Skip to main content
Due to the lapse in federal government funding, NASA is not updating this website. See the Operations FAQ for GCN impacts.
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 070309: Swift/UVOT Upper Limits
  2. GRB 070306, optical observation
  3. Swift UVOT Finding Charts for GRB 070309
  4. GRB 070309: A long GRB detected by INTEGRAL
  5. GRB 070125: X-ray light curve analysis
  6. VLA observation of GRB 070306
  7. IBAS Alert 4162: Not a GRB
  8. GRB 070306: NOT observations
  9. GRB 070306 Swift/UVOT refined analysis
  10. GRB070306: confirmation of near infrared afterglow
  11. GRB 070306: ART-3 early optical and near infrared constraints
  12. GRB 070306: IR observations and candidate afterglow
  13. GRB 070306, Swift-BAT refined analysis
  14. GRB 070306: XRT Team Refined Analysis
  15. GRB 070306: Optical and IR observations with KANATA
  16. GRB070306 - SDSS Pre-burst Observations
  17. GRB 070306: Swift detection of a burst
  18. GRB 070223: NIR observations at WHT
  19. GRB070227: Swift-XRT refined analysis
  20. GRB 060605 new redshift
  21. GRB 070125, deep late-time optical observation
  22. VLA observation of GRB 070224
  23. GRB 070227: optical observations
  24. GRB 070223: Optical Observations
  25. GRB 070227: optical observations
  26. GRB 070227: Swift/UVOT Upper Limits
  27. GRB 070227: TAROT La Silla observatory optical observations
  28. GRB 070227, Swift-BAT refined analysis
  29. GRB070227: possible X-ray afterglow detection
  30. GRB 070227: Swift detection of a burst in ground analysis
  31. GRB 920925C: optical afterglow candidate
  32. GRB 070224: Optical afterglow confirmation
  33. IBAS Alert n. 4144: not a GRB
  34. GRB 070224: Swift/UVOT Upper Limits
  35. GRB070224: Swift-XRT Astrometrically Corrected Position
  36. VLA observation of GRB 070223
  37. VLA observation of GRB 070220
  38. GRB070224: Magellan Imaging Observations
  39. GRB 070224: WHT K-band imaging
  40. GRB 070224: MDM Observations
  41. GRB070224: Gemini Imaging Observations
  42. GRB 070224: SARA upper limit
  43. GRB070224: Swift-XRT Refined Analysis
  44. GRB 070224: optical afterglow candidate
  45. GRB 070224, Swift-BAT refined analysis
  46. GRB 070224: MASTER-Net refind analysis
  47. GRB 070224: MASTER-VWF-Kislovodsk observations
  48. GRB 070224: MASTER observations
  49. GRB 070224: Swift detection of a burst
  50. GRB 070223: Optical observations
  51. RHESSI Spectrum of GRB070220
  52. GRB070223: Swift/UVOT refined analysis
  53. GRB 070223: Optical-IR observation with KANATA
  54. GRB 070223, Swift-BAT refined analysis
  55. GRB070223: MASTER-VWF-Kislovodsk observations
  56. GRB 070223: Swift-XRT Refined Analysis
  57. GRB 070220: pseudo-z~2.15 from spectral parameters of the prompt
  58. GRB070223 - SDSS Pre-Burst Observations
  59. GRB 070223: Liverpool Telescope Possible Afterglow Candidate
  60. GRB 070223: MDM Observations
  61. GRB070223: Swift burst
  62. Konus-Wind and Konus-A observations of GRB 070220
  63. GRB 070220: MITSuME Okayama Optical Observation
  64. GRB 070220: ART-3 Optical and NIR limits
  65. GRB 070220 Swift-BAT Refined Analysis
  66. Swift/UVOT refined analysis of GRB070220
  67. GRB 070209: Swift XRT refined analysis
  68. GRB 070220: Swift-XRT Refined Analysis
  69. GRB 070220: Observation with the KANATA 1.5m telescope
  70. GRB 070219: Gemini Observations
  71. GRB 070220 : Faulkes Telescope North optical limit
  72. GRB 070220: Swift detection of a burst
  73. GRB070219: MASTER-VWF-Kislovodsk observations
  74. GRB 070219: XRT Refined Analysis
  75. GRB 070219: Swift/UVOT Upper limits
  76. GRB 070219: I-band observations
  77. GRB 070219, Swift-BAT refined analysis
  78. GRB 070219: optical TNG observations
  79. GRB 070219: Liverpool Telescope Observations
  80. GRB 070219: ROTSE-III Optical Limits
  81. GRB070219 - SDSS Pre-Burst Observations
  82. GRB 070219: Swift detection of a burst
  83. IPN triangulation of GRB070201 (refined error box using MESSENGER data)
  84. GRB 070125 observations with the GMRT
  85. GRB 070209: Redshift of a galaxy in the error circle of XRT source
  86. Swift-BAT trigger 260304 is NOT a burst or transient
  87. GRB 060927: PROMPT Observations
  88. GRB 070201: Correction to GCN 6094
  89. GRB 070129: MDM I-band Detection
  90. GRB 070125: Break in Optical Decay
  91. GRB 070209: Swift XRT analysis
  92. GRB 070201: clarification on localization and Konus-Wind spectra
  93. GRB070208: optical observations
  94. GRB 070201: IPN constraints and nearby galaxies
  95. GRB 070201: Proximity of IPN annulus to M31
  96. GRB 070208: MARGE Optical Observations
  97. IPN localization of very bright long hard GRB 070207
  98. IPN localization of very intense short GRB 070201
  99. GRB 070209, Swift-BAT refined analysis of the short hard burst
  100. GRB 070209: Swift detection of a short hard burst

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