Skip to main content
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"

25803 results found.

  1. IPN localization of GRB000727
  2. GRB 990712: Late time HST/STIS Observations
  3. GRB 991216, HST/STIS observations
  4. GRB000620, Radio Observations
  5. GRB000630, optical observations
  6. GRB000630, Revised BVRI Field Photometry
  7. GRB000630, Optical Observations
  8. GRB000630, optical observations
  9. GRB000630, optical observations
  10. GRB000630, BVRI Field Photometry
  11. GRB000630, optical observations
  12. GRB000630: Optical observations
  13. GRB000630, Radio Observations
  14. possible optical counterpart of GRB 000630
  15. GRB 000620, optical observations
  16. GRB000418, HST/STIS Observations
  17. GRB990123: Late-time HST/STIS observations of the host
  18. GRB000620, optical observations
  19. GRB000615: H-band observations
  20. GRB990308, HST/STIS observations of the host galaxy
  21. GRB000620 - Optical observations
  22. GRB000620 Optical observations
  23. GRB000620: BeppoSAX WFC and GRBM detection
  24. GRB000607, optical observations
  25. GRB 000615: NIR further observations
  26. GRB990123, HST/STIS observations of the host galaxy
  27. GRB000616 optical observations
  28. GRB 000615, near-infrared observations
  29. GRB 990123: Late-time HST/STIS 50CCD observations of the host
  30. GRB000615, further R-band photometry
  31. GRB 000615: NIR observations
  32. GRB000615: BeppoSAX NFI follow-up preliminary analysis
  33. GRB000615, R-band photometry
  34. The Hosts of GRB 980703 and GRB 971214
  35. GRB 000301C: Further Late-Time HST/STIS observations
  36. GRB000528: follow-up X-ray measurements and update of IPN annulus
  37. GRB980519, HST/STIS observations of the host galaxy
  38. GRB000604 optical non-detection
  39. GRB000604 - Optical observations
  40. GRB000604, optical observations
  41. GRB000528, optical observations at ESO
  42. GRB 000604 optical observations
  43. GRB 000418: Detection of the Host Galaxy
  44. GRB000604, optical observations, comparison with DPOSS
  45. GRB000528, Radio Observations
  46. X-ray Afterglow of GRB 000529
  47. GRB000529: BeppoSAX NFI follow-up preliminary analysis
  48. GRB000528: BeppoSAX NFI follow-up preliminary analysis
  49. GRB 000528 - WFC measurements
  50. GRB000519, BVRI field photometry
  51. IPN triangulation of GRB000519
  52. GRB000508B, optical photometry
  53. GRB000508B, BVR field photometry
  54. Possible GRB-related phenomenon
  55. RXTE/ASM and IPN localization of GRB 000508B
  56. GRB000424, UBVRI field photometry
  57. GRB000418, UBVRI field photometry update
  58. GRB000424, optical observations
  59. GRB 000429, optical observation
  60. GRB 000429, UBVRI field photometry
  61. GRB 000418, UBVRI field photometry
  62. GRB 000418, optical observation
  63. GRB 000418, Optical Observation
  64. GRB000418, near-infrared observations
  65. Correction to IPN error box for GRB000419
  66. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  67. GRB000416 BRJK observations
  68. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  69. GRB 000408, optical observations
  70. GRB 991208, UBVRI field photometry
  71. GRB000408, lotis optical observations
  72. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  73. GRB000301C - Addendum to GCN 623
  74. GRB 000323, optical observations
  75. GRB 000326: Optical Observations
  76. GRB000326, Radio observations
  77. GRB000313, Radio observations
  78. GRB 000313 - optical transient in the BATSE error box
  79. GRB 000307, Optical Observations
  80. GRB 000307, BVRI Field Photometry
  81. GRB 000301C: A Precise Redshift Determination
  82. GRB 000301C, Optical Observation
  83. GRB 000301C: HST/STIS CCD Imaging of the field
  84. IPN error box for GRB000307
  85. GRB000301C, optical R-band observations
  86. GRB 000301C Optical Observations
  87. GRB 000301C: K' Observations
  88. GRB000301C OT candidate optical observations
  89. GRB000301C - Host galaxy not detected in R (?)
  90. Optical observations of GRB000301c
  91. GRB000301C, Radio observations
  92. GRB000301C, Radio observations
  93. GRB000301C, near-infrared observations (JHK' imaging)
  94. GRB 000301c near-IR observations
  95. GRB 000301C, UBVRI field photometry
  96. GRB 000301C: OT confirmed
  97. GRB000301c optical observations
  98. GRB000301C, optical observations
  99. GRB000301C
  100. GRB 000301C : Optical Candidate

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