Skip to main content
New! Browse Circulars by Event, Advanced Search, Sample Codes, Schema Release. 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"

24754 results found.

  1. GRB001109, Radio observations
  2. GRB001105 BVRI field photometry correction
  3. GRB001105, BVRI field photometry
  4. IPN TRIANGULATION OF GRB001105
  5. GRB 001025B, Optical obervations
  6. GRB 991208: HST Imaging of the Host Galaxy
  7. GRB 001025B, I-band observations
  8. XMM-Newton observation of GRB001025
  9. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)
  10. CORRECTION TO IPN/RXTE ERROR BOX FOR GRB001025
  11. GRB001007: Optical observations
  12. ASM Localization of GRB 001025
  13. GRB001007, Radio observations
  14. GRB 001018, Possible Radio Afterglow
  15. GRB001018, Gamma Ray Observations
  16. IPN TRIANGULATION OF GRB001019
  17. IPN TRIANGULATION OF GRB001018
  18. IPN TRIANGULATION OF GRB 001017
  19. V,R,I band observations of GRB000926
  20. HETE positions added to GCN
  21. GRB000926 - Amateur Optical Observations
  22. CONCAM null result on GRB001005
  23. IPN triangulation of GRB001005
  24. GRB000926: X-ray afterglow by BeppoSAX. Refined analysis
  25. GRB000926 - Optical observations
  26. GRB000926 - Optical observations
  27. GRB 000926, Optical Decay
  28. GRB000911: VLT infrared observation
  29. GRB 000926, Optical Observations
  30. GRB000926 K'-band Observation
  31. J and K band observations of GRB 000926
  32. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  33. CONCAM crude optical limits before and after GRB000926
  34. GRB 000926: Preliminary R-band Lightcurve
  35. Spectroscopic Redshift of GRB 000926
  36. GRB 000926: Optical candidate
  37. Optical candidate for GRB000926
  38. GRB 000911, BVRI field photometry
  39. GRB000911, Radio and Optical observations
  40. GRB000911: Optical observations
  41. GRB000830, BVRI field photometry
  42. GRB000210, Optical observations
  43. "Snapshot" afterglow IDs and GRB 000830
  44. GRB000730, Gamma Ray Observations
  45. GRB000812, Radio observations
  46. GRB000801, Gamma Ray Observations
  47. GRB000801, VLT-Antu R-band observations
  48. GRB 991208 Host Galaxy Imaging
  49. IPN localization of GRB000730B
  50. GRB 990510: Possible detection of a host galaxy
  51. GRB 990510 Host Galaxy Discovery
  52. IPN localization of GRB000727
  53. GRB 990712: Late time HST/STIS Observations
  54. GRB 991216, HST/STIS observations
  55. GRB000620, Radio Observations
  56. GRB000630, optical observations
  57. GRB000630, Revised BVRI Field Photometry
  58. GRB000630, Optical Observations
  59. GRB000630, optical observations
  60. GRB000630, optical observations
  61. GRB000630, BVRI Field Photometry
  62. GRB000630, optical observations
  63. GRB000630: Optical observations
  64. GRB000630, Radio Observations
  65. possible optical counterpart of GRB 000630
  66. GRB 000620, optical observations
  67. GRB000418, HST/STIS Observations
  68. GRB990123: Late-time HST/STIS observations of the host
  69. GRB000620, optical observations
  70. GRB000615: H-band observations
  71. GRB990308, HST/STIS observations of the host galaxy
  72. GRB000620 - Optical observations
  73. GRB000620 Optical observations
  74. GRB000620: BeppoSAX WFC and GRBM detection
  75. GRB000607, optical observations
  76. GRB 000615: NIR further observations
  77. GRB990123, HST/STIS observations of the host galaxy
  78. GRB000616 optical observations
  79. GRB 000615, near-infrared observations
  80. GRB 990123: Late-time HST/STIS 50CCD observations of the host
  81. GRB000615, further R-band photometry
  82. GRB 000615: NIR observations
  83. GRB000615: BeppoSAX NFI follow-up preliminary analysis
  84. GRB000615, R-band photometry
  85. The Hosts of GRB 980703 and GRB 971214
  86. GRB 000301C: Further Late-Time HST/STIS observations
  87. GRB000528: follow-up X-ray measurements and update of IPN annulus
  88. GRB980519, HST/STIS observations of the host galaxy
  89. GRB000604 optical non-detection
  90. GRB000604 - Optical observations
  91. GRB000604, optical observations
  92. GRB000528, optical observations at ESO
  93. GRB 000604 optical observations
  94. GRB 000418: Detection of the Host Galaxy
  95. GRB000604, optical observations, comparison with DPOSS
  96. GRB000528, Radio Observations
  97. X-ray Afterglow of GRB 000529
  98. GRB000529: BeppoSAX NFI follow-up preliminary analysis
  99. GRB000528: BeppoSAX NFI follow-up preliminary analysis
  100. GRB 000528 - WFC measurements

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