Skip to main content
GCN at AAS 245, Legacy Circulars Address Retirement. 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').
  1. GRB 050803: Swift-BAT refined analysis
  2. GRB 050802.422: Fading of the afterglow and detection of the host
  3. GRB050803: MASTER further analys
  4. GRB 050803, optical observations
  5. GRB 050803: Magellan Observations
  6. GRB 050803: early Swift XRT analysis results
  7. GRB 050803: TAROT optical limits
  8. GRB050803: MASTER optical observations
  9. GRB050802: Tentative absorption redshift
  10. GRB050803: Swift-BAT detection of a very long burst
  11. GCN GRB observation 050713A
  12. GRB050730: FORS1 and UVES/VLT low- and high-resolution spectroscopy
  13. GRB 050802: Swift/UVOT optical and UV detections
  14. GRB050802: CrAO optical observations
  15. GRB050801: Unchanged decay slope
  16. GRB050802 radio non-detection
  17. GRB 050730: OHP optical observations
  18. GRB 050802: early Swift XRT analysis results
  19. GRB 050802: Swift/UVOT observations
  20. GRB 050802 : Lulin Optical follow-up observation
  21. GRB 050802: Swift-BAT refined analysis
  22. GRB050801: Optical photometry and decay index
  23. GRB 050802: XRT position
  24. GRB 050802: Swift Gamma-ray Burst
  25. GRB050801: Swift/UVOT Optical and UV detections
  26. GRB 050730: Preliminary Analysis of MIKE Spectrum
  27. GCN 050801: early Swift XRT analysis results
  28. GRB 050801: Swift-BAT refined analysis
  29. GRB 050801, SMARTS optical/IR afterglow observations
  30. GRB 050801, afterglow observations
  31. GRB 050730, corrected photometry and break?
  32. GRB 050801: ROTSE-III Early Afterglow Break
  33. GRB050801: Swift-BAT detection of a burst
  34. GRB050801: GCN XRT position is incorrect
  35. GRB 050801: ROTSE-III Detection of Possible Counterpart
  36. GRB 050730: XRT refined analysis
  37. Correction to GCN Circ 3476 on GRB050525A
  38. GRB 050730: early TAROT optical observations
  39. GRB 050726: PROMPT Rc Observations
  40. GRB 050730: RTT150 optical observations
  41. Swift/UVOT photometry of GRB050730
  42. GRB 050730, spectra and optical photometry
  43. GRB050730: Refined BAT analysis of the Swift-BAT burst
  44. GRB 050730: Swift XRT afterglow observations
  45. GRB 050730 XMM-Newton observation
  46. GRB 050730: PROMPT VRcIc Observations
  47. GRB050730, afterglow observations
  48. GRB050730: confirmation of redshift
  49. GRB 050730: Redshift Measurement based on Magellan/MIKE Observations
  50. GRB 050730, SMARTS optical/IR afterglow observations
  51. GRB 050730 : Planned XMM-Newton observation
  52. GRB050730: Liverpool Telescope optical observations
  53. GRB 050730, optical candidate
  54. GRB050730: Swift-BAT detection of a weak burst
  55. GRB 050713A: Swift XRT extended light curve
  56. GRB 050709: PROMPT Rc Observations
  57. GRB050713b: Maidanak optical observations
  58. GRB 050724: Secure Host Redshift from Keck
  59. GRB 050724: WHT optical observations
  60. GRB050726: Swift UVOT observations
  61. GRB 050724: Chandra Observations of the X-ray Afterglow
  62. GRB050724: Refined Radio Position
  63. GRB050713: analysis of the XMM-Newton observation
  64. GRB 050724, SMARTS optical/IR afterglow observations
  65. GRB 050726, SMARTS optical/IR observations
  66. Swift-BAT trigger 147918 is not a real GRB
  67. GRB 050727: RTT150 optical observations
  68. GRB050724: VLT observations of the variable source
  69. GRB050727: KAIT optical limit
  70. GRB050709: Second Epoch Chandra Observation
  71. GRB 050726: PROMPT Rc Observations
  72. GRB050709: Second Epoch Chandra Observation
  73. GRB 050724: dust-scattered X-ray halo detected in SWIFT/XRT observation
  74. GRB050724: Further Radio Observations
  75. GRB 050726: early Swift XRT analysis results
  76. GRB050726: Swift-BAT detection of a weak burst
  77. GRB 050724: Optical Variability in Nearby Galaxy
  78. GRB 050724: J-band observations
  79. GRB 050724: GMOS Imaging and Spectroscopy
  80. GRB 050724: SWIFT XRT refined position
  81. RXTE ASM Detection of GRB050724
  82. GRB050724: Radio Observation
  83. GRB 050724: spectroscopy of object in the XRT error circle
  84. GRB 050724: Optical limit
  85. GRB 050724: optical and near-IR observations
  86. GRB 050724: Optical imaging/astrometry
  87. GRB 050724: RTT150 optical observations
  88. GRB 050724: Swift/UVOT Upper Limit
  89. GRB 050724: early Swift XRT analysis results
  90. GRB 050724 : Lulin early R-band monitoring observations
  91. GRB050724: Refined analysis of the Swift-BAT possible short burst
  92. GRB 050724: possible host galaxy in DSS
  93. GRB050724: a short-burst detected by Swift
  94. Swift-BAT trigger 147325 is not due to a real GRB
  95. GRB050723: XRT distributed coordinates are not related to the burst
  96. GRB 050721: early afterglow light curve
  97. GRB 050721A: Swift-BAT refined analysis
  98. Correction to GCN Circ 3474 on GRB050525A
  99. GRB 050721A: Early Swift XRT analysis results
  100. GRB050721A: optical decay

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