Skip to main content
New! Circulars over Kafka, Heartbeat Topic, and Schema v4.1.0. 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').
  1. BeppoSAX MAIL n. 99/24: GRB ALERT: GRB990907
  2. GRB 990712 Late Optical Decay and Host Galaxy
  3. GRB 990712, Optical Observation
  4. GRB990806 BeppoSAX follow up
  5. GRB990806: BATSE Observations
  6. GRB 990806 Optical observations
  7. Optical Observations of GRB990806
  8. GRB 990806, Optical Observations
  9. GRB 990806, optical observations
  10. GRB 990806, Optical Observations
  11. GRB990806 UBVRIJHK observations
  12. GRB990806: possible X-ray afterglow, BeppoSAX
  13. BeppoSAX ALERT GRB990806: Summer GRB
  14. GRB 990712 Optical Observations
  15. GRB990705: No Evidence for Neutrino Signal
  16. GRB 990712 Optical Decay: Indication of Bright Host Galaxy
  17. VLT spectrum of GRB990712
  18. GRB 990712
  19. Late-time HST/STIS Observations of GRB 990510
  20. Refined BeppoSAX-WFC position of GRB990712
  21. BeppoSAX NFI Observation of GRB990705
  22. BeppoSAX NFI Observation of GRB990705
  23. Updated Astrometry for the IR Counterpart of GRB990705
  24. GRB 990705, R-band observations
  25. Updated IPN localization of GRB990705
  26. IPN localization of GRB990704
  27. IPN localization of GRB990705
  28. Infrared and Optical Observations of GRB990705
  29. GRB 990705, radio observations
  30. GRB990704: SAX-NFI results summary
  31. GRB990704 radio and optical observations
  32. BeppoSAX GRB990705: possible X-ray afterglow
  33. GRB 990704 X-ray Observations
  34. GRB 990704 Optical Observations
  35. GRB 990704, optical observations
  36. GRB990704
  37. GRB990705: Intriguing Positional Coincidences
  38. GRB990704
  39. Refined BeppoSAX-WFC position of GRB990704: Errata Corrige
  40. GRB990704, optical observations
  41. GRB990704: possible X-ray afterglow
  42. Identification of a possible optical counterpart for GRB990704
  43. GRB990704
  44. Refined BeppoSAX-WFC position of GRB990704
  45. GRB990704: BeppoSAX detection
  46. BeppoSAX NFI Observation of GRB990627 X-ray afterglow
  47. Optical Observations of GRB990627
  48. GRB 990627, radio observations
  49. GRB990627: BeppoSAX-WFC final location
  50. BeppoSAX: GRB990625
  51. Late-time HST/STIS Observation of GRB 990123
  52. GRB 990506 - clarification to GCN 352
  53. GRB 990506 - Optical Observations
  54. Optical Observations of GRB 990506
  55. GRB 990506 Radio Transient
  56. GRB990527 Optical Observations
  57. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  58. IPN error box for GRB990527
  59. Late Afterglows of GRBs 990510, 990123
  60. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  61. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  62. X-ray/GRB 1SAX J0835.9+5118, Optical Observations
  63. GRB 990506 optical observation
  64. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  65. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  66. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  67. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  68. radio observations of X-ray/GRB transient field
  69. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  70. Optical report on X-ray/GRB transient
  71. radio detection of X-ray/GRB transient
  72. BeppoSAX: A new fast X-ray transient
  73. GRB 990510: optical observations
  74. GRB990510: photometric and spectroscopic observations with the VLT
  75. GRB 990510: optical linear polarization
  76. GRB 990510: optical observations
  77. GRB990510, VI observations
  78. GRB 990506 R band observations
  79. GRB990510: X-ray afterglow
  80. GRB 990510: optical observation
  81. VLT spectrum of GRB990510
  82. GRB 990510: Broad Band Break
  83. GRB 990510: BATSE Observations
  84. GRB990510: optical observation
  85. GRB 990510 Optical Observations
  86. GRB 990510, BVI photometry
  87. GRB 990510 optical observations
  88. GRB 990510: BeppoSAX/GRBM observations
  89. GRB990510 optical observations
  90. GRB990510
  91. GRB 990510 optical observations
  92. GRB 990510 optical observations
  93. Galactic extinction towards GRB 990510
  94. GRB990510: NFI X-ray source
  95. GRB 990510 optical observations
  96. IPN localization of GRB990510
  97. GRB 990506 Radio Observations
  98. GRB 990123, optical monitoring
  99. GRB 990506: BATSE Observations
  100. GRB 990506, optical 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