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"

3995 results found.

  1. SGR1806 VLA Observations
  2. VLA observations of SGR 1806-20
  3. SGR1806-20: RXTE-PCA observation of the 041227 super-flare
  4. Detection of the SGR 1806-20 giant outburst back-scattered by the
  5. The giant outburst from SGR 1806-20
  6. Giant flare from SGR 1806-20 detected by INTEGRAL
  7. Very high activity of SGR 1806-20
  8. Summary of the recent bursts from SGR 1806-20
  9. IBAS GRB Alert # 2034
  10. Bright bursts from SGR1806-20
  11. GRB041006, submillimetre observations
  12. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  13. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  14. Very strong outburst from SGR 1806-20 detected with INTEGRAL
  15. SGR 1806-20 still active
  16. GRB 040924: Second Epoch WSRT Radio Observations
  17. GRB040929,optical observation
  18. GRB040916: Optical observations
  19. ROTSE-IIIb Observations of GRB 040916 (HETE #3558)
  20. An intense burst from SGR1806-20
  21. Very bright burst detected from SGR 1806-20
  22. GRB 040827 : Planned XMM-Newton observation
  23. GRB 040827 - A long GRB detected by INTEGRAL
  24. Increase of SGR 1806-20 activity
  25. Bursting activity from SGR 1806-20 detected with IBAS
  26. Ongoing activity of SGR 1806-20
  27. XRF040701: Second-Epoch Chandra Observations
  28. XRF040701: First-Epoch Chandra Observations
  29. GRB040709 J,H-band observations
  30. GRB040706:observation at University of Miyazaki
  31. IPN Summary of SGR1806-20 Activity in 2004
  32. SGR 1806-20: no IR variability of the proposed counterparts
  33. SGR 1806-20, potential NIR counterpart
  34. MASTER: HETE Alert 3274 optical observation
  35. Activivty of SGR 1806-20
  36. IBAS GRB Alerts n.1785 to 1791
  37. GRB 040422: a long GRB detected with INTEGRAL
  38. Summary of recent bursts from SGR 1806-20 detected by INTEGRAL
  39. IBAS GRB Alert 1694
  40. short hard GRB 040322
  41. IBAS GRB alerts 1679, 1680, 1681
  42. IBAS results on a burst from SGR1806-20
  43. RXTE GRB040229 optical observation: no candidate
  44. GRB031220: observation at Univercity of Miyazaki
  45. GRB 031220: Optical observation at Tokyo Tech
  46. GRB 031203: Discovery of a dust echo
  47. GRB031203: K' Photometry of the likely GRB host
  48. XRF031109 (=H2919): A very long XRF localized by HETE
  49. IPN triangulation of GRB031026B (large error box)
  50. IBAS alert 1180 refers to a burst from SGR 1806-20
  51. Ongoing Bursting Activity from SGR 1806-20 detected with IBAS
  52. SGR1806-20 bursts on 031008. Helicon detection and small error box.
  53. SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
  54. XRF 030723: Subaru Optical Observations
  55. A burst from SGR 1806-20 detected with IBAS
  56. IPN triangulation of GRB030926 (short/hard; large error box)
  57. GRB030913: AAVSO optical observations
  58. IBAS detection of bursts from SGR 1806-20
  59. Radio Observations of SGR1806-20
  60. INTEGRAL ToO OBSERVATIONS OF SGR1806-20: CALL FOR CORRELATED OBSERVATIONS
  61. Summary of recent IPN and HETE detections of SGR bursts
  62. Clarification of GCN 2354 on SGR1806-20
  63. IPN detection of continued activity from SGR1806-20
  64. 030813 SGR event (Konus-Wind observation)
  65. SGR 1808-20 (=H2802): A Possible new SGR
  66. IPN triangulation of GRB030721 (large error box)
  67. GRB030723: Upper limits from historical observations
  68. XRF030723, optical observations
  69. SGR 1806-20, submm observations
  70. RXTE PCA Observations of SGR1806-20 Region
  71. IPN triangulation of GRB030715 (two large error boxes)
  72. GRB030329: RTT150 optical observations
  73. GRB030329, optical observation in May
  74. HETE detection of burst from SGR1806-20
  75. IPN triangulation of GRB030606 (two alternate error boxes)
  76. GRB 030528: tentative NIR counterpart
  77. GRB 030329/SN 2003dh: Jitter Episode
  78. GRB030519B (=H2716): A Long, Bright GRB Localized by the HETE WXM
  79. GRB 030329: Optical limit (contemporaneous imaging)
  80. IPN triangulation of GRB030509 (single error box)
  81. GRB030429, refiend optical brightness
  82. GRB 030329: Optical limit (contemporaneous photography)
  83. GRB030429 (=H2695): A Long GRB Localized by the HETE WXM and SXC
  84. GRB 030329 Optical Observations
  85. GRB030328, optical observation
  86. GRB030429: Optical Observations
  87. GRB030329 observed as a sudden ionospheric disturbance (SID)
  88. OT GRB 030329: early UBVRcIc spectral evolution
  89. GRB030329, UBVRI polarimetry, R-polarization
  90. OT GRB 030329: early spectrum
  91. IPN triangulation of GRB030413 (small error box)
  92. GRB030329: Near Infrared Observations at Gunma
  93. GRB030329: Kiso B and R band observations
  94. GRB030328: R upper limit after 6 hours by MASTER
  95. GRB030329: final R-band light curve by MASTER
  96. GRB030329: optical observations at Tokyo Tech
  97. Further AAVSO V,B,R observations of GRB030329
  98. GRB 030329: Additional Mt. Laguna Optical Observations
  99. GRB 030329: Observations with ANDICAM
  100. GRB030329: 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