Skip to main content
Updates to LVK & CHIME Notices, Schema v7.2.3! 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: KAIT observations
  2. GRB 041211: Optical follow-up in East Asian region
  3. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  4. GRB041211: P60 optical imaging
  5. GRB970815: Discovery of Optical Afterglow
  6. Distribution of IBAS Alerts for NON-GRB sources
  7. Triangulation of short GRB 041116 (large error box)
  8. GRB041015: Near-Infrared observations
  9. GRB 040924: Afterglow Color
  10. GRB 041006: GETS Optical Afterglow Observation
  11. Summary of the recent bursts from SGR 1806-20
  12. GRB 041006: Optical Observations
  13. GRB041006, late-time optical photometry
  14. GRB041015, optical observation in CrAO
  15. IBAS GRB Alert # 2034
  16. GRB041006: RTT150 Optical Observations
  17. GRB041015 : Multi epoch optical observations
  18. HST Observations: XRF 040701 and 040812
  19. Bright bursts from SGR1806-20
  20. GRB 041016: BOOTES-2 simultaneous observation
  21. GRB041006: RTT150 Optical Observations
  22. GRB041016,optical observation
  23. GRB 041016: Optical limits
  24. GRB 041016: Optical limits in V, R, I
  25. GRB 041016:Optical limit during first minute
  26. GRB041016: MASTER: Optical observations
  27. GRB 041015: Optical Observations at Rikubetsu
  28. GRB041006: Near Infrared observations
  29. GRB 041016: Optical limit
  30. GRB 041015 R band observations
  31. GRB040924, BVRcIc field calibration
  32. GRB041015: MASTER: Optical observations
  33. GRB041015,optical observation
  34. GRB041006: Fading X-ray Afterglow Observed with Chandra
  35. GRB 041015: Optical limit at Osaka University
  36. GRB041015 : Optical follow-up at Kiso
  37. GRB 041015 - A long GRB detected by INTEGRAL
  38. GRB 041006 R observations in Loiano
  39. GRB041006: VLT observations of the afterglow and host galaxy
  40. GRB041006: Optical observations and Potential host galaxy
  41. GRB041006, BVRcIc field calibration
  42. GRB 040924: VLT spectroscopy
  43. GRB 041006: SARA afterglow observations
  44. GRB041006, optical observation in CrAO
  45. Search for SN light in XRF 040912 with MEGACAM
  46. GRB 040916: Afterglow Color at Early Times
  47. GRB 041006 Optical afterglow observations
  48. IBAS GRB Alert # 2010
  49. GRB 041006: BR observations with VATT
  50. GRB 041006: Redshift confirmed
  51. GRB041006: Liverpool Telescope optical observations
  52. GRB 041006: Colour measurement
  53. GRB041006: break in the light curve
  54. GRB 041006: Radio Observations
  55. GRB041006, further submilllimetre observations
  56. GRB 041006 : optical follow-up observation at Lulin Observatory
  57. GRB 041006 : Optical follow-up observation at TAROT
  58. GRB041006: Optical photometry and spectroscopy at TNG
  59. GRB 041006: presice astrometry
  60. GRB041006 (= H3570): Chandra Observations In Progress
  61. GRB 041006 : optical observation at Bisei
  62. GRB041006, optical I observation
  63. GRB041006 (=HETE3570): optical observations
  64. ROTSE-IIIa Observations of GRB 041006
  65. GRB041006, optical observation
  66. GRB041006, submillimetre observations
  67. GRB041006: MASTER optical observations
  68. GRB041006,optical observation
  69. GRB 041006: Optical decay
  70. GRB 041006 (=H3570): An X-Ray Rich GRB Localized in Real Time by HETE
  71. Konus-Wind observation of a series SGR 1806-20 bursts on 041005
  72. GRB041006: Fading of optical afterglow candidate
  73. GRB 041006 : Optical follow-up observation at KISO
  74. GRB 041006: Finding chart
  75. GRB 041006: Optical afterglow candidate
  76. Bursts from SGR 1806-20: Preliminary INTEGRAL results
  77. Very strong outburst from SGR 1806-20 detected with INTEGRAL
  78. XRF 020903: Observations of the Host Galaxy (authors)
  79. XRF 020903: Observations of the Host Galaxy
  80. SGR 1806-20 still active
  81. GRB 040924: Second Epoch WSRT Radio Observations
  82. radio observations, GRB 040924
  83. IBAS Alert 1991. Not a real GRB
  84. GRB040929,optical observation
  85. GRB040929: MASTER optical observations
  86. Konus-Wind and Helicon-Coronas-F observations of GRB040924
  87. GRB040924,optical observation
  88. GRB040924, RTT150 optical observation
  89. GRB040924,optical observation
  90. GRB 040924: detection of possible host galaxy by Subaru
  91. GRB040924, RTT150 optical observation
  92. GRB040924: KAIT observations
  93. GRB040924: Afterglow magnitude at t=17.5hr
  94. GRB 040924: WSRT Radio Observations
  95. GRB 040924: NIR finding chart
  96. GRB040924 : Optical candidate observations at Lulin observatory
  97. GRB040924 : Optical candidate observations at Lulin observatory
  98. GRB 040924: Subaru NIR observation
  99. GRB040924: Optical afterglow properties
  100. GRB 040924: RTT150 optical observations

Advanced

Download all Circulars as a .tar.gz archive (updated once a day):
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