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"

21788 results found.

  1. GRB 050509b: No Optical Variability in XRT Error Circle
  2. GRB 050509c: ROTSE-III Optical Limits
  3. GRB 050505, early TAROT observation
  4. GRB050509c: REM NIR and Optical observations
  5. GRB 050505: SARA Observations
  6. Swift UVOT Follow-up Observations of GRB 050509B
  7. GRB 050509A: Optical observations
  8. GRB050509b: Radio Observations
  9. GRB 050509B: ROTSE-III Optical Limits
  10. Swift Detection of GRB050509b: A short duration burst
  11. Swift Detection of the Burst GRB050509
  12. GRB 050505: Keck I-band Magnitude
  13. GRB 050505, simultaneous optical observation
  14. GRB 050505: Further Swift UVOT observations.
  15. GRB050505: AAVSO observations
  16. GRB050416A : 1 GHz limit from GMRT
  17. GRB 050505 UVOT
  18. GRB050505: Optical Afterglow Candidate
  19. GRB 050416b:Swift XRT afterglow upper limits
  20. GRB 050416b:Swift XRT afterglow upper limits
  21. GRB050502b: Afterglow Confirmation: Correction to OT Coordinates
  22. GRB050502b: Afterglow Confirmation
  23. GRB050502: P200 Observations (Correction)
  24. GRB050502: P200 Observations
  25. Swift UVOT observation of GRB 050504
  26. GRB050504: P60 Observations
  27. GRB (?) 050504: IR Observations, Intriguing Source
  28. GRB 050502b, Optical observations
  29. GRB050502a: P60 Observations (Correction)
  30. GRB050502a: P60 Observations
  31. Renewal of SGR 1806-20 activity
  32. GRB050502A: Optical Observations
  33. GRB050502B Swift-BAT refined analysis
  34. GRB 050502b: Swift XRT Position
  35. Swift Detection of the Bright Burst GRB050502b
  36. GRB050502: ANU 1m optical Observations
  37. GRB 050502: ROTSE-III Detection of Possible Counterpart
  38. Swift/BAT possible detection of a weak burst GRB050430
  39. GRB050416a: Radio Detection
  40. GRB 050422: Swift-UVOT observation
  41. GRB 050422: Swift XRT Position
  42. Swift Detection of GRB 050422
  43. GRB 050421: SLOTIS observations
  44. GRB 050421: Further Analysis of IR imaging
  45. GRB050421: Radio Observations
  46. GRB050421: Radio Observations
  47. GRB 050421: IR Observations
  48. GRB 050421: ROTSE-III Optical Limits
  49. GRB050421
  50. GRB 050421: early Swift XRT analysis results
  51. GRB 050421: NIR observations
  52. GRB050421: P60 Observations
  53. GRB 050421: BOOTES-2 simultaneous optical observations
  54. Swift Detection of GRB050421
  55. GRB 050416b: Tentative Swift XRT Position
  56. GRB 050315: potential host galaxy
  57. GRB050326: analysis of the XMM-Newton observation
  58. GRB050418: Null Optical Observations
  59. GRB 050412: Chandra observations
  60. GRB050416A, optical observations
  61. GRB 050418: Swift-BAT refined analysis
  62. GRB 050416: Mitsume optical observation
  63. GRB 050416b: LCO observations
  64. GRB 050416b: LCO observations
  65. GRB050416B: IR observations
  66. GRB 050416: Swift/UVOT refined analysis
  67. Swift-BAT detection of GRB 050416b
  68. GRB050412: Radio Observations
  69. GRB 050416: Swift/UVOT detection of afterglow emission
  70. GRB050416: Refined Swift-XRT analysis
  71. GRB 050416,optical observation
  72. GRB050416: P200 NIR Observations
  73. GRB 050416: Swift XRT Position
  74. GRB 050416: Radio observations
  75. Swift BAT/XRT Detection of GRB 050416
  76. GRB 050412: Subaru observations
  77. GRB 050408: RTT150 optical observations
  78. GRB 050412: PROMPT VRcIc Observations
  79. GRB 050408: Kuiper 1.5m observations
  80. GRB 050412: optical observations
  81. GRB 050412: early Swift XRT analysis results
  82. GRB 050412: Swift-BAT refined analysis
  83. GRB 050412: Early Optical/Ultraviolet Observations with
  84. GRB 050408: SDSS Field Calibration
  85. GRB050412: P60 Observations
  86. GRB 050412: Swift XRT Position
  87. GRB050412: ROTSE-III Optical Limits
  88. GRB 050412: IR and Optical observations
  89. GRB 050412: IR Observations
  90. GRB050408: Radio Observations
  91. GRB050410: P60 Observations
  92. GRB 050410: Early Optical/Ultraviolet Observations with Swift/UVOT
  93. GRB 050408: Early Optical/Ultraviolet Observations with Swift/UVOT
  94. GRB050410: Radio Observations
  95. GRB050410: MASTER optical observations
  96. GRB 050410: Early observations with Swift-UVOT
  97. GRB 050410: Swift XRT Position
  98. GRB 050408: Inconsistency of host galaxy identification
  99. GRB 050408: Subaru Observations
  100. GRB 050408: WIDGET simultaneous 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