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"

25045 results found.

  1. SGR 1900+14: Detection of extended X-ray emission
  2. SGR 1900+14, Chandra observations
  3. SGR1900+14, I-band observations
  4. GRB010412, field photometry
  5. Giant flare from SGR1900+14
  6. GRB 010326b Optical Observations
  7. GRB010412: BeppoSAX GRBM and WFC observations
  8. GRB010324, revised field photometry
  9. REVISED LOCATION OF GRB010326A
  10. GRB 980326: Late-time HST/STIS observations
  11. GRB010324, field photometry
  12. GRB010326B, field photometry
  13. GRB010326, field photometry
  14. GRB010220, field photometry
  15. Further Optical Observations of GRB 010324
  16. GRB010222, CXO X-ray observations
  17. GRB010324, optical observations
  18. GRB010326B: Localization by HETE (2nd GRB for this date)
  19. GRB 010326 optical observations
  20. GRB010326: Refined Localization by HETE
  21. GRB010326: Localization by HETE
  22. Optical Observations of GRB 010324
  23. GRB010222, late-time optical observation
  24. Support extension to the BeppoSAX mission
  25. GRB 010222 - HEGRA GeV/TeV Observations
  26. GRB010222: Chandra X-ray Observatory Observation
  27. GRB010222: Sub-millimeter vanishing act
  28. GRB010222 - Optical observation
  29. GRB 010222, Optical Observations
  30. GRB010222 - Optical observation
  31. GRB 010222: High-Resolution Keck Spectroscopy
  32. GRB 010214, I-band data
  33. GRB 010222
  34. GRB010222 further R-band photometry
  35. GRB010222: R-band data
  36. GRB 010222: Keck Spectroscopy
  37. GRB010214, field photometry
  38. GRB010222, field photometry
  39. GRB010222 further R-band photometry
  40. GRB010222, possible increase of optical decay slope
  41. GRB 010222 Kyoto optical observation
  42. GRB010222 R-BAND OBSERVATION
  43. GRB010214 follow-up from Hanle
  44. GRB 010222: Near-IR Observations
  45. GRB 010222: Optical Observations
  46. GRB010222: Optical decay slope
  47. GRB 010214, Optical Observations
  48. GRB010222, radio observations
  49. GRB010222, optical observations
  50. GRB010222: BeppoSAX/NFI Observations
  51. GRB010214B,Gamma Ray Observations
  52. GRB 010220, simultaneous optical observations
  53. GRB010220: BeppoSAX WFC and GRBM preliminary data
  54. GRB010214, candidate optical afterglow
  55. GRB010214, optical observations
  56. GRB010214: BeppoSAX WFC and GRBM preliminary data
  57. GRB 010214: X-Ray afterglow
  58. GRB 010214 optical observation
  59. GRB010213, Radio Observations
  60. J-Band Observation of GRB 010214.
  61. GRB010213, Near-IR observations
  62. Possible InfraRed Transient of GRB 010214.
  63. GRB 010214, optical observations
  64. GRB010213 detected by HETE
  65. IPN Status Report
  66. HETE Status
  67. IPN/RXTE TRIANGULATION OF GRB010126
  68. GRB010126 Optical Observations
  69. IPN TRIANGULATION OF GRB010126
  70. Optical Observations of GRB 001018 at Keck
  71. IPN TRIANGULATION OF GRB010119 (SHORT/HARD)
  72. Optical observations of GRB 001018 with JCAM
  73. IPN TRIANGULATION OF GRB010115
  74. IPN TRIANGULATION OF GRB010109
  75. IPN TRIANGULATION OF GRB010109
  76. IPN triangulation of GRB010104
  77. IPN triangulation of GRB010103
  78. H band observation of GRB 001212
  79. IPN triangulation of GRB001219
  80. GRB 001212 Optical Observation
  81. GRB 001212 Optical Observation
  82. GRB 001212 possible OA in 2MASS
  83. IPN triangulation of GRB001212
  84. Confirmation of IPN position for GRB001204
  85. IPN triangulation of GRB001204 (short/hard)
  86. GRB001120, optical observations
  87. WSRT 4.8 GHz observations of GRB001109
  88. IPN triangulation of GRB001120
  89. GRB 001109: deep JHK upper limits
  90. GRB 001109 X-ray afterglow with BeppoSAX
  91. CORRECTION to XMM-Newton observation of GRB001025
  92. GRB001109, Radio observations
  93. GRB001105 BVRI field photometry correction
  94. GRB001105, BVRI field photometry
  95. IPN TRIANGULATION OF GRB001105
  96. GRB 001025B, Optical obervations
  97. GRB 991208: HST Imaging of the Host Galaxy
  98. GRB 001025B, I-band observations
  99. XMM-Newton observation of GRB001025
  100. IPN TRIANGULATION OF GRB001025B (SHORT/HARD)

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