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 070311: PAIRITEL confirmation of variability of REM candidate
  2. GRB 070311: REM candidate afterglow
  3. GRB 070311: a long GRB detected by INTEGRAL
  4. GRB060901: Candidate optical afterglow
  5. GRB070309: Swift/XRT possible afterglow detection
  6. GRB 070125: Chandra X-ray Confirmation of Jet Break
  7. GRB 070309: Swift/UVOT Upper Limits
  8. GRB 070306, optical observation
  9. Swift UVOT Finding Charts for GRB 070309
  10. GRB 070309: A long GRB detected by INTEGRAL
  11. GRB 070125: X-ray light curve analysis
  12. VLA observation of GRB 070306
  13. IBAS Alert 4162: Not a GRB
  14. GRB 070306: NOT observations
  15. GRB 070306 Swift/UVOT refined analysis
  16. GRB070306: confirmation of near infrared afterglow
  17. GRB 070306: ART-3 early optical and near infrared constraints
  18. GRB 070306: IR observations and candidate afterglow
  19. GRB 070306, Swift-BAT refined analysis
  20. GRB 070306: XRT Team Refined Analysis
  21. GRB 070306: Optical and IR observations with KANATA
  22. GRB070306 - SDSS Pre-burst Observations
  23. GRB 070306: Swift detection of a burst
  24. GRB 070223: NIR observations at WHT
  25. GRB070227: Swift-XRT refined analysis
  26. GRB 060605 new redshift
  27. GRB 070125, deep late-time optical observation
  28. VLA observation of GRB 070224
  29. GRB 070227: optical observations
  30. GRB 070223: Optical Observations
  31. GRB 070227: optical observations
  32. GRB 070227: Swift/UVOT Upper Limits
  33. GRB 070227: TAROT La Silla observatory optical observations
  34. GRB 070227, Swift-BAT refined analysis
  35. GRB070227: possible X-ray afterglow detection
  36. GRB 070227: Swift detection of a burst in ground analysis
  37. GRB 920925C: optical afterglow candidate
  38. GRB 070224: Optical afterglow confirmation
  39. IBAS Alert n. 4144: not a GRB
  40. GRB 070224: Swift/UVOT Upper Limits
  41. GRB070224: Swift-XRT Astrometrically Corrected Position
  42. VLA observation of GRB 070223
  43. VLA observation of GRB 070220
  44. GRB070224: Magellan Imaging Observations
  45. GRB 070224: WHT K-band imaging
  46. GRB 070224: MDM Observations
  47. GRB070224: Gemini Imaging Observations
  48. GRB 070224: SARA upper limit
  49. GRB070224: Swift-XRT Refined Analysis
  50. GRB 070224: optical afterglow candidate
  51. GRB 070224, Swift-BAT refined analysis
  52. GRB 070224: MASTER-Net refind analysis
  53. GRB 070224: MASTER-VWF-Kislovodsk observations
  54. GRB 070224: MASTER observations
  55. GRB 070224: Swift detection of a burst
  56. GRB 070223: Optical observations
  57. RHESSI Spectrum of GRB070220
  58. GRB070223: Swift/UVOT refined analysis
  59. GRB 070223: Optical-IR observation with KANATA
  60. GRB 070223, Swift-BAT refined analysis
  61. GRB070223: MASTER-VWF-Kislovodsk observations
  62. GRB 070223: Swift-XRT Refined Analysis
  63. GRB 070220: pseudo-z~2.15 from spectral parameters of the prompt
  64. GRB070223 - SDSS Pre-Burst Observations
  65. GRB 070223: Liverpool Telescope Possible Afterglow Candidate
  66. GRB 070223: MDM Observations
  67. GRB070223: Swift burst
  68. Konus-Wind and Konus-A observations of GRB 070220
  69. GRB 070220: MITSuME Okayama Optical Observation
  70. GRB 070220: ART-3 Optical and NIR limits
  71. GRB 070220 Swift-BAT Refined Analysis
  72. Swift/UVOT refined analysis of GRB070220
  73. GRB 070209: Swift XRT refined analysis
  74. GRB 070220: Swift-XRT Refined Analysis
  75. GRB 070220: Observation with the KANATA 1.5m telescope
  76. GRB 070219: Gemini Observations
  77. GRB 070220 : Faulkes Telescope North optical limit
  78. GRB 070220: Swift detection of a burst
  79. GRB070219: MASTER-VWF-Kislovodsk observations
  80. GRB 070219: XRT Refined Analysis
  81. GRB 070219: Swift/UVOT Upper limits
  82. GRB 070219: I-band observations
  83. GRB 070219, Swift-BAT refined analysis
  84. GRB 070219: optical TNG observations
  85. GRB 070219: Liverpool Telescope Observations
  86. GRB 070219: ROTSE-III Optical Limits
  87. GRB070219 - SDSS Pre-Burst Observations
  88. GRB 070219: Swift detection of a burst
  89. IPN triangulation of GRB070201 (refined error box using MESSENGER data)
  90. GRB 070125 observations with the GMRT
  91. GRB 070209: Redshift of a galaxy in the error circle of XRT source
  92. Swift-BAT trigger 260304 is NOT a burst or transient
  93. GRB 060927: PROMPT Observations
  94. GRB 070201: Correction to GCN 6094
  95. GRB 070129: MDM I-band Detection
  96. GRB 070125: Break in Optical Decay
  97. GRB 070209: Swift XRT analysis
  98. GRB 070201: clarification on localization and Konus-Wind spectra
  99. GRB070208: optical observations
  100. GRB 070201: IPN constraints and nearby galaxies

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