Skip to main content
Announcing GCN Classic Migration Survey, End of Legacy Circulars Email. 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. GRB 000926, Optical Observations
  2. GRB000926 - Optical observations
  3. GRB000911: optical VLT observations
  4. GRB000926 K'-band Observation
  5. GRB000926 : increasing optical decay slope
  6. GRB000926 optical observations
  7. GRB000926 - Optical observations
  8. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  9. J and K band observations of GRB 000926
  10. GRB000911 Optical Observations
  11. GRB 000926: Lightcurve Update and Predictions
  12. GRB 000926, optical observation by Oksanen (vsnet-grb)
  13. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  14. GRB000926: Optical observations
  15. CONCAM crude optical limits before and after GRB000926
  16. GRB 000926: Preliminary R-band Lightcurve
  17. GRB 000926 HST/Chandra TOO Status
  18. Spectroscopic Redshift of GRB 000926
  19. GRB 000926, Optical Observation
  20. GRB000926, radio observations
  21. GRB 000926: Optical candidate
  22. Optical candidate for GRB000926
  23. IPN triangulation of GRB000926
  24. IPN triangulation of GRB000926
  25. GRB 000911, BVRI field photometry
  26. GRB000911: Corrected coordinates
  27. GRB000911: Sub-millimeter observations
  28. IPN triangulation of GRB000925
  29. GRB000911: Optical Transient
  30. GRB000911, Radio and Optical observations
  31. GRB000911, Radio observations
  32. GRB000911: Optical observations
  33. IPN triangulation of GRB000911
  34. IPN triangulation of GRB000910
  35. False GRB alarm from RXTE/ASM on 8 Sept 2000
  36. GRB 000830: Optical observations
  37. GRB000830: Optical observations
  38. GRB000830, TNG B-band observations
  39. GRB000830, BVRI field photometry
  40. GRB000830: Optical observations
  41. GRB000210, Optical observations
  42. Chandra Position of GRB000210
  43. "Snapshot" afterglow IDs and GRB 000830
  44. GRB000830: Optical observations
  45. IPN triangulation of GRB000830
  46. HST/STIS observations of the host galaxy of GRB 980329
  47. HST/STIS observations of the chaotic environment of GRB 980613
  48. IPN localization of GRB000820
  49. SGR 1806-20 burst activity
  50. GRB000812, TNG R-band observations
  51. GRB000801 & GRB000730, Gamma Ray Observations
  52. GRB000730, Gamma Ray Observations
  53. GRB000812, Radio observations
  54. IPN localization of GRB000812
  55. IPN localization of GRB000811
  56. GRB000801, Gamma Ray Observations
  57. GRB000801, VLT-Antu R-band observations
  58. GRB000301C, UBVI optical observations
  59. GRB000801, Radio Observations
  60. GRB 991208 Host Galaxy Imaging
  61. Updated IPN coordinates for GRB000801
  62. IPN localization of GRB000801
  63. IPN localization of GRB000801
  64. IPN localization of GRB000730B
  65. IPN localization of GRB000730B
  66. IPN localization of GRB000730
  67. GRB 990510: Possible detection of a host galaxy
  68. GRB 990510 Host Galaxy Discovery
  69. GRB 000727, optical observations
  70. IPN localization of GRB000727
  71. GRB 990705, HST/STIS observations of the host galaxy
  72. GRB 990712: Late time HST/STIS Observations
  73. GRB 991216, HST/STIS observations
  74. GRB000620, Radio Observations
  75. GRB981226, HST/STIS observations of the host galaxy
  76. GRB000630, optical observations
  77. GRB 000630: Detection of the Optical Afterglow
  78. GRB000630, Revised BVRI Field Photometry
  79. GRB000630, Optical Observations
  80. GRB000630, optical observations
  81. GRB000630, optical observations
  82. GRB000630, BVRI Field Photometry
  83. GRB000630, optical observations
  84. GRB000630, optical observations
  85. GRB000630: Optical observations
  86. GRB000630, Radio Observations
  87. possible optical counterpart of GRB 000630
  88. IPN triangulation of GRB000630
  89. GRB 000623, optical observations
  90. GRB 000620, optical observations
  91. GRB000418, HST/STIS Observations
  92. GRB990123: Late-time HST/STIS observations of the host
  93. GRB 990506, HST/STIS Observations of the Host Galaxy
  94. GRB000623
  95. GRB 000620: J-band observations
  96. GRB000620, optical observations
  97. GRB000615: H-band observations
  98. GRB990308, HST/STIS observations of the host galaxy
  99. GRB000620 - Optical observations
  100. GRB000620 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