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. GRB 071003: Infrared Photometry with Keck Adaptive Optics
  2. GRB 071018: Revised BAT position
  3. GRB 071025A: RAPTOR Observations of Complex Early Optical Behavior
  4. GRB071021: MARGE Optical Limits
  5. GRB071020, optical upper limit
  6. GRB 071025: SARA VRI upper limits
  7. GRB 071025 Milagro GeV/TeV Observations
  8. GRB 071025: SQIID JHK photometry
  9. GRB 071025A: Complex Early-Time IR Behavior, Simultaneous with Gamma- and X-rays
  10. GRB071025: Optical Pre-imaging from Palomar
  11. Swift UVOT upper limits
  12. GRB071025: Xinglong TNT I-band upper limit
  13. GRB 071025: Swift-XRT Team refined analysis
  14. GRB 060602A: host redshift
  15. GRB 071025, Swift-BAT refined analysis
  16. GRB 071025: Early Super-LOTIS Observations
  17. GRB 071025: R/I-band update
  18. GRB071021 : CFHT Ks-band observation
  19. GRB 071025: ROTSE-III Refined Analysis
  20. GRB 071025: I-detection, R-dropout?
  21. GRB 071025: Swift XRT refined position
  22. GRB 071025a: PAIRITEL observations
  23. GRB071025: REM NIR afterglow
  24. GRB 071025: ROTSE-III Detection of Optical Counterpart
  25. GRB 071025: Swift detection of a burst
  26. GRB 071021: R-band detection and analysis
  27. GRB 071020: BTA spectroscopy
  28. GRB071021: Optical+NIR observations
  29. Possible radio detection of GRB 071021 with the VLA
  30. Optical observations of GRB 071020
  31. GRB 071021: (Relatively shallow) IR non-detections; motivation for optical spectroscopy
  32. GRB 071020: SARA observations
  33. Radio detection of GRB 071020 with the VLA
  34. GRB071010b: optical observation
  35. GRB 071021: Subaru NIR observation
  36. GRB071021: MITSuME Okayama Optical Upper Limits
  37. GRB 071021: Magellan i-band observation
  38. GRB 071021: Magellan R-band observation
  39. GRB 071021: Z-band detection
  40. GRB 071021: correction to GCNC 6968
  41. GRB 071020: Fading slowly?
  42. GRB 071010B: Fading quickly
  43. GRB 071021: optical and NIR observations
  44. GRB 071021: possible high-z burst
  45. GRB 071021, Swift-BAT refined analysis
  46. GRB071018: 2nd epoch obsevations of Xinglong TNT
  47. GRB 071021: retraction of Faulkes Telescope South candidate
  48. GRB 071021: Swift-XRT Team refined analysis
  49. GRB 071021: Xinglong TNT optical Upper Limit
  50. GRB 071021 : Lulin R-band limit
  51. Konus-Wind observation of GRB 071020
  52. GRB 071021: Faulkes Telescope South optical candidate
  53. GRB 071021: Swift detection of a burst
  54. GRB 071010B: Independent Confirmation of Break
  55. GRB071020A: Xinglong TNT Optical afterglow observations
  56. GRB 071020: Swift-XRT refined analysis
  57. GRB 071020, Swift-BAT refined analysis
  58. GRB 071020A: IR Imaging with PAIRITEL
  59. GRB 071020: VLT spectroscopy
  60. GRB 071020: ROTSE-III Analysis of Optical Counterpart
  61. GRB071020 - SDSS Pre-burst Observations
  62. GRB 071020: Swift detection of a bright burst
  63. GRB 071020A: ROTSE-III Detection of Optical Counterpart
  64. GRB 071018: Mercator Telescope optical observations
  65. Swift autonomous slewing re-enabled
  66. GRB071010b: optical observations
  67. GRB 071018: SARA observations
  68. GRB 071018: Swift-XRT observation
  69. GRB 071017 - Swift XRT observations
  70. VLA radio observation of GRB 071018
  71. GRB071018: Correction to the GCN 6936
  72. GRB071018: Correction to the GCN 6936
  73. GRB071018: Correction to the GCN 6936
  74. GRB071018: Correction to the title of the GCN 6936
  75. GRB 071018: Possible OT from Xinglong TNT observation
  76. GRB 071010B: Light Curve Break Confirmed
  77. GRB 071010A: Late-time Keck/LRIS photometry - possible host galaxy and jet break
  78. GRB 071018, Swift-BAT refined analysis
  79. GRB 071018?: Swift detection of a possible burst
  80. GRB 071010B: Suzaku WAM observation of the prompt emission
  81. GRB 071013: 3rd TLS Epoch - constraints on variability
  82. GRB 071013: TNT optical data refined analysis
  83. GRB 071010B: Keck/DEIMOS emission-line redshift
  84. GRB 071017: a SHORT GRB detected by INTEGRAL
  85. GRB 071013: TLS 2nd epoch - Kornienko candidate constant
  86. GRB071013: optical observations
  87. GRB 071010B: Optical observations of EST
  88. GRB 071010B: TLS 3rd Epoch - finally a break??
  89. GRB 071011: MITSuME Optical Observations
  90. GRB 070920A: deep optical observations at the NOT
  91. GRB 071010B: Photometry after 1.6 days
  92. GRB 071010B: Keck/LRIS Photometry
  93. GRB 071010B: TLS 2nd Epoch, refined analysis
  94. GRB 071013: TLS Upper Limit
  95. Correction to GCN circular no. # 6915 for GRB 071010B
  96. VLA detection of radio afterglow of GRB 071010B
  97. VLA non-detection of GRB 071011
  98. GRB 071013: Optical observations
  99. GRB 071013: optical observations at NOT
  100. GRB 071013, 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