Skip to main content
Retirement of GCN Classic VOEvent Brokers. 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. Swift trigger 358760 is probably a noise event
  2. GRB 090717A: Suzaku WAM observation of the prompt emission
  3. GRB 090709A : Quick look analysis of the Suzaku observation
  4. GRB 090728: Swift-BAT refined analysis
  5. GRB 090727: GRT Optical Observation
  6. GRB 090728: Swift XRT refined analysis
  7. GRB 090727: optical observations
  8. GRB 090726: GRT Optical Observation
  9. GRB 090727: Swift/UVOT Upper Limits
  10. GRB 090728: Swift/UVOT Upper Limits
  11. GRB 090728: Enhanced Swift-XRT position
  12. GRB 090727: I-band observations from 1.23m CAHA
  13. GRB 090728, RIMOTS optical upper limits
  14. GRB 090728A: Faulkes Telescope North Optical Afterglow Candidate
  15. GRB 090728: Swift detection of a burst
  16. GRB 090727: Swift-BAT refined analysis
  17. GRB 090727: Swift-XRT refined analysis
  18. GRB 090727: Liverpool Telescope Afterglow Confirmation and Optical Flare
  19. GRB 090727: Enhanced Swift-XRT position
  20. GRB 090715B: Late-time Lick 3m observations
  21. GRB 090727: Liverpool Telescope possible OT candidate
  22. GRB 090727: Swift detection of a burst
  23. GRB090726: Swift/UVOT observations
  24. GRB 090726, Swift-BAT refined analysis
  25. GRB 090726: Afterglow candidate photometryfrom Crni Vrh
  26. GRB 090726: D50 optical observations
  27. GRB 090711: Fermi GBM detection
  28. GRB090726: 6-meter telescope redshift
  29. GRB 090726: Swift-XRT Team refined analysis
  30. GRB 090726: Enhanced Swift-XRT position
  31. GRB 090726: optical transient candidate
  32. GRB 090726: Swift/UVOT Finding Chart Observation
  33. GRB 090726: Swift-XRT position of probable counterpart
  34. GRB 090726: Swift detection of a burst
  35. Swift Trigger 358354 is not a GRB
  36. Konus-Wind and Konus-RF observations of GRB 090719
  37. Konus-RF and Konus-Wind observations of GRB 090718B
  38. Fermi Gamma-ray Burst Monitor triggers 269935914 through 270021937 are not GRBs
  39. Konus-Wind observations of bright hard GRB 090720B
  40. IPN Triangulation of bright GRB 090720B
  41. GRB 090720: Gemini-North Imaging and Optical Afterglow
  42. GRB 090720B: Fermi GBM detection
  43. Swift XRT and UVOT refned analysis of GRB 090720
  44. GRB 090709A: Swift XRT Timing Analysis
  45. GRB 090715B: VLA radio detection
  46. GRB 090720 Source found in ground processing of Swift-BAT data
  47. GRB 090717B: Fermi GBM detection
  48. GRB 090717: Fermi GBM detection
  49. GRB 090719: Fermi GBM detection
  50. GRB 090718B: Fermi GBM detection
  51. GRB 090718: Fermi GBM detection
  52. GRB 090720: Fermi GBM detection
  53. GRB 090715B: further NOT optical observations
  54. GRB 090715A: Suzaku WAM observation of the prompt emission
  55. GRB 090709A - CARMA mm Observations
  56. GRB 090715B: Lick observations
  57. GRB 090715A: VLA observations
  58. Konus-Wind observations of short/hard GRB 090715A
  59. GRB 090715B: MASTER optical limit
  60. GRB 090715A: Swift-BAT refined analysis
  61. Konus-Wind and Konus-RF observations of GRB 090715B
  62. GRB 090715B: Swift/UVOT followup observations
  63. GRB 090715B: break in the optical afterglow decay
  64. GRB 090715B: Enhanced Swift-XRT position
  65. GRB 090715B: Observation of the optical afterglow
  66. GRB 090715B: Swift XRT Refined Analysis
  67. GRB090715B: WHT redshift
  68. GRB 090715B: Swift-BAT refined analysis
  69. GRB 090715B: NOT optical observations
  70. GRB 090715B - Liverpool Telescope Optical Afterglow Candidate
  71. Swift problem fixed
  72. GRB 090715B: Swift detection of a burst with a possible optical counterpart
  73. GRB 090715A: ROTSE-III Optical Limits
  74. GRB 090715: Swift detection of a short hard burst
  75. Detection of GRB 090618 by RT-2 Experiment onboard the CORONAS-PHOTON Satellite
  76. Swift satellite anomaly
  77. GRB090713 optical limit by "Pi of the Sky"
  78. GRB 090712: Fermi GBM observation
  79. GRB 090713: Fermi GBM detection
  80. GRB 090712: Swift-BAT refined analysis
  81. GRB 090712: Swift detection of a burst
  82. GRB 090709A: Xinglong TNT optical upper limit
  83. VLA radio observations of GRB 090709A
  84. GRB 090621B: MTM-500 optical observations
  85. GRB 090709A: deep optical observation with the 10.4m GTC
  86. GRB090709A : WSRT Radio observation
  87. GRB 090709A: Suzaku WAM observation of the prompt emission
  88. GRB 090709A: Swift UVOT upper limits
  89. GRB 090709A: WHT LIRIS observations
  90. GRB 090709B: Fermi GBM detection
  91. GRB 090709A: confirmation of the periodicity in the SPI-ACS data
  92. GRB 090709A: evidence for a very red afterglow at low z
  93. Konus-Wind and Konus-RF observations of GRB 090709A
  94. GRB 090709A: P60 Observations
  95. GRB 090709A: Quasiperiodic variations in the BAT light curve
  96. GRB 090709A: NOT optical observations
  97. GRB 090709A: RAPTOR Limits During Gamma-Ray Emission
  98. GRB 090709A: Swift XRT Refined Analysis
  99. GRB 090709B, Swift-BAT refined analysis
  100. GRB 090709A: Swift-BAT refined analysis

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