Skip to main content
New! BOOM Notices and Schema v7.0.0. 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"

41593 results found.

  1. GRB 000926: Improved Absorber Redshift
  2. V,R,I band observations of GRB000926
  3. The Likely Optical/Infrared Afterglow of GRB 001011
  4. HETE positions added to GCN
  5. GRB001011 BeppoSAX/WFC refined position
  6. BeppoSAX ALERT: GRB001011
  7. GRB 001007, BVR-band observations
  8. GRB000926 - Amateur Optical Observations
  9. GRB001007: Optical observations
  10. CONCAM null result on GRB001005
  11. IPN triangulation of GRB001007
  12. GRB 000926 : the host galaxy
  13. HETE-2 Launches Successfully
  14. IPN triangulation of GRB001005
  15. HETE-2 48 hour Launch Delay
  16. GRB 000926 Chandra Observation
  17. IPN triangulation of GRB 001004
  18. Public availability of BeppoSAX data of GRB000926
  19. GRB000926: X-ray afterglow by BeppoSAX: revised fluxes (fwd)
  20. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  21. GRB000926 - Optical observations
  22. GRB000926 - Optical observations
  23. GRB 000926, Optical Decay
  24. GRB000911: VLT infrared observation
  25. GRB000926 - Optical observations
  26. GRB000926 - Optical observations
  27. GRB 000926: optical observations
  28. GRB000926 - Optical observations
  29. GRB000911: optical VLT observations
  30. GRB000926 K'-band Observation
  31. GRB000926 : increasing optical decay slope
  32. GRB000926 optical observations
  33. GRB000926 - Optical observations
  34. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  35. J and K band observations of GRB 000926
  36. GRB000911 Optical Observations
  37. GRB 000926: Lightcurve Update and Predictions
  38. GRB 000926, optical observation by Oksanen (vsnet-grb)
  39. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  40. GRB000926: Optical observations
  41. CONCAM crude optical limits before and after GRB000926
  42. GRB 000926: Preliminary R-band Lightcurve
  43. GRB 000926 HST/Chandra TOO Status
  44. Spectroscopic Redshift of GRB 000926
  45. GRB 000926, Optical Observation
  46. GRB000926, radio observations
  47. GRB 000926: Optical candidate
  48. Optical candidate for GRB000926
  49. IPN triangulation of GRB000926
  50. IPN triangulation of GRB000926
  51. GRB 000911, BVRI field photometry
  52. GRB000911: Corrected coordinates
  53. GRB000911: Sub-millimeter observations
  54. IPN triangulation of GRB000925
  55. GRB000911: Optical Transient
  56. GRB000911, Radio and Optical observations
  57. GRB000911, Radio observations
  58. IPN triangulation of GRB000911
  59. IPN triangulation of GRB000910
  60. False GRB alarm from RXTE/ASM on 8 Sept 2000
  61. GRB 000830: Optical observations
  62. GRB000830: Optical observations
  63. GRB000830, TNG B-band observations
  64. GRB000830, BVRI field photometry
  65. GRB000830: Optical observations
  66. GRB000210, Optical observations
  67. "Snapshot" afterglow IDs and GRB 000830
  68. GRB000830: Optical observations
  69. IPN triangulation of GRB000830
  70. HST/STIS observations of the host galaxy of GRB 980329
  71. HST/STIS observations of the chaotic environment of GRB 980613
  72. IPN localization of GRB000820
  73. SGR 1806-20 burst activity
  74. GRB000812, TNG R-band observations
  75. GRB000730, Gamma Ray Observations
  76. GRB000812, Radio observations
  77. IPN localization of GRB000812
  78. IPN localization of GRB000811
  79. GRB000801, Gamma Ray Observations
  80. GRB000801, VLT-Antu R-band observations
  81. GRB000301C, UBVI optical observations
  82. GRB000801, Radio Observations
  83. GRB 991208 Host Galaxy Imaging
  84. IPN localization of GRB000801
  85. IPN localization of GRB000730B
  86. IPN localization of GRB000730B
  87. IPN localization of GRB000730
  88. GRB 990510: Possible detection of a host galaxy
  89. GRB 990510 Host Galaxy Discovery
  90. GRB 000727, optical observations
  91. IPN localization of GRB000727
  92. GRB 990705, HST/STIS observations of the host galaxy
  93. GRB 990712: Late time HST/STIS Observations
  94. GRB 991216, HST/STIS observations
  95. GRB000620, Radio Observations
  96. GRB981226, HST/STIS observations of the host galaxy
  97. GRB000630, optical observations
  98. GRB 000630: Detection of the Optical Afterglow
  99. GRB000630, Revised BVRI Field Photometry
  100. GRB000630, 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