  72. GRB 000301c: K' observations
  73. GRB000301C, optical R-band observations
  74. GRB000301c - R photometry and nearby faint source confirmation
  75. GRB 000301C, Optical Observation
  76. GRB 000301c: K' observations
  77. GRB 000301C Optical Observations
  78. GRB 000301C: K' Observations
  79. GRB000301C OT candidate optical observations
  80. GRB000301C - Host galaxy not detected in R (?)
  81. Optical observations of GRB000301c
  82. GRB000301C, Radio observations
  83. GRB000301C, Radio observations
  84. GRB000301C optical observations
  85. GRB000301C, near-infrared observations (JHK' imaging)
  86. GRB 000301c near-IR observations
  87. GRB 000301C, Optical Color
  88. GRB000301C, Optical Spectroscopy
  89. GRB 000301C, UBVRI field photometry
  90. GRB 000301C, Optical Observation
  91. GRB000301C, optical observations
  92. GRB000301C 250 GHz detection
  93. GRB 000301C R-band observation
  94. GRB 000301C, Optical Observation
  95. GRB000301C, near-infrared observations (JHK' photometry)
  96. GRB 000301C: OT confirmed
  97. GRB000301c optical observations
  98. GRB 000301A, Radio Observations
  99. GRB000301C, optical observations
  100. GRB000301c, near-infrared 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