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"

35937 results found.

  1. GRB 041217: Optical observations
  2. GRB041219, early time observations
  3. IPN localization of giant flare from SGR1806-20
  4. GRB041219; RXTE ASM Observations
  5. NIR Observations of GRB 041219
  6. GRB041223: decay of the afterglow
  7. GRB 041224: near-infrared observations with REM
  8. GRB 041223: XRT afterglow spectrum and light curve
  9. GRB 041223 Fluence measured by Swift-BAT
  10. GRB041223: optical and NIR observations with REM
  11. GRB 041219: TAROT optical observations
  12. GRB 041218: TAROT optical observations
  13. GRB 041223: J-band observations of the afterglow
  14. GRB 041223: Detection of Optical Transient with LCO40
  15. GRB 041219c: PROMPT Observations
  16. GRB 041218: optical observations
  17. GRB 041219: Second Epoch WSRT Radio Observations
  18. GRB 041219: WSRT Radio Afterglow Detection
  19. GRB 041219: Keck IR Observations and Astrometric Refinement of the
  20. GRB 041218: Optical observations
  21. GRB 041219 : optical follow-up observations
  22. Deep RAPTOR observations during GRB 041219
  23. GRB 041218 Optical Observations
  24. GRB 041219 Optical Observations
  25. GRB041219c: Third Burst in One Day from Swift-BAT
  26. GRB041219: Optical Afterglow Detection
  27. GRB041219: Continued NIR Observations
  28. GRB 041219 ,optical observation
  29. GRB 041219: Radio Afterglow Detection
  30. GRB 041218 : Radio Observations
  31. GRB 041218: R-band optical observations
  32. GRB041219: Confirmed NIR Afterglow
  33. GRB041218: Continued P60 Optical Observations
  34. GRB 041218: Optical Observation
  35. GRB 041219: Infrared Afterglow Candidate
  36. GRB041219, BVRcIc field calibration
  37. GRB 041219: Infrared Afterglow Candidate
  38. GRB041218, BVRcIc field calibration
  39. GRB041219: Prompt Optical Observations from ROTSE-IIIb
  40. GRB041219: P60 Optical Observations
  41. GRB 041219 - A long GRB detected by INTEGRAL
  42. GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
  43. GRB 041217: PROMPT Observations
  44. GRB041218: optical observations
  45. GRB041217: optical limit 30 min after GRB
  46. GRB 041218; optical candidate
  47. GRB 041218: Optical observations
  48. GRB 041217: LCO40 Optical Observations and Possible Candidates
  49. GRB 041218 - A long GRB detected by integral
  50. GRB041217: Optical Observations
  51. GRB041217: P60 Optical Observations
  52. GRB041217: Infrared Observations
  53. GRB041217: The First GRB Located On-Board Swift
  54. GRB041211: Faulkes Telescope continued optical monitoring
  55. Optical Transient in Lynx not a GRB
  56. Optical transient (GRB?) in Lynx
  57. Optical transient (GRB?) in Lynx, UT Dec 11.4436
  58. GRB041211: Continued P60 Observations
  59. GRB041211: RAPTOR observations
  60. GRB041211: Ashra Prototype optical observation
  61. GRB041211, Faulkes Telescope optical observation
  62. GRB041211, BVRcIc field calibration
  63. GRB 041211: Infrared Observations
  64. GRB 041211: KAIT observations
  65. GRB 041211: Optical follow-up in East Asian region
  66. GRB 041211(=H3622): A Long GRB Localized by the HETE WXM and SXC
  67. GRB041211: P60 optical imaging
  68. GRB970815: Discovery of Optical Afterglow
  69. Distribution of IBAS Alerts for NON-GRB sources
  70. Triangulation of short GRB 041116 (large error box)
  71. GRB 040924: Afterglow Color
  72. GRB 041006: GETS Optical Afterglow Observation
  73. Summary of the recent bursts from SGR 1806-20
  74. GRB 041006: Optical Observations
  75. GRB041006, late-time optical photometry
  76. IBAS GRB Alert # 2034
  77. GRB041006: RTT150 Optical Observations
  78. Bright bursts from SGR1806-20
  79. GRB 041016: BOOTES-2 simultaneous observation
  80. GRB041006: RTT150 Optical Observations
  81. GRB 041016: Optical limits
  82. GRB 041016: Optical limits in V, R, I
  83. GRB 041016:Optical limit during first minute
  84. GRB041016: MASTER: Optical observations
  85. GRB 041015: Optical Observations at Rikubetsu
  86. GRB041006: Near Infrared observations
  87. GRB 041016: Optical limit
  88. GRB 041015 R band observations
  89. GRB040924, BVRcIc field calibration
  90. GRB041015: MASTER: Optical observations
  91. GRB041015,optical observation
  92. GRB 041015: Optical limit at Osaka University
  93. GRB041015 : Optical follow-up at Kiso
  94. GRB 041015 - A long GRB detected by INTEGRAL
  95. GRB 041006 R observations in Loiano
  96. GRB041006: VLT observations of the afterglow and host galaxy
  97. GRB041006: Optical observations and Potential host galaxy
  98. GRB041006, BVRcIc field calibration
  99. GRB 040924: VLT spectroscopy
  100. GRB 041006: SARA afterglow 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