Skip to main content
New! Super-Kamiokande JSON Notices and Schema v4.5.0. 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 090510: Enhanced Swift-XRT position
  2. GRB 090510: NOT afterglow confirmation
  3. GRB 090510: Swift-BAT refined analysis
  4. GRB 090510: Fermi GBM detection
  5. GRB 090509: Swift-BAT refined analysis
  6. Fermi LAT detection of GRB 090510
  7. GRB 090509, SMARTS optical/IR afterglow observations
  8. GRB 090510: Swift/UVOT Detection of a Candidate Optical Afterglow
  9. GRB 090510: Swift detection of a short hard burst
  10. GRB 090408: optical upper limit
  11. GRB 090418A: optical observation
  12. GRB 090509: GROND further analysis and redshift limit
  13. GRB 090509: REM NIR afterglow
  14. GRB 090509: GROND afterglow candidate
  15. GRB 090509: Swift detection of a burst
  16. GRB 090323: optical observations
  17. GRB 090423: optical limit
  18. GRB 090423: 250 GHz upper limit for a z=8.2 GRB with MAMBO-2 at the IRAM 30m
  19. GRB 080913: 250 GHz upper limit for a z=6.7 GRB with MAMBO-2 at the IRAM 30m
  20. GRB 090424: optical observations
  21. GRB 090427: GROND observations
  22. GRB 090429A: ROVOR magnitude limit
  23. ICSP VLF observation of GRB090427 from two receivers
  24. ICSP VLF observation of GRB090424 from four receivers
  25. Refined analysis of ICSP VLF observation of SGR J1550-5418 bursts on 22nd January, 2009
  26. GRB 090428B: Suzaku WAM observation of the prompt emission
  27. GRB 090424, SMARTS optical/IR afterglow monitoring
  28. GRB 090426: optical observations
  29. GRB 090429D: Fermi GBM detection
  30. GRB 090429C: Fermi GBM detection
  31. GRB 090429B: Swift/UVOT Upper Limits
  32. GRB 090429A: Swift/UVOT Upper Limits
  33. GRB 090427: pseudo-z= 1.48 from prompt emission spectrum
  34. GRB 090429B: Gemini-N further nIR observations
  35. GRB 090424: YNAO-GMG observations
  36. GRB 090429A: Swift-XRT refined analysis
  37. GRB 090429A: GROND upper limits
  38. GRB 090427C: Fermi GBM detection
  39. GRB 090427B: Fermi GBM detection
  40. GRB 090426C: Fermi GBM detection
  41. GRB 090426B: Fermi GBM detection/observation
  42. GRB 090429B: Swift XRT refined analysis
  43. GRB 090429A: Enhanced Swift-XRT position
  44. Konus-Wind observation of very bright GRB 090427
  45. GRB 090428B: Fermi GBM detection
  46. GRB 090428: Fermi GBM detection
  47. GRB 090418A BVRcIc field calibration
  48. GRB 090426: GAO 150cm telescope Optical Observation
  49. GRB 090429B: RIMOTS optical upper limits
  50. GRB 090429B: Swift-BAT refined analysis
  51. GRB 090429A: Swift-BAT refined analysis
  52. GRB 090429B: Enhanced Swift-XRT position
  53. GRB 090429A - Correction to XRT position
  54. GRB090429B: Gemini-N infrared IR candidate
  55. GRB 090426: YNAO-GMG observations
  56. GRB 090429B: VLT upper limits
  57. GRB 090429B: GROND Observations
  58. GRB 090429B: Super-LOTIS early observations
  59. GRB 090429B: Swift detection of a burst
  60. GRB 090429: Swift detection of a burst
  61. GRB 090423: pseudo burst at z=1 and its relation to GRB 080913
  62. GRB 090424 : Multiband Optical observation from Nainital
  63. IPN triangulation of very bright GRB 090427
  64. GRB 090426: R-band limit
  65. GRB 090424: Continued R-band monitoring
  66. GRB 090423: CARMA mm observations
  67. GRB 090423: millimeter detection
  68. GRB 090426: Swift/BAT spectral lag results
  69. GRB 090425: Fermi GBM detection
  70. GRB 090424: Suzaku WAM observation of the prompt emission
  71. GRB 090426: VLT spectroscopy
  72. GRB 090426: GROND Observations of the Optical/NIR Afterglow
  73. GRB 090426: Near infrared observation with ISLE at OAO
  74. GRB 090426: Okayama MITSuME optical observation
  75. GRB090426 Swift/UVOT observations
  76. GRB 090426 Keck LRIS redshift
  77. GRB 090426: Swift-BAT refined analysis
  78. GRB 090426: Swift-XRT refined analysis
  79. GRB 090423: GROND second epoch imaging and refined SED
  80. Detection of bright radio afterglow of GRB 090424 with the VLA
  81. GRB 090426: Enhanced Swift-XRT position
  82. GRB090426: Observation for Optical counterpart from MIRO
  83. GRB 090426, RIMOTS optical upper limits
  84. GRB 090426: inspection of SDSS images
  85. GRB 090426: TNT confimation of optical counterpart
  86. GRB 090426: Swift detection of a burst with an optical counterpart
  87. GRB090424: R-band detection (37.5 hrs post-burst), jet break?
  88. GRB 090424: MASTER-Net prompt optical limit
  89. GRB 090423: Fermi GBM observation (correction of isotropic equivalent energy)
  90. GRB 090424: WHT ISIS spectroscopy
  91. VLA radio observation of high-z GRB 090423
  92. GRB090424: BVRI/R-band detection after 15 hrs burst
  93. GRB 090424 : Lulin 1m telescope optical observations
  94. GRB 090424: THO optical observations
  95. GRB 090424: GROND Observations of the Optical/NIR Afterglow
  96. GRB090423: Y-band limit
  97. GRB 090424 Gemini-South Redshift
  98. GRB 090423: Y-band field calibration update/correction
  99. GRB 090423: Swift/BAT spectral lag results
  100. GRB 090424 : TAOS optical detection

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