Skip to main content
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"
  1. GRB 041219 ,optical observation
  2. GRB 041219: Radio Afterglow Detection
  3. GRB 041218 : Radio Observations
  4. GRB 041218: R-band optical observations
  5. GRB041218: Liverpool Telescope optical observations
  6. GRB041218: optical observations
  7. GRB041219: Confirmed NIR Afterglow
  8. GRB041218: Continued P60 Optical Observations
  9. Swift-BAT detection of the bright long burst GRB041219
  10. GRB 041218: Optical Observation
  11. GRB 041219: Infrared Afterglow Candidate
  12. GRB041219, BVRcIc field calibration
  13. GRB 041219: Infrared Afterglow Candidate
  14. GRB041218, BVRcIc field calibration
  15. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  16. GRB041219: P60 Optical Observations
  17. GRB 041219 - A long GRB detected by INTEGRAL
  18. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  19. GRB 041217: PROMPT Observations
  20. GRB041218: optical observations
  21. GRB041217: optical limit 30 min after GRB
  22. GRB 041218; optical candidate
  23. GRB 041218: Optical observations
  24. GRB 041217: LCO40 Optical Observations and Possible Candidates
  25. GRB 041218 - A long GRB detected by integral
  26. GRB041217: Optical Observations
  27. GRB041217: NIR and optical observations with REM
  28. GRB041217: P60 Optical Observations
  29. GRB041217: Infrared Observations
  30. GRB041217: The First GRB Located On-Board Swift
  31. GRB041211: Faulkes Telescope continued optical monitoring
  32. Optical Transient in Lynx not a GRB
  33. Optical transient (GRB?) in Lynx
  34. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  35. GRB041211: Continued P60 Observations
  36. GRB041211: RAPTOR observations
  37. GRB041211: Ashra Prototype optical observation
  38. GRB041211, Faulkes Telescope optical observation
  39. GRB041211, BVRcIc field calibration
  40. GRB041211,optical observation
  41. GRB 041211: Infrared Observations
  42. GRB 041211: KAIT observations
  43. GRB 041211: Optical follow-up in East Asian region
  44. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  45. GRB041211: P60 optical imaging
  46. GRB970815: Discovery of Optical Afterglow
  47. Distribution of IBAS Alerts for NON-GRB sources
  48. Triangulation of short GRB 041116 (large error box)
  49. GRB041015: Near-Infrared observations
  50. GRB 040924: Afterglow Color
  51. GRB 041006: GETS Optical Afterglow Observation
  52. Summary of the recent bursts from SGR 1806-20
  53. GRB 041006: Optical Observations
  54. GRB041006, late-time optical photometry
  55. GRB041015, optical observation in CrAO
  56. IBAS GRB Alert # 2034
  57. GRB041006: RTT150 Optical Observations
  58. GRB041015 : Multi epoch optical observations
  59. HST Observations: XRF 040701 and 040812
  60. Bright bursts from SGR1806-20
  61. GRB 041016: BOOTES-2 simultaneous observation
  62. GRB041006: RTT150 Optical Observations
  63. GRB041016,optical observation
  64. GRB 041016: Optical limits
  65. GRB 041016: Optical limits in V, R, I
  66. GRB 041016:Optical limit during first minute
  67. GRB041016: MASTER: Optical observations
  68. GRB 041015: Optical Observations at Rikubetsu
  69. GRB041006: Near Infrared observations
  70. GRB 041016: Optical limit
  71. GRB 041015 R band observations
  72. GRB040924, BVRcIc field calibration
  73. GRB041015: MASTER: Optical observations
  74. GRB041015,optical observation
  75. GRB041006: Fading X-ray Afterglow Observed with Chandra
  76. GRB 041015: Optical limit at Osaka University
  77. GRB041015 : Optical follow-up at Kiso
  78. GRB 041015 - A long GRB detected by INTEGRAL
  79. GRB 041006 R observations in Loiano
  80. GRB041006: VLT observations of the afterglow and host galaxy
  81. GRB041006: Optical observations and Potential host galaxy
  82. GRB041006, BVRcIc field calibration
  83. GRB 040924: VLT spectroscopy
  84. GRB 041006: SARA afterglow observations
  85. GRB041006, optical observation in CrAO
  86. Search for SN light in XRF 040912 with MEGACAM
  87. GRB 040916: Afterglow Color at Early Times
  88. GRB 041006 Optical afterglow observations
  89. IBAS GRB Alert # 2010
  90. GRB 041006: BR observations with VATT
  91. GRB 041006: Redshift confirmed
  92. GRB041006: Liverpool Telescope optical observations
  93. GRB 041006: Colour measurement
  94. GRB041006: break in the light curve
  95. GRB 041006: Radio Observations
  96. GRB041006, further submilllimetre observations
  97. GRB 041006 : optical follow-up observation at Lulin Observatory
  98. GRB 041006 : Optical follow-up observation at TAROT
  99. GRB041006: Optical photometry and spectroscopy at TNG
  100. GRB 041006: presice astrometry

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