Skip to main content
New! BOOM Notices and Schema v7.0.0. 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: Second Epoch WSRT Radio Observations
  2. GRB 041219: WSRT Radio Afterglow Detection
  3. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  4. GRB 041218: Optical observations
  5. GRB 041219 : optical follow-up observations
  6. GRB041220: Swift-BAT burst
  7. Deep RAPTOR observations during GRB 041219
  8. GRB 041218 Optical Observations
  9. GRB 041219 Optical Observations
  10. GRB041219c: Third Burst in One Day from Swift-BAT
  11. GRB041219: Optical Afterglow Detection
  12. GRB041219: Continued NIR Observations
  13. GRB041219b: A Swift-BAT burst
  14. GRB 041219 ,optical observation
  15. GRB 041219: Radio Afterglow Detection
  16. GRB 041218 : Radio Observations
  17. GRB 041218: R-band optical observations
  18. GRB041218: Liverpool Telescope optical observations
  19. GRB041218: optical observations
  20. GRB041219: Confirmed NIR Afterglow
  21. GRB041218: Continued P60 Optical Observations
  22. Swift-BAT detection of the bright long burst GRB041219
  23. GRB 041218: Optical Observation
  24. GRB 041219: Infrared Afterglow Candidate
  25. GRB041219, BVRcIc field calibration
  26. GRB 041219: Infrared Afterglow Candidate
  27. GRB041218, BVRcIc field calibration
  28. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  29. GRB041219: P60 Optical Observations
  30. GRB 041219 - A long GRB detected by INTEGRAL
  31. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  32. GRB 041217: PROMPT Observations
  33. GRB041218: optical observations
  34. GRB041217: optical limit 30 min after GRB
  35. GRB 041218; optical candidate
  36. GRB 041218: Optical observations
  37. GRB 041217: LCO40 Optical Observations and Possible Candidates
  38. GRB 041218 - A long GRB detected by integral
  39. GRB041217: Optical Observations
  40. GRB041217: NIR and optical observations with REM
  41. GRB041217: P60 Optical Observations
  42. GRB041217: Infrared Observations
  43. GRB041217: The First GRB Located On-Board Swift
  44. GRB041211: Faulkes Telescope continued optical monitoring
  45. Optical Transient in Lynx not a GRB
  46. Optical transient (GRB?) in Lynx
  47. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  48. GRB041211: Continued P60 Observations
  49. GRB041211: RAPTOR observations
  50. GRB041211: Ashra Prototype optical observation
  51. GRB041211, Faulkes Telescope optical observation
  52. GRB041211, BVRcIc field calibration
  53. GRB041211,optical observation
  54. GRB 041211: Infrared Observations
  55. GRB 041211: KAIT observations
  56. GRB 041211: Optical follow-up in East Asian region
  57. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  58. GRB041211: P60 optical imaging
  59. GRB970815: Discovery of Optical Afterglow
  60. Distribution of IBAS Alerts for NON-GRB sources
  61. Triangulation of short GRB 041116 (large error box)
  62. GRB041015: Near-Infrared observations
  63. GRB 040924: Afterglow Color
  64. GRB 041006: GETS Optical Afterglow Observation
  65. Summary of the recent bursts from SGR 1806-20
  66. GRB 041006: Optical Observations
  67. GRB041006, late-time optical photometry
  68. GRB041015, optical observation in CrAO
  69. IBAS GRB Alert # 2034
  70. GRB041006: RTT150 Optical Observations
  71. GRB041015 : Multi epoch optical observations
  72. HST Observations: XRF 040701 and 040812
  73. Bright bursts from SGR1806-20
  74. GRB 041016: BOOTES-2 simultaneous observation
  75. GRB041006: RTT150 Optical Observations
  76. GRB041016,optical observation
  77. GRB 041016: Optical limits
  78. GRB 041016: Optical limits in V, R, I
  79. GRB 041016:Optical limit during first minute
  80. GRB041016: MASTER: Optical observations
  81. GRB 041015: Optical Observations at Rikubetsu
  82. GRB041006: Near Infrared observations
  83. GRB 041016: Optical limit
  84. GRB 041015 R band observations
  85. GRB040924, BVRcIc field calibration
  86. GRB041015: MASTER: Optical observations
  87. GRB041015,optical observation
  88. GRB041006: Fading X-ray Afterglow Observed with Chandra
  89. GRB 041015: Optical limit at Osaka University
  90. GRB041015 : Optical follow-up at Kiso
  91. GRB 041015 - A long GRB detected by INTEGRAL
  92. GRB 041006 R observations in Loiano
  93. GRB041006: VLT observations of the afterglow and host galaxy
  94. GRB041006: Optical observations and Potential host galaxy
  95. GRB041006, BVRcIc field calibration
  96. GRB 040924: VLT spectroscopy
  97. GRB 041006: SARA afterglow observations
  98. GRB041006, optical observation in CrAO
  99. Search for SN light in XRF 040912 with MEGACAM
  100. GRB 040916: Afterglow Color at Early Times

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