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 041211: Optical follow-up in East Asian region
  2. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  3. GRB041211: P60 optical imaging
  4. GRB970815: Discovery of Optical Afterglow
  5. Distribution of IBAS Alerts for NON-GRB sources
  6. Triangulation of short GRB 041116 (large error box)
  7. GRB041015: Near-Infrared observations
  8. GRB 040924: Afterglow Color
  9. GRB 041006: GETS Optical Afterglow Observation
  10. Summary of the recent bursts from SGR 1806-20
  11. GRB 041006: Optical Observations
  12. GRB041006, late-time optical photometry
  13. GRB041015, optical observation in CrAO
  14. IBAS GRB Alert # 2034
  15. GRB041006: RTT150 Optical Observations
  16. GRB041015 : Multi epoch optical observations
  17. HST Observations: XRF 040701 and 040812
  18. Bright bursts from SGR1806-20
  19. GRB 041016: BOOTES-2 simultaneous observation
  20. GRB041006: RTT150 Optical Observations
  21. GRB041016,optical observation
  22. GRB 041016: Optical limits
  23. GRB 041016: Optical limits in V, R, I
  24. GRB 041016:Optical limit during first minute
  25. GRB041016: MASTER: Optical observations
  26. GRB 041015: Optical Observations at Rikubetsu
  27. GRB041006: Near Infrared observations
  28. GRB 041016: Optical limit
  29. GRB 041015 R band observations
  30. GRB040924, BVRcIc field calibration
  31. GRB041015: MASTER: Optical observations
  32. GRB041015,optical observation
  33. GRB041006: Fading X-ray Afterglow Observed with Chandra
  34. GRB 041015: Optical limit at Osaka University
  35. GRB041015 : Optical follow-up at Kiso
  36. GRB 041015 - A long GRB detected by INTEGRAL
  37. GRB 041006 R observations in Loiano
  38. GRB041006: VLT observations of the afterglow and host galaxy
  39. GRB041006: Optical observations and Potential host galaxy
  40. GRB041006, BVRcIc field calibration
  41. GRB 040924: VLT spectroscopy
  42. GRB 041006: SARA afterglow observations
  43. GRB041006, optical observation in CrAO
  44. Search for SN light in XRF 040912 with MEGACAM
  45. GRB 040916: Afterglow Color at Early Times
  46. GRB 041006 Optical afterglow observations
  47. IBAS GRB Alert # 2010
  48. GRB 041006: BR observations with VATT
  49. GRB 041006: Redshift confirmed
  50. GRB041006: Liverpool Telescope optical observations
  51. GRB 041006: Colour measurement
  52. GRB041006: break in the light curve
  53. GRB 041006: Radio Observations
  54. GRB041006, further submilllimetre observations
  55. GRB 041006 : optical follow-up observation at Lulin Observatory
  56. GRB 041006 : Optical follow-up observation at TAROT
  57. GRB041006: Optical photometry and spectroscopy at TNG
  58. GRB 041006: presice astrometry
  59. GRB041006 (= H3570): Chandra Observations In Progress
  60. GRB 041006 : optical observation at Bisei
  61. GRB041006, optical I observation
  62. GRB041006 (=HETE3570): optical observations
  63. ROTSE-IIIa Observations of GRB 041006
  64. GRB041006, optical observation
  65. GRB041006, submillimetre observations
  66. GRB041006: MASTER optical observations
  67. GRB041006,optical observation
  68. GRB 041006: Optical decay
  69. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  70. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  71. GRB041006: Fading of optical afterglow candidate
  72. GRB 041006 : Optical follow-up observation at KISO
  73. GRB 041006: Finding chart
  74. GRB 041006: Optical afterglow candidate
  75. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  76. Very strong outburst from SGR 1806-20 detected with INTEGRAL
  77. XRF 020903: Observations of the Host Galaxy (authors)
  78. XRF 020903: Observations of the Host Galaxy
  79. SGR 1806-20 still active
  80. GRB 040924: Second Epoch WSRT Radio Observations
  81. radio observations, GRB 040924
  82. IBAS Alert 1991. Not a real GRB
  83. GRB040929,optical observation
  84. GRB040929: MASTER optical observations
  85. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  86. GRB040924,optical observation
  87. GRB040924, RTT150 optical observation
  88. GRB040924,optical observation
  89. GRB 040924: detection of possible host galaxy by Subaru
  90. GRB040924, RTT150 optical observation
  91. GRB040924: KAIT observations
  92. GRB040924: Afterglow magnitude at t=17.5hr
  93. GRB 040924: WSRT Radio Observations
  94. GRB 040924: NIR finding chart
  95. GRB040924 : Optical candidate observations at Lulin observatory
  96. GRB040924 : Optical candidate observations at Lulin observatory
  97. GRB 040924: Subaru NIR observation
  98. GRB040924: Optical afterglow properties
  99. GRB 040924: RTT150 optical observations
  100. GRB 040924, optical follow-up

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