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"
  1. GRB 030227, possible optical counterpart of XMM-Newton source
  2. GRB030227 - faint tentative OT candidate
  3. GRB 030226, optical observations
  4. XMM-Newton observation of GRB030227
  5. GRB030227: Kiso optical observations
  6. GRB 030227: Kyoto optical observation
  7. GRB 030226, optical light curve
  8. GRB 030226 spectroscopy
  9. GRB030227: refined INTEGRAL position
  10. GRB030227 localized by INTEGRAL
  11. Possible break in the GRB 030226 light curve
  12. GRB 030226 : Predicted light curve
  13. GRB030226: optical observation
  14. IPN triangulation of GRB030225 (annulus)
  15. GRB 030226: Confirmed decay index
  16. GRB030226: ESI spectroscopy
  17. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  18. GRB 030226 simultaneous optical observations
  19. Two absorption systems in GRB 030226
  20. GRB 030226, optical observations
  21. GRB030226: optical observations and refined redshift
  22. GRB030226: Optical decay index
  23. GRB 030226 Optical Spectra and R,I,z' Imaging
  24. GRB 030226, optical observations
  25. GRB 030226: Optical afterglow
  26. GRB030226: Candidate optical afterglow
  27. GRB 030217: Optical Observations at 4, 5, and 6 Days
  28. IPN triangulation of GRB030223 (annulus)
  29. IPN triangulation of GRB030220 (annulus)
  30. GRB: Non-Referencing of GCN Circulars.
  31. IPN triangulation of GRB030218 (annulus)
  32. GRB030217: optical observations
  33. IPN triangulation of GRB030217 (small error box)
  34. IPN triangulation of GRB030215C (annulus)
  35. IPN triangulation of GRB030217 (annulus)
  36. IPN triangulation of GRB030216 (annulus)
  37. IPN triangulation of GRB030215A and GRB030215B (annuli)
  38. GRB030115, WSRT radio observations - correction to GCN 1864
  39. GRB 030131: marginal optical detection
  40. GCN/INTEGRAL Mistake Fixed
  41. GRB030115, WSRT radio observations
  42. IPN triangulation of GRB030206 (annulus)
  43. IPN triangulation of GRB030208 (annulus)
  44. GRB 030204: Optical Observations
  45. GRB030204 field photometry
  46. GRB020819: Kiso R and I band observations
  47. GRB 030204: Correction to GCN 1856
  48. GRB030131: Candidate Optical Afterglow
  49. GRB 030115: Optical Observations
  50. GRB 030204, optical observations
  51. IPN triangulation of GRB030204 (small error box)
  52. IPN triangulation of GRB030202 (annulus)
  53. GRB 030131, optical observations
  54. GRB030131: Kiso optical limit for corrected position
  55. GRB030131: Optical limits for corrected position
  56. GRB 030131: afterglow candidate
  57. GRB 030115, late-time optical observations
  58. GRB030131: corrected INTEGRAL position
  59. Type Ic SN2003L (SN/GRB?), optical spectrum
  60. GRB030131: Kiso Observations
  61. GRB 020819: Host galaxy at Radio Position
  62. IPN triangulation of GRB030131 - CORRECTION
  63. GRB 020819: afterglow candidate
  64. IPN triangulation of GRB030131
  65. GRB030131: Optical limit
  66. GRB 030131 optical observations
  67. GRB030131: refined position
  68. GRB 030131 optical observations
  69. A long GRB detected by INTEGRAL
  70. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  71. Type Ic SN2003L (SN/GRB?) Radio Observations
  72. IPN triangulation of GRB030127 (annulus)
  73. GRB030115 submm upper limit
  74. IPN triangulation of GRB030119 (two large error boxes)
  75. GRB 030115: Further IR observations with IRSF/SIRIUS
  76. IPN triangulation of GRB030117 (two large error boxes)
  77. Publicizing GRB Discoveries - A Message from NASA HQ
  78. GRB 030115: Radio detection of IR candidate
  79. GRB 030115, simultaneous observations by BOOTES-1
  80. GRB 030115: IR observations with IRSF/SIRIUS
  81. IPN triangulation of GRB030115C (large error box)
  82. GRB030115: R-band counterpart of IR candidate
  83. GRB030115, afterglow candidate
  84. GRB 021211: R-band observations at late-time
  85. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  86. IPN triangulation of GRB030115B (small error box)
  87. GRB 030115 : Possible IR counterpart
  88. GRB 030115: Radio Observations
  89. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  90. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  91. IPN triangulation of GRB030115B (annulus)
  92. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  93. Distribution of INTEGRAL SPI-ACS triggers
  94. GRB030115: R-band observations at Asiago
  95. GRB030115: TAROT optical observations
  96. GRB 021211: VLT spectrum
  97. GRB 030115: APO Optical Observations
  98. GRB 030115, no optical candidate
  99. GRB 030115, optical observations
  100. GRB 030115, 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