Skip to main content
Passing of Scott Barthelmy, GCN Founder 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 090426, RIMOTS optical upper limits
  2. GRB 090426: inspection of SDSS images
  3. GRB 090426: TNT confimation of optical counterpart
  4. GRB 090426: Swift detection of a burst with an optical counterpart
  5. GRB090424: R-band detection (37.5 hrs post-burst), jet break?
  6. GRB 090424: MASTER-Net prompt optical limit
  7. GRB 090423: Fermi GBM observation (correction of isotropic equivalent energy)
  8. GRB 090424: WHT ISIS spectroscopy
  9. VLA radio observation of high-z GRB 090423
  10. GRB090424: BVRI/R-band detection after 15 hrs burst
  11. GRB 090424 : Lulin 1m telescope optical observations
  12. GRB 090424: THO optical observations
  13. GRB 090424: GROND Observations of the Optical/NIR Afterglow
  14. GRB090423: Y-band limit
  15. GRB 090424 Gemini-South Redshift
  16. GRB 090423: Y-band field calibration update/correction
  17. GRB 090423: Swift/BAT spectral lag results
  18. GRB 090424 : TAOS optical detection
  19. GRB 090424 optical observations
  20. GRB 090424: Liverpool Telescope observations
  21. GRB 090424: Swift-XRT refined analysis
  22. GRB 090424: Optical observations from 1.23m CAHA
  23. GRB 090423: energetic, luminosity and jet break
  24. Swift/UVOT observations of GRB 090424
  25. GRB 090424: MASTER-Net prompt optical observations
  26. GRB 090424: Enhanced Swift-XRT position
  27. GRB 090424: Swift-BAT refined analysis
  28. GRB 090424: Fermi GBM Observation
  29. GRB 090423: Fermi GBM observation
  30. GRB 090422: Fermi GBM observation
  31. GRB 090423: Ep,i - Eiso correlation
  32. GRB 090424: SDSS Galaxy at the Swift position
  33. GRB 090424: TNT optical observations
  34. GRB 090424: ROTSE-III Confimation of Optical Counterpart
  35. GRB 090424: Swift detection of a burst with an optical counterpart
  36. GRB 090423: Refined TNG analysis
  37. GRB090423: Y-band field calibration
  38. GRB 090423 limiting magnitudes
  39. GRB 090423: VLT/ISAAC spectroscopy
  40. GRB 090423: Near infrared observation at Okayama Observatory
  41. GRB 090423: Deep z-band upper limit and confirmation of photo-z
  42. GRB 090423: TNG Amici spectrum
  43. GRB 090423: GROND detection and preliminary photo-z
  44. GRB 090423: NOT z-band limit
  45. GRB 090423: Correction to NIR photometry
  46. GRB 090423: Swift-XRT refined analysis
  47. GRB090418A Rc-band photometry
  48. GRB090423 - Swift/UVOT upper limits.
  49. GRB 090423: NIR photometry and evidence for spectral break
  50. GRB 090422: Swift-XRT refined analysis
  51. GRB090423, RIMOTS optical upper limits
  52. GRB 090423: UKIRT data further analysis
  53. GRB 090423: Enhanced Swift-XRT position
  54. GRB 090423: Swift-BAT refined analysis
  55. GRB 090422: Swift/UVOT Upper Limits
  56. GRB 090423: UKIRT K-band observations
  57. GRB 090423: P60 Observations
  58. GRB 090423: Faulkes Telescope South observations
  59. GRB 090418A: R and I band observation
  60. GRB 090423: Swift detection of a burst
  61. GRB 090422: Liverpool Telescope possible candidate
  62. GRB 090418A: Konus-Wind and Swift/BAT joint spectral analysis
  63. GRB 090422: Swift-BAT refined analysis
  64. GRB 090422: Enhanced Swift-XRT position
  65. GRB 090410: Erratum in GCN 9189
  66. GRB 090408A: Erratum in GCN 9188
  67. GRB 090418B: RTT150 optical observations
  68. GRB 090418A: RTT150 optical observations
  69. GRB 080410: GAO 150cm telescope Optical Observation
  70. GRB 080408A: GAO 150cm telescope Optical Observation
  71. GRB 090422: Liverpool Telescope observations
  72. GRB 090418B: Suzaku WAM observation of the prompt emission
  73. GRB 090422: Swift detection of a burst
  74. GRB 090418C: Fermi GBM Detection
  75. GRB 090418A: Swift/UVOT Detection of the Neighbouring Galaxy
  76. Swift-BAT trigger 349718 is not a burst
  77. GRB 090418B: GRAS002 observatios
  78. GRB 090417B: Optical observation
  79. GRB 090418A: optical observations
  80. GRB 090418B: GROND observations
  81. GRB 090419: Swift/UVOT Observations
  82. GRB 090418B: Faulkes Telescope North observations
  83. GRB 090418A: Swift/UVOT Observations
  84. GRB 090417B: Swift/UVOT Upper Limits
  85. GRB 090417B Correction to the BAT refined analysis position
  86. GRB 090419: Swift-XRT refined analysis
  87. Konus-Wind observation of GRB 090418B
  88. GRB 090418: Erratum in GCN 9168
  89. GRB 090419: GROND detection of afterglow candidate
  90. GRB 090418: Optical observations with MITSuME Okayama and Ishigaki 1m telescope
  91. GRB 090419: Swift-BAT refined analysis
  92. VLA radio detection of GRB 090418
  93. VLA radio upper limit on GRB 090417B
  94. GRB 090419: Enhanced Swift-XRT position
  95. GRB 090418: Swift XRT refined analysis
  96. GRB 090418A: ROTSE-III Refined Analysis
  97. GRB 090419: Swift detection of a burst
  98. VLA observations of short burst GRB 090417A
  99. GRB 090418B: Detection of a bright burst from Swift-BAT slew data
  100. GRB 090417B: Gemini imaging

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